Programs & Examples On #Chr

programming a servo thru a barometer

You could define a mapping of air pressure to servo angle, for example:

def calc_angle(pressure, min_p=1000, max_p=1200):     return 360 * ((pressure - min_p) / float(max_p - min_p))  angle = calc_angle(pressure) 

This will linearly convert pressure values between min_p and max_p to angles between 0 and 360 (you could include min_a and max_a to constrain the angle, too).

To pick a data structure, I wouldn't use a list but you could look up values in a dictionary:

d = {1000:0, 1001: 1.8, ...}  angle = d[pressure] 

but this would be rather time-consuming to type out!

need to add a class to an element

Try using setAttribute on the result:

result.setAttribute("class","red"); 

AngularJs directive not updating another directive's scope

Just wondering why you are using 2 directives?

It seems like, in this case it would be more straightforward to have a controller as the parent - handle adding the data from your service to its $scope, and pass the model you need from there into your warrantyDirective.

Or for that matter, you could use 0 directives to achieve the same result. (ie. move all functionality out of the separate directives and into a single controller).

It doesn't look like you're doing any explicit DOM transformation here, so in this case, perhaps using 2 directives is overcomplicating things.

Alternatively, have a look at the Angular documentation for directives: http://docs.angularjs.org/guide/directive The very last example at the bottom of the page explains how to wire up dependent directives.

Setting default checkbox value in Objective-C?

Documentation on UISwitch says:

[mySwitch setOn:NO]; 

In Interface Builder, select your switch and in the Attributes inspector you'll find State which can be set to on or off.

Use NSInteger as array index

According to the error message, you declared myLoc as a pointer to an NSInteger (NSInteger *myLoc) rather than an actual NSInteger (NSInteger myLoc). It needs to be the latter.

Is it possible to execute multiple _addItem calls asynchronously using Google Analytics?

From the docs:

_trackTrans() Sends both the transaction and item data to the Google Analytics server. This method should be called after _trackPageview(), and used in conjunction with the _addItem() and addTrans() methods. It should be called after items and transaction elements have been set up.

So, according to the docs, the items get sent when you call trackTrans(). Until you do, you can add items, but the transaction will not be sent.

Edit: Further reading led me here:

http://www.analyticsmarket.com/blog/edit-ecommerce-data

Where it clearly says you can start another transaction with an existing ID. When you commit it, the new items you listed will be added to that transaction.

DevTools failed to load SourceMap: Could not load content for chrome-extension

Extensions without enough permission on chrome can cause these warnings, for example for React developer tools, check if the following procedure solves your problem:

  1. Right click on the extension icon.

Or

  1. Go to extensions.
  2. Click the three-dot in the row of React developer tool.

Then choose "this can read and write site data". You should see 3 options in the list, pick one that is strict enough based on how much you trust the extension and also satisfies the extensions's needs.

When adding a Javascript library, Chrome complains about a missing source map, why?

I had similar problem when i was trying to work with coco-ssd. I think this problem is caused because of the version. I changed version of tfjs to 0.9.0 and coco-ssd version to 1.1.0 and it worked for me. (you can search for posenet versions on : https://www.jsdelivr.com/package/npm/@tensorflow-models/posenet)

<!-- Load TensorFlow.js-->
<script src="https://cdn.jsdelivr.net/npm/@tensorflow/[email protected]"></script>
<!-- Load the coco-ssd model. -->
<script src="https://cdn.jsdelivr.net/npm/@tensorflow-models/[email protected]"</script>

SessionNotCreatedException: Message: session not created: This version of ChromeDriver only supports Chrome version 81

I got this error when the chrome driver was not closed properly. Eg, if I try to find something and click it and it doesn't exist, the driver throws an exception and the thread ended there ( I did not close the driver ).

So, when I ran the same method again later where I had to reinitialize the driver, the driver didn't initialize and it threw the exception.

My solve was simply to wrap the selenium tasks in a try catch and close the driver properly

error NG6002: Appears in the NgModule.imports of AppModule, but could not be resolved to an NgModule class

I had this error message because I was trying to import a component in a new module instead of importing the other module where my component was declared.

Removing the component import from my new module and importing the other module solved it for me.

error TS1086: An accessor cannot be declared in an ambient context in Angular 9

First please check in module.ts file that in @NgModule all properties are only one time. If any of are more than one time then also this error come. Because I had also occur this error but in module.ts file entryComponents property were two time that's why I was getting this error. I resolved this error by removing one time entryComponents from @NgModule. So, I recommend that first you check it properly.

SameSite warning Chrome 77

I had to disable this in chrome://flags

enter image description here

What's the net::ERR_HTTP2_PROTOCOL_ERROR about?

We experienced this problem on pages with long Base64 strings. The problem occurs because we use CloudFlare.

Details: https://community.cloudflare.com/t/err-http2-protocol-error/119619.

Key section from the forum post:

After further testing on Incognito tabs on multiple browsers, then doing the changes on the code from a BASE64 to a real .png image, the issue never happened again, in ANY browser. The .png had around 500kb before becoming a base64,so CloudFlare has issues with huge lines of text on same line (since base64 is a long string) as a proxy between the domain and the heroku. As mentioned before, directly hitting Heroku url also never happened the issue.

The temporary hack is to disable HTTP/2 on CloudFlare.

Hope someone else can produce a better solution that doesn't require disabling HTTP/2 on CloudFlare.

How to fix "set SameSite cookie to none" warning?

I ended up fixing our Ubuntu 18.04 / Apache 2.4.29 / PHP 7.2 install for Chrome 80 by installing mod_headers:

a2enmod headers

Adding the following directive to our Apache VirtualHost configurations:

Header edit Set-Cookie ^(.*)$ "$1; Secure; SameSite=None"

And restarting Apache:

service apache2 restart

In reviewing the docs (http://www.balkangreenfoundation.org/manual/en/mod/mod_headers.html) I noticed the "always" condition has certain situations where it does not work from the same pool of response headers. Thus not using "always" is what worked for me with PHP but the docs suggest that if you want to cover all your bases you could add the directive both with and without "always". I have not tested that.

How to prevent Google Colab from disconnecting?

create a python code in your pc with pynput

from pynput.mouse import Button, Controller
import time

mouse = Controller()

while True:
    mouse.click(Button.left, 1)
    time.sleep(30)

Run this code in your Desktop, Then point mouse arrow over (colabs left panel - file section) directory structure on any directory this code will keep clicking on directory on every 30 seconds so it will expand and shrink every 30 seconds so your session will not get expired Important - you have to run this code in your pc

session not created: This version of ChromeDriver only supports Chrome version 74 error with ChromeDriver Chrome using Selenium

I checked the version of my google chrome browser installed on my pc and then downloaded ChromeDriver suited to my browser version. You can download it from https://chromedriver.chromium.org/

Jupyter Notebook not saving: '_xsrf' argument missing from post

This is the easiest way.

I did not need to open a new notebook. Instead, I reopened the tree, and reconnected the kernel. At some point I also restarted the kernel. – user650654 Oct 9 '19 at 0:17

How to fix 'Unchecked runtime.lastError: The message port closed before a response was received' chrome issue?

I disabled Chrome extension "Coupons at Checkout" and this problem was solved.

Can't perform a React state update on an unmounted component

I had a similar problem and solved it :

I was automatically making the user logged-in by dispatching an action on redux ( placing authentication token on redux state )

and then I was trying to show a message with this.setState({succ_message: "...") in my component.

Component was looking empty with the same error on console : "unmounted component".."memory leak" etc.

After I read Walter's answer up in this thread

I've noticed that in the Routing table of my application , my component's route wasn't valid if user is logged-in :

{!this.props.user.token &&
        <div>
            <Route path="/register/:type" exact component={MyComp} />                                             
        </div>
}

I made the Route visible whether the token exists or not.

Selenium: WebDriverException:Chrome failed to start: crashed as google-chrome is no longer running so ChromeDriver is assuming that Chrome has crashed

in my case, the error was with www-data user but not with normal user on development. The error was a problem to initialize an x display for this user. So, the problem was resolved running my selenium test without opening a browser window, headless:

opts.set_headless(True)

How to resolve TypeError: can only concatenate str (not "int") to str

Use f-strings to resolve the TypeError

# the following line causes a TypeError
# test = 'Here is a test that can be run' + 15 + 'times'

# same intent with a f-string
i = 15

test = f'Here is a test that can be run {i} times'

print(test)

# output
'Here is a test that can be run 15 times'
i = 15
# t = 'test' + i  # will cause a TypeError

# should be
t = f'test{i}'

print(t)

# output
'test15'
  • The issue may be attempting to evaluate an expression where a variable is the string of a numeric.
  • Convert the string to an int.
  • This scenario is specific to this question
  • When iterating, it's important to be aware of the dtype
i = '15'
# t = 15 + i  # will cause a TypeError

# convert the string to int
t = 15 + int(i)
print(t)

# output
30

Note

  • The preceding part of the answer addresses the TypeError shown in the question title, which is why people seem to be coming to this question.
  • However, this doesn't resolve the issue in relation to the example provided by the OP, which is addressed below.

Original Code Issues

  • TypeError is caused because message type is a str.
  • The code iterates each character and attempts to add char, a str type, to an int
  • That issue can be resolved by converting char to an int
  • As the code is presented, secret_string needs to be initialized with 0 instead of "".
  • The code also results in a ValueError: chr() arg not in range(0x110000) because 7429146 is out of range for chr().
  • Resolved by using a smaller number
  • The output is not a string, as was intended, which leads to the Updated Code in the question.
message = input("Enter a message you want to be revealed: ")

secret_string = 0

for char in message:
    char = int(char)
    value = char + 742146
    secret_string += ord(chr(value))
    
print(f'\nRevealed: {secret_string}')

# Output
Enter a message you want to be revealed:  999

Revealed: 2226465

Updated Code Issues

  • message is now an int type, so for char in message: causes TypeError: 'int' object is not iterable
  • message is converted to int to make sure the input is an int.
  • Set the type with str()
  • Only convert value to Unicode with chr
  • Don't use ord
while True:
    try:
        message = str(int(input("Enter a message you want to be decrypt: ")))
        break
    except ValueError:
        print("Error, it must be an integer")
        
secret_string = ""
for char in message:
    
    value = int(char) + 10000
    
    secret_string += chr(value)

print("Decrypted", secret_string)

# output
Enter a message you want to be decrypt:  999
Decrypted ???

Enter a message you want to be decrypt:  100
Decrypted ???

Everytime I run gulp anything, I get a assertion error. - Task function must be specified

Try replacing your last line of gulpfile.js

gulp.task('default', ['server', 'watch']);

with

gulp.task('default', gulp.series('server', 'watch'));

Enable CORS in fetch api

Browser have cross domain security at client side which verify that server allowed to fetch data from your domain. If Access-Control-Allow-Origin not available in response header, browser disallow to use response in your JavaScript code and throw exception at network level. You need to configure cors at your server side.

You can fetch request using mode: 'cors'. In this situation browser will not throw execption for cross domain, but browser will not give response in your javascript function.

So in both condition you need to configure cors in your server or you need to use custom proxy server.

How to add image in Flutter

The problem is in your pubspec.yaml, here you need to delete the last comma.

uses-material-design: true,

Cross-Origin Read Blocking (CORB)

I encountered this problem because the format of the jsonp response from the server is wrong. The incorrect response is as follows.

callback(["apple", "peach"])

The problem is, the object inside callback should be a correct json object, instead of a json array. So I modified some server code and changed its format:

callback({"fruit": ["apple", "peach"]})

The browser happily accepted the response after the modification.

WebDriverException: unknown error: DevToolsActivePort file doesn't exist while trying to initiate Chrome Browser

update capabilities in conf.js as

exports.config = {
  seleniumAddress: 'http://localhost:4444/wd/hub',
  specs: ['todo-spec.js'],
  capabilities: {
    browserName: 'chrome',
    chromeOptions: {
      args: ['--disable-gpu', '--no-sandbox', '--disable-extensions', '--disable-dev-shm-usage']
    }
  },

};

How to make audio autoplay on chrome

i used pixi.js and pixi-sound.js to achieve the auto play in chrome and firefox.

<script>

            PIXI.sound.Sound.from({
            url: 'audios/tuto.mp3',
            loop:true,
            preload: true,
            loaded: function(err, sound) {
                    sound.play();

            document.querySelector("#paused").addEventListener('click', function() {
            const paused = PIXI.sound.togglePauseAll();

            this.className = this.className.replace(/\b(on|off)/g, '');
            this.className += paused ? 'on' : 'off';

            });
            }
            });

</script>

HTML:

<button class="btn1 btn-lg off" id="paused">
    <span class="glyphicon glyphicon-pause off"></span>
    <span class="glyphicon glyphicon-play on"></span>
</button>

it also works on mobile devices but user have to touch somewhere on the screen to trigger the sound.

Can not find module “@angular-devkit/build-angular”

If you are updating from angular 7 to angular 8 then do this

ng update @angular/cli @angular/core

for more information read here https://github.com/just-jeb/angular-builders/blob/master/MIGRATION.MD

Could not find module "@angular-devkit/build-angular"

Just execute the following command and error was solved

  • ng update @angular/cli @angular/core
  • npm uninstall @angular-devkit/build-angular
  • npm install --save-dev @angular-devkit/build-angular

    if this error could not resolve by above command so you update node version

    • npm update npm -g

How to handle "Uncaught (in promise) DOMException: play() failed because the user didn't interact with the document first." on Desktop with Chrome 66?

I had some issues playing on Android Phone. After few tries I found out that when Data Saver is on there is no auto play:

There is no autoplay if Data Saver mode is enabled. If Data Saver mode is enabled, autoplay is disabled in Media settings.

Source

Uncaught (in promise): Error: StaticInjectorError(AppModule)[options]

I had the same error and I solved it by importing HttpModule in app.module.ts

import { HttpModule } from '@angular/http';

and then in the imports[] array:

HttpModule

What could cause an error related to npm not being able to find a file? No contents in my node_modules subfolder. Why is that?

Following what @viveknuna suggested, I upgraded to the latest version of node.js and npm using the downloaded installer. I also installed the latest version of yarn using a downloaded installer. Then, as you can see below, I upgraded angular-cli and typescript. Here's what that process looked like:

D:\Dev\AspNetBoilerplate\MyProject\3.5.0\angular>npm install -g @angular/cli@latest
C:\Users\Jack\AppData\Roaming\npm\ng -> C:\Users\Jack\AppData\Roaming\npm\node_modules\@angular\cli\bin\ng
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: [email protected] (node_modules\@angular\cli\node_modules\fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for [email protected]: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})

+ @angular/[email protected]
added 75 packages, removed 166 packages, updated 61 packages and moved 24 packages in 29.084s

D:\Dev\AspNetBoilerplate\MyProject\3.5.0\angular>npm install -g typescript
C:\Users\Jack\AppData\Roaming\npm\tsserver -> C:\Users\Jack\AppData\Roaming\npm\node_modules\typescript\bin\tsserver
C:\Users\Jack\AppData\Roaming\npm\tsc -> C:\Users\Jack\AppData\Roaming\npm\node_modules\typescript\bin\tsc
+ [email protected]
updated 1 package in 2.427s

D:\Dev\AspNetBoilerplate\MyProject\3.5.0\angular>node -v
v8.10.0

D:\Dev\AspNetBoilerplate\MyProject\3.5.0\angular>npm -v
5.6.0

D:\Dev\AspNetBoilerplate\MyProject\3.5.0\angular>yarn --version
1.5.1

Thereafter, I ran yarn and npm start in my angular folder and all appears to be well. Here's what that looked like:

D:\Dev\AspNetBoilerplate\MyProject\3.5.0\angular>yarn
yarn install v1.5.1
[1/4] Resolving packages...
[2/4] Fetching packages...
info [email protected]: The platform "win32" is incompatible with this module.
info "[email protected]" is an optional dependency and failed compatibility check. Excluding it from installation.
[3/4] Linking dependencies...
warning "@angular/cli > @schematics/[email protected]" has incorrect peer dependency "@angular-devkit/[email protected]".
warning "@angular/cli > @angular-devkit/schematics > @schematics/[email protected]" has incorrect peer dependency "@angular-devkit/[email protected]".
warning " > [email protected]" has incorrect peer dependency "@angular/compiler@^2.3.1 || >=4.0.0-beta <5.0.0".
warning " > [email protected]" has incorrect peer dependency "@angular/core@^2.3.1 || >=4.0.0-beta <5.0.0".
[4/4] Building fresh packages...
Done in 232.79s.

D:\Dev\AspNetBoilerplate\MyProject\3.5.0\angular>npm start

> [email protected] start D:\Dev\AspNetBoilerplate\MyProject\3.5.0\angular
> ng serve --host 0.0.0.0 --port 4200

** NG Live Development Server is listening on 0.0.0.0:4200, open your browser on http://localhost:4200/ **
Date: 2018-03-22T13:17:28.935Z
Hash: 8f226b6fa069b7c201ea
Time: 22494ms
chunk {account.module} account.module.chunk.js () 129 kB  [rendered]
chunk {app.module} app.module.chunk.js () 497 kB  [rendered]
chunk {common} common.chunk.js (common) 1.46 MB  [rendered]
chunk {inline} inline.bundle.js (inline) 5.79 kB [entry] [rendered]
chunk {main} main.bundle.js (main) 515 kB [initial] [rendered]
chunk {polyfills} polyfills.bundle.js (polyfills) 1.1 MB [initial] [rendered]
chunk {styles} styles.bundle.js (styles) 1.53 MB [initial] [rendered]
chunk {vendor} vendor.bundle.js (vendor) 15.1 MB [initial] [rendered]

webpack: Compiled successfully.

Stylesheet not loaded because of MIME-type

This error can also come up when you're not referring to your CSS file properly.

For example, if your link tag is

<link rel="stylesheet" href="styles.css">

but your CSS file is named style.css (without the second s) then there is a good chance that you will see this error.

Read response headers from API response - Angular 5 + TypeScript

You can get headers using below code

let main_headers = {}
this.http.post(url,
  {email: this.username, password: this.password},
  {'headers' : new HttpHeaders ({'Content-Type' : 'application/json'}), 'responseType': 'text', observe:'response'})
  .subscribe(response => {
    const keys = response.headers.keys();
    let headers = keys.map(key => {
      `${key}: ${response.headers.get(key)}`
        main_headers[key] = response.headers.get(key)
       }
      );
  });

later we can get the required header form the json object.

header_list['X-Token']

'mat-form-field' is not a known element - Angular 5 & Material2

You're trying to use the MatFormFieldComponent in SearchComponent but you're not importing the MatFormFieldModule (which exports MatFormFieldComponent); you only export it.

Your MaterialModule needs to import it.

@NgModule({
  imports: [
    MatFormFieldModule,
  ],
  exports: [
    MatButtonModule,
    MatFormFieldModule,
    MatInputModule,
    MatRippleModule,
  ],
  declarations: [
    SearchComponent,
  ],
})
export class MaterialModule { }

axios post request to send form data

Using application/x-www-form-urlencoded format in axios

By default, axios serializes JavaScript objects to JSON. To send data in the application/x-www-form-urlencoded format instead, you can use one of the following options.

Browser

In a browser, you can use the URLSearchParams API as follows:

const params = new URLSearchParams();

params.append('param1', 'value1');

params.append('param2', 'value2');

axios.post('/foo', params);

Note that URLSearchParams is not supported by all browsers (see caniuse.com), but there is a polyfill available (make sure to polyfill the global environment).

Alternatively, you can encode data using the qs library:

const qs = require('qs');

axios.post('/foo', qs.stringify({ 'bar': 123 }));

Or in another way (ES6),

import qs from 'qs';

const data = { 'bar': 123 };

const options = {

method: 'POST',

headers: { 'content-type': 'application/x-www-form-urlencoded' },

data: qs.stringify(data),

url, };

axios(options);

No provider for HttpClient

In my case, the error occured when using a service from an angular module located in an npm package, where the service requires injection of HttpClient. When installing the npm package, a duplicate node_modules directory was created inside the package directory due to version conflict handling of npm (engi-sdk-client is the module containing the service):

enter image description here

Obviously, the dependency to HttpClient is not resolved correctly, as the locations of HttpClientModule injected into the service (lives in the duplicate node_modules directory) and the one injected in app.module (the correct node_modules) don't match.

I've also had this error in other setups containing a duplicate node_modules directory due to a wrong npm install call.

This defective setup also leads to the described runtime exception No provider for HttpClient!.

TL;DR; Check for duplicate node_modules directories, if none of the other solutions work!

I get "Http failure response for (unknown url): 0 Unknown Error" instead of actual error message in Angular

If you are using Laravel as your Backend, then edit your .htaccess file by just pasting this code, to solve problem CROS in your Angular or IONIC project

Header add Access-Control-Allow-Origin "*"
Header add Access-Control-Allow-Methods: "GET,POST,OPTIONS,DELETE,PUT"

How to configure ChromeDriver to initiate Chrome browser in Headless mode through Selenium?

It should look like this:

from selenium import webdriver
from selenium.webdriver.chrome.options import Options

options = Options()
options.add_argument('--headless')
options.add_argument('--disable-gpu')  # Last I checked this was necessary.
driver = webdriver.Chrome(CHROMEDRIVER_PATH, chrome_options=options)

This works for me using Python 3.6, I'm sure it'll work for 2.7 too.

Update 2018-10-26: These days you can just do this:

from selenium import webdriver
from selenium.webdriver.chrome.options import Options

options = Options()
options.headless = True
driver = webdriver.Chrome(CHROMEDRIVER_PATH, chrome_options=options)

how to open Jupyter notebook in chrome on windows

In the windows when we open jupyter notebook in command prompt we can see the instructions in first 10 lines in that there is one instruction- "to open notebook, open this file in browser file://C:/Users/{username}/appdata/roaming/jupyetr/runtime/nbserver-xywz-open.html " , open this html with browser of your choice.

Angular: Cannot Get /

For me the issue was that my local CLI was not the same version as my global CLI - updating it by running the following command solved the problem:

npm install --save-dev @angular/cli@latest

How can I use async/await at the top level?

Node -
You can run node --experimental-repl-await while in the REPL. I'm not so sure about scripting.

Deno -
Deno already has it built in.

Angular HttpClient "Http failure during parsing"

if you have options

return this.http.post(`${this.endpoint}/account/login`,payload, { ...options, responseType: 'text' })

Set cookies for cross origin requests

In order for the client to be able to read cookies from cross-origin requests, you need to have:

  1. All responses from the server need to have the following in their header:

    Access-Control-Allow-Credentials: true

  2. The client needs to send all requests with withCredentials: true option

In my implementation with Angular 7 and Spring Boot, I achieved that with the following:


Server-side:

@CrossOrigin(origins = "http://my-cross-origin-url.com", allowCredentials = "true")
@Controller
@RequestMapping(path = "/something")
public class SomethingController {
  ...
}

The origins = "http://my-cross-origin-url.com" part will add Access-Control-Allow-Origin: http://my-cross-origin-url.com to every server's response header

The allowCredentials = "true" part will add Access-Control-Allow-Credentials: true to every server's response header, which is what we need in order for the client to read the cookies


Client-side:

import { HttpInterceptor, HttpXsrfTokenExtractor, HttpRequest, HttpHandler, HttpEvent } from "@angular/common/http";
import { Injectable } from "@angular/core";
import { Observable } from 'rxjs';

@Injectable()
export class CustomHttpInterceptor implements HttpInterceptor {

    constructor(private tokenExtractor: HttpXsrfTokenExtractor) {
    }

    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
        // send request with credential options in order to be able to read cross-origin cookies
        req = req.clone({ withCredentials: true });

        // return XSRF-TOKEN in each request's header (anti-CSRF security)
        const headerName = 'X-XSRF-TOKEN';
        let token = this.tokenExtractor.getToken() as string;
        if (token !== null && !req.headers.has(headerName)) {
            req = req.clone({ headers: req.headers.set(headerName, token) });
        }
        return next.handle(req);
    }
}

With this class you actually inject additional stuff to all your request.

The first part req = req.clone({ withCredentials: true });, is what you need in order to send each request with withCredentials: true option. This practically means that an OPTION request will be send first, so that you get your cookies and the authorization token among them, before sending the actual POST/PUT/DELETE requests, which need this token attached to them (in the header), in order for the server to verify and execute the request.

The second part is the one that specifically handles an anti-CSRF token for all requests. Reads it from the cookie when needed and writes it in the header of every request.

The desired result is something like this:

response request

npm WARN ... requires a peer of ... but none is installed. You must install peer dependencies yourself

I had a similar issue and solved after running these instructions!

npm install npm -g
npm install --save-dev @angular/cli@latest
npm install
npm start

Property 'json' does not exist on type 'Object'

The other way to tackle it is to use this code snippet:

JSON.parse(JSON.stringify(response)).data

This feels so wrong but it works

Access Control Origin Header error using Axios in React Web throwing error in Chrome

npm i cors
const app = require('express')()
app.use(cors())

Above code worked for me.

CSS Grid Layout not working in IE11 even with prefixes

The answer has been given by Faisal Khurshid and Michael_B already.
This is just an attempt to make a possible solution more obvious.

For IE11 and below you need to enable grid's older specification in the parent div e.g. body or like here "grid" like so:

.grid-parent{display:-ms-grid;}

then define the amount and width of the columns and rows like e.g. so:

.grid-parent{
  -ms-grid-columns: 1fr 3fr;
  -ms-grid-rows: 4fr;
}

finally you need to explicitly tell the browser where your element (item) should be placed in e.g. like so:

.grid-item-1{
  -ms-grid-column: 1;
  -ms-grid-row: 1;
}

.grid-item-2{
  -ms-grid-column: 2;
  -ms-grid-row: 1;
}

Input type number "only numeric value" validation

In HTML file you can add ngIf for you pattern like this

<div class="form-control-feedback" *ngIf="Mobile.errors && (Mobile.dirty || Mobile.touched)">
        <p *ngIf="Mobile.errors.pattern" class="text-danger">Number Only</p>
      </div>

In .ts file you can add the Validators pattern - "^[0-9]*$"

this.Mobile = new FormControl('', [
  Validators.required,
  Validators.pattern("^[0-9]*$"),
  Validators.minLength(8),
]);

How do I test axios in Jest?

I used axios-mock-adapter. In this case the service is described in ./chatbot. In the mock adapter you specify what to return when the API endpoint is consumed.

import axios from 'axios';
import MockAdapter from 'axios-mock-adapter';
import chatbot from './chatbot';

describe('Chatbot', () => {
    it('returns data when sendMessage is called', done => {
        var mock = new MockAdapter(axios);
        const data = { response: true };
        mock.onGet('https://us-central1-hutoma-backend.cloudfunctions.net/chat').reply(200, data);

        chatbot.sendMessage(0, 'any').then(response => {
            expect(response).toEqual(data);
            done();
        });
    });
});

You can see it the whole example here:

Service: https://github.com/lnolazco/hutoma-test/blob/master/src/services/chatbot.js

Test: https://github.com/lnolazco/hutoma-test/blob/master/src/services/chatbot.test.js

Android dependency has different version for the compile and runtime

I had the same error, what solve my problem was. In my library instead of using compile or implementation i use "api". So in the end my dependencies:

dependencies {
api fileTree(dir: 'libs', include: ['*.jar'])
api files('libs/model.jar')
testApi 'junit:junit:4.12'
api 'com.android.support:percent:26.0.0-beta2'
api 'com.android.support:appcompat-v7:26.0.0-beta2'
api 'com.android.support:support-core-utils:26.0.0-beta2'

api 'com.squareup.retrofit2:retrofit:2.0.2'
api 'com.squareup.picasso:picasso:2.4.0'
api 'com.squareup.retrofit2:converter-gson:2.0.2'
api 'com.squareup.okhttp3:logging-interceptor:3.2.0'
api 'uk.co.chrisjenx:calligraphy:2.2.0'
api 'com.google.code.gson:gson:2.2.4'
api 'com.android.support:design:26.0.0-beta2'
api 'com.github.PhilJay:MPAndroidChart:v3.0.1'
}

You can find more info about "api", "implementation" in this link https://stackoverflow.com/a/44493379/3479489

ASP.NET Core form POST results in a HTTP 415 Unsupported Media Type response

In my case, I received the HTTP 415 Unsupported Media Type response, since I specified the content type to be TEXT and NOT JSON, so simply changing the type solved the issue. Please check the solution in more detail in the following blog post: https://www.howtodevelop.net/article/20/unsupported-media-type-415-in-aspnet-core-web-api

ReactJS lifecycle method inside a function Component

You can make your own "lifecycle methods" using hooks for maximum nostalgia.

Utility functions:

import { useEffect, useRef } from "react";

export const useComponentDidMount = handler => {
  return useEffect(() => {
    return handler();
  }, []);
};

export const useComponentDidUpdate = (handler, deps) => {
  const isInitialMount = useRef(true);

  useEffect(() => {
    if (isInitialMount.current) {
      isInitialMount.current = false;

      return;
    }

    return handler();
  }, deps);
};

Usage:

import { useComponentDidMount, useComponentDidUpdate } from "./utils";

export const MyComponent = ({ myProp }) => {
  useComponentDidMount(() => {
    console.log("Component did mount!");
  });

  useComponentDidUpdate(() => {
    console.log("Component did update!");
  });

  useComponentDidUpdate(() => {
    console.log("myProp did update!");
  }, [myProp]);
};  

Angular: 'Cannot find a differ supporting object '[object Object]' of type 'object'. NgFor only supports binding to Iterables such as Arrays'

Remember to pipe Observables to async, like *ngFor item of items$ | async, where you are trying to *ngFor item of items$ where items$ is obviously an Observable because you notated it with the $ similar to items$: Observable<IValuePair>, and your assignment may be something like this.items$ = this.someDataService.someMethod<IValuePair>() which returns an Observable of type T.

Adding to this... I believe I have used notation like *ngFor item of (items$ | async)?.someProperty

display: flex not working on Internet Explorer

Internet Explorer doesn't fully support Flexbox due to:

Partial support is due to large amount of bugs present (see known issues).

enter image description here Screenshot and infos taken from caniuse.com

Notes

Internet Explorer before 10 doesn't support Flexbox, while IE 11 only supports the 2012 syntax.

Known issues

  • IE 11 requires a unit to be added to the third argument, the flex-basis property see MSFT documentation.
  • In IE10 and IE11, containers with display: flex and flex-direction: column will not properly calculate their flexed childrens' sizes if the container has min-height but no explicit height property. See bug.
  • In IE10 the default value for flex is 0 0 auto rather than 0 1 auto as defined in the latest spec.
  • IE 11 does not vertically align items correctly when min-height is used. See bug.

Workarounds

Flexbugs is a community-curated list of Flexbox issues and cross-browser workarounds for them. Here's a list of all the bugs with a workaround available and the browsers that affect.

  1. Minimum content sizing of flex items not honored
  2. Column flex items set to align-items: center overflow their container
  3. min-height on a flex container won't apply to its flex items
  4. flex shorthand declarations with unitless flex-basis values are ignored
  5. Column flex items don't always preserve intrinsic aspect ratios
  6. The default flex value has changed
  7. flex-basis doesn't account for box-sizing: border-box
  8. flex-basis doesn't support calc()
  9. Some HTML elements can't be flex containers
  10. align-items: baseline doesn't work with nested flex containers
  11. Min and max size declarations are ignored when wrapping flex items
  12. Inline elements are not treated as flex-items
  13. Importance is ignored on flex-basis when using flex shorthand
  14. Shrink-to-fit containers with flex-flow: column wrap do not contain their items
  15. Column flex items ignore margin: auto on the cross axis
  16. flex-basis cannot be animated
  17. Flex items are not correctly justified when max-width is used

No 'Access-Control-Allow-Origin' header is present on the requested resource—when trying to get data from a REST API

The problem arose because you added the following code as request header in your front-end :

headers.append('Access-Control-Allow-Origin', 'http://localhost:3000');
headers.append('Access-Control-Allow-Credentials', 'true');

Those headers belong to response, not request. So remove them, including the line :

headers.append('GET', 'POST', 'OPTIONS');

Your request had 'Content-Type: application/json', hence triggered what is called CORS preflight. This caused the browser sent the request with OPTIONS method. See CORS preflight for detailed information.

Therefore in your back-end, you have to handle this preflighted request by returning the response headers which include :

Access-Control-Allow-Origin : http://localhost:3000
Access-Control-Allow-Credentials : true
Access-Control-Allow-Methods : GET, POST, OPTIONS
Access-Control-Allow-Headers : Origin, Content-Type, Accept

Of course, the actual syntax depends on the programming language you use for your back-end.

In your front-end, it should be like so :

function performSignIn() {
    let headers = new Headers();

    headers.append('Content-Type', 'application/json');
    headers.append('Accept', 'application/json');
    headers.append('Authorization', 'Basic ' + base64.encode(username + ":" +  password));
    headers.append('Origin','http://localhost:3000');

    fetch(sign_in, {
        mode: 'cors',
        credentials: 'include',
        method: 'POST',
        headers: headers
    })
    .then(response => response.json())
    .then(json => console.log(json))
    .catch(error => console.log('Authorization failed : ' + error.message));
}

How to extract svg as file from web page

1. Inspect the page with the svg on.

2. Click on the link that displays the imagine in full resolution.

3. Do CMD/CTRL+S

4. You are done!

Open Url in default web browser

You should use Linking.

Example from the docs:

class OpenURLButton extends React.Component {
  static propTypes = { url: React.PropTypes.string };
  handleClick = () => {
    Linking.canOpenURL(this.props.url).then(supported => {
      if (supported) {
        Linking.openURL(this.props.url);
      } else {
        console.log("Don't know how to open URI: " + this.props.url);
      }
    });
  };
  render() {
    return (
      <TouchableOpacity onPress={this.handleClick}>
        {" "}
        <View style={styles.button}>
          {" "}<Text style={styles.text}>Open {this.props.url}</Text>{" "}
        </View>
        {" "}
      </TouchableOpacity>
    );
  }
}

Here's an example you can try on Expo Snack:

import React, { Component } from 'react';
import { View, StyleSheet, Button, Linking } from 'react-native';
import { Constants } from 'expo';

export default class App extends Component {
  render() {
    return (
      <View style={styles.container}>
       <Button title="Click me" onPress={ ()=>{ Linking.openURL('https://google.com')}} />
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    alignItems: 'center',
    justifyContent: 'center',
    paddingTop: Constants.statusBarHeight,
    backgroundColor: '#ecf0f1',
  },
});

Invalid self signed SSL cert - "Subject Alternative Name Missing"

The Issue

As others have mentioned, the NET::ERR_CERT_COMMON_NAME_INVALID error is occurring because the generated certificate does not include the SAN (subjectAltName) field.

RFC2818 has deprecated falling back to the commonName field since May of 2000. The use of the subjectAltName field has been enforced in Chrome since version 58 (see Chrome 58 deprecations).

OpenSSL accepts x509v3 configuration files to add extended configurations to certificates (see the subjectAltName field for configuration options).


Bash Script

I created a self-signed-tls bash script with straightforward options to make it easy to generate certificate authorities and sign x509 certificates with OpenSSL (valid in Chrome using the subjectAltName field).

The script will guide you through a series of questions to include the necessary information (including the subjectAltName field). You can reference the README.md for more details and options for automation.

Be sure to restart chrome after installing new certificates.

chrome://restart

Other Resources

  • The Docker documentation has a great straightforward example for creating a self-signed certificate authority and signing certificates with OpenSSL.
  • cfssl is also a very robust tool that is widely used and worth checking out.

I am getting an "Invalid Host header" message when connecting to webpack-dev-server remotely

Rather than editing the webpack config file, the easier way to disable the host check is by adding a .env file to your root folder and putting this:

DANGEROUSLY_DISABLE_HOST_CHECK=true

As the variable name implies, disabling it is insecure and is only advisable to use only in dev environment.

Gradle error: Minimum supported Gradle version is 3.3. Current version is 3.2

  • changed distrubutionUrl from 4.1 to 4.4

  • changed build gradle version to 3.1.1 under project/android

works for me.

How do we download a blob url video

If you can NOT find the .m3u8 file you will need to do a couple of steps different.

1) Go to the network tab and sort by Media

Sort by media

2) You will see something here and select the first item. In my example, it's an mpd file. then copy the Request URL.

3) Next, download the file using your favorite command line tool using the URL from step 2.

youtube-dl -f bestvideo+bestaudio https://url.com/destination/stream.mpd

4) Depending on the encoding you might have to join the audio and video files together but this will depend on a video by video case.

Visual Studio 2017 errors on standard headers

This problem may also happen if you have a unit test project that has a different C++ version than the project you want to test.

Example:

  • EXE with C++ 17 enabled explicitly
  • Unit Test with C++ version set to "Default"

Solution: change the Unit Test to C++17 as well.

Screenshot

Android emulator not able to access the internet

This happend to me when the emulator froze and I had to kill the process. The signal icon always showed the small "x" as in the screenshot and no internet connection was successful.

The only thing that helped was uninstalling and reinstalling the emulator (not the AVD images)

In Android Studio:

Tools-> Android -> SDK Manager Uncheck "Android Emulator" and let it uninstall then check again and let it install again.

Screenshot

Visual Studio 2017 error: Unable to start program, An operation is not legal in the current state

Solution with JavaScript debugging enabled

From the Chrome browser, go to: Settings>Advanced>System and disable "Continue running background apps when Google Chrome is closed".

IMPORTANT! The option above must be set for the correct Chrome User Profile!
Visual Studio has its own Chrome User Profile, preferences you set when using your "normal" Chrome browser wont have any affect on the Chrome browser launched from VS (with JS debugging enabled).

  1. Run your project from VS with "Enable JavaScript debugging..." enabled. The Chrome browser should open and you'll get the error in VS.
  2. Go back to the same instance of Chrome that VS started and disable "Continue running background apps when Google Chrome is closed" as explained above.
    If you don't have "Enable JavaScript debugging..." enabled/checked, the Chrome instance would use your Default User Profile and the error would persist.
  3. Stop and rerun your project, Chrome should load the project as expected without any errors and with JS debugging enabled.

Whenever you stop debugging, you must close the Chrome instance initiated by VS or the error will return the next time you run the project. If there are other Chrome instances, you can leave these open.

To make sure Chrome is using the correct User Profile, go to chrome://version/ by typing it in the url bar, then look at the value for Profile Path. On Windows, the correct value should look something like this:
"C:\Users\[UserName]\AppData\Local\Microsoft\VisualStudio\15.*\WebTools\ChromeUserData_*\Default"

If Chrome is using the browser default or if you're logged in to Chrome with an account, it will look something like this:
"C:\Users\[UserName]\AppData\Local\Google\Chrome\User Data\[ProfileName] OR Default"

Bonus note. If you use Chrome Extensions when debugging, these has to be installed when the VS Profile is active.

Cannot find module '@angular/compiler'

Try to delete that "angular/cli": "1.0.0-beta.28.3", in the devDependencies it is useless , and add instead of it "@angular/compiler-cli": "^2.3.1", (since it is the current version, else add it by npm i --save-dev @angular/compiler-cli ), then in your root app folder run those commands:

  1. rm -r node_modules (or delete your node_modules folder manually)
  2. npm cache clean (npm > v5 add --force so: npm cache clean --force)
  3. npm install

Python Selenium Chrome Webdriver

You need to specify the path where your chromedriver is located.

  1. Download chromedriver for your desired platform from here.

  2. Place chromedriver on your system path, or where your code is.

  3. If not using a system path, link your chromedriver.exe (For non-Windows users, it's just called chromedriver):

    browser = webdriver.Chrome(executable_path=r"C:\path\to\chromedriver.exe")
    

    (Set executable_path to the location where your chromedriver is located.)

    If you've placed chromedriver on your System Path, you can shortcut by just doing the following:

    browser = webdriver.Chrome()

  4. If you're running on a Unix-based operating system, you may need to update the permissions of chromedriver after downloading it in order to make it executable:

    chmod +x chromedriver

  5. That's all. If you're still experiencing issues, more info can be found on this other StackOverflow article: Can't use chrome driver for Selenium

Cannot read property 'style' of undefined -- Uncaught Type Error

It's currently working, I've just changed the operator > in order to work in the snippet, take a look:

_x000D_
_x000D_
window.onload = function() {_x000D_
_x000D_
  if (window.location.href.indexOf("test") <= -1) {_x000D_
    var search_span = document.getElementsByClassName("securitySearchQuery");_x000D_
    search_span[0].style.color = "blue";_x000D_
    search_span[0].style.fontWeight = "bold";_x000D_
    search_span[0].style.fontSize = "40px";_x000D_
_x000D_
  }_x000D_
_x000D_
}
_x000D_
<h1 class="keyword-title">Search results for<span class="securitySearchQuery"> "hi".</span></h1>
_x000D_
_x000D_
_x000D_

Chrome violation : [Violation] Handler took 83ms of runtime

It seems you have found your solution, but still it will be helpful to others, on this page on point based on Chrome 59.

4.Note the red triangle in the top-right of the Animation Frame Fired event. Whenever you see a red triangle, it's a warning that there may be an issue related to this event.

If you hover on these triangle you can see those are the violation handler errors and as per point 4. yes there is some issue related to that event.

Unable to preventDefault inside passive event listener

I am getting this issue when using owl carousal and scrolling the images.

So get solved just adding below CSS in your page.

.owl-carousel {
-ms-touch-action: pan-y;
touch-action: pan-y;
}

or

.owl-carousel {
-ms-touch-action: none;
touch-action: none;
}

Getting Error "Form submission canceled because the form is not connected"

I faced the same issue in one of our implementation.

we were using jquery.forms.js. which is a forms plugin and available here. http://malsup.com/jquery/form/

we used the same answer provided above and pasted

$(document.body).append(form);

and it worked.Thanks.

What is correct media query for IPad Pro?

I tried several of the proposed answers but the problem is that the media queries conflicted with other queries and instead of displaying the mobile CSS on the iPad Pro, it was displaying the desktop CSS. So instead of using max and min for dimensions, I used the EXACT VALUES and it works because on the iPad pro you can't resize the browser.

Note that I added a query for mobile CSS that I use for devices with less than 900px width; feel free to remove it if needed.

This is the query, it combines both landscape and portrait, it works for the 12.9" and if you need to target the 10.5" you can simply add the queries for these dimensions:

@media only screen and (max-width: 900px), 
(height: 1024px) and (width: 1366px) and (-webkit-min-device-pixel-ratio: 1.5) and (orientation: landscape), 
(width: 1024px) and (height: 1366px) and (-webkit-min-device-pixel-ratio: 1.5) and (orientation: portrait)  {

     // insert mobile and iPad Pro 12.9" CSS here    
}

ES6 modules in the browser: Uncaught SyntaxError: Unexpected token import

Unfortunately, modules aren't supported by many browsers right now.

This feature is only just beginning to be implemented in browsers natively at this time. It is implemented in many transpilers, such as TypeScript and Babel, and bundlers such as Rollup and Webpack.

Found on MDN

How to upgrade Angular CLI project?

Solution that worked for me:

  • Delete node_modules and dist folder
  • (in cmd)>> ng update --all --force
  • (in cmd)>> npm install typescript@">=3.4.0 and <3.5.0" --save-dev --save-exact
  • (in cmd)>> npm install --save core-js
  • Commenting import 'core-js/es7/reflect'; in polyfill.ts
  • (in cmd)>> ng serve

WebSocket connection failed: Error during WebSocket handshake: Unexpected response code: 400

if you are using httpd/apache, you can add a file something like ws.conf and add this code to it. Also, this solution can proxy something like this "http://localhost:6001/socket.io" to just this "http://localhost/socket.io"

<VirtualHost *:80>
    RewriteEngine on

    #redirect WebSocket
    RewriteCond %{REQUEST_URI}  ^/socket.io            [NC]
    RewriteCond %{QUERY_STRING} transport=websocket    [NC]
    RewriteRule /(.*)           ws://localhost:6001/$1 [P,L]

    ProxyPass        /socket.io http://localhost:6001/socket.io
    ProxyPassReverse /socket.io http://localhost:6001/socket.io
</VirtualHost>

angular2: Error: TypeError: Cannot read property '...' of undefined

That's because abc is undefined at the moment of the template rendering. You can use safe navigation operator (?) to "protect" template until HTTP call is completed:

{{abc?.xyz?.name}}

You can read more about safe navigation operator here.

Update:

Safe navigation operator can't be used in arrays, you will have to take advantage of NgIf directive to overcome this problem:

<div *ngIf="arr && arr.length > 0">
    {{arr[0].name}}
</div>

Read more about NgIf directive here.

Violation Long running JavaScript task took xx ms

A couple of ideas:

  • Remove half of your code (maybe via commenting it out).

    • Is the problem still there? Great, you've narrowed down the possibilities! Repeat.

    • Is the problem not there? Ok, look at the half you commented out!

  • Are you using any version control system (eg, Git)? If so, git checkout some of your more recent commits. When was the problem introduced? Look at the commit to see exactly what code changed when the problem first arrived.

How to prevent a browser from storing passwords

One way would be to generate random input names and work with them.

This way, browsers will be presented with the new form each time and won't be able to pre-populate the input fields.

If you provide us with some sample code (do you have a JavaScript single-page application (SPA) app or some server side rendering) I would be happy to help you in the implementation.

can not find module "@angular/material"

I followed each of the suggestions here (I'm using Angular 7), but nothing worked. My app refused to acknowledge that @angular/material existed, so it showed an error on this line:

import { MatCheckboxModule } from '@angular/material';

Even though I was using the --save parameter to add Angular Material to my project:

npm install --save @angular/material @angular/cdk

...it refused to add anything to my "package.json" file.

I even tried deleting the package-lock.json file, as some articles suggest that this causes problems, but this had no effect.

To fix this issue, I had to manually add these two lines to my "package.json" file.

{
    "devDependencies": {
        ...
        "@angular/material": "~7.2.2",
        "@angular/cdk": "~7.2.2",
        ...

What I can't tell is whether this is an issue related to using Angular 7, or if it's been around for years....

Which ChromeDriver version is compatible with which Chrome Browser version?

At the time of writing this I have discovered that chromedriver 2.46 or 2.36 works well with Chrome 75.0.3770.100

Documentation here: http://chromedriver.chromium.org/downloads states align driver and browser alike but I found I had issues even with the most up-to-date driver when using Chrome 75

I am running Selenium 2 on Windows 10 Machine.

In Chrome 55, prevent showing Download button for HTML 5 video

As for current Chrome version (56) you can't remove it yet. Solution provided in other posts leads to overflowing some part of the video.

I've found another solution - you can make the preceding button to overlap the download button and simply cover it, by using this technique:

video::-webkit-media-controls-fullscreen-button {
   margin-right: -48px;
   z-index: 10;
   position: relative;
   background: #fafafa;
   background-image: url(https://image.flaticon.com/icons/svg/151/151926.svg);
   background-size: 35%;
   background-position: 50% 50%;
   background-repeat: no-repeat;
}

Example: https://jsfiddle.net/dk4q6hh2/

PS You might want to customise the icon, since it's for example only.

Ionic 2: Cordova is not available. Make sure to include cordova.js or run in a device/simulator (running in emulator)

import { Component } from '@angular/core';
import { NavController } from 'ionic-angular';
import { EmailComposer } from '@ionic-native/email-composer';

@Component({
  selector: 'page-about',
  templateUrl: 'about.html'
})
export class AboutPage {
  sendObj = {
    to: '',
    cc: '',
    bcc: '',
    attachments:'',
    subject:'',
    body:''
  }

  constructor(public navCtrl: NavController,private emailComposer: EmailComposer) {}

  sendEmail(){
  let email = {
    to: this.sendObj.to,
    cc: this.sendObj.cc,
    bcc: this.sendObj.bcc,
    attachments: [this.sendObj.attachments],
    subject: this.sendObj.subject,
    body: this.sendObj.body,
    isHtml: true
  }; 
  this.emailComposer.open(email);
  }  
 }

starts here html about

<ion-header>
  <ion-navbar>
    <ion-title>
      Send Invoice
    </ion-title>
  </ion-navbar>
</ion-header>

<ion-content padding>
  <ion-item>
    <ion-label stacked>To</ion-label>
    <ion-input [(ngModel)]="sendObj.to"></ion-input>
  </ion-item>
  <ion-item>
    <ion-label stacked>CC</ion-label>
    <ion-input [(ngModel)]="sendObj.cc"></ion-input>
  </ion-item>
  <ion-item>
    <ion-label stacked>BCC</ion-label>
    <ion-input [(ngModel)]="sendObj.bcc"></ion-input>
  </ion-item>
  <ion-item>
    <ion-label stacked>Add pdf</ion-label>
    <ion-input [(ngModel)]="sendObj.attachments" type="file"></ion-input>
  </ion-item>
  <ion-item>
    <ion-label stacked>Subject</ion-label>
    <ion-input [(ngModel)]="sendObj.subject"></ion-input>
  </ion-item>
  <ion-item>
    <ion-label stacked>Text message</ion-label>
    <ion-input [(ngModel)]="sendObj.body"></ion-input>
  </ion-item>

  <button ion-button full (click)="sendEmail()">Send Email</button>

</ion-content>


other stuff here

import { NgModule, ErrorHandler } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { IonicApp, IonicModule, IonicErrorHandler } from 'ionic-angular';
import { MyApp } from './app.component';

import { AboutPage } from '../pages/about/about';
import { ContactPage } from '../pages/contact/contact';
import { HomePage } from '../pages/home/home';
import { TabsPage } from '../pages/tabs/tabs';

import { StatusBar } from '@ionic-native/status-bar';
import { SplashScreen } from '@ionic-native/splash-screen';

import { File } from '@ionic-native/file';
import { FileOpener } from '@ionic-native/file-opener';
import { EmailComposer } from '@ionic-native/email-composer';

@NgModule({
  declarations: [
    MyApp,
    AboutPage,
    ContactPage,
    HomePage,
    TabsPage
  ],
  imports: [
    BrowserModule,
    IonicModule.forRoot(MyApp)
  ],
  bootstrap: [IonicApp],
  entryComponents: [
    MyApp,
    AboutPage,
    ContactPage,
    HomePage,
    TabsPage
  ],
  providers: [
    StatusBar,
    SplashScreen,
    EmailComposer,
    {provide: ErrorHandler, useClass: IonicErrorHandler},  
    File,
    FileOpener
  ]
})
export class AppModule {}

selenium - chromedriver executable needs to be in PATH

You can download ChromeDriver here: https://sites.google.com/a/chromium.org/chromedriver/downloads

Then you have multiple options:

  • add it to your system path
  • put it in the same directory as your python script
  • specify the location directly via executable_path

    driver = webdriver.Chrome(executable_path='C:/path/to/chromedriver.exe')
    

Vue.js dynamic images not working

I also hit this problem and it seems that both most upvoted answers work but there is a tiny problem, webpack throws an error into browser console (Error: Cannot find module './undefined' at webpackContextResolve) which is not very nice.

So I've solved it a bit differently. The whole problem with variable inside require statement is that require statement is executed during bundling and variable inside that statement appears only during app execution in browser. So webpack sees required image as undefined either way, as during compilation that variable doesn't exist.

What I did is place random image into require statement and hiding that image in css, so nobody sees it.

// template
<img class="user-image-svg" :class="[this.hidden? 'hidden' : '']" :src="userAvatar" alt />

//js
data() {
  return {
    userAvatar: require('@/assets/avatar1.svg'),
    hidden: true
  }
}

//css
.hidden {display: none}

Image comes as part of information from database via Vuex and is mapped to component as a computed

computed: {
  user() {
    return this.$store.state.auth.user;
  }
}

So once this information is available I swap initial image to the real one

watch: {
  user(userData) {
    this.userAvatar = require(`@/assets/${userData.avatar}`);
    this.hidden = false;
  }
}

Why does C++ code for testing the Collatz conjecture run faster than hand-written assembly?

C++ programs are translated to assembly programs during the generation of machine code from the source code. It would be virtually wrong to say assembly is slower than C++. Moreover, the binary code generated differs from compiler to compiler. So a smart C++ compiler may produce binary code more optimal and efficient than a dumb assembler's code.

However I believe your profiling methodology has certain flaws. The following are general guidelines for profiling:

  1. Make sure your system is in its normal/idle state. Stop all running processes (applications) that you started or that use CPU intensively (or poll over the network).
  2. Your datasize must be greater in size.
  3. Your test must run for something more than 5-10 seconds.
  4. Do not rely on just one sample. Perform your test N times. Collect results and calculate the mean or median of the result.

JavaScript ES6 promise for loop

As you already hinted in your question, your code creates all promises synchronously. Instead they should only be created at the time the preceding one resolves.

Secondly, each promise that is created with new Promise needs to be resolved with a call to resolve (or reject). This should be done when the timer expires. That will trigger any then callback you would have on that promise. And such a then callback (or await) is a necessity in order to implement the chain.

With those ingredients, there are several ways to perform this asynchronous chaining:

  1. With a for loop that starts with an immediately resolving promise

  2. With Array#reduce that starts with an immediately resolving promise

  3. With a function that passes itself as resolution callback

  4. With ECMAScript2017's async / await syntax

  5. With ECMAScript2020's for await...of syntax

See a snippet and comments for each of these options below.

1. With for

You can use a for loop, but you must make sure it doesn't execute new Promise synchronously. Instead you create an initial immediately resolving promise, and then chain new promises as the previous ones resolve:

_x000D_
_x000D_
for (let i = 0, p = Promise.resolve(); i < 10; i++) {
    p = p.then(_ => new Promise(resolve =>
        setTimeout(function () {
            console.log(i);
            resolve();
        }, Math.random() * 1000)
    ));
}
_x000D_
_x000D_
_x000D_

2. With reduce

This is just a more functional approach to the previous strategy. You create an array with the same length as the chain you want to execute, and start out with an immediately resolving promise:

_x000D_
_x000D_
[...Array(10)].reduce( (p, _, i) => 
    p.then(_ => new Promise(resolve =>
        setTimeout(function () {
            console.log(i);
            resolve();
        }, Math.random() * 1000)
    ))
, Promise.resolve() );
_x000D_
_x000D_
_x000D_

This is probably more useful when you actually have an array with data to be used in the promises.

3. With a function passing itself as resolution-callback

Here we create a function and call it immediately. It creates the first promise synchronously. When it resolves, the function is called again:

_x000D_
_x000D_
(function loop(i) {
    if (i < 10) new Promise((resolve, reject) => {
        setTimeout( () => {
            console.log(i);
            resolve();
        }, Math.random() * 1000);
    }).then(loop.bind(null, i+1));
})(0);
_x000D_
_x000D_
_x000D_

This creates a function named loop, and at the very end of the code you can see it gets called immediately with argument 0. This is the counter, and the i argument. The function will create a new promise if that counter is still below 10, otherwise the chaining stops.

The call to resolve() will trigger the then callback which will call the function again. loop.bind(null, i+1) is just a different way of saying _ => loop(i+1).

4. With async/await

Modern JS engines support this syntax:

_x000D_
_x000D_
(async function loop() {
    for (let i = 0; i < 10; i++) {
        await new Promise(resolve => setTimeout(resolve, Math.random() * 1000));
        console.log(i);
    }
})();
_x000D_
_x000D_
_x000D_

It may look strange, as it seems like the new Promise() calls are executed synchronously, but in reality the async function returns when it executes the first await. Every time an awaited promise resolves, the function's running context is restored, and proceeds after the await, until it encounters the next one, and so it continues until the loop finishes.

As it may be a common thing to return a promise based on a timeout, you could create a separate function for generating such a promise. This is called promisifying a function, in this case setTimeout. It may improve the readability of the code:

_x000D_
_x000D_
const delay = ms => new Promise(resolve => setTimeout(resolve, ms));

(async function loop() {
    for (let i = 0; i < 10; i++) {
        await delay(Math.random() * 1000);
        console.log(i);
    }
})();
_x000D_
_x000D_
_x000D_

5. With for await...of

With EcmaScript 2020, the for await...of found its way to modern JavaScript engines. Although it does not really reduce code in this case, it allows to isolate the definition of the random interval chain from the actual iteration of it:

_x000D_
_x000D_
const delay = ms => new Promise(resolve => setTimeout(resolve, ms));
async function * randomDelays(count ,max) {
    for (let i = 0; i < count; i++) yield delay(Math.random() * max).then(() => i);
}

(async function loop() {
    for await (let i of randomDelays(10, 1000)) console.log(i);
})();
_x000D_
_x000D_
_x000D_

Disable nginx cache for JavaScript files

The expires and add_header directives have no impact on NGINX caching the files, those are purely about what the browser sees.

What you likely want instead is:

location stuffyoudontwanttocache {
    # don't cache it
    proxy_no_cache 1;
    # even if cached, don't try to use it
    proxy_cache_bypass 1; 
}

Though usually .js etc is the thing you would cache, so perhaps you should just disable caching entirely?

How to Inspect Element using Safari Browser

Press CMD + , than click in show develop menu in menu bar. After that click Option + CMD + i to open and close the inspector

enter image description here

Why does this "Slow network detected..." log appear in Chrome?

I have network throttling disabled but started to get this error today on a 75mb/s business connection...

To fix it in my build of Chrome 60.0.3112.90 (Official Build) (64-bit) I opened the DevTools then navigated to the DevTools Settings then ticked 'Log XMLHttpRequests', unticked 'User messages only' and 'Hide network messages'

Use async await with Array.map

Solution below to process all elements of the array in parallel, asynchronously AND preserve the order:

const arr = [1, 2, 3, 4, 5, 6, 7, 8];
const randomDelay = () => new Promise(resolve => setTimeout(resolve, Math.random() * 1000));

const calc = async n => {
  await randomDelay();
  return n * 2;
};

const asyncFunc = async () => {
  const unresolvedPromises = arr.map(n => calc(n));
  const results = await Promise.all(unresolvedPromises);
};

asyncFunc();

Also codepen.

Notice we only "await" for Promise.all. We call calc without "await" multiple times, and we collect an array of unresolved promises right away. Then Promise.all waits for resolution of all of them and returns an array with the resolved values in order.

Angular 2 : No NgModule metadata found

I had the same problem and couldn't solve it after reading all the above answers. Then I noticed that an extra comma in declarations was creating a problem. Removed it, problem solved.

@NgModule({
    imports: [
        PagesRoutingModule,
        ThemeModule,
        DashboardModule,
    ],
    declarations: [
        ...PAGES_COMPONENTS,
        **,**
    ],
})

A Parser-blocking, cross-origin script is invoked via document.write - how to circumvent it?

Don't use document.write, here is workaround:

var script = document.createElement('script');  
script.src = "....";  
document.head.appendChild(script);

In reactJS, how to copy text to clipboard?

This work for me:

const handleCopyLink = useCallback(() => {
    const textField = document.createElement('textarea')
    textField.innerText = url
    document.body.appendChild(textField)
    if (window.navigator.platform === 'iPhone') {
      textField.setSelectionRange(0, 99999)
    } else {
      textField.select()
    }
    document.execCommand('copy')
    textField.remove()
    
    toast.success('Link successfully copied')
  }, [url])

http post - how to send Authorization header?

I believe you need to map the result before you subscribe to it. You configure it like this:

  updateProfileInformation(user: User) {
    var headers = new Headers();
    headers.append('Content-Type', this.constants.jsonContentType);

    var t = localStorage.getItem("accessToken");
    headers.append("Authorization", "Bearer " + t;
    var body = JSON.stringify(user);

    return this.http.post(this.constants.userUrl + "UpdateUser", body, { headers: headers })
      .map((response: Response) => {
        var result = response.json();
        return result;
      })
      .catch(this.handleError)
      .subscribe(
      status => this.statusMessage = status,
      error => this.errorMessage = error,
      () => this.completeUpdateUser()
      );
  }

Disable Chrome strict MIME type checking

For Windows Users :

If this issue occurs on your self hosted server (eg: your custom CDN) and the browser (Chrome) says something like ... ('text/plain') is not executable ... when trying to load your javascript file ...

Here is what you need to do :

  1. Open the Registry Editor i.e Win + R > regedit
  2. Head over to HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.js
  3. Check to if the Content Type is application/javascript or not
  4. If not, then change it to application/javascript and try again

Send POST data via raw json with postman

Just check JSON option from the drop down next to binary; when you click raw. This should do

skill synon pass json to postman

Cannot open local file - Chrome: Not allowed to load local resource

You just need to replace all image network paths to byte strings in stored Encoded HTML string. For this you required HtmlAgilityPack to convert Html string to Html document. https://www.nuget.org/packages/HtmlAgilityPack

Find Below code to convert each image src network path(or local path) to byte sting. It will definitely display all images with network path(or local path) in IE,chrome and firefox.

string encodedHtmlString = Emailmodel.DtEmailFields.Rows[0]["Body"].ToString();

// Decode the encoded string.
StringWriter myWriter = new StringWriter();
HttpUtility.HtmlDecode(encodedHtmlString, myWriter);
string DecodedHtmlString = myWriter.ToString();

//find and replace each img src with byte string
HtmlDocument document = new HtmlDocument();
document.LoadHtml(DecodedHtmlString);
document.DocumentNode.Descendants("img")
    .Where(e =>
    {
        string src = e.GetAttributeValue("src", null) ?? "";
        return !string.IsNullOrEmpty(src);//&& src.StartsWith("data:image");
    })
    .ToList()
    .ForEach(x =>
        {
        string currentSrcValue = x.GetAttributeValue("src", null);                                
        string filePath = Path.GetDirectoryName(currentSrcValue) + "\\";
        string filename = Path.GetFileName(currentSrcValue);
        string contenttype = "image/" + Path.GetExtension(filename).Replace(".", "");
        FileStream fs = new FileStream(filePath + filename, FileMode.Open, FileAccess.Read);
        BinaryReader br = new BinaryReader(fs);
        Byte[] bytes = br.ReadBytes((Int32)fs.Length);
        br.Close();
        fs.Close();
        x.SetAttributeValue("src", "data:" + contenttype + ";base64," + Convert.ToBase64String(bytes));                                
    });

string result = document.DocumentNode.OuterHtml;
//Encode HTML string
string myEncodedString = HttpUtility.HtmlEncode(result);

Emailmodel.DtEmailFields.Rows[0]["Body"] = myEncodedString;

Chrome dev tools fails to show response even the content returned has header Content-Type:text/html; charset=UTF-8

For me, the issue happens when the returned JSON file is too large.

If you just want to see the response, you can get it with the help of Postman. See the steps below:

  1. Copy the request with all information(including URL, header, token, etc) from chrome debugger through Chrome Developer Tools->Network Tab->find the request->right click on it->Copy->Copy as cURL.
  2. Open postman, import->Rawtext, paste the content. Postman will recreate the same request. Then run the request you should see the JSON response. [Import cURL in postmain][1]: https://i.stack.imgur.com/dL9Qo.png

If you want to reduce the size of the API response, maybe you can return fewer fields in the response. For mongoose, you can easily do this by providing a field name list when calling the find() method. For exmaple, convert the method from:

const users = await User.find().lean();

To:

const users = await User.find({}, '_id username email role timecreated').lean();

In my case, there is field called description, which is a large string. After removing it from the field list, the response size is reduced from 6.6 MB to 404 KB.

How can I use/create dynamic template to compile dynamic Component with Angular 2.0?

I must have arrived at the party late, none of the solutions here seemed helpful to me - too messy and felt like too much of a workaround.

What I ended up doing is using Angular 4.0.0-beta.6's ngComponentOutlet.

This gave me the shortest, simplest solution all written in the dynamic component's file.

  • Here is a simple example which just receives text and places it in a template, but obviously you can change according to your need:
import {
  Component, OnInit, Input, NgModule, NgModuleFactory, Compiler
} from '@angular/core';

@Component({
  selector: 'my-component',
  template: `<ng-container *ngComponentOutlet="dynamicComponent;
                            ngModuleFactory: dynamicModule;"></ng-container>`,
  styleUrls: ['my.component.css']
})
export class MyComponent implements OnInit {
  dynamicComponent;
  dynamicModule: NgModuleFactory<any>;

  @Input()
  text: string;

  constructor(private compiler: Compiler) {
  }

  ngOnInit() {
    this.dynamicComponent = this.createNewComponent(this.text);
    this.dynamicModule = this.compiler.compileModuleSync(this.createComponentModule(this.dynamicComponent));
  }

  protected createComponentModule (componentType: any) {
    @NgModule({
      imports: [],
      declarations: [
        componentType
      ],
      entryComponents: [componentType]
    })
    class RuntimeComponentModule
    {
    }
    // a module for just this Type
    return RuntimeComponentModule;
  }

  protected createNewComponent (text:string) {
    let template = `dynamically created template with text: ${text}`;

    @Component({
      selector: 'dynamic-component',
      template: template
    })
    class DynamicComponent implements OnInit{
       text: any;

       ngOnInit() {
       this.text = text;
       }
    }
    return DynamicComponent;
  }
}
  • Short explanation:
    1. my-component - the component in which a dynamic component is rendering
    2. DynamicComponent - the component to be dynamically built and it is rendering inside my-component

Don't forget to upgrade all the angular libraries to ^Angular 4.0.0

Hope this helps, good luck!

UPDATE

Also works for angular 5.

Why is my asynchronous function returning Promise { <pending> } instead of a value?

I know this question was asked 2 years ago, but I run into the same issue and the answer for the problem is since ES2017, that you can simply await the functions return value (as of now, only works in async functions), like:

let AuthUser = function(data) {
  return google.login(data.username, data.password).then(token => { return token } )
}

let userToken = await AuthUser(data)
console.log(userToken) // your data

"Uncaught TypeError: a.indexOf is not a function" error when opening new foundation project

This error might be caused by the jQuery event-aliases like .load(), .unload() or .error() that all are deprecated since jQuery 1.8. Lookup for these aliases in your code and replace them with the .on() method instead. For example, replace the following deprecated excerpt:

$(window).load(function(){...});

with the following:

$(window).on('load', function(){ ...});

Only local connections are allowed Chrome and Selenium webdriver

First off, What you are seeing is not an error. It is an informational message.

When you run this driver, it will enable your scripts to access this and run commands on Google Chrome.

This can be done via scripts running in the local network (Only local connections are allowed.) or via scripts running on outside networks (All remote connections are allowed.). It is always safer to use the Local Connection option. By default your Chromedriver is accessible via port 9515.

See this answer if you wish to allow all connections instead of just local.


If your Chromedriver only shows the above two messages (as per the question), then there is a problem. It has to show a message like this, which says it started successfully.

Starting ChromeDriver 83.0.4103.39 (ccbf011cb2d2b19b506d844400483861342c20cd-refs/branch-heads/4103@{#416}) on port 9515
Only local connections are allowed.
Please see https://chromedriver.chromium.org/security-considerations for suggestions on keeping ChromeDriver safe.
ChromeDriver was started successfully.

To troubleshoot this...

Step 1: Check your Chromedriver version

$ chromedriver --version

ChromeDriver 83.0.4103.39 (ccbf011cb2d2b19b506d844400483861342c20cd-refs/branch-heads/4103@{#416})

My version is 83.0.4103.39.

Step 2: Check your Chrome Browser version

Open Google Chrome.

Options --> Help --> About Google Chrome

enter image description here

Or open a terminal and run the following command (works on Ubuntu).

$ google-chrome --version

Google Chrome 83.0.4103.61

My version is: Version 83.0.4103.61

Step 3: Compare versions of Chromedriver and Google Chrome

Both these versions are starting with 83, which means they are both compatible. Hence, you should see a message like below, when you run the below command.

$ chromedriver 

Starting ChromeDriver 83.0.4103.39 (ccbf011cb2d2b19b506d844400483861342c20cd-refs/branch-heads/4103@{#416}) on port 9515
Only local connections are allowed.
Please see https://chromedriver.chromium.org/security-considerations for suggestions on keeping ChromeDriver safe.
ChromeDriver was started successfully. 

If your versions mismatch, then you will see the following message. You will not see the line which says, ChromeDriver was started successfully..

$ chromedriver

Starting ChromeDriver 80.0.3987.106 (f68069574609230cf9b635cd784cfb1bf81bb53a-refs/branch-heads/3987@{#882}) on port 9515
Only local connections are allowed.
Please protect ports used by ChromeDriver and related test frameworks to prevent access by malicious code.

Step 4: Download the correct version of Chromedriver

Download the correct version that matches your browser version. Use this page for downloads. After you download, extract the content, and move it to one of the following two folders. Open each of the following two folders and see whether your current Chromedriver is there. If it is on both folders, replace both. And do STEP 3 again.

/usr/bin/chromedriver
/usr/local/bin/chromedriver

Difference between chr(13) and chr(10)

Chr(10) is the Line Feed character and Chr(13) is the Carriage Return character.

You probably won't notice a difference if you use only one or the other, but you might find yourself in a situation where the output doesn't show properly with only one or the other. So it's safer to include both.


Historically, Line Feed would move down a line but not return to column 1:

This  
    is  
        a  
            test.

Similarly Carriage Return would return to column 1 but not move down a line:

This  
is  
a  
test.

Paste this into a text editor and then choose to "show all characters", and you'll see both characters present at the end of each line. Better safe than sorry.

why $(window).load() is not working in jQuery?

<script type="text/javascript">
   $(window).ready(function () {
      alert("Window Loaded");
   });
</script>

formGroup expects a FormGroup instance

I was facing this issue and fixed by putting a check in form attribute. This issue can happen when the FormGroup is not initialized.

<form [formGroup]="loginForm" *ngIf="loginForm">
OR
<form [formGroup]="loginForm" *ngIf="this.loginForm">

This will not render the form until it is initialized.

React - Component Full Screen (with height 100%)

You could also do:

body > #root > div {
  height: 100vh;
}

React Native fetch() Network Request Failed

You can handle it using this :

catch((error) => {
      this.setState({
        typing_animation_button: false,
      });
      console.log(error);
      if ('Timeout' || 'Network request failed') {
        toast_show = true;
        toast_type = 'error';
        toast_text = 'Network failure';
      }
      this.setState({
        disable_button: false,
      });
    });

Moment.js - How to convert date string into date?

if you have a string of date, then you should try this.

const FORMAT = "YYYY ddd MMM DD HH:mm";

const theDate = moment("2019 Tue Apr 09 13:30", FORMAT);
// Tue Apr 09 2019 13:30:00 GMT+0300

const theDate1 = moment("2019 Tue Apr 09 13:30", FORMAT).format('LL')
// April 9, 2019

or try this :

const theDate1 = moment("2019 Tue Apr 09 13:30").format(FORMAT);

Is there any way to debug chrome in any IOS device

Old Answer (July 2016):

You can't directly debug Chrome for iOS due to restrictions on the published WKWebView apps, but there are a few options already discussed in other SO threads:

  1. If you can reproduce the issue in Safari as well, then use Remote Debugging with Safari Web Inspector. This would be the easiest approach.

  2. WeInRe allows some simple debugging, using a simple client-server model. It's not fully featured, but it may well be enough for your problem. See instructions on set up here.

  3. You could try and create a simple WKWebView browser app (some instructions here), or look for an existing one on GitHub. Since Chrome uses the same rendering engine, you could debug using that, as it will be close to what Chrome produces.

There's a "bug" opened up for WebKit: Allow Web Inspector usage for release builds of WKWebView. If and when we get an API to WKWebView, Chrome for iOS would be debuggable.

Update January 2018:

Since my answer back in 2016, some work has been done to improve things.

There is a recent project called RemoteDebug iOS WebKit Adapter, by some of the Microsoft team. It's an adapter that handles the API differences between Webkit Remote Debugging Protocol and Chrome Debugging Protocol, and this allows you to debug iOS WebViews in any app that supports the protocol - Chrome DevTools, VS Code etc.

Check out the getting started guide in the repo, which is quite detailed.

If you are interesting, you can read up on the background and architecture here.

Failed to load resource 404 (Not Found) - file location error?

Looks like the path you gave doesn't have any bootstrap files in them.

href="~/lib/bootstrap/dist/css/bootstrap.min.css"

Make sure the files exist over there , else point the files to the correct path, which should be in your case

href="~/node_modules/bootstrap/dist/css/bootstrap.min.css"

Flexbox not working in Internet Explorer 11

See "Can I Use" for the full list of IE11 Flexbox bugs and more

There are numerous Flexbox bugs in IE11 and other browsers - see flexbox on Can I Use -> Known Issues, where the following are listed under IE11:

  • IE 11 requires a unit to be added to the third argument, the flex-basis property
  • In IE10 and IE11, containers with display: flex and flex-direction: column will not properly calculate their flexed childrens' sizes if the container has min-height but no explicit height property
  • IE 11 does not vertically align items correctly when min-height is used

Also see Philip Walton's Flexbugs list of issues and workarounds.

"Object doesn't support property or method 'find'" in IE

The Array.find method support for Microsoft's browsers started with Edge.

The W3Schools compatibility table states that the support started on version 12, while the Can I Use compatibility table says that the support was unknown between version 12 and 14, being officially supported starting at version 15.

How do I select and store columns greater than a number in pandas?

Sample DF:

In [79]: df = pd.DataFrame(np.random.randint(5, 15, (10, 3)), columns=list('abc'))

In [80]: df
Out[80]:
    a   b   c
0   6  11  11
1  14   7   8
2  13   5  11
3  13   7  11
4  13   5   9
5   5  11   9
6   9   8   6
7   5  11  10
8   8  10  14
9   7  14  13

present only those rows where b > 10

In [81]: df[df.b > 10]
Out[81]:
   a   b   c
0  6  11  11
5  5  11   9
7  5  11  10
9  7  14  13

Minimums (for all columns) for the rows satisfying b > 10 condition

In [82]: df[df.b > 10].min()
Out[82]:
a     5
b    11
c     9
dtype: int32

Minimum (for the b column) for the rows satisfying b > 10 condition

In [84]: df.loc[df.b > 10, 'b'].min()
Out[84]: 11

UPDATE: starting from Pandas 0.20.1 the .ix indexer is deprecated, in favor of the more strict .iloc and .loc indexers.

Selenium 2.53 not working on Firefox 47

New Selenium libraries are now out, according to: https://github.com/SeleniumHQ/selenium/issues/2110

The download page http://www.seleniumhq.org/download/ seems not to be updated just yet, but by adding 1 to the minor version in the link, I could download the C# version: http://selenium-release.storage.googleapis.com/2.53/selenium-dotnet-2.53.1.zip

It works for me with Firefox 47.0.1.

As a side note, I was able build just the webdriver.xpi Firefox extension from the master branch in GitHub, by running ./go //javascript/firefox-driver:webdriver:run – which gave an error message but did build the build/javascript/firefox-driver/webdriver.xpi file, which I could rename (to avoid a name clash) and successfully load with the FirefoxProfile.AddExtension method. That was a reasonable workaround without having to rebuild the entire Selenium library.

Using an array from Observable Object with ngFor and Async Pipe Angular 2

I think what u r looking for is this

<article *ngFor="let news of (news$ | async)?.articles">
<h4 class="head">{{news.title}}</h4>
<div class="desc"> {{news.description}}</div>
<footer>
    {{news.author}}
</footer>

How to hide a mobile browser's address bar?

I know this is old, but I have to add this in here..

And while this is not a full answer, it is an 'IN ADDITION TO'

The address bar will not disappear if you're NOT using https.

ALSO

If you are using https and the address bar still won't hide, you might have some https errors in your webpage (such as certain images being served from a non-https location.)

Hope this helps..

PHP: Inserting Values from the Form into MySQL

Try this:

dbConfig.php

<?php
$mysqli = new mysqli('localhost', 'root', 'pwd', 'yr db name');
    if($mysqli->connect_error)
        {
        echo $mysqli->connect_error;
        }
    ?>

Index.php

<html>
<head><title>Inserting data in database table </title>
</head>
<body>
<form action="control_table.php" method="post">
<table border="1" background="red" align="center">
<tr>
<td>Login Name</td>
<td><input type="text" name="txtname" /></td>
</tr>
<br>
<tr>
<td>Password</td>
<td><input type="text" name="txtpwd" /></td>
</tr>
<tr>
<td>&nbsp;</td>
<td><input type="submit" name="txtbutton" value="SUBMIT" /></td>
</tr>
</table>
control_table.php
<?php include 'config.php'; ?>
<?php
$name=$pwd="";
    if(isset($_POST['txtbutton']))
        {
            $name = $_POST['txtname'];
            $pwd = $_POST['txtpwd'];
            $mysqli->query("insert into users(name,pwd) values('$name', '$pwd')");
        if(!$mysqli) 
        { echo mysqli_error(); }
    else
    {
        echo "Successfully Inserted <br />";
        echo "<a href='show.php'>View Result</a>";
    }

         }  

    ?>

net::ERR_INSECURE_RESPONSE in Chrome

I was having this issue when testing my Cordova app on android. It just so happens that this android device does not persist its date, and will reset back to its factory date somehow. The API that it calls has a cert that is valid starting this year, while the device date after bootup is in 2017. For now, I have to adb shell and change the date manually.

"SyntaxError: Unexpected token < in JSON at position 0"

Those who are using create-react-app and trying to fetch local json files.

As in create-react-app, webpack-dev-server is used to handle the request and for every request it serves the index.html. So you are getting

SyntaxError: Unexpected token < in JSON at position 0.

To solve this, you need to eject the app and modify the webpack-dev-server configuration file.

You can follow the steps from here.

Is it possible to open developer tools console in Chrome on Android phone?

When you don't have a PC on hand, you could use Eruda, which is devtools for mobile browsers https://github.com/liriliri/eruda
It is provided as embeddable javascript and also a bookmarklet (pasting bookmarklet in chrome removes the javascript: prefix, so you have to type it yourself)

How to change the locale in chrome browser

Open chrome, go to chrome://settings/languages

On the left, you should see a list of languages. Use mouse to drag the language you want to the top, that will change the order for the values in Accept-language of requests.

If you still don't see the language you prefer, it may be cookies. Go to cookies and clean it up you should be good.

Enzyme - How to access and set <input> value?

In my case i was using ref callbacks,

  <input id="usuario" className="form-control" placeholder="Usuario"
                                                       name="usuario" type="usuario"
                                                       onKeyUp={this._validateMail.bind(this)}
                                                       onChange={()=> this._validateMail()}
                                                       ref={(val) =>{ this._username = val}}
                                                    >

To obtain the value. So enzyme will not change the value of this._username.

So i had to:

login.node._username.value = "[email protected]";
    user.simulate('change');
    expect(login.state('mailValid')).toBe(true);

To be able to set the value then call change . And then assert.

Re-render React component when prop changes

I would recommend having a look at this answer of mine, and see if it is relevant to what you are doing. If I understand your real problem, it's that your just not using your async action correctly and updating the redux "store", which will automatically update your component with it's new props.

This section of your code:

componentDidMount() {
      if (this.props.isManager) {
        this.props.dispatch(actions.fetchAllSites())
      } else {
        const currentUserId = this.props.user.get('id')
        this.props.dispatch(actions.fetchUsersSites(currentUserId))
      }  
    }

Should not be triggering in a component, it should be handled after executing your first request.

Have a look at this example from redux-thunk:

function makeASandwichWithSecretSauce(forPerson) {

  // Invert control!
  // Return a function that accepts `dispatch` so we can dispatch later.
  // Thunk middleware knows how to turn thunk async actions into actions.

  return function (dispatch) {
    return fetchSecretSauce().then(
      sauce => dispatch(makeASandwich(forPerson, sauce)),
      error => dispatch(apologize('The Sandwich Shop', forPerson, error))
    );
  };
}

You don't necessarily have to use redux-thunk, but it will help you reason about scenarios like this and write code to match.

What does ==$0 (double equals dollar zero) mean in Chrome Developer Tools?

This is Chrome's hint to tell you that if you type $0 on the console, it will be equivalent to that specific element.

Internally, Chrome maintains a stack, where $0 is the selected element, $1 is the element that was last selected, $2 would be the one that was selected before $1 and so on.

Here are some of its applications:

  • Accessing DOM elements from console: $0
  • Accessing their properties from console: $0.parentElement
  • Updating their properties from console: $1.classList.add(...)
  • Updating CSS elements from console: $0.styles.backgroundColor="aqua"
  • Triggering CSS events from console: $0.click()
  • And doing a lot more complex stuffs, like: $0.appendChild(document.createElement("div"))

Watch all of this in action:

enter image description here

Backing statement:

Yes, I agree there are better ways to perform these actions, but this feature can come out handy in certain intricate scenarios, like when a DOM element needs to be clicked but it is not possible to do so from the UI because it is covered by other elements or, for some reason, is not visible on UI at that moment.

How to configure CORS in a Spring Boot + Spring Security application?

You can finish this with only a Single Class, Just add this on your class path.

This one is enough for Spring Boot, Spring Security, nothing else. :

        @Component
        @Order(Ordered.HIGHEST_PRECEDENCE)
        public class MyCorsFilterConfig implements Filter {

            @Override
            public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
                final HttpServletResponse response = (HttpServletResponse) res;
                response.setHeader("Access-Control-Allow-Origin", "*");
                response.setHeader("Access-Control-Allow-Methods", "POST, PUT, GET, OPTIONS, DELETE");
                response.setHeader("Access-Control-Allow-Headers", "Authorization, Content-Type, enctype");
                response.setHeader("Access-Control-Max-Age", "3600");
                if (HttpMethod.OPTIONS.name().equalsIgnoreCase(((HttpServletRequest) req).getMethod())) {
                    response.setStatus(HttpServletResponse.SC_OK);
                } else {
                    chain.doFilter(req, res);
                }
            }

            @Override
            public void destroy() {
            }

            @Override
            public void init(FilterConfig config) throws ServletException {
            }


        }

fetch gives an empty response body

I just ran into this. As mentioned in this answer, using mode: "no-cors" will give you an opaque response, which doesn't seem to return data in the body.

opaque: Response for “no-cors” request to cross-origin resource. Severely restricted.

In my case I was using Express. After I installed cors for Express and configured it and removed mode: "no-cors", I was returned a promise. The response data will be in the promise, e.g.

fetch('http://example.com/api/node', {
  // mode: 'no-cors',
  method: 'GET',
  headers: {
    Accept: 'application/json',
  },
},
).then(response => {
  if (response.ok) {
    response.json().then(json => {
      console.log(json);
    });
  }
});

Uncaught TypeError: $(...).datepicker is not a function(anonymous function)

The error is because you are including the script links at two places which will do the override and re-initialization of date-picker

_x000D_
_x000D_
<meta charset="utf-8">_x000D_
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />_x000D_
_x000D_
_x000D_
<script src="http://code.jquery.com/jquery-1.9.1.js"></script>_x000D_
<script src="http://code.jquery.com/ui/1.11.0/jquery-ui.js"></script>_x000D_
_x000D_
<script type="text/javascript">_x000D_
$(document).ready(function() {_x000D_
    $('.dateinput').datepicker({ format: "yyyy/mm/dd" });_x000D_
}); _x000D_
</script>_x000D_
_x000D_
      <!-- Bootstrap core JavaScript_x000D_
================================================== -->_x000D_
<!-- Placed at the end of the document so the pages load faster -->_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>
_x000D_
_x000D_
_x000D_

So exclude either src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"

or src="http://code.jquery.com/ui/1.11.0/jquery-ui.js"

It will work..

Postman: How to make multiple requests at the same time

In postman's collection runner you can't make simultaneous asynchronous requests, so instead use Apache JMeter instead. It allows you to add multiple threads and add synchronizing timer to it

Why is setState in reactjs Async instead of Sync?

1) setState actions are asynchronous and are batched for performance gains. This is explained in the documentation of setState.

setState() does not immediately mutate this.state but creates a pending state transition. Accessing this.state after calling this method can potentially return the existing value. There is no guarantee of synchronous operation of calls to setState and calls may be batched for performance gains.


2) Why would they make setState async as JS is a single threaded language and this setState is not a WebAPI or server call?

This is because setState alters the state and causes rerendering. This can be an expensive operation and making it synchronous might leave the browser unresponsive.

Thus the setState calls are asynchronous as well as batched for better UI experience and performance.

ESRI : Failed to parse source map

I noticed that problem because of AdBlock Extension, I turned off AdBlock extension the issue got resolve.

Angular2 get clicked element id

If you want to have access to the id attribute of the button you can leverage the srcElement property of the event:

import {Component} from 'angular2/core';

@Component({
  selector: 'my-app',
  template: `
    <button (click)="onClick($event)" id="test">Click</button>
  `
})
export class AppComponent {
  onClick(event) {
    var target = event.target || event.srcElement || event.currentTarget;
    var idAttr = target.attributes.id;
    var value = idAttr.nodeValue;
  }
}

See this plunkr: https://plnkr.co/edit/QGdou4?p=preview.

See this question:

The request was rejected because no multipart boundary was found in springboot

I was having the same problem while making a POST request from Postman and later I could solve the problem by setting a custom Content-Type with a boundary value set along with it like this.

I thought people can run into similar problem and hence, I'm sharing my solution.

postman

How can I display a modal dialog in Redux that performs asynchronous actions?

Update: React 16.0 introduced portals through ReactDOM.createPortal link

Update: next versions of React (Fiber: probably 16 or 17) will include a method to create portals: ReactDOM.unstable_createPortal() link


Use portals

Dan Abramov answer first part is fine, but involves a lot of boilerplate. As he said, you can also use portals. I'll expand a bit on that idea.

The advantage of a portal is that the popup and the button remain very close into the React tree, with very simple parent/child communication using props: you can easily handle async actions with portals, or let the parent customize the portal.

What is a portal?

A portal permits you to render directly inside document.body an element that is deeply nested in your React tree.

The idea is that for example you render into body the following React tree:

<div className="layout">
  <div className="outside-portal">
    <Portal>
      <div className="inside-portal">
        PortalContent
      </div>
    </Portal>
  </div>
</div>

And you get as output:

<body>
  <div class="layout">
    <div class="outside-portal">
    </div>
  </div>
  <div class="inside-portal">
    PortalContent
  </div>
</body>

The inside-portal node has been translated inside <body>, instead of its normal, deeply-nested place.

When to use a portal

A portal is particularly helpful for displaying elements that should go on top of your existing React components: popups, dropdowns, suggestions, hotspots

Why use a portal

No z-index problems anymore: a portal permits you to render to <body>. If you want to display a popup or dropdown, this is a really nice idea if you don't want to have to fight against z-index problems. The portal elements get added do document.body in mount order, which means that unless you play with z-index, the default behavior will be to stack portals on top of each others, in mounting order. In practice, it means that you can safely open a popup from inside another popup, and be sure that the 2nd popup will be displayed on top of the first, without having to even think about z-index.

In practice

Most simple: use local React state: if you think, for a simple delete confirmation popup, it's not worth to have the Redux boilerplate, then you can use a portal and it greatly simplifies your code. For such a use case, where the interaction is very local and is actually quite an implementation detail, do you really care about hot-reloading, time-traveling, action logging and all the benefits Redux brings you? Personally, I don't and use local state in this case. The code becomes as simple as:

class DeleteButton extends React.Component {
  static propTypes = {
    onDelete: PropTypes.func.isRequired,
  };

  state = { confirmationPopup: false };

  open = () => {
    this.setState({ confirmationPopup: true });
  };

  close = () => {
    this.setState({ confirmationPopup: false });
  };

  render() {
    return (
      <div className="delete-button">
        <div onClick={() => this.open()}>Delete</div>
        {this.state.confirmationPopup && (
          <Portal>
            <DeleteConfirmationPopup
              onCancel={() => this.close()}
              onConfirm={() => {
                this.close();
                this.props.onDelete();
              }}
            />
          </Portal>
        )}
      </div>
    );
  }
}

Simple: you can still use Redux state: if you really want to, you can still use connect to choose whether or not the DeleteConfirmationPopup is shown or not. As the portal remains deeply nested in your React tree, it is very simple to customize the behavior of this portal because your parent can pass props to the portal. If you don't use portals, you usually have to render your popups at the top of your React tree for z-index reasons, and usually have to think about things like "how do I customize the generic DeleteConfirmationPopup I built according to the use case". And usually you'll find quite hacky solutions to this problem, like dispatching an action that contains nested confirm/cancel actions, a translation bundle key, or even worse, a render function (or something else unserializable). You don't have to do that with portals, and can just pass regular props, since DeleteConfirmationPopup is just a child of the DeleteButton

Conclusion

Portals are very useful to simplify your code. I couldn't do without them anymore.

Note that portal implementations can also help you with other useful features like:

  • Accessibility
  • Espace shortcuts to close the portal
  • Handle outside click (close portal or not)
  • Handle link click (close portal or not)
  • React Context made available in portal tree

react-portal or react-modal are nice for popups, modals, and overlays that should be full-screen, generally centered in the middle of the screen.

react-tether is unknown to most React developers, yet it's one of the most useful tools you can find out there. Tether permits you to create portals, but will position automatically the portal, relative to a given target. This is perfect for tooltips, dropdowns, hotspots, helpboxes... If you have ever had any problem with position absolute/relative and z-index, or your dropdown going outside of your viewport, Tether will solve all that for you.

You can, for example, easily implement onboarding hotspots, that expands to a tooltip once clicked:

Onboarding hotspot

Real production code here. Can't be any simpler :)

<MenuHotspots.contacts>
  <ContactButton/>
</MenuHotspots.contacts>

Edit: just discovered react-gateway which permits to render portals into the node of your choice (not necessarily body)

Edit: it seems react-popper can be a decent alternative to react-tether. PopperJS is a library that only computes an appropriate position for an element, without touching the DOM directly, letting the user choose where and when he wants to put the DOM node, while Tether appends directly to the body.

Edit: there's also react-slot-fill which is interesting and can help solve similar problems by allowing to render an element to a reserved element slot that you put anywhere you want in your tree

Response to preflight request doesn't pass access control check

enter image description here

Using the Cors option in the API gateway, I used the following settings shown above

Also, note, that your function must return a HTTP status 200 in response to an OPTIONS request, or else CORS will also fail.

How to use a client certificate to authenticate and authorize in a Web API

I came upon a similar issue recently and following Fabian's advice actually led me to the solution. Turns out with client certs you have to ensure two things:

  1. The private key is actually being exported as part of the cert.

  2. The application pool identity running the app has access to said private key.

In our case I had to:

  1. Import the pfx file into the local server store while checking the export checkbox to ensure the private key was sent out.
  2. Using MMC console, grant the service account used access to the private key for the cert.

The trusted root issue explained in other answers is a valid one, it was just not the issue in our case.

XMLHttpRequest cannot load XXX No 'Access-Control-Allow-Origin' header

This bug cost me 2 days. I checked my Server log, the Preflight Option request/response between browser Chrome/Edge and Server was ok. The main reason is that GET/POST/PUT/DELETE server response for XHTMLRequest must also have the following header:

access-control-allow-origin: origin  

"origin" is in the request header (Browser will add it to request for you). for example:

Origin: http://localhost:4221

you can add response header like the following to accept for all:

access-control-allow-origin: *  

or response header for a specific request like:

access-control-allow-origin: http://localhost:4221 

The message in browsers is not clear to understand: "...The requested resource"

note that: CORS works well for localhost. different port means different Domain. if you get error message, check the CORS config on the server side.

Disable-web-security in Chrome 48+

I'm seeing the same thing. A quick google found this question and a bug on the chromium forums. It seems that the --user-data-dir flag is now required. Edit to add user-data-dir guide

When you use 'badidea' or 'thisisunsafe' to bypass a Chrome certificate/HSTS error, does it only apply for the current site?

This is specific for each site. So if you type that once, you will only get through that site and all other sites will need a similar type-through.

It is also remembered for that site and you have to click on the padlock to reset it (so you can type it again):

enter image description here

Needless to say use of this "feature" is a bad idea and is unsafe - hence the name.

You should find out why the site is showing the error and/or stop using it until they fix it. HSTS specifically adds protections for bad certs to prevent you clicking through them. The fact it's needed suggests there is something wrong with the https connection - like the site or your connection to it has been hacked.

The chrome developers also do change this periodically. They changed it recently from badidea to thisisunsafe so everyone using badidea, suddenly stopped being able to use it. You should not depend on it. As Steffen pointed out in the comments below, it is available in the code should it change again though they now base64 encode it to make it more obscure. The last time they changed they put this comment in the commit:

Rotate the interstitial bypass keyword

The security interstitial bypass keyword hasn't changed in two years and awareness of the bypass has been increased in blogs and social media. Rotate the keyword to help prevent misuse.

I think the message from the Chrome team is clear - you should not use it. It would not surprise me if they removed it completely in future.

If you are using this when using a self-signed certificate for local testing then why not just add your self-signed certificate certificate to your computer's certificate store so you get a green padlock and do not have to type this? Note Chrome insists on a SAN field in certificates now so if just using the old subject field then even adding it to the certificate store will not result in a green padlock.

If you leave the certificate untrusted then certain things do not work. Caching for example is completely ignored for untrusted certificates. As is HTTP/2 Push.

HTTPS is here to stay and we need to get used to using it properly - and not bypassing the warnings with a hack that is liable to change and doesn't work the same as a full HTTPS solution.

Conda command not found

If you have the PATH in your .bashrc file and are still getting

conda: command not found

Your terminal might not be looking for the bash file. Type bash in the terminal to insure you are in bash and then try: conda --version

Angular 2 Scroll to bottom (Chat style)

After reading other solutions, the best solution I can think of, so you run only what you need is the following: You use ngOnChanges to detect the proper change

ngOnChanges() {
  if (changes.messages) {
      let chng = changes.messages;
      let cur  = chng.currentValue;
      let prev = chng.previousValue;
      if(cur && prev) {
        // lazy load case
        if (cur[0].id != prev[0].id) {
          this.lazyLoadHappened = true;
        }
        // new message
        if (cur[cur.length -1].id != prev[prev.length -1].id) {
          this.newMessageHappened = true;
        }
      }
    }

}

And you use ngAfterViewChecked to actually enforce the change before it renders but after the full height is calculated

ngAfterViewChecked(): void {
    if(this.newMessageHappened) {
      this.scrollToBottom();
      this.newMessageHappened = false;
    }
    else if(this.lazyLoadHappened) {
      // keep the same scroll
      this.lazyLoadHappened = false
    }
  }

If you are wondering how to implement scrollToBottom

@ViewChild('scrollWrapper') private scrollWrapper: ElementRef;
scrollToBottom(){
    try {
      this.scrollWrapper.nativeElement.scrollTop = this.scrollWrapper.nativeElement.scrollHeight;
    } catch(err) { }
  }

API Gateway CORS: no 'Access-Control-Allow-Origin' header

In my case, since I was using AWS_IAM as the Authorization method for API Gateway, I needed to grant my IAM role permissions to hit the endpoint.

Angular 2 / 4 / 5 not working in IE11

As of Feb 2017

Using an Angular-Cli project, all lines in the polyfills.ts file were already uncommented so all polyfills were already being utilised.

I found this solution here to fix my issue.

To summarize the above link, IE doesn't support lambda arrow / fat arrow functions which are a feature of es6. (This is if polyfills.ts doesn't work for you).

Solution: you need to target es5 for it to run in any IE versions, support for this was only introduced in the new Edge Browser by Microsoft.

This is found under src/tsconfig.json:

"outDir": "../dist/out-tsc",
"sourceMap": true,
"target": "es5",

Text in a flex container doesn't wrap in IE11

As Tyler has suggested in one of the comments here, using

max-width: 100%;

on the child may work (worked for me). Using align-self: stretch only works if you aren't using align-items: center (which I did). width: 100% only works if you haven't multiple childs inside your flexbox which you want to show side by side.

Async await in linq select

With current methods available in Linq it looks quite ugly:

var tasks = items.Select(
    async item => new
    {
        Item = item,
        IsValid = await IsValid(item)
    });
var tuples = await Task.WhenAll(tasks);
var validItems = tuples
    .Where(p => p.IsValid)
    .Select(p => p.Item)
    .ToList();

Hopefully following versions of .NET will come up with more elegant tooling to handle collections of tasks and tasks of collections.

Forward X11 failed: Network error: Connection refused

X display location : localhost:0 Worked for me :)

How to open a link in new tab (chrome) using Selenium WebDriver?

I checked with below code and it works fine for me. I found answer from here.

    driver = new ChromeDriver();
    driver.manage().window().maximize();
            
    String baseUrl = "http://www.google.co.uk/";
    driver.get(baseUrl);
    driver.findElement(By.cssSelector("body")).sendKeys(Keys.CONTROL +"t");

    ArrayList<String> tabs = new ArrayList<String> (driver.getWindowHandles());
    driver.switchTo().window(tabs.get(1)); //switches to new tab
    driver.get("https://www.facebook.com");
    
    driver.switchTo().window(tabs.get(0)); // switch back to main screen        
    driver.get("https://www.news.google.com");

How to open google chrome from terminal?

UPDATE:

  1. How do I open google chrome from the terminal?

Thank you for the quick response. open http://localhost/ opened that domain in my default browser on my Mac.

  1. What alias could I use to open the current git project in the browser?

I ended up writing this alias, did the trick:

# Opens git file's localhost; ${PWD##*/} is the current directory's name
alias lcl='open "http://localhost/${PWD##*/}/"'

Thank you again!

HTML 5 Video "autoplay" not automatically starting in CHROME

You need to add playsinline autoplay muted loop, chrome do not allow a video to autostart if it is not muted, also right now I dont know why it is not working in all android devices, im trying to look if it's a version specific, If I found something I'll let you know

Chrome issue: After some research i have found that it doesnt work on chrome sometimes because in responsive you can activate the data saver, and it blocks any video to autostart

What is the hamburger menu icon called and the three vertical dots icon called?

According to Reddit, more options icon and kabob menu are popular names. I prefer the latter as it goes well with hamburger menu.

Error reading JObject from JsonReader. Current JsonReader item is not an object: StartArray. Path

The first part of your question is a duplicate of Why do I get a JsonReaderException with this code?, but the most relevant part from that (my) answer is this:

[A] JObject isn't the elementary base type of everything in JSON.net, but JToken is. So even though you could say,

object i = new int[0];

in C#, you can't say,

JObject i = JObject.Parse("[0, 0, 0]");

in JSON.net.

What you want is JArray.Parse, which will accept the array you're passing it (denoted by the opening [ in your API response). This is what the "StartArray" in the error message is telling you.

As for what happened when you used JArray, you're using arr instead of obj:

var rcvdData = JsonConvert.DeserializeObject<LocationData>(arr /* <-- Here */.ToString(), settings);

Swap that, and I believe it should work.

Although I'd be tempted to deserialize arr directly as an IEnumerable<LocationData>, which would save some code and effort of looping through the array. If you aren't going to use the parsed version separately, it's best to avoid it.

Why do we need middleware for async flow in Redux?

The short answer: seems like a totally reasonable approach to the asynchrony problem to me. With a couple caveats.

I had a very similar line of thought when working on a new project we just started at my job. I was a big fan of vanilla Redux's elegant system for updating the store and rerendering components in a way that stays out of the guts of a React component tree. It seemed weird to me to hook into that elegant dispatch mechanism to handle asynchrony.

I ended up going with a really similar approach to what you have there in a library I factored out of our project, which we called react-redux-controller.

I ended up not going with the exact approach you have above for a couple reasons:

  1. The way you have it written, those dispatching functions don't have access to the store. You can somewhat get around that by having your UI components pass in all of the info the dispatching function needs. But I'd argue that this couples those UI components to the dispatching logic unnecessarily. And more problematically, there's no obvious way for the dispatching function to access updated state in async continuations.
  2. The dispatching functions have access to dispatch itself via lexical scope. This limits the options for refactoring once that connect statement gets out of hand -- and it's looking pretty unwieldy with just that one update method. So you need some system for letting you compose those dispatcher functions if you break them up into separate modules.

Take together, you have to rig up some system to allow dispatch and the store to be injected into your dispatching functions, along with the parameters of the event. I know of three reasonable approaches to this dependency injection:

  • redux-thunk does this in a functional way, by passing them into your thunks (making them not exactly thunks at all, by dome definitions). I haven't worked with the other dispatch middleware approaches, but I assume they're basically the same.
  • react-redux-controller does this with a coroutine. As a bonus, it also gives you access to the "selectors", which are the functions you may have passed in as the first argument to connect, rather than having to work directly with the raw, normalized store.
  • You could also do it the object-oriented way by injecting them into the this context, through a variety of possible mechanisms.

Update

It occurs to me that part of this conundrum is a limitation of react-redux. The first argument to connect gets a state snapshot, but not dispatch. The second argument gets dispatch but not the state. Neither argument gets a thunk that closes over the current state, for being able to see updated state at the time of a continuation/callback.

Why is my JQuery selector returning a n.fn.init[0], and what is it?

I just want to add something to these great answers. If your DOM element ins't loading in time. You can still set the value.

let Ctrl = $('#mySelectElement'); ... Ctrl.attr('value', myValue);

after that most DOM elements that accept a value attribute should populate correctly.

How to send an HTTP request with a header parameter?

If it says the API key is listed as a header, more than likely you need to set it in the headers option of your http request. Normally something like this :

headers: {'Authorization': '[your API key]'}

Here is an example from another Question

$http({method: 'GET', url: '[the-target-url]', headers: {
  'Authorization': '[your-api-key]'}
});

Edit : Just saw you wanted to store the response in a variable. In this case I would probably just use AJAX. Something like this :

$.ajax({ 
   type : "GET", 
   url : "[the-target-url]", 
   beforeSend: function(xhr){xhr.setRequestHeader('Authorization', '[your-api-key]');},
   success : function(result) { 
       //set your variable to the result 
   }, 
   error : function(result) { 
     //handle the error 
   } 
 }); 

I got this from this question and I'm at work so I can't test it at the moment but looks solid

Edit 2: Pretty sure you should be able to use this line :

headers: {'Authorization': '[your API key]'},

instead of the beforeSend line in the first edit. This may be simpler for you

Failed to decode downloaded font, OTS parsing error: invalid version tag + rails 4

I was getting the following errors:

Failed to decode downloaded font: [...]/fonts/glyphicons-halflings-regular.woff2
OTS parsing error: invalid version tag

which was fixed after downloading the raw file directly from:
https://github.com/twbs/bootstrap/blob/master/fonts/glyphicons-halflings-regular.woff2

The problem was that there was a proxy error when downloading the file (it contained the HTML error message).

Webpack "OTS parsing error" loading fonts

In my case adding following lines to lambda.js {my deployed is on AWS Lambda} fixed the issue.

 'font/opentype',
 'font/sfnt',
 'font/ttf',
 'font/woff',
 'font/woff2'

Getting request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource

In case of Request to a REST Service:

You need to allow the CORS (cross origin sharing of resources) on the endpoint of your REST Service with Spring annotation:

@CrossOrigin(origins = "http://localhost:8080")

Very good tutorial: https://spring.io/guides/gs/rest-service-cors/

Postman - How to see request with headers and body data with variables substituted

If, like me, you are still using the browser version (which will be deprecated soon), have you tried the "Code" button?

enter image description here

This should generate a snippet which contains the entire request Postman is firing. You can even choose the language for the snippet. I find it quite handy when I need to debug stuff.

Hope this helps.

How to send push notification to web browser?

I suggest using pubnub. I tried using ServiceWorkers and PushNotification from the browser however, however when I tried it webviews did not support this.

https://www.pubnub.com/docs/web-javascript/pubnub-javascript-sdk

ES6 modules implementation, how to load a json file

First of all you need to install json-loader:

npm i json-loader --save-dev

Then, there are two ways how you can use it:

  1. In order to avoid adding json-loader in each import you can add to webpack.config this line:

    loaders: [
      { test: /\.json$/, loader: 'json-loader' },
      // other loaders 
    ]
    

    Then import json files like this

    import suburbs from '../suburbs.json';
    
  2. Use json-loader directly in your import, as in your example:

    import suburbs from 'json!../suburbs.json';
    

Note: In webpack 2.* instead of keyword loaders need to use rules.,

also webpack 2.* uses json-loader by default

*.json files are now supported without the json-loader. You may still use it. It's not a breaking change.

v2.1.0-beta.28

Why my $.ajax showing "preflight is invalid redirect error"?

My problem was caused by the exact opposite of @ehacinom. My Laravel generated API didn't like the trailing '/' on POST requests. Worked fine on localhost but didn't work when uploaded to server.

Chrome / Safari not filling 100% height of flex parent

Solution

Use nested flex containers.

Get rid of percentage heights. Get rid of table properties. Get rid of vertical-align. Avoid absolute positioning. Just stick with flexbox all the way through.

Apply display: flex to the flex item (.item), making it a flex container. This automatically sets align-items: stretch, which tells the child (.item-inner) to expand the full height of the parent.

Important: Remove specified heights from flex items for this method to work. If a child has a height specified (e.g. height: 100%), then it will ignore the align-items: stretch coming from the parent. For the stretch default to work, the child's height must compute to auto (full explanation).

Try this (no changes to HTML):

_x000D_
_x000D_
.container {_x000D_
    display: flex;_x000D_
    flex-direction: column;_x000D_
    height: 20em;_x000D_
    border: 5px solid black_x000D_
}_x000D_
_x000D_
.item {_x000D_
    display: flex;                      /* new; nested flex container */_x000D_
    flex: 1;_x000D_
    border-bottom: 1px solid white;_x000D_
}_x000D_
_x000D_
.item-inner {_x000D_
    display: flex;                      /* new; nested flex container */_x000D_
    flex: 1;                            /* new */_x000D_
_x000D_
    /* height: 100%;                    <-- remove; unnecessary */_x000D_
    /* width: 100%;                     <-- remove; unnecessary */_x000D_
    /* display: table;                  <-- remove; unnecessary */  _x000D_
}_x000D_
_x000D_
a {_x000D_
    display: flex;                      /* new; nested flex container */_x000D_
    flex: 1;                            /* new */_x000D_
    align-items: center;                /* new; vertically center text */_x000D_
    background: orange;_x000D_
_x000D_
    /* display: table-cell;             <-- remove; unnecessary */_x000D_
    /* vertical-align: middle;          <-- remove; unnecessary */_x000D_
}
_x000D_
<div class="container">_x000D_
  <div class="item">_x000D_
    <div class="item-inner">_x000D_
      <a>Button</a>_x000D_
    </div>_x000D_
  </div>_x000D_
_x000D_
  <div class="item">_x000D_
    <div class="item-inner">_x000D_
      <a>Button</a>_x000D_
    </div>_x000D_
  </div>_x000D_
_x000D_
  <div class="item">_x000D_
    <div class="item-inner">_x000D_
      <a>Button</a>_x000D_
    </div>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

jsFiddle demo


Explanation

My problem is that .item-inner { height: 100% } is not working in webkit (Chrome).

It's not working because you're using percentage height in a way that doesn't conform with the traditional implementation of the spec.

10.5 Content height: the height property

percentage
Specifies a percentage height. The percentage is calculated with respect to the height of the generated box's containing block. If the height of the containing block is not specified explicitly and this element is not absolutely positioned, the value computes to auto.

auto
The height depends on the values of other properties.

In other words, for percentage height to work on an in-flow child, the parent must have a set height.

In your code, the top-level container has a defined height: .container { height: 20em; }

The third-level container has a defined height: .item-inner { height: 100%; }

But between them, the second-level container – .itemdoes not have a defined height. Webkit sees that as a missing link.

.item-inner is telling Chrome: give me height: 100%. Chrome looks to the parent (.item) for reference and responds: 100% of what? I don't see anything (ignoring the flex: 1 rule that is there). As a result, it applies height: auto (content height), in accordance with the spec.

Firefox, on the other hand, now accepts a parent's flex height as a reference for the child's percentage height. IE11 and Edge accept flex heights, as well.

Also, Chrome will accept flex-grow as an adequate parent reference if used in conjunction with flex-basis (any numerical value works (auto won't), including flex-basis: 0). As of this writing, however, this solution fails in Safari.

_x000D_
_x000D_
#outer {_x000D_
  display: flex;_x000D_
  flex-direction: column;_x000D_
  height: 300px;_x000D_
  background-color: white;_x000D_
  border: 1px solid red;_x000D_
}_x000D_
#middle {_x000D_
  flex-grow: 1;_x000D_
  flex-basis: 1px;_x000D_
  background-color: yellow;_x000D_
}_x000D_
#inner {_x000D_
  height: 100%;_x000D_
  background-color: lightgreen;_x000D_
}
_x000D_
<div id="outer">_x000D_
  <div id="middle">_x000D_
    <div id="inner">_x000D_
      INNER_x000D_
    </div>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_


Four Solutions

1. Specify a height on all parent elements

A reliable cross-browser solution is to specify a height on all parent elements. This prevents missing links, which Webkit-based browsers consider a violation of the spec.

Note that min-height and max-height are not acceptable. It must be the height property.

More details here: Working with the CSS height property and percentage values

2. CSS Relative & Absolute Positioning

Apply position: relative to the parent and position: absolute to the child.

Size the child with height: 100% and width: 100%, or use the offset properties: top: 0, right: 0, bottom: 0, left: 0.

With absolute positioning, percentage height works without a specified height on the parent.

3. Remove unnecessary HTML containers (recommended)

Is there a need for two containers around button? Why not remove .item or .item-inner, or both? Although button elements sometimes fail as flex containers, they can be flex items. Consider making button a child of .container or .item, and removing gratuitous mark-up.

Here's an example:

_x000D_
_x000D_
.container {_x000D_
    height: 20em;_x000D_
    display: flex;_x000D_
    flex-direction: column;_x000D_
    border: 5px solid black_x000D_
}_x000D_
_x000D_
a {_x000D_
    flex: 1;_x000D_
    background: orange;_x000D_
    border-bottom: 1px solid white;_x000D_
    display: flex;                   /* nested flex container (for aligning text) */_x000D_
    align-items: center;             /* center text vertically */_x000D_
    justify-content: center;         /* center text horizontally */_x000D_
}
_x000D_
<div class="container">_x000D_
    <a>Button</a>_x000D_
    <a>Button</a>_x000D_
    <a>Button</a>_x000D_
</div>
_x000D_
_x000D_
_x000D_

4. Nested Flex Containers (recommended)

Get rid of percentage heights. Get rid of table properties. Get rid of vertical-align. Avoid absolute positioning. Just stick with flexbox all the way through.

Apply display: flex to the flex item (.item), making it a flex container. This automatically sets align-items: stretch, which tells the child (.item-inner) to expand the full height of the parent.

Important: Remove specified heights from flex items for this method to work. If a child has a height specified (e.g. height: 100%), then it will ignore the align-items: stretch coming from the parent. For the stretch default to work, the child's height must compute to auto (full explanation).

Try this (no changes to HTML):

_x000D_
_x000D_
.container {_x000D_
    display: flex;_x000D_
    flex-direction: column;_x000D_
    height: 20em;_x000D_
    border: 5px solid black_x000D_
}_x000D_
_x000D_
.item {_x000D_
    display: flex;                      /* new; nested flex container */_x000D_
    flex: 1;_x000D_
    border-bottom: 1px solid white;_x000D_
}_x000D_
_x000D_
.item-inner {_x000D_
    display: flex;                      /* new; nested flex container */_x000D_
    flex: 1;                            /* new */_x000D_
_x000D_
    /* height: 100%;                    <-- remove; unnecessary */_x000D_
    /* width: 100%;                     <-- remove; unnecessary */_x000D_
    /* display: table;                  <-- remove; unnecessary */  _x000D_
}_x000D_
_x000D_
a {_x000D_
    display: flex;                      /* new; nested flex container */_x000D_
    flex: 1;                            /* new */_x000D_
    align-items: center;                /* new; vertically center text */_x000D_
    background: orange;_x000D_
_x000D_
    /* display: table-cell;             <-- remove; unnecessary */_x000D_
    /* vertical-align: middle;          <-- remove; unnecessary */_x000D_
}
_x000D_
<div class="container">_x000D_
  <div class="item">_x000D_
    <div class="item-inner">_x000D_
      <a>Button</a>_x000D_
    </div>_x000D_
  </div>_x000D_
_x000D_
  <div class="item">_x000D_
    <div class="item-inner">_x000D_
      <a>Button</a>_x000D_
    </div>_x000D_
  </div>_x000D_
_x000D_
  <div class="item">_x000D_
    <div class="item-inner">_x000D_
      <a>Button</a>_x000D_
    </div>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

jsFiddle

Chrome:The website uses HSTS. Network errors...this page will probably work later

I had this issue with sites running on XAMPP with private hostnames. Not so private, it turns out! They were all domain.dev, which Google has now registered as a private gTLD, and is forcing HSTS at the domain level. Changed every virtual host to .devel (eugh), restarted Apache and all is now well.

typesafe select onChange event using reactjs and typescript

In addition to @thoughtrepo's answer:

Until we do not have definitely typed events in React it might be useful to have a special target interface for input controls:

export interface FormControlEventTarget extends EventTarget{
    value: string;
}

And then in your code cast to this type where is appropriate to have IntelliSense support:

 import {FormControlEventTarget} from "your.helper.library"

 (event.target as FormControlEventTarget).value;

Can a website detect when you are using Selenium with chromedriver?

Firefox is said to set window.navigator.webdriver === true if working with a webdriver. That was according to one of the older specs (e.g.: archive.org) but I couldn't find it in the new one except for some very vague wording in the appendices.

A test for it is in the selenium code in the file fingerprint_test.js where the comment at the end says "Currently only implemented in firefox" but I wasn't able to identify any code in that direction with some simple greping, neither in the current (41.0.2) Firefox release-tree nor in the Chromium-tree.

I also found a comment for an older commit regarding fingerprinting in the firefox driver b82512999938 from January 2015. That code is still in the Selenium GIT-master downloaded yesterday at javascript/firefox-driver/extension/content/server.js with a comment linking to the slightly differently worded appendix in the current w3c webdriver spec.

Mockito - NullpointerException when stubbing Method

None of the above answers helped me. I was struggling to understand why code works in Java but not in Kotlin.

Then I figured it out from this thread.

You have to make class and member functions open, otherwise NPE was being thrown.

After making function open tests started to pass.

You might as well consider using compiler's "all-open" plugin:

Kotlin has classes and their members final by default, which makes it inconvenient to use frameworks and libraries such as Spring AOP that require classes to be open. The all-open compiler plugin adapts Kotlin to the requirements of those frameworks and makes classes annotated with a specific annotation and their members open without the explicit open keyword.

Unprotect workbook without password

No longer works for spreadsheets Protected with Excel 2013 or later -- they improved the pw hash. So now need to unzip .xlsx and hack the internals.

How do I "shake" an Android device within the Android emulator to bring up the dev menu to debug my React Native app

Within your app in the Android Emulator press Command + M on macOS or Ctrl + M on Linux and Windows.

How to load CSS Asynchronously

I have try to use:

<link rel="preload stylesheet" href="mystyles.css" as="style">

It works fines, but It also raises cumulative layout shift because when we use rel="preload", it just download css , not apply immediate.

Example when the DOM load a list contains ul, li tags, there is an bullets before li tags by default, then CSS applied that I remove these bullets to custom styles for listing. So that, the cumulative layout shift is happening here.

Is there any solution for that?

HTML input time in 24 format

In my case, it is taking time in AM and PM but sending data in 00-24 hours format to the server on form submit. and when use that DB data in its value then it will automatically select the appropriate AM or PM to edit form value.

Best way to verify string is empty or null

You can make use of Optional and Apache commons Stringutils library

Optional.ofNullable(StringUtils.noEmpty(string1)).orElse(string2);

here it will check if the string1 is not null and not empty else it will return string2

ReflectionException: Class ClassName does not exist - Laravel

You may try to write app in use uppercase, so App. Worked for me.

Google maps Marker Label with multiple characters

First of all, Thanks to code author!

I found the below link while googling and it is very simple and works best. Would never fail unless SVG is deprecated.

https://codepen.io/moistpaint/pen/ywFDe/

There is some js loading error in the code here but its perfectly working on the codepen.io link provided.

_x000D_
_x000D_
var mapOptions = {_x000D_
    zoom: 16,_x000D_
    center: new google.maps.LatLng(-37.808846, 144.963435)_x000D_
  };_x000D_
  map = new google.maps.Map(document.getElementById('map-canvas'),_x000D_
      mapOptions);_x000D_
_x000D_
_x000D_
var pinz = [_x000D_
    {_x000D_
        'location':{_x000D_
            'lat' : -37.807817,_x000D_
            'lon' : 144.958377_x000D_
        },_x000D_
        'lable' : 2_x000D_
    },_x000D_
    {_x000D_
        'location':{_x000D_
            'lat' : -37.807885,_x000D_
            'lon' : 144.965415_x000D_
        },_x000D_
        'lable' : 42_x000D_
    },_x000D_
    {_x000D_
        'location':{_x000D_
            'lat' : -37.811377,_x000D_
            'lon' : 144.956596_x000D_
        },_x000D_
        'lable' : 87_x000D_
    },_x000D_
    {_x000D_
        'location':{_x000D_
            'lat' : -37.811293,_x000D_
            'lon' : 144.962883_x000D_
        },_x000D_
        'lable' : 145_x000D_
    },_x000D_
    {_x000D_
        'location':{_x000D_
            'lat' : -37.808089,_x000D_
            'lon' : 144.962089_x000D_
        },_x000D_
        'lable' : 999_x000D_
    },_x000D_
];_x000D_
_x000D_
 _x000D_
_x000D_
for(var i = 0; i <= pinz.length; i++){_x000D_
   var image = 'data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%2238%22%20height%3D%2238%22%20viewBox%3D%220%200%2038%2038%22%3E%3Cpath%20fill%3D%22%23808080%22%20stroke%3D%22%23ccc%22%20stroke-width%3D%22.5%22%20d%3D%22M34.305%2016.234c0%208.83-15.148%2019.158-15.148%2019.158S3.507%2025.065%203.507%2016.1c0-8.505%206.894-14.304%2015.4-14.304%208.504%200%2015.398%205.933%2015.398%2014.438z%22%2F%3E%3Ctext%20transform%3D%22translate%2819%2018.5%29%22%20fill%3D%22%23fff%22%20style%3D%22font-family%3A%20Arial%2C%20sans-serif%3Bfont-weight%3Abold%3Btext-align%3Acenter%3B%22%20font-size%3D%2212%22%20text-anchor%3D%22middle%22%3E' + pinz[i].lable + '%3C%2Ftext%3E%3C%2Fsvg%3E';_x000D_
_x000D_
  _x000D_
   var myLatLng = new google.maps.LatLng(pinz[i].location.lat, pinz[i].location.lon);_x000D_
   var marker = new google.maps.Marker({_x000D_
      position: myLatLng,_x000D_
      map: map,_x000D_
      icon: image_x000D_
  });_x000D_
}
_x000D_
html, body, #map-canvas {_x000D_
  height: 100%;_x000D_
  margin: 0px;_x000D_
  padding: 0px_x000D_
}
_x000D_
<div id="map-canvas"></div>_x000D_
<script async defer src="https://maps.googleapis.com/maps/api/js?key=AIzaSyDtc3qowwB96ObzSu2vvjEoM2pVhZRQNSA&signed_in=true&callback=initMap&libraries=drawing,places"></script>
_x000D_
_x000D_
_x000D_

You just need to uri-encode your SVG html and replace the one in the image variable after "data:image/svg+xml" in the for loop.

For uri encoding you can use uri-encoder-decoder

You can decode the existing svg code first to get a better understanding of what is written.

Failed to load resource: net::ERR_FILE_NOT_FOUND loading json.js

Same thing happened to me. Eventually my solution was to navigate to the repository using terminal (on mac) and create a new js file with a slightly different name. It linked immediately so i copied contents of original file to new one. You also might want to lose the first / after src= and use "".

How to remove error about glyphicons-halflings-regular.woff2 not found

For me, the problem was twofold: First, the version of IIS I was dealing with didn't know about the .woff2 MIME type, only about .woff. I fixed that using IIS Manager at the server level, not at the web app level, so the setting wouldn't get overridden with each new app deployment. (Under IIS Manager, I went to MIME types, and added the missing .woff2, then updated .woff.)

Second, and more importantly, I was bundling bootstrap.css along with some other files as "~/bundles/css/site". Meanwhile, my font files were in "~/fonts". bootstrap.css looks for the glyphicon fonts in "../fonts", which translated to "~/bundles/fonts" -- wrong path.

In other words, my bundle path was one directory too deep. I renamed it to "~/bundles/siteCss", and updated all the references to it that I found in my project. Now bootstrap looked in "~/fonts" for the glyphicon files, which worked. Problem solved.

Before I fixed the second problem above, none of the glyphicon font files were loading. The symptom was that all instances of glyphicon glyphs in the project just showed an empty box. However, this symptom only occurred in the deployed versions of the web app, not on my dev machine. I'm still not sure why that was the case.

getCurrentPosition() and watchPosition() are deprecated on insecure origins

Found a likely answer in /jstillwell's posts here: https://github.com/stefanocudini/leaflet-gps/issues/15 basically this feature will not be supported (in Chrome only?) in the future, but only for HTTP sites. HTTPS will still be ok, and there are no plans to create an equivalent replacement for HTTP use.

Using Postman to access OAuth 2.0 Google APIs

Postman will query Google API impersonating a Web Application

Generate an OAuth 2.0 token:

  1. Ensure that the Google APIs are enabled
  2. Create an OAuth 2.0 client ID

    • Go to Google Console -> API -> OAuth consent screen
      • Add getpostman.com to the Authorized domains. Click Save.
    • Go to Google Console -> API -> Credentials
      • Click 'Create credentials' -> OAuth client ID -> Web application
        • Name: 'getpostman'
        • Authorized redirect URIs: https://www.getpostman.com/oauth2/callback
    • Copy the generated Client ID and Client secret fields for later use
  3. In Postman select Authorization tab and select "OAuth 2.0" type. Click 'Get New Access Token'

    • Fill the GET NEW ACCESS TOKEN form as following
      • Token Name: 'Google OAuth getpostman'
      • Grant Type: 'Authorization Code'
      • Callback URL: https://www.getpostman.com/oauth2/callback
      • Auth URL: https://accounts.google.com/o/oauth2/auth
      • Access Token URL: https://accounts.google.com/o/oauth2/token
      • Client ID: Client ID generated in the step 2 (e.g., '123456789012-abracadabra1234546789blablabla12.apps.googleusercontent.com')
      • Client Secret: Client secret generated in the step 2 (e.g., 'ABRACADABRAus1ZMGHvq9R-L')
      • Scope: see the Google docs for the required OAuth scope (e.g., https://www.googleapis.com/auth/cloud-platform)
      • State: Empty
      • Client Authentication: "Send as Basic Auth header"
    • Click 'Request Token' and 'Use Token'
  4. Set the method, parameters, and body of your request according to the Google docs

fs.writeFile in a promise, asynchronous-synchronous stuff

Update Sept 2017: fs-promise has been deprecated in favour of fs-extra.


I haven't used it, but you could look into fs-promise. It's a node module that:

Proxies all async fs methods exposing them as Promises/A+ compatible promises (when, Q, etc). Passes all sync methods through as values.

What is the "Upgrade-Insecure-Requests" HTTP header?

Short answer: it's closely related to the Content-Security-Policy: upgrade-insecure-requests response header, indicating that the browser supports it (and in fact prefers it).

It took me 30mins of Googling, but I finally found it buried in the W3 spec.

The confusion comes because the header in the spec was HTTPS: 1, and this is how Chromium implemented it, but after this broke lots of websites that were poorly coded (particularly WordPress and WooCommerce) the Chromium team apologized:

"I apologize for the breakage; I apparently underestimated the impact based on the feedback during dev and beta."
— Mike West, in Chrome Issue 501842

Their fix was to rename it to Upgrade-Insecure-Requests: 1, and the spec has since been updated to match.

Anyway, here is the explanation from the W3 spec (as it appeared at the time)...

The HTTPS HTTP request header field sends a signal to the server expressing the client’s preference for an encrypted and authenticated response, and that it can successfully handle the upgrade-insecure-requests directive in order to make that preference as seamless as possible to provide.

...

When a server encounters this preference in an HTTP request’s headers, it SHOULD redirect the user to a potentially secure representation of the resource being requested.

When a server encounters this preference in an HTTPS request’s headers, it SHOULD include a Strict-Transport-Security header in the response if the request’s host is HSTS-safe or conditionally HSTS-safe [RFC6797].

iframe refuses to display

The reason for the error is that the host server for https://cw.na1.hgncloud.com has provided some HTTP headers to protect the document. One of which is that the frame ancestors must be from the same domain as the original content. It seems you are attempting to put the iframe at a domain location that is not the same as the content of the iframe - thus violating the Content Security Policy that the host has set.

Check out this link on Content Security Policy for more details.

Making an asynchronous task in Flask

Threading is another possible solution. Although the Celery based solution is better for applications at scale, if you are not expecting too much traffic on the endpoint in question, threading is a viable alternative.

This solution is based on Miguel Grinberg's PyCon 2016 Flask at Scale presentation, specifically slide 41 in his slide deck. His code is also available on github for those interested in the original source.

From a user perspective the code works as follows:

  1. You make a call to the endpoint that performs the long running task.
  2. This endpoint returns 202 Accepted with a link to check on the task status.
  3. Calls to the status link returns 202 while the taks is still running, and returns 200 (and the result) when the task is complete.

To convert an api call to a background task, simply add the @async_api decorator.

Here is a fully contained example:

from flask import Flask, g, abort, current_app, request, url_for
from werkzeug.exceptions import HTTPException, InternalServerError
from flask_restful import Resource, Api
from datetime import datetime
from functools import wraps
import threading
import time
import uuid

tasks = {}

app = Flask(__name__)
api = Api(app)


@app.before_first_request
def before_first_request():
    """Start a background thread that cleans up old tasks."""
    def clean_old_tasks():
        """
        This function cleans up old tasks from our in-memory data structure.
        """
        global tasks
        while True:
            # Only keep tasks that are running or that finished less than 5
            # minutes ago.
            five_min_ago = datetime.timestamp(datetime.utcnow()) - 5 * 60
            tasks = {task_id: task for task_id, task in tasks.items()
                     if 'completion_timestamp' not in task or task['completion_timestamp'] > five_min_ago}
            time.sleep(60)

    if not current_app.config['TESTING']:
        thread = threading.Thread(target=clean_old_tasks)
        thread.start()


def async_api(wrapped_function):
    @wraps(wrapped_function)
    def new_function(*args, **kwargs):
        def task_call(flask_app, environ):
            # Create a request context similar to that of the original request
            # so that the task can have access to flask.g, flask.request, etc.
            with flask_app.request_context(environ):
                try:
                    tasks[task_id]['return_value'] = wrapped_function(*args, **kwargs)
                except HTTPException as e:
                    tasks[task_id]['return_value'] = current_app.handle_http_exception(e)
                except Exception as e:
                    # The function raised an exception, so we set a 500 error
                    tasks[task_id]['return_value'] = InternalServerError()
                    if current_app.debug:
                        # We want to find out if something happened so reraise
                        raise
                finally:
                    # We record the time of the response, to help in garbage
                    # collecting old tasks
                    tasks[task_id]['completion_timestamp'] = datetime.timestamp(datetime.utcnow())

                    # close the database session (if any)

        # Assign an id to the asynchronous task
        task_id = uuid.uuid4().hex

        # Record the task, and then launch it
        tasks[task_id] = {'task_thread': threading.Thread(
            target=task_call, args=(current_app._get_current_object(),
                               request.environ))}
        tasks[task_id]['task_thread'].start()

        # Return a 202 response, with a link that the client can use to
        # obtain task status
        print(url_for('gettaskstatus', task_id=task_id))
        return 'accepted', 202, {'Location': url_for('gettaskstatus', task_id=task_id)}
    return new_function


class GetTaskStatus(Resource):
    def get(self, task_id):
        """
        Return status about an asynchronous task. If this request returns a 202
        status code, it means that task hasn't finished yet. Else, the response
        from the task is returned.
        """
        task = tasks.get(task_id)
        if task is None:
            abort(404)
        if 'return_value' not in task:
            return '', 202, {'Location': url_for('gettaskstatus', task_id=task_id)}
        return task['return_value']


class CatchAll(Resource):
    @async_api
    def get(self, path=''):
        # perform some intensive processing
        print("starting processing task, path: '%s'" % path)
        time.sleep(10)
        print("completed processing task, path: '%s'" % path)
        return f'The answer is: {path}'


api.add_resource(CatchAll, '/<path:path>', '/')
api.add_resource(GetTaskStatus, '/status/<task_id>')


if __name__ == '__main__':
    app.run(debug=True)

How can I open a website in my web browser using Python?

If you want to open any website first you need to import a module called "webbrowser". Then just use webbrowser.open() to open a website. e.g.

 import webbrowser

 webbrowser.open('https://yashprogrammer.wordpress.com/', new= 2)

Why does the html input with type "number" allow the letter 'e' to be entered in the field?

To hide both letter e and minus sign - just go for:

onkeydown="return event.keyCode !== 69 && event.keyCode !== 189"

How to use cookies in Python Requests

Summary (@Freek Wiekmeijer, @gtalarico) other's answer:

Logic of Login

  • Many resource(pages, api) need authentication, then can access, otherwise 405 Not Allowed
  • Common authentication=grant access method are:
    • cookie
    • auth header
      • Basic xxx
      • Authorization xxx

How use cookie in requests to auth

  1. first get/generate cookie
  2. send cookie for following request
  • manual set cookie in headers
  • auto process cookie by requests's
    • session to auto manage cookies
    • response.cookies to manually set cookies

use requests's session auto manage cookies

curSession = requests.Session() 
# all cookies received will be stored in the session object

payload={'username': "yourName",'password': "yourPassword"}
curSession.post(firstUrl, data=payload)
# internally return your expected cookies, can use for following auth

# internally use previously generated cookies, can access the resources
curSession.get(secondUrl)

curSession.get(thirdUrl)

manually control requests's response.cookies

payload={'username': "yourName",'password': "yourPassword"}
resp1 = requests.post(firstUrl, data=payload)

# manually pass previously returned cookies into following request
resp2 = requests.get(secondUrl, cookies= resp1.cookies)

resp3 = requests.get(thirdUrl, cookies= resp2.cookies)

Java 6 Unsupported major.minor version 51.0

i also faced similar issue. I could able to solve this by setting JAVA_HOME in Environment variable in windows. Setting JAVA_HOME in batch file is not working in this case.

includes() not working in all browsers

One more solution is to use contains which will return true or false

_.contains($(".right-tree").css("background-image"), "stage1")

Hope this helps

How to post object and List using postman

In case of simple example if your api is below

@POST
    @Path("update_accounts")
    @Consumes(MediaType.APPLICATION_JSON)
    @PermissionRequired(Permissions.UPDATE_ACCOUNTS)
    void createLimit(List<AccountUpdateRequest> requestList) throws RuntimeException;

where AccountUpdateRequest :

public class AccountUpdateRequest {
    private Long accountId;
    private AccountType accountType;
    private BigDecimal amount;
...
}

then your postman request would be: http://localhost:port/update_accounts

[
         {
            "accountType": "LEDGER",
            "accountId": 11111,
            "amount": 100
         },
         {
            "accountType": "LEDGER",
            "accountId": 2222,
            "amount": 300
          },
         {
            "accountType": "LEDGER",
            "accountId": 3333,
            "amount": 1000
          }
]

How to convert seconds to HH:mm:ss in moment.js

My solution for changing seconds (number) to string format (for example: 'mm:ss'):

const formattedSeconds = moment().startOf('day').seconds(S).format('mm:ss');

Write your seconds instead 'S' in example. And just use the 'formattedSeconds' where you need.

C++ How do I convert a std::chrono::time_point to long and back

time_point objects only support arithmetic with other time_point or duration objects.

You'll need to convert your long to a duration of specified units, then your code should work correctly.

Refused to load the script because it violates the following Content Security Policy directive

The probable reason why you get this error is likely because you've added the /build folder to your .gitignore file or generally haven't checked it into Git.

So when you Git push Heroku master, the build folder you're referencing don't get pushed to Heroku. And that's why it shows this error.

That's the reason it works properly locally, but not when you deployed to Heroku.

Delay/Wait in a test case of Xcode UI testing

Based on @Ted's answer, I've used this extension:

extension XCTestCase {

    // Based on https://stackoverflow.com/a/33855219
    func waitFor<T>(object: T, timeout: TimeInterval = 5, file: String = #file, line: UInt = #line, expectationPredicate: @escaping (T) -> Bool) {
        let predicate = NSPredicate { obj, _ in
            expectationPredicate(obj as! T)
        }
        expectation(for: predicate, evaluatedWith: object, handler: nil)

        waitForExpectations(timeout: timeout) { error in
            if (error != nil) {
                let message = "Failed to fulful expectation block for \(object) after \(timeout) seconds."
                let location = XCTSourceCodeLocation(filePath: file, lineNumber: line)
                let issue = XCTIssue(type: .assertionFailure, compactDescription: message, detailedDescription: nil, sourceCodeContext: .init(location: location), associatedError: nil, attachments: [])
                self.record(issue)
            }
        }
    }

}

You can use it like this

let element = app.staticTexts["Name of your element"]
waitFor(object: element) { $0.exists }

It also allows for waiting for an element to disappear, or any other property to change (by using the appropriate block)

waitFor(object: element) { !$0.exists } // Wait for it to disappear

Cordova - Error code 1 for command | Command failed for

I have had this problem several times and it can be usually resolved with a clean and rebuild as answered by many before me. But this time this would not fix it.

I use my cordova app to build 2 seperate apps that share majority of the same codebase and it drives off the config.xml. I could not build in end up because i had a space in my id.

com.company AppName

instead of:

com.company.AppName

If anyone is in there config as regular as me. This could be your problem, I also have 3 versions of each app. Live / Demo / Test - These all have different ids.

com.company.AppName.Test

Easy mistake to make, but even easier to overlook. Spent loads of time rebuilding, checking plugins, versioning etc. Where I should have checked my config. First Stop Next Time!

I'm getting favicon.ico error

For me the answer didn't work too, but this work fine:

<link rel="shortcut icon" href="data:image/x-icon;," type="image/x-icon">

Where does Chrome store cookies?

On Windows the path is:

C:\Users\<current_user>\AppData\Local\Google\Chrome\User Data\<Profile 1>\Cookies(Type:File)

Chrome doesn't store each cookies in separate text file. It stores all of the cookies together in a single file in the profile folder. That file is not readable.

Sending cookies with postman

Based @RBT's answer above, I tried Postman native app and want to give a couple of additional details.

In the latest postman desktop app, you can find the cookies option on the extreme right:

enter image description here

You can see the cookies for your localhost (these cookies are linked with the cookies in your chrome browser, although the app is running natively). Also you can set the cookies for a particular domain too.

enter image description here

Code not running in IE 11, works fine in Chrome

I also recently faced the prob. I solved using ^ which is similar to startwith in jquery. Say,

var str = array[a].id;
if (str.startsWith('REP')) {..........}

we can use

if($("[id^=str]").length){..........}

Here, str is id of element.

Swift 2: Call can throw, but it is not marked with 'try' and the error is not handled

You have to catch the error just as you're already doing for your save() call and since you're handling multiple errors here, you can try multiple calls sequentially in a single do-catch block, like so:

func deleteAccountDetail() {
    let entityDescription = NSEntityDescription.entityForName("AccountDetail", inManagedObjectContext: Context!)
    let request = NSFetchRequest()
    request.entity = entityDescription

    do {
        let fetchedEntities = try self.Context!.executeFetchRequest(request) as! [AccountDetail]

        for entity in fetchedEntities {
            self.Context!.deleteObject(entity)
        }

        try self.Context!.save()
    } catch {
        print(error)
    }
}

Or as @bames53 pointed out in the comments below, it is often better practice not to catch the error where it was thrown. You can mark the method as throws then try to call the method. For example:

func deleteAccountDetail() throws {
    let entityDescription = NSEntityDescription.entityForName("AccountDetail", inManagedObjectContext: Context!)
    let request = NSFetchRequest()

    request.entity = entityDescription

    let fetchedEntities = try Context.executeFetchRequest(request) as! [AccountDetail]

    for entity in fetchedEntities {
        self.Context!.deleteObject(entity)
    }

    try self.Context!.save()
}

CFNetwork SSLHandshake failed iOS 9

Another useful tool is nmap (brew install nmap)

nmap --script ssl-enum-ciphers -p 443 google.com

Gives output

Starting Nmap 7.12 ( https://nmap.org ) at 2016-08-11 17:25 IDT
Nmap scan report for google.com (172.217.23.46)
Host is up (0.061s latency).
Other addresses for google.com (not scanned): 2a00:1450:4009:80a::200e
PORT    STATE SERVICE
443/tcp open  https
| ssl-enum-ciphers: 
|   TLSv1.0: 
|     ciphers: 
|       TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA (secp256r1) - A
|       TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA (secp256r1) - A
|       TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (secp256r1) - A
|       TLS_RSA_WITH_AES_128_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_3DES_EDE_CBC_SHA (rsa 2048) - C
|       TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (secp256r1) - A
|       TLS_RSA_WITH_AES_256_CBC_SHA (rsa 2048) - A
|     compressors: 
|       NULL
|     cipher preference: server
|   TLSv1.1: 
|     ciphers: 
|       TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA (secp256r1) - A
|       TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA (secp256r1) - A
|       TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (secp256r1) - A
|       TLS_RSA_WITH_AES_128_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_3DES_EDE_CBC_SHA (rsa 2048) - C
|       TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (secp256r1) - A
|       TLS_RSA_WITH_AES_256_CBC_SHA (rsa 2048) - A
|     compressors: 
|       NULL
|     cipher preference: server
|   TLSv1.2: 
|     ciphers: 
|       TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA (secp256r1) - A
|       TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 (secp256r1) - A
|       TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 (secp256r1) - A
|       TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA (secp256r1) - A
|       TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384 (secp256r1) - A
|       TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 (secp256r1) - A
|       TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256 (secp256r1) - A
|       TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA (secp256r1) - A
|       TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 (secp256r1) - A
|       TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (secp256r1) - A
|       TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA (secp256r1) - A
|       TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 (secp256r1) - A
|       TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (secp256r1) - A
|       TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 (secp256r1) - A
|       TLS_RSA_WITH_3DES_EDE_CBC_SHA (rsa 2048) - C
|       TLS_RSA_WITH_AES_128_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_AES_128_CBC_SHA256 (rsa 2048) - A
|       TLS_RSA_WITH_AES_128_GCM_SHA256 (rsa 2048) - A
|       TLS_RSA_WITH_AES_256_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_AES_256_CBC_SHA256 (rsa 2048) - A
|       TLS_RSA_WITH_AES_256_GCM_SHA384 (rsa 2048) - A
|     compressors: 
|       NULL
|     cipher preference: client
|_  least strength: C

Nmap done: 1 IP address (1 host up) scanned in 5.48 seconds

When should I use Async Controllers in ASP.NET MVC?

Asynchronous action methods are useful when an action must perform several independent long running operations.

A typical use for the AsyncController class is long-running Web service calls.

Should my database calls be asynchronous ?

The IIS thread pool can often handle many more simultaneous blocking requests than a database server. If the database is the bottleneck, asynchronous calls will not speed up the database response. Without a throttling mechanism, efficiently dispatching more work to an overwhelmed database server by using asynchronous calls merely shifts more of the burden to the database. If your DB is the bottleneck, asynchronous calls won’t be the magic bullet.

You should have a look at 1 and 2 references

Derived from @PanagiotisKanavos comments:

Moreover, async doesn't mean parallel. Asynchronous execution frees a valuable threadpool thread from blocking for an external resource, for no complexity or performance cost. This means the same IIS machine can handle more concurrent requests, not that it will run faster.

You should also consider that blocking calls start with a CPU-intensive spinwait. During stress times, blocking calls will result in escalating delays and app pool recycling. Asynchronous calls simply avoid this

google map API zoom range

Available Zoom Levels

Zoom level 0 is the most zoomed out zoom level available and each integer step in zoom level halves the X and Y extents of the view and doubles the linear resolution.

Google Maps was built on a 256x256 pixel tile system where zoom level 0 was a 256x256 pixel image of the whole earth. A 256x256 tile for zoom level 1 enlarges a 128x128 pixel region from zoom level 0.

As correctly stated by bkaid, the available zoom range depends on where you are looking and the kind of map you are using:

  • Road maps - seem to go up to zoom level 22 everywhere
  • Hybrid and satellite maps - the max available zoom levels depend on location. Here are some examples:
  • Remote regions of Antarctica: 13
  • Gobi Desert: 17
  • Much of the U.S. and Europe: 21
  • "Deep zoom" locations: 22-23 (see bkaid's link)

Note that these values are for the Google Static Maps API which seems to give one more zoom level than the Javascript API. It appears that the extra zoom level available for Static Maps is just an upsampled version of the max-resolution image from the Javascript API.

Map Scale at Various Zoom Levels

Google Maps uses a Mercator projection so the scale varies substantially with latitude. A formula for calculating the correct scale based on latitude is:

meters_per_pixel = 156543.03392 * Math.cos(latLng.lat() * Math.PI / 180) / Math.pow(2, zoom)

Formula is from Chris Broadfoot's comment.


Google Maps basics

Zoom Level - zoom

0 - 19

0 lowest zoom (whole world)

19 highest zoom (individual buildings, if available) Retrieve current zoom level using mapObject.getZoom()


What you're looking for are the scales for each zoom level. Use these:

20 : 1128.497220
19 : 2256.994440
18 : 4513.988880
17 : 9027.977761
16 : 18055.955520
15 : 36111.911040
14 : 72223.822090
13 : 144447.644200
12 : 288895.288400
11 : 577790.576700
10 : 1155581.153000
9  : 2311162.307000
8  : 4622324.614000
7  : 9244649.227000
6  : 18489298.450000
5  : 36978596.910000
4  : 73957193.820000
3  : 147914387.600000
2  : 295828775.300000
1  : 591657550.500000

Why do I get java.lang.AbstractMethodError when trying to load a blob in the db?

Just put ojdbc6.jar in class path, so that we can fix CallbaleStatement exception:

oracle.jdbc.driver.T4CPreparedStatement.setBinaryStream(ILjava/io/InputStream;J)V)

in Oracle.

How to find the difference in days between two dates?

This is the simplest i managed to get working on centos 7:

OLDDATE="2018-12-31"
TODAY=$(date -d $(date +%Y-%m-%d) '+%s')
LINUXDATE=$(date -d "$OLDDATE" '+%s')
DIFFDAYS=$(( ($TODAY - $LINUXDATE) / (60*60*24) ))

echo $DIFFDAYS

Where is a log file with logs from a container?

To see the size of logs per container, you can use this bash command :

for cont_id in $(docker ps -aq); do cont_name=$(docker ps | grep $cont_id | awk '{ print $NF }') && cont_size=$(docker inspect --format='{{.LogPath}}' $cont_id | xargs sudo ls -hl | awk '{ print $5 }') && echo "$cont_name ($cont_id): $cont_size"; done

Example output:

container_name (6eed984b29da): 13M
elegant_albattani (acd8f73aa31e): 2.3G

Roblox Admin Command Script

for i=1,#target do
    game.Players.target[i].Character:BreakJoints()
end

Is incorrect, if "target" contains "FakeNameHereSoNoStalkers" then the run code would be:

game.Players.target.1.Character:BreakJoints()

Which is completely incorrect.


c = game.Players:GetChildren()

Never use "Players:GetChildren()", it is not guaranteed to return only players.

Instead use:

c = Game.Players:GetPlayers()

if msg:lower()=="me" then
    table.insert(people, source)
    return people

Here you add the player's name in the list "people", where you in the other places adds the player object.


Fixed code:

local Admins = {"FakeNameHereSoNoStalkers"}

function Kill(Players)
    for i,Player in ipairs(Players) do
        if Player.Character then
            Player.Character:BreakJoints()
        end
    end
end

function IsAdmin(Player)
    for i,AdminName in ipairs(Admins) do
        if Player.Name:lower() == AdminName:lower() then return true end
    end
    return false
end

function GetPlayers(Player,Msg)
    local Targets = {}
    local Players = Game.Players:GetPlayers()

    if Msg:lower() == "me" then
        Targets = { Player }
    elseif Msg:lower() == "all" then
        Targets = Players
    elseif Msg:lower() == "others" then
        for i,Plr in ipairs(Players) do
            if Plr ~= Player then
                table.insert(Targets,Plr)
            end
        end
    else
        for i,Plr in ipairs(Players) do
            if Plr.Name:lower():sub(1,Msg:len()) == Msg then
                table.insert(Targets,Plr)
            end
        end
    end
    return Targets
end

Game.Players.PlayerAdded:connect(function(Player)
    if IsAdmin(Player) then
        Player.Chatted:connect(function(Msg)
            if Msg:lower():sub(1,6) == ":kill " then
                Kill(GetPlayers(Player,Msg:sub(7)))
            end
        end)
    end
end)

Phone Number Validation MVC

The phone number data annotation attribute is for the data type, which is not related to the data display format. It's just a misunderstanding. Phone number means you can accept numbers and symbols used for phone numbers for this locale, but is not checking the format, length, range, or else. For display string format use the javascript to have a more dynamic user interaction, or a plugin for MVC mask, or just use a display format string properly.

If you are new to MVC programming put this code at the very end of your view file (.cshtml) and see the magic:

<script src="https://code.jquery.com/jquery-3.5.1.min.js" integrity="sha256-9/aliU8dGd2tb6OSsuzixeV4y/faTqgFtohetphbbj0=" crossorigin="anonymous"></script>
<script type="text/javascript">
    $(document).ready(function () {
        $("#the_id_of_your_field_control").keyup(function () {
            $(this).val($(this).val().replace(/^(\d{2})(\d{5})(\d{4})+$/, "($1) $2-$3"));
        });
    });
</script>

This format is currently used for mobile phones in Brazil. Adapt for your standard.

This will add the parenthesis and spaces to your field, which will increase the string length of your input data. If you want to save just the numbers you will have to trim out the non-numbers from the string before saving.

The static keyword and its various uses in C++

I'm not a C programmer so I can't give you information on the uses of static in a C program properly, but when it comes to Object Oriented programming static basically declares a variable, or a function or a class to be the same throughout the life of the program. Take for example.

class A
{
public:
    A();
    ~A();
    void somePublicMethod();
private:
    void somePrivateMethod();
};

When you instantiate this class in your Main you do something like this.

int main()
{
   A a1;
   //do something on a1
   A a2;
   //do something on a2
}

These two class instances are completely different from each other and operate independently from one another. But if you were to recreate the class A like this.

class A
{
public:
    A();
    ~A();
    void somePublicMethod();
    static int x;
private:
    void somePrivateMethod();
};

Lets go back to the main again.

int main()
{
   A a1;
   a1.x = 1;
   //do something on a1
   A a2;
   a2.x++;
   //do something on a2
}

Then a1 and a2 would share the same copy of int x whereby any operations on x in a1 would directly influence the operations of x in a2. So if I was to do this

int main()
{
   A a1;
   a1.x = 1;
   //do something on a1
   cout << a1.x << endl; //this would be 1
   A a2;
   a2.x++;
   cout << a2.x << endl; //this would be 2 
   //do something on a2
}

Both instances of the class A share static variables and functions. Hope this answers your question. My limited knowledge of C allows me to say that defining a function or variable as static means it is only visible to the file that the function or variable is defined as static in. But this would be better answered by a C guy and not me. C++ allows both C and C++ ways of declaring your variables as static because its completely backwards compatible with C.

Unable to set variables in bash script

here's your amended script

#!/bin/bash    
folder="ABC" #no spaces between assignment    
useracct='test'    
day=$(date "+%d") # use $() to assign return value of date command to variable    
month=$(date "+%B")     
year=$(date "+%Y")    
folderToBeMoved="/users/$useracct/Documents/Archive/Primetime.eyetv"    
newfoldername="/Volumes/Media/Network/$folder/$month$day$year"    
ECHO "Network is $network" $network    
ECHO "day is $day"    
ECHO "Month is $month"    
ECHO "YEAR is $year"    
ECHO "source is $folderToBeMoved"    
ECHO "dest is $newfoldername"    

mkdir "$newfoldername"    
cp -R "$folderToBeMoved" "$newfoldername"
if [ -f "$newfoldername/Primetime.eyetv" ]; then # <-- put a space at square brackets and quote your variables.
 rm "$folderToBeMoved";
fi

How to convert current date into string in java?

String date = new SimpleDateFormat("dd-MM-yyyy").format(new Date());

How do I open port 22 in OS X 10.6.7

I couldn't solve the problem; Then I did the following and the issue was resolved: Refer here:

sudo launchctl unload -w /System/Library/LaunchDaemons/ssh.plist  
    (Supply your password when it is requested)   
sudo launchctl load -w /System/Library/LaunchDaemons/ssh.plist  
ssh -v localhost  
sudo launchctl list | grep "sshd"  
    46427   -   com.openssh.sshd  

CMD: How do I recursively remove the "Hidden"-Attribute of files and directories

For example folder named new under E: drive

type the command:

e:\cd new

e:\new\attrib *.* -s -h /s /d

and all the files and folders are un-hidden

Angularjs loading screen on ajax request

The best way to do this is to use response interceptors along with custom directive. And the process can further be improved using pub/sub mechanism using $rootScope.$broadcast & $rootScope.$on methods.

As the whole process is documented in a well written blog article, I'm not going to repeat that here again. Please refer to that article to come up with your needed implementation.

Linux Script to check if process is running and act on the result

Programs to monitor if a process on a system is running.

Script is stored in crontab and runs once every minute.

This works with if process is not running or process is running multiple times:

#! /bin/bash

case "$(pidof amadeus.x86 | wc -w)" in

0)  echo "Restarting Amadeus:     $(date)" >> /var/log/amadeus.txt
    /etc/amadeus/amadeus.x86 &
    ;;
1)  # all ok
    ;;
*)  echo "Removed double Amadeus: $(date)" >> /var/log/amadeus.txt
    kill $(pidof amadeus.x86 | awk '{print $1}')
    ;;
esac

0 If process is not found, restart it.
1 If process is found, all ok.
* If process running 2 or more, kill the last.


A simpler version. This just test if process is running, and if not restart it.

It just tests the exit flag $? from the pidof program. It will be 0 of process is running and 1 if not.

#!/bin/bash
pidof  amadeus.x86 >/dev/null
if [[ $? -ne 0 ]] ; then
        echo "Restarting Amadeus:     $(date)" >> /var/log/amadeus.txt
        /etc/amadeus/amadeus.x86 &
fi

And at last, a one liner

pidof amadeus.x86 >/dev/null ; [[ $? -ne 0 ]] && echo "Restarting Amadeus:     $(date)" >> /var/log/amadeus.txt && /etc/amadeus/amadeus.x86 &

cccam oscam

What does the "no version information available" error from linux dynamic linker mean?

The "no version information available" means that the library version number is lower on the shared object. For example, if your major.minor.patch number is 7.15.5 on the machine where you build the binary, and the major.minor.patch number is 7.12.1 on the installation machine, ld will print the warning.

You can fix this by compiling with a library (headers and shared objects) that matches the shared object version shipped with your target OS. E.g., if you are going to install to RedHat 3.4.6-9 you don't want to compile on Debian 4.1.1-21. This is one of the reasons that most distributions ship for specific linux distro numbers.

Otherwise, you can statically link. However, you don't want to do this with something like PAM, so you want to actually install a development environment that matches your client's production environment (or at least install and link against the correct library versions.)

Advice you get to rename the .so files (padding them with version numbers,) stems from a time when shared object libraries did not use versioned symbols. So don't expect that playing with the .so.n.n.n naming scheme is going to help (much - it might help if you system has been trashed.)

You last option will be compiling with a library with a different minor version number, using a custom linking script: http://www.redhat.com/docs/manuals/enterprise/RHEL-4-Manual/gnu-linker/scripts.html

To do this, you'll need to write a custom script, and you'll need a custom installer that runs ld against your client's shared objects, using the custom script. This requires that your client have gcc or ld on their production system.

Differences between Octave and MATLAB?

I just started using Octave. And I have seen people use Matlab. And one major difference as mentioned above is that Octave has a command line interface and Matlab has a GUI. According to me having a GUI is very good for debugging. In Ocatve you have to execute commands to see what is the length of a matrix is etc, but in Matlab it nicely shows everything using a good interface. But Octave is free and good for the basic tasks that I do. If you are sure that you are going to do just basic stuff or you are unsure what you need right now, then go for Octave. You can pay for the Matlab when you really feel the need.

Allow 2 decimal places in <input type="number">

You can use this. react hooks

_x000D_
_x000D_
<input
                  type="number"
                  name="price"
                  placeholder="Enter price"
                  step="any"
                  required
                />
_x000D_
_x000D_
_x000D_

Using ping in c#

private async void Ping_Click(object sender, RoutedEventArgs e)
{
    Ping pingSender = new Ping();
    string host = @"stackoverflow.com";
    await Task.Run(() =>{
         PingReply reply = pingSender.Send(host);
         if (reply.Status == IPStatus.Success)
         {
            Console.WriteLine("Address: {0}", reply.Address.ToString());
            Console.WriteLine("RoundTrip time: {0}", reply.RoundtripTime);
            Console.WriteLine("Time to live: {0}", reply.Options.Ttl);
            Console.WriteLine("Don't fragment: {0}", reply.Options.DontFragment);
            Console.WriteLine("Buffer size: {0}", reply.Buffer.Length);
         }
         else
         {
            Console.WriteLine("Address: {0}", reply.Status);
         }
   });           
}

Convert a matrix to a 1 dimensional array

If we're talking about data.frame, then you should ask yourself are the variables of the same type? If that's the case, you can use rapply, or unlist, since data.frames are lists, deep down in their souls...

 data(mtcars)
 unlist(mtcars)
 rapply(mtcars, c) # completely stupid and pointless, and slower

PHP form send email to multiple recipients

If you need to add emails as CC or BCC, add the following part in the variable you use as for your header :

$headers .= "CC: [email protected]".PHP_EOL;
$headers .= "BCC: [email protected]".PHP_EOL;

Regards

Set database timeout in Entity Framework

You can use this simple :
dbContext.Database.SetCommandTimeout(300);

VBA Check if variable is empty

For a number, it is tricky because if a numeric cell is empty VBA will assign a default value of 0 to it, so it is hard for your VBA code to tell the difference between an entered zero and a blank numeric cell.

The following check worked for me to see if there was an actual 0 entered into the cell:

If CStr(rng.value) = "0" then
    'your code here'
End If

Can we rely on String.isEmpty for checking null condition on a String in Java?

No, absolutely not - because if acct is null, it won't even get to isEmpty... it will immediately throw a NullPointerException.

Your test should be:

if (acct != null && !acct.isEmpty())

Note the use of && here, rather than your || in the previous code; also note how in your previous code, your conditions were wrong anyway - even with && you would only have entered the if body if acct was an empty string.

Alternatively, using Guava:

if (!Strings.isNullOrEmpty(acct))

How to detect page zoom level in all modern browsers?

Your calculations are still based on a number of CSS pixels. They're just a different size on the screen now. That's the point of full page zoom.

What would you want to happen on a browser on a 192dpi device which therefore normally displayed four device pixels for each pixel in an image? At 50% zoom this device now displays one image pixel in one device pixel.

Catch multiple exceptions in one line (except block)

If you frequently use a large number of exceptions, you can pre-define a tuple, so you don't have to re-type them many times.

#This example code is a technique I use in a library that connects with websites to gather data

ConnectErrs  = (URLError, SSLError, SocketTimeoutError, BadStatusLine, ConnectionResetError)

def connect(url, data):
    #do connection and return some data
    return(received_data)

def some_function(var_a, var_b, ...):
    try: o = connect(url, data)
    except ConnectErrs as e:
        #do the recovery stuff
    blah #do normal stuff you would do if no exception occurred

NOTES:

  1. If you, also, need to catch other exceptions than those in the pre-defined tuple, you will need to define another except block.

  2. If you just cannot tolerate a global variable, define it in main() and pass it around where needed...

How (and why) to use display: table-cell (CSS)

How (and why) to use display: table-cell (CSS)

I just wanted to mention, since I don't think any of the other answers did directly, that the answer to "why" is: there is no good reason, and you should probably never do this.

In my over a decade of experience in web development, I can't think of a single time I would have been better served to have a bunch of <div>s with display styles than to just have table elements.

The only hypothetical I could come up with is if you have tabular data stored in some sort of non-HTML-table format (eg. a CSV file). In a very specific version of this case it might be easier to just add <div> tags around everything and then add descendent-based styles, instead of adding actual table tags.

But that's an extremely contrived example, and in all real cases I know of simply using table tags would be better.

Get current language in CultureInfo

I think something like this would give you the current CultureInfo:

CultureInfo currentCulture = Thread.CurrentThread.CurrentCulture;

Is that what you're looking for?

How to convert integer to char in C?

 void main ()
 {
    int temp,integer,count=0,i,cnd=0;
    char ascii[10]={0};
    printf("enter a number");
    scanf("%d",&integer);


     if(integer>>31)
     {
     /*CONVERTING 2's complement value to normal value*/    
     integer=~integer+1;    
     for(temp=integer;temp!=0;temp/=10,count++);    
     ascii[0]=0x2D;
     count++;
     cnd=1;
     }
     else
     for(temp=integer;temp!=0;temp/=10,count++);    
     for(i=count-1,temp=integer;i>=cnd;i--)
     {

        ascii[i]=(temp%10)+0x30;
        temp/=10;
     }
    printf("\n count =%d ascii=%s ",count,ascii);

 }

Keep background image fixed during scroll using css

Just add background-attachment to your code

body {
    background-position: center;
    background-image: url(../images/images5.jpg);
    background-attachment: fixed;
}

What is the HTML tabindex attribute?

The HTML tabindex atribute is responsible for indicating if an element is reachable by keyboard navigation. When the user presses the Tab key the focus is shifted from one element to another. By using the tabindex atribute, the tab order flow is shifted.

document.getElementById("remember").visibility = "hidden"; not working on a checkbox

you can use

style="display:none"

Ex:

<asp:TextBox ID="txbProv" runat="server" style="display:none"></asp:TextBox>

How to mount host volumes into docker containers in Dockerfile during build

It's ugly, but I achieved a semblance of this like so:

Dockerfile:

FROM foo
COPY ./m2/ /root/.m2
RUN stuff

imageBuild.sh:

docker build . -t barImage
container="$(docker run -d barImage)"
rm -rf ./m2
docker cp "$container:/root/.m2" ./m2
docker rm -f "$container"

I have a java build that downloads the universe into /root/.m2, and did so every single time. imageBuild.sh copies the contents of that folder onto the host after the build, and Dockerfile copies them back into the image for the next build.

This is something like how a volume would work (i.e. it persists between builds).

Laravel - Model Class not found

If after changing the namespace and the config/auth.php it still fails, you could try the following:

  1. In the file vendor/composer/autoload_classmap.php change the line App\\User' => $baseDir . '/app/User.php',, to App\\Models\\User' => $baseDir . '/app/Models/User.php',

  2. At the beginning of the file app/Services/Registrar.php change "use App\User" to "App\Models\User"

What is the best way to seed a database in Rails?

Usually there are 2 types of seed data required.

  • Basic data upon which the core of your application may rely. I call this the common seeds.
  • Environmental data, for example to develop the app it is useful to have a bunch of data in a known state that us can use for working on the app locally (the Factory Girl answer above covers this kind of data).

In my experience I was always coming across the need for these two types of data. So I put together a small gem that extends Rails' seeds and lets you add multiple common seed files under db/seeds/ and any environmental seed data under db/seeds/ENV for example db/seeds/development.

I have found this approach is enough to give my seed data some structure and gives me the power to setup my development or staging environment in a known state just by running:

rake db:setup

Fixtures are fragile and flakey to maintain, as are regular sql dumps.

I want to remove double quotes from a String

If you want to remove all double quotes in string, use

var str = '"some "quoted" string"';
console.log( str.replace(/"/g, '') );
// some quoted string

Otherwise you want to remove only quotes around the string, use:

var str = '"some "quoted" string"';
console.log( clean = str.replace(/^"|"$/g, '') );
// some "quoted" string

How to fire an event on class change using jQuery?

Use trigger to fire your own event. When ever you change class add trigger with name

JS Fiddle DEMO

$("#main").on('click', function () {
    $("#chld").addClass("bgcolorRed").trigger("cssFontSet");
});

$('#chld').on('cssFontSet', function () {

    alert("Red bg set ");
});

Learn jQuery: Simple and easy jQuery tutorials blog

Java GC (Allocation Failure)

When use CMS GC in jdk1.8 will appeare this error, i change the G1 Gc solve this problem.

 -Xss512k -Xms6g -Xmx6g -XX:+UseG1GC -XX:MaxGCPauseMillis=200 -XX:InitiatingHeapOccupancyPercent=70 -XX:NewRatio=1 -XX:SurvivorRatio=6 -XX:G1ReservePercent=10 -XX:G1HeapRegionSize=32m -XX:ConcGCThreads=6 -Xloggc:gc.log -XX:+HeapDumpOnOutOfMemoryError -XX:+PrintGC -XX:+PrintGCDetails -XX:+PrintGCTimeStamps 

Extract a substring from a string in Ruby using a regular expression

A simpler scan would be:

String1.scan(/<(\S+)>/).last

How to show Bootstrap table with sort icon

You could try using FontAwesome. It contains a sort-icon (http://fontawesome.io/icon/sort/).

To do so, you would

  1. need to include fontawesome:

    <link href="//maxcdn.bootstrapcdn.com/font-awesome/4.1.0/css/font-awesome.min.css" rel="stylesheet">
    
  2. and then simply use the fontawesome-icon instead of the default-bootstrap-icons in your th's:

    <th><b>#</b> <i class="fa fa-fw fa-sort"></i></th>
    

Hope that helps.

mysql select from n last rows

Take advantage of SORT and LIMIT as you would with pagination. If you want the ith block of rows, use OFFSET.

SELECT val FROM big_table
where val = someval
ORDER BY id DESC
LIMIT n;

In response to Nir: The sort operation is not necessarily penalized, this depends on what the query planner does. Since this use case is crucial for pagination performance, there are some optimizations (see link above). This is true in postgres as well "ORDER BY ... LIMIT can be done without sorting " E.7.1. Last bullet

explain extended select id from items where val = 48 order by id desc limit 10;
+----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+
| id | select_type | table | type  | possible_keys | key     | key_len | ref   | rows | Extra       |
+----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+
|  1 | SIMPLE      | items | const | PRIMARY       | PRIMARY | 4       | const |    1 | Using index | 
+----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+

How can I call a shell command in my Perl script?

You might want to look into open2 and open3 in case you need bidirectional communication.

How to download a file via FTP with Python ftplib

Please note if you are downloading from the FTP to your local, you will need to use the following:

with open( filename, 'wb' ) as file :
        ftp.retrbinary('RETR %s' % filename, file.write)

Otherwise, the script will at your local file storage rather than the FTP.

I spent a few hours making the mistake myself.

Script below:

import ftplib

# Open the FTP connection
ftp = ftplib.FTP()
ftp.cwd('/where/files-are/located')


filenames = ftp.nlst()

for filename in filenames:

    with open( filename, 'wb' ) as file :
        ftp.retrbinary('RETR %s' % filename, file.write)

        file.close()

ftp.quit()

JavaScript/regex: Remove text between parentheses

I found this version most suitable for all cases. It doesn't remove all whitespaces.

For example "a (test) b" -> "a b"

"Hello, this is Mike (example)".replace(/ *\([^)]*\) */g, " ").trim(); "Hello, this is (example) Mike ".replace(/ *\([^)]*\) */g, " ").trim();

Is there an upside down caret character?

I'd use a couple of tiny images. Would look better too.

Alternatively, you can try the Character Map utility that comes with Windows or try looking here.

Another solution I've seen is to use the Wingdings font for symbols. That has a lot fo arrows.

Java JDBC - How to connect to Oracle using Service Name instead of SID

Try this: jdbc:oracle:thin:@oracle.hostserver2.mydomain.ca:1522/ABCD

Edit: per comment below this is actualy correct: jdbc:oracle:thin:@//oracle.hostserver2.mydomain.ca:1522/ABCD (note the //)

Here is a link to a helpful article

echo key and value of an array without and with loop

If you must not use a loop (why?), you could use array_walk,

function printer($v, $k) {
   echo "$k is at $v\n";
}

array_walk($page, "printer");

See http://www.ideone.com/aV5X6.

Reading CSV file and storing values into an array

I am just student working on my master's thesis, but this is the way I solved it and it worked well for me. First you select your file from directory (only in csv format) and then you put the data into the lists.

List<float> t = new List<float>();
List<float> SensorI = new List<float>();
List<float> SensorII = new List<float>();
List<float> SensorIII = new List<float>();
using (OpenFileDialog dialog = new OpenFileDialog())
{
    try
    {
        dialog.Filter = "csv files (*.csv)|*.csv";
        dialog.Multiselect = false;
        dialog.InitialDirectory = ".";
        dialog.Title = "Select file (only in csv format)";
        if (dialog.ShowDialog() == DialogResult.OK)
        {
            var fs = File.ReadAllLines(dialog.FileName).Select(a => a.Split(';'));
            int counter = 0;
            foreach (var line in fs)
            {
                counter++;
                if (counter > 2)    // Skip first two headder lines
                {
                    this.t.Add(float.Parse(line[0]));
                    this.SensorI.Add(float.Parse(line[1]));
                    this.SensorII.Add(float.Parse(line[2]));
                    this.SensorIII.Add(float.Parse(line[3]));
                }
            }
        }
    }
    catch (Exception exc)
    {
        MessageBox.Show(
            "Error while opening the file.\n" + exc.Message, 
            this.Text, 
            MessageBoxButtons.OK, 
            MessageBoxIcon.Error
        );
    }
}

How to hash a password

I think using KeyDerivation.Pbkdf2 is better than Rfc2898DeriveBytes.

Example and explanation: Hash passwords in ASP.NET Core

using System;
using System.Security.Cryptography;
using Microsoft.AspNetCore.Cryptography.KeyDerivation;
 
public class Program
{
    public static void Main(string[] args)
    {
        Console.Write("Enter a password: ");
        string password = Console.ReadLine();
 
        // generate a 128-bit salt using a secure PRNG
        byte[] salt = new byte[128 / 8];
        using (var rng = RandomNumberGenerator.Create())
        {
            rng.GetBytes(salt);
        }
        Console.WriteLine($"Salt: {Convert.ToBase64String(salt)}");
 
        // derive a 256-bit subkey (use HMACSHA1 with 10,000 iterations)
        string hashed = Convert.ToBase64String(KeyDerivation.Pbkdf2(
            password: password,
            salt: salt,
            prf: KeyDerivationPrf.HMACSHA1,
            iterationCount: 10000,
            numBytesRequested: 256 / 8));
        Console.WriteLine($"Hashed: {hashed}");
    }
}
 
/*
 * SAMPLE OUTPUT
 *
 * Enter a password: Xtw9NMgx
 * Salt: NZsP6NnmfBuYeJrrAKNuVQ==
 * Hashed: /OOoOer10+tGwTRDTrQSoeCxVTFr6dtYly7d0cPxIak=
 */

This is a sample code from the article. And it's a minimum security level. To increase it I would use instead of KeyDerivationPrf.HMACSHA1 parameter

KeyDerivationPrf.HMACSHA256 or KeyDerivationPrf.HMACSHA512.

Don't compromise on password hashing. There are many mathematically sound methods to optimize password hash hacking. Consequences could be disastrous. Once a malefactor can get his hands on password hash table of your users it would be relatively easy for him to crack passwords given algorithm is weak or implementation is incorrect. He has a lot of time (time x computer power) to crack passwords. Password hashing should be cryptographically strong to turn "a lot of time" to "unreasonable amount of time".

One more point to add

Hash verification takes time (and it's good). When user enters wrong user name it's takes no time to check that user name is incorrect. When user name is correct we start password verification - it's relatively long process.

For a hacker it would be very easy to understand if user exists or doesn't.

Make sure not to return immediate answer when user name is wrong.

Needless to say : never give an answer what is wrong. Just general "Credentials are wrong".

Inner join vs Where

i had this conundrum today when inspecting one of our sp's timing out in production, changed an inner join on a table built from an xml feed to a 'where' clause instead....average exec time is now 80ms over 1000 executions, whereas before average exec was 2.2 seconds...major difference in the execution plan is the dissapearance of a key lookup... The message being you wont know until youve tested using both methods.

cheers.

How to extract numbers from a string and get an array of ints?

  StringBuffer sBuffer = new StringBuffer();
  Pattern p = Pattern.compile("[0-9]+.[0-9]*|[0-9]*.[0-9]+|[0-9]+");
  Matcher m = p.matcher(str);
  while (m.find()) {
    sBuffer.append(m.group());
  }
  return sBuffer.toString();

This is for extracting numbers retaining the decimal

Find and replace string values in list

words = [w.replace('[br]', '<br />') for w in words]

These are called List Comprehensions.

what is this value means 1.845E-07 in excel?

Highlight the cells, format cells, select Custom then select zero.

Tomcat is web server or application server?

It runs Java compiled code, it can maintain database connection pools, it can log errors of various types. I'd call it an application server, in fact I do. In our environment we have Apache as the webserver fronting a number of different application servers, including Tomcat and Coldfusion, and others.

How do I make WRAP_CONTENT work on a RecyclerView

Here is the c# version for mono android

/* 
* Ported by Jagadeesh Govindaraj (@jaganjan)
 *Copyright 2015 serso aka se.solovyev
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * Contact details
 *
 * Email: se.solovyev @gmail.com
 * Site:  http://se.solovyev.org
 */


using Android.Content;
using Android.Graphics;
using Android.Support.V4.View;
using Android.Support.V7.Widget;
using Android.Util;
using Android.Views;
using Java.Lang;
using Java.Lang.Reflect;
using System;
using Math = Java.Lang.Math;

namespace Droid.Helper
{
    public class WrapLayoutManager : LinearLayoutManager
    {
        private const int DefaultChildSize = 100;
        private static readonly Rect TmpRect = new Rect();
        private int _childSize = DefaultChildSize;
        private static bool _canMakeInsetsDirty = true;
        private static readonly int[] ChildDimensions = new int[2];
        private const int ChildHeight = 1;
        private const int ChildWidth = 0;
        private static bool _hasChildSize;
        private static  Field InsetsDirtyField = null;
        private static int _overScrollMode = ViewCompat.OverScrollAlways;
        private static RecyclerView _view;

        public WrapLayoutManager(Context context, int orientation, bool reverseLayout)
            : base(context, orientation, reverseLayout)
        {
            _view = null;
        }

        public WrapLayoutManager(Context context) : base(context)
        {
            _view = null;
        }

        public WrapLayoutManager(RecyclerView view) : base(view.Context)
        {
            _view = view;
            _overScrollMode = ViewCompat.GetOverScrollMode(view);
        }

        public WrapLayoutManager(RecyclerView view, int orientation, bool reverseLayout)
            : base(view.Context, orientation, reverseLayout)
        {
            _view = view;
            _overScrollMode = ViewCompat.GetOverScrollMode(view);
        }

        public void SetOverScrollMode(int overScrollMode)
        {
            if (overScrollMode < ViewCompat.OverScrollAlways || overScrollMode > ViewCompat.OverScrollNever)
                throw new ArgumentException("Unknown overscroll mode: " + overScrollMode);
            if (_view == null) throw new ArgumentNullException(nameof(_view));
            _overScrollMode = overScrollMode;
            ViewCompat.SetOverScrollMode(_view, overScrollMode);
        }

        public static int MakeUnspecifiedSpec()
        {
            return View.MeasureSpec.MakeMeasureSpec(0, MeasureSpecMode.Unspecified);
        }

        public override void OnMeasure(RecyclerView.Recycler recycler, RecyclerView.State state, int widthSpec,
            int heightSpec)
        {
            var widthMode = View.MeasureSpec.GetMode(widthSpec);
            var heightMode = View.MeasureSpec.GetMode(heightSpec);

            var widthSize = View.MeasureSpec.GetSize(widthSpec);
            var heightSize = View.MeasureSpec.GetSize(heightSpec);

            var hasWidthSize = widthMode != MeasureSpecMode.Unspecified;
            var hasHeightSize = heightMode != MeasureSpecMode.Unspecified;

            var exactWidth = widthMode == MeasureSpecMode.Exactly;
            var exactHeight = heightMode == MeasureSpecMode.Exactly;

            var unspecified = MakeUnspecifiedSpec();

            if (exactWidth && exactHeight)
            {
                // in case of exact calculations for both dimensions let's use default "onMeasure" implementation
                base.OnMeasure(recycler, state, widthSpec, heightSpec);
                return;
            }

            var vertical = Orientation == Vertical;

            InitChildDimensions(widthSize, heightSize, vertical);

            var width = 0;
            var height = 0;

            // it's possible to get scrap views in recycler which are bound to old (invalid) adapter
            // entities. This happens because their invalidation happens after "onMeasure" method.
            // As a workaround let's clear the recycler now (it should not cause any performance
            // issues while scrolling as "onMeasure" is never called whiles scrolling)
            recycler.Clear();

            var stateItemCount = state.ItemCount;
            var adapterItemCount = ItemCount;
            // adapter always contains actual data while state might contain old data (f.e. data
            // before the animation is done). As we want to measure the view with actual data we
            // must use data from the adapter and not from the state
            for (var i = 0; i < adapterItemCount; i++)
            {
                if (vertical)
                {
                    if (!_hasChildSize)
                    {
                        if (i < stateItemCount)
                        {
                            // we should not exceed state count, otherwise we'll get
                            // IndexOutOfBoundsException. For such items we will use previously
                            // calculated dimensions
                            MeasureChild(recycler, i, widthSize, unspecified, ChildDimensions);
                        }
                        else
                        {
                            LogMeasureWarning(i);
                        }
                    }
                    height += ChildDimensions[ChildHeight];
                    if (i == 0)
                    {
                        width = ChildDimensions[ChildWidth];
                    }
                    if (hasHeightSize && height >= heightSize)
                    {
                        break;
                    }
                }
                else
                {
                    if (!_hasChildSize)
                    {
                        if (i < stateItemCount)
                        {
                            // we should not exceed state count, otherwise we'll get
                            // IndexOutOfBoundsException. For such items we will use previously
                            // calculated dimensions
                            MeasureChild(recycler, i, unspecified, heightSize, ChildDimensions);
                        }
                        else
                        {
                            LogMeasureWarning(i);
                        }
                    }
                    width += ChildDimensions[ChildWidth];
                    if (i == 0)
                    {
                        height = ChildDimensions[ChildHeight];
                    }
                    if (hasWidthSize && width >= widthSize)
                    {
                        break;
                    }
                }
            }

            if (exactWidth)
            {
                width = widthSize;
            }
            else
            {
                width += PaddingLeft + PaddingRight;
                if (hasWidthSize)
                {
                    width = Math.Min(width, widthSize);
                }
            }

            if (exactHeight)
            {
                height = heightSize;
            }
            else
            {
                height += PaddingTop + PaddingBottom;
                if (hasHeightSize)
                {
                    height = Math.Min(height, heightSize);
                }
            }

            SetMeasuredDimension(width, height);

            if (_view == null || _overScrollMode != ViewCompat.OverScrollIfContentScrolls) return;
            var fit = (vertical && (!hasHeightSize || height < heightSize))
                      || (!vertical && (!hasWidthSize || width < widthSize));

            ViewCompat.SetOverScrollMode(_view, fit ? ViewCompat.OverScrollNever : ViewCompat.OverScrollAlways);
        }

        private void LogMeasureWarning(int child)
        {
#if DEBUG
            Log.WriteLine(LogPriority.Warn, "LinearLayoutManager",
                "Can't measure child #" + child + ", previously used dimensions will be reused." +
                "To remove this message either use #SetChildSize() method or don't run RecyclerView animations");
#endif
        }

        private void InitChildDimensions(int width, int height, bool vertical)
        {
            if (ChildDimensions[ChildWidth] != 0 || ChildDimensions[ChildHeight] != 0)
            {
                // already initialized, skipping
                return;
            }
            if (vertical)
            {
                ChildDimensions[ChildWidth] = width;
                ChildDimensions[ChildHeight] = _childSize;
            }
            else
            {
                ChildDimensions[ChildWidth] = _childSize;
                ChildDimensions[ChildHeight] = height;
            }
        }

        public void ClearChildSize()
        {
            _hasChildSize = false;
            SetChildSize(DefaultChildSize);
        }

        public void SetChildSize(int size)
        {
            _hasChildSize = true;
            if (_childSize == size) return;
            _childSize = size;
            RequestLayout();
        }

        private void MeasureChild(RecyclerView.Recycler recycler, int position, int widthSize, int heightSize,
            int[] dimensions)
        {
            View child = null;
            try
            {
                child = recycler.GetViewForPosition(position);
            }
            catch (IndexOutOfRangeException e)
            {
                Log.WriteLine(LogPriority.Warn, "LinearLayoutManager",
                    "LinearLayoutManager doesn't work well with animations. Consider switching them off", e);
            }

            if (child != null)
            {
                var p = child.LayoutParameters.JavaCast<RecyclerView.LayoutParams>()

                var hPadding = PaddingLeft + PaddingRight;
                var vPadding = PaddingTop + PaddingBottom;

                var hMargin = p.LeftMargin + p.RightMargin;
                var vMargin = p.TopMargin + p.BottomMargin;

                // we must make insets dirty in order calculateItemDecorationsForChild to work
                MakeInsetsDirty(p);
                // this method should be called before any getXxxDecorationXxx() methods
                CalculateItemDecorationsForChild(child, TmpRect);

                var hDecoration = GetRightDecorationWidth(child) + GetLeftDecorationWidth(child);
                var vDecoration = GetTopDecorationHeight(child) + GetBottomDecorationHeight(child);

                var childWidthSpec = GetChildMeasureSpec(widthSize, hPadding + hMargin + hDecoration, p.Width,
                    CanScrollHorizontally());
                var childHeightSpec = GetChildMeasureSpec(heightSize, vPadding + vMargin + vDecoration, p.Height,
                    CanScrollVertically());

                child.Measure(childWidthSpec, childHeightSpec);

                dimensions[ChildWidth] = GetDecoratedMeasuredWidth(child) + p.LeftMargin + p.RightMargin;
                dimensions[ChildHeight] = GetDecoratedMeasuredHeight(child) + p.BottomMargin + p.TopMargin;

                // as view is recycled let's not keep old measured values
                MakeInsetsDirty(p);
            }
            recycler.RecycleView(child);
        }

        private static void MakeInsetsDirty(RecyclerView.LayoutParams p)
        {
            if (!_canMakeInsetsDirty)
            {
                return;
            }
            try
            {
                if (InsetsDirtyField == null)
                {
                   var klass = Java.Lang.Class.FromType (typeof (RecyclerView.LayoutParams));
                    InsetsDirtyField = klass.GetDeclaredField("mInsetsDirty");
                    InsetsDirtyField.Accessible = true;
                }
                InsetsDirtyField.Set(p, true);
            }
            catch (NoSuchFieldException e)
            {
                OnMakeInsertDirtyFailed();
            }
            catch (IllegalAccessException e)
            {
                OnMakeInsertDirtyFailed();
            }
        }

        private static void OnMakeInsertDirtyFailed()
        {
            _canMakeInsetsDirty = false;
#if DEBUG
            Log.Warn("LinearLayoutManager",
                "Can't make LayoutParams insets dirty, decorations measurements might be incorrect");
#endif
        }
    }
}

Table header to stay fixed at the top when user scrolls it out of view with jQuery

I have tried it using transformation:translate. While it works good in Firefox and Chrome, there is simply no function in IE11. No double scroll bars. Supports table tfoot and caption. Pure Javascript, no jQuery.

http://jsfiddle.net/wbLqzrfb/42/

thead.style.transform="translate(0,"+(dY-top-1)+"px)";

How to add an element to the beginning of an OrderedDict?

If you need functionality that isn't there, just extend the class with whatever you want:

from collections import OrderedDict

class OrderedDictWithPrepend(OrderedDict):
    def prepend(self, other):
        ins = []
        if hasattr(other, 'viewitems'):
            other = other.viewitems()
        for key, val in other:
            if key in self:
                self[key] = val
            else:
                ins.append((key, val))
        if ins:
            items = self.items()
            self.clear()
            self.update(ins)
            self.update(items)

Not terribly efficient, but works:

o = OrderedDictWithPrepend()

o['a'] = 1
o['b'] = 2
print o
# OrderedDictWithPrepend([('a', 1), ('b', 2)])

o.prepend({'c': 3})
print o
# OrderedDictWithPrepend([('c', 3), ('a', 1), ('b', 2)])

o.prepend([('a',11),('d',55),('e',66)])
print o
# OrderedDictWithPrepend([('d', 55), ('e', 66), ('c', 3), ('a', 11), ('b', 2)])

Creating a zero-filled pandas data frame

Assuming having a template DataFrame, which one would like to copy with zero values filled here...

If you have no NaNs in your data set, multiplying by zero can be significantly faster:

In [19]: columns = ["col{}".format(i) for i in xrange(3000)]                                                                                       

In [20]: indices = xrange(2000)

In [21]: orig_df = pd.DataFrame(42.0, index=indices, columns=columns)

In [22]: %timeit d = pd.DataFrame(np.zeros_like(orig_df), index=orig_df.index, columns=orig_df.columns)
100 loops, best of 3: 12.6 ms per loop

In [23]: %timeit d = orig_df * 0.0
100 loops, best of 3: 7.17 ms per loop

Improvement depends on DataFrame size, but never found it slower.

And just for the heck of it:

In [24]: %timeit d = orig_df * 0.0 + 1.0
100 loops, best of 3: 13.6 ms per loop

In [25]: %timeit d = pd.eval('orig_df * 0.0 + 1.0')
100 loops, best of 3: 8.36 ms per loop

But:

In [24]: %timeit d = orig_df.copy()
10 loops, best of 3: 24 ms per loop

EDIT!!!

Assuming you have a frame using float64, this will be the fastest by a huge margin! It is also able to generate any value by replacing 0.0 to the desired fill number.

In [23]: %timeit d = pd.eval('orig_df > 1.7976931348623157e+308 + 0.0')
100 loops, best of 3: 3.68 ms per loop

Depending on taste, one can externally define nan, and do a general solution, irrespective of the particular float type:

In [39]: nan = np.nan
In [40]: %timeit d = pd.eval('orig_df > nan + 0.0')
100 loops, best of 3: 4.39 ms per loop

Changing background color of selected item in recyclerview

I made this implementation in kotlin I thing is not very efficient but works ivIsSelected is a ImageView that represent in my case a check mark

var selectedItems = mutableListOf<Int>(-1)

override fun onBindViewHolder(holder: ContactViewHolder, position: Int) {
    // holder.setData(ContactViewModel, position)  // I'm passing this to the ViewHolder
    holder.itemView.setBackgroundColor(Color.WHITE)   
    holder.itemView.ivIsSelected.visibility = INVISIBLE
    selectedItems.forEach {
        if (it == position) {
            holder.itemView.setBackgroundColor(Color.argb(45, 0, 255, 43))
            holder.itemView.ivIsSelected.visibility = VISIBLE
        }
    }

    holder.itemView.setOnClickListener { it ->
        it.setBackgroundColor(Color.BLUE)  
        selectedItems.add(position)
        selectedItems.forEach { selectedItem ->  // this forEach is required to refresh all the list
            notifyItemChanged(selectedItem)
        }

    }
}

Automatically run %matplotlib inline in IPython Notebook

Create any .py file in ~/.ipython/profile_default/startup/ containing

get_ipython().magic('matplotlib inline')

PHP: Get the key from an array in a foreach loop

Use foreach with key and value.

Example:

foreach($samplearr as $key => $val) {
     print "<tr><td>" 
         . $key 
         . "</td><td>" 
         . $val['value1'] 
         . "</td><td>" 
         . $val['value2'] 
         . "</td></tr>";
}

Switch between two frames in tkinter

Note: According to JDN96, the answer below may cause a memory leak by repeatedly destroying and recreating frames. However, I have not tested to verify this myself.

One way to switch frames in tkinter is to destroy the old frame then replace it with your new frame.

I have modified Bryan Oakley's answer to destroy the old frame before replacing it. As an added bonus, this eliminates the need for a container object and allows you to use any generic Frame class.

# Multi-frame tkinter application v2.3
import tkinter as tk

class SampleApp(tk.Tk):
    def __init__(self):
        tk.Tk.__init__(self)
        self._frame = None
        self.switch_frame(StartPage)

    def switch_frame(self, frame_class):
        """Destroys current frame and replaces it with a new one."""
        new_frame = frame_class(self)
        if self._frame is not None:
            self._frame.destroy()
        self._frame = new_frame
        self._frame.pack()

class StartPage(tk.Frame):
    def __init__(self, master):
        tk.Frame.__init__(self, master)
        tk.Label(self, text="This is the start page").pack(side="top", fill="x", pady=10)
        tk.Button(self, text="Open page one",
                  command=lambda: master.switch_frame(PageOne)).pack()
        tk.Button(self, text="Open page two",
                  command=lambda: master.switch_frame(PageTwo)).pack()

class PageOne(tk.Frame):
    def __init__(self, master):
        tk.Frame.__init__(self, master)
        tk.Label(self, text="This is page one").pack(side="top", fill="x", pady=10)
        tk.Button(self, text="Return to start page",
                  command=lambda: master.switch_frame(StartPage)).pack()

class PageTwo(tk.Frame):
    def __init__(self, master):
        tk.Frame.__init__(self, master)
        tk.Label(self, text="This is page two").pack(side="top", fill="x", pady=10)
        tk.Button(self, text="Return to start page",
                  command=lambda: master.switch_frame(StartPage)).pack()

if __name__ == "__main__":
    app = SampleApp()
    app.mainloop()

Start page Page one Page two

Explanation

switch_frame() works by accepting any Class object that implements Frame. The function then creates a new frame to replace the old one.

  • Deletes old _frame if it exists, then replaces it with the new frame.
  • Other frames added with .pack(), such as menubars, will be unaffected.
  • Can be used with any class that implements tkinter.Frame.
  • Window automatically resizes to fit new content

Version History

v2.3

- Pack buttons and labels as they are initialized

v2.2

- Initialize `_frame` as `None`.
- Check if `_frame` is `None` before calling `.destroy()`.

v2.1.1

- Remove type-hinting for backwards compatibility with Python 3.4.

v2.1

- Add type-hinting for `frame_class`.

v2.0

- Remove extraneous `container` frame.
    - Application now works with any generic `tkinter.frame` instance.
- Remove `controller` argument from frame classes.
    - Frame switching is now done with `master.switch_frame()`.

v1.6

- Check if frame attribute exists before destroying it.
- Use `switch_frame()` to set first frame.

v1.5

  - Revert 'Initialize new `_frame` after old `_frame` is destroyed'.
      - Initializing the frame before calling `.destroy()` results
        in a smoother visual transition.

v1.4

- Pack frames in `switch_frame()`.
- Initialize new `_frame` after old `_frame` is destroyed.
    - Remove `new_frame` variable.

v1.3

- Rename `parent` to `master` for consistency with base `Frame` class.

v1.2

- Remove `main()` function.

v1.1

- Rename `frame` to `_frame`.
    - Naming implies variable should be private.
- Create new frame before destroying old frame.

v1.0

- Initial version.

Overlapping Views in Android

Android handles transparency across views and drawables (including PNG images) natively, so the scenario you describe (a partially transparent ImageView in front of a Gallery) is certainly possible.

If you're having problems it may be related to either the layout or your image. I've replicated the layout you describe and successfully achieved the effect you're after. Here's the exact layout I used.

<RelativeLayout 
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@+id/gallerylayout"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent">
  <Gallery
    android:id="@+id/overview"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"
  />
  <ImageView
    android:id="@+id/navigmaske"
    android:background="#0000"      
    android:src="@drawable/navigmask"
    android:scaleType="fitXY"
    android:layout_alignTop="@id/overview"
    android:layout_alignBottom="@id/overview"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"
  />
</RelativeLayout>

Note that I've changed the parent RelativeLayout to a height and width of fill_parent as is generally what you want for a main Activity. Then I've aligned the top and bottom of the ImageView to the top and bottom of the Gallery to ensure it's centered in front of it.

I've also explicitly set the background of the ImageView to be transparent.

As for the image drawable itself, if you put the PNG file somewhere for me to look at I can use it in my project and see if it's responsible.

Loop in react-native

render() {
var myloop = [];

for (let i = 0; i < 10; i++) {
  myloop.push(
    <View key={i}>
    <Text>{i}</Text>
    </View>
  );
}

 return (

        <View >
          <Text >Welcome to React Native!</Text>
           {myloop}
        </View>


    );
  }
}

Recommended way of making React component/div draggable

I should probably turn this into a blog post, but here's pretty solid example.

The comments should explain things pretty well, but let me know if you have questions.

And here's the fiddle to play with: http://jsfiddle.net/Af9Jt/2/

var Draggable = React.createClass({
  getDefaultProps: function () {
    return {
      // allow the initial position to be passed in as a prop
      initialPos: {x: 0, y: 0}
    }
  },
  getInitialState: function () {
    return {
      pos: this.props.initialPos,
      dragging: false,
      rel: null // position relative to the cursor
    }
  },
  // we could get away with not having this (and just having the listeners on
  // our div), but then the experience would be possibly be janky. If there's
  // anything w/ a higher z-index that gets in the way, then you're toast,
  // etc.
  componentDidUpdate: function (props, state) {
    if (this.state.dragging && !state.dragging) {
      document.addEventListener('mousemove', this.onMouseMove)
      document.addEventListener('mouseup', this.onMouseUp)
    } else if (!this.state.dragging && state.dragging) {
      document.removeEventListener('mousemove', this.onMouseMove)
      document.removeEventListener('mouseup', this.onMouseUp)
    }
  },

  // calculate relative position to the mouse and set dragging=true
  onMouseDown: function (e) {
    // only left mouse button
    if (e.button !== 0) return
    var pos = $(this.getDOMNode()).offset()
    this.setState({
      dragging: true,
      rel: {
        x: e.pageX - pos.left,
        y: e.pageY - pos.top
      }
    })
    e.stopPropagation()
    e.preventDefault()
  },
  onMouseUp: function (e) {
    this.setState({dragging: false})
    e.stopPropagation()
    e.preventDefault()
  },
  onMouseMove: function (e) {
    if (!this.state.dragging) return
    this.setState({
      pos: {
        x: e.pageX - this.state.rel.x,
        y: e.pageY - this.state.rel.y
      }
    })
    e.stopPropagation()
    e.preventDefault()
  },
  render: function () {
    // transferPropsTo will merge style & other props passed into our
    // component to also be on the child DIV.
    return this.transferPropsTo(React.DOM.div({
      onMouseDown: this.onMouseDown,
      style: {
        left: this.state.pos.x + 'px',
        top: this.state.pos.y + 'px'
      }
    }, this.props.children))
  }
})

Thoughts on state ownership, etc.

"Who should own what state" is an important question to answer, right from the start. In the case of a "draggable" component, I could see a few different scenarios.

Scenario 1

the parent should own the current position of the draggable. In this case, the draggable would still own the "am I dragging" state, but would call this.props.onChange(x, y) whenever a mousemove event occurs.

Scenario 2

the parent only needs to own the "non-moving position", and so the draggable would own it's "dragging position" but onmouseup it would call this.props.onChange(x, y) and defer the final decision to the parent. If the parent doesn't like where the draggable ended up, it would just not update it's state, and the draggable would "snap back" to it's initial position before dragging.

Mixin or component?

@ssorallen pointed out that, because "draggable" is more an attribute than a thing in itself, it might serve better as a mixin. My experience with mixins is limited, so I haven't seen how they might help or get in the way in complicated situations. This might well be the best option.

Sorting a set of values

From a comment:

I want to sort each set.

That's easy. For any set s (or anything else iterable), sorted(s) returns a list of the elements of s in sorted order:

>>> s = set(['0.000000000', '0.009518000', '10.277200999', '0.030810999', '0.018384000', '4.918560000'])
>>> sorted(s)
['0.000000000', '0.009518000', '0.018384000', '0.030810999', '10.277200999', '4.918560000']

Note that sorted is giving you a list, not a set. That's because the whole point of a set, both in mathematics and in almost every programming language,* is that it's not ordered: the sets {1, 2} and {2, 1} are the same set.


You probably don't really want to sort those elements as strings, but as numbers (so 4.918560000 will come before 10.277200999 rather than after).

The best solution is most likely to store the numbers as numbers rather than strings in the first place. But if not, you just need to use a key function:

>>> sorted(s, key=float)
['0.000000000', '0.009518000', '0.018384000', '0.030810999', '4.918560000', '10.277200999']

For more information, see the Sorting HOWTO in the official docs.


* See the comments for exceptions.

PHP form - on submit stay on same page

What I do is I want the page to stay after submit when there are errors...So I want the page to be reloaded :

($_SERVER["PHP_SELF"])

While I include the sript from a seperate file e.g

include_once "test.php";

I also read somewhere that

if(isset($_POST['submit']))

Is a beginners old fasion way of posting a form, and

if ($_SERVER['REQUEST_METHOD'] == 'POST')

Should be used (Not my words, read it somewhere)

XPath:: Get following Sibling

/html/body/table/tbody/tr[9]/td[1]

In Chrome (possible Safari too) you can inspect an element, then right click on the tag you want to get the xpath for, then you can copy the xpath to select that element.

Node.js - SyntaxError: Unexpected token import

I've been trying to get this working. Here's what works:

  1. Use a recent node version. I'm using v14.15.5. Verify your version by running: node --version
  2. Name the files so that they all end with .mjs rather than .js

Example:

mod.mjs

export const STR = 'Hello World'

test.mjs

import {STR} from './mod.mjs'
console.log(STR)

Run: node test.mjs

You should see "Hello World".

How to rename a single column in a data.frame?

You can use the rename.vars in the gdata package.

library(gdata)
df <- rename.vars(df, from = "oldname", to = "newname")

This is particularly useful where you have more than one variable name to change or you want to append or pre-pend some text to the variable names, then you can do something like:

df <- rename.vars(df, from = c("old1", "old2", "old3", 
         to = c("new1", "new2", "new3"))

For an example of appending text to a subset of variables names see: https://stackoverflow.com/a/28870000/180892

How to implement endless list with RecyclerView?

I have a pretty detailed example of how to paginate with a RecyclerView. At a high level, I have a set PAGE_SIZE , lets say 30. So I request 30 items and if I get 30 back then I request the next page. If I get less than 30 items I flag a variable to indicate that the last page has been reached and then I stop requesting for more pages. Check it out and let me know what you think.

https://medium.com/@etiennelawlor/pagination-with-recyclerview-1cb7e66a502b

How to select distinct query using symfony2 doctrine query builder?

you could write

select DISTINCT f from t;

as

select f from t group by f;

thing is, I am just currently myself getting into Doctrine, so I cannot give you a real answer. but you could as shown above, simulate a distinct with group by and transform that into Doctrine. if you want add further filtering then use HAVING after group by.

How to reload page every 5 seconds?

To reload the same page you don't need the 2nd argument. You can just use:

 <meta http-equiv="refresh" content="30" />

This triggers a reload every 30 seconds.

HowTo Generate List of SQL Server Jobs and their owners

A colleague told me about this stored procedure...

USE msdb

EXEC dbo.sp_help_job

How to SELECT WHERE NOT EXIST using LINQ?

The outcome sql will be different but the result should be the same:

var shifts = Shifts.Where(s => !EmployeeShifts.Where(es => es.ShiftID == s.ShiftID).Any());

How to remove package using Angular CLI?

I think best approach until Angular team add this feature to cli is first create angular (ng new something) in other place and then add what you want to delete. Using git to check witch files are changed or added by angular cli. then you can revert that changes. Be careful of untracked files from .gitignore.

Regular expression to allow spaces between words

It was my regex: @"^(?=.{3,15}$)(?:(?:\p{L}|\p{N})[._()\[\]-]?)*$"

I just added ([\w ]+) at the end of my regex before *

@"^(?=.{3,15}$)(?:(?:\p{L}|\p{N})[._()\[\]-]?)([\w ]+)*$"

Now string is allowed to have spaces.

Regular expression to match URLs in Java

When using regular expressions from RegexBuddy's library, make sure to use the same matching modes in your own code as the regex from the library. If you generate a source code snippet on the Use tab, RegexBuddy will automatically set the correct matching options in the source code snippet. If you copy/paste the regex, you have to do that yourself.

In this case, as others pointed out, you missed the case insensitivity option.

How to commit changes to a new branch

git checkout -b your-new-branch

git add <files>

git commit -m <message>

First, checkout your new branch. Then add all the files you want to commit to staging. Lastly, commit all the files you just added. You might want to do a git push origin your-new-branch afterward so your changes show up on the remote.

remove legend title in ggplot

Since you may have more than one legends in a plot, a way to selectively remove just one of the titles without leaving an empty space is to set the name argument of the scale_ function to NULL, i.e.

scale_fill_discrete(name = NULL)

(kudos to @pascal for a comment on another thread)

Difference between 2 dates in seconds

$timeFirst  = strtotime('2011-05-12 18:20:20');
$timeSecond = strtotime('2011-05-13 18:20:20');
$differenceInSeconds = $timeSecond - $timeFirst;

You will then be able to use the seconds to find minutes, hours, days, etc.

How to auto-format code in Eclipse?

The secret is simple: Ctrl+Shift+F

PostgreSQL Autoincrement

This way will work for sure, I hope it helps:

CREATE TABLE fruits(
   id SERIAL PRIMARY KEY,
   name VARCHAR NOT NULL
);

INSERT INTO fruits(id,name) VALUES(DEFAULT,'apple');

or

INSERT INTO fruits VALUES(DEFAULT,'apple');

You can check this the details in the next link: http://www.postgresqltutorial.com/postgresql-serial/

How to add a custom HTTP header to every WCF call?

This is similar to NimsDotNet answer but shows how to do it programmatically.

Simply add the header to the binding

var cl = new MyServiceClient();

var eab = new EndpointAddressBuilder(cl.Endpoint.Address);

eab.Headers.Add( 
      AddressHeader.CreateAddressHeader("ClientIdentification",  // Header Name
                                         string.Empty,           // Namespace
                                         "JabberwockyClient"));  // Header Value

cl.Endpoint.Address = eab.ToEndpointAddress();

In Perl, how can I read an entire file into a string?

This is more of a suggestion on how NOT to do it. I've just had a bad time finding a bug in a rather big Perl application. Most of the modules had its own configuration files. To read the configuration files as-a-whole, I found this single line of Perl somewhere on the Internet:

# Bad! Don't do that!
my $content = do{local(@ARGV,$/)=$filename;<>};

It reassigns the line separator as explained before. But it also reassigns the STDIN.

This had at least one side effect that cost me hours to find: It does not close the implicit file handle properly (since it does not call closeat all).

For example, doing that:

use strict;
use warnings;

my $filename = 'some-file.txt';

my $content = do{local(@ARGV,$/)=$filename;<>};
my $content2 = do{local(@ARGV,$/)=$filename;<>};
my $content3 = do{local(@ARGV,$/)=$filename;<>};

print "After reading a file 3 times redirecting to STDIN: $.\n";

open (FILE, "<", $filename) or die $!;

print "After opening a file using dedicated file handle: $.\n";

while (<FILE>) {
    print "read line: $.\n";
}

print "before close: $.\n";
close FILE;
print "after close: $.\n";

results in:

After reading a file 3 times redirecting to STDIN: 3
After opening a file using dedicated file handle: 3
read line: 1
read line: 2
(...)
read line: 46
before close: 46
after close: 0

The strange thing is, that the line counter $. is increased for every file by one. It's not reset, and it does not contain the number of lines. And it is not reset to zero when opening another file until at least one line is read. In my case, I was doing something like this:

while($. < $skipLines) {<FILE>};

Because of this problem, the condition was false because the line counter was not reset properly. I don't know if this is a bug or simply wrong code... Also calling close; oder close STDIN; does not help.

I replaced this unreadable code by using open, string concatenation and close. However, the solution posted by Brad Gilbert also works since it uses an explicit file handle instead.

The three lines at the beginning can be replaced by:

my $content = do{local $/; open(my $f1, '<', $filename) or die $!; my $tmp1 = <$f1>; close $f1 or die $!; $tmp1};
my $content2 = do{local $/; open(my $f2, '<', $filename) or die $!; my $tmp2 = <$f2>; close $f2 or die $!; $tmp2};
my $content3 = do{local $/; open(my $f3, '<', $filename) or die $!; my $tmp3 = <$f3>; close $f3 or die $!; $tmp3};

which properly closes the file handle.

Determine if an element has a CSS class with jQuery

As for the negation, if you want to know if an element hasn't a class you can simply do as Mark said.

if (!currentPage.parent().hasClass('home')) { do what you want }

Access multiple viewchildren using @viewchild

Use @ViewChildren from @angular/core to get a reference to the components

template

<div *ngFor="let v of views">
    <customcomponent #cmp></customcomponent>
</div>

component

import { ViewChildren, QueryList } from '@angular/core';

/** Get handle on cmp tags in the template */
@ViewChildren('cmp') components:QueryList<CustomComponent>;

ngAfterViewInit(){
    // print array of CustomComponent objects
    console.log(this.components.toArray());
}

l?i?v?e? ?d?e?m?o?

How do I find what Java version Tomcat6 is using?

For Windows, launch cmd prompt and route to the path(usually bin) where you have your tomcat startup script.

C:\opt\isv\tomcat-7.0\grid\bin>version
Using CATALINA_BASE:   "C:\opt\isv\tomcat-7.0\grid"
Using CATALINA_HOME:   "C:\opt\isv\tomcat-7.0\grid"
Using CATALINA_TMPDIR: "C:\opt\isv\tomcat-7.0\grid\temp"
Using JRE_HOME:        "C:\opt\isv\devtools\jdk1.8.0_45"
Using CLASSPATH:       "C:\opt\isv\tomcat-7.0\grid\bin\bootstrap.jar;C:\opt\isv\tomcat-7.0\grid\bin\tomcat-juli.jar"
Server version: Apache Tomcat/7.0.55
Server built:   Jul 18 2014 05:34:04
Server number:  7.0.55.0
OS Name:        Windows 7
OS Version:     6.1
Architecture:   x86
JVM Version:    1.8.0_45-b15
JVM Vendor:     Oracle Corporation
C:\opt\isv\tomcat-7.0\grid\bin>

VS 2017 Git Local Commit DB.lock error on every commit

Just add the .vs folder to the .gitignore file.

Here is the template for Visual Studio from GitHub's collection of .gitignore templates, as an example:
https://github.com/github/gitignore/blob/master/VisualStudio.gitignore


If you have any trouble adding the .gitignore file, just follow these steps:

  1. On the Team Explorer's window, go to Settings.

Team Explorer - Settings

  1. Then access Repository Settings.

Repository Settings

  1. Finally, click Add in the Ignore File section.

enter image description here

Done. ;)
This default file already includes the .vs folder.

enter image description here

Connect Java to a MySQL database

DriverManager is a fairly old way of doing things. The better way is to get a DataSource, either by looking one up that your app server container already configured for you:

Context context = new InitialContext();
DataSource dataSource = (DataSource) context.lookup("java:comp/env/jdbc/myDB");

or instantiating and configuring one from your database driver directly:

MysqlDataSource dataSource = new MysqlDataSource();
dataSource.setUser("scott");
dataSource.setPassword("tiger");
dataSource.setServerName("myDBHost.example.org");

and then obtain connections from it, same as above:

Connection conn = dataSource.getConnection();
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT ID FROM USERS");
...
rs.close();
stmt.close();
conn.close();

How do I give text or an image a transparent background using CSS?

<div align="center" style="width:100%;height:100%;background:white;opacity:0.5;position:absolute;z-index:1001">
    <img id="search_img" style="margin-top:20%;" src="../resources/images/loading_small.gif">
</div>

http://jsfiddle.net/x2ukko7u/?

How to sort an array of objects with jquery or javascript

Well, it appears that instead of creating a true multidimensional array, you've created an array of (almost) JavaScript Objects. Try defining your arrays like this ->

var array = [ [id,name,value], [id,name,value] ]

Hopefully that helps!

How to place Text and an Image next to each other in HTML?

img {
    float:left;
}
h3 {
    float:right;
}

jsFiddle example

Note that you will probably want to use the style clear:both on whatever elements comes after the code you provided so that it doesn't slide up directly beneath the floated elements.

Smooth scroll to div id jQuery

here is my 2 cents:

Javascript:

$('.scroll').click(function() {
    $('body').animate({
        scrollTop: eval($('#' + $(this).attr('target')).offset().top - 70)
    }, 1000);
});

Html:

<a class="scroll" target="contact">Contact</a>

and the target:

<h2 id="contact">Contact</h2>

How to remove components created with Angular-CLI

No As of now you can't do this by any command. You've to remove Manually from app.module.ts and app.routing.module.ts if you're using Angular 5

How can I style even and odd elements?

The :nth-child(n) selector matches every element that is the nth child, regardless of type, of its parent. Odd and even are keywords that can be used to match child elements whose index is odd or even (the index of the first child is 1).

this is what you want:

<html>
    <head>
        <style>
            li { color: blue }<br>
            li:nth-child(even) { color:red }
            li:nth-child(odd) { color:green}
        </style>
    </head>
    <body>
        <ul>
            <li>ho</li>
            <li>ho</li>
            <li>ho</li>
            <li>ho</li>
            <li>ho</li>
        </ul>
    </body>
</html>

OOP vs Functional Programming vs Procedural

I think that they are often not "versus", but you can combine them. I also think that oftentimes, the words you mention are just buzzwords. There are few people who actually know what "object-oriented" means, even if they are the fiercest evangelists of it.

Subset a dataframe by multiple factor levels

You can use %in%

  data[data$Code %in% selected,]
  Code Value
1    A     1
2    B     2
7    A     3
8    A     4

How to remove focus from single editText

If I understand your question correctly, this should help you:

TextView tv1 = (TextView) findViewById(R.id.tv1);
tv1 .setFocusable(false);

Setting onSubmit in React.js

I'd also suggest moving the event handler outside render.

var OnSubmitTest = React.createClass({

  submit: function(e){
    e.preventDefault();
    alert('it works!');
  }

  render: function() {
    return (
      <form onSubmit={this.submit}>
        <button>Click me</button>
      </form>
    );
  }
});

Plotting multiple curves same graph and same scale

points or lines comes handy if

  • y2 is generated later, or
  • the new data does not have the same x but still should go into the same coordinate system.

As your ys share the same x, you can also use matplot:

matplot (x, cbind (y1, y2), pch = 19)

matplot (x, cbind (y1, y2), pch = 19)

(without the pch matplopt will plot the column numbers of the y matrix instead of dots).

invalid use of non-static data member

You try to access private member of one class from another. The fact that bar-class is declared within foo-class means that bar in visible only inside foo class, but that is still other class.

And what is p->param?

Actually, it isn't clear what do you want to do

Fast and simple String encrypt/decrypt in JAVA

Java - encrypt / decrypt user name and password from a configuration file

Code from above link

DESKeySpec keySpec = new DESKeySpec("Your secret Key phrase".getBytes("UTF8"));
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
SecretKey key = keyFactory.generateSecret(keySpec);
sun.misc.BASE64Encoder base64encoder = new BASE64Encoder();
sun.misc.BASE64Decoder base64decoder = new BASE64Decoder();
.........

// ENCODE plainTextPassword String
byte[] cleartext = plainTextPassword.getBytes("UTF8");      

Cipher cipher = Cipher.getInstance("DES"); // cipher is not thread safe
cipher.init(Cipher.ENCRYPT_MODE, key);
String encryptedPwd = base64encoder.encode(cipher.doFinal(cleartext));
// now you can store it 
......

// DECODE encryptedPwd String
byte[] encrypedPwdBytes = base64decoder.decodeBuffer(encryptedPwd);

Cipher cipher = Cipher.getInstance("DES");// cipher is not thread safe
cipher.init(Cipher.DECRYPT_MODE, key);
byte[] plainTextPwdBytes = (cipher.doFinal(encrypedPwdBytes));

System.BadImageFormatException An attempt was made to load a program with an incorrect format

I was having problems with a new install of VS with an x64 project - for Visual Studio 2013, Visual Studio 2015 and Visual Studio 2017:

Tools
  -> Options
   -> Projects and Solutions
    -> Web Projects
     -> Check "Use the 64 bit version of IIS Express for web sites and projects"

Java Embedded Databases Comparison

We use HSQLDB in production as a "no-configuration" option for our application. It allows people to trial without the hassle of setting up a real database.

However we do not support it for normal use. The reasons are several:

  1. Slows down proportionally to the size of the data.
  2. Difficult to access outside of our app (e.g. for custom reports).
  3. Transactions / disk-sync is difficult to get right, so it's easy to lose data.

For at least (2) and (3), there are ways around it but it's difficult; it's much easier to e.g. install MySQL.

Bootstrap Align Image with text

I think this is helpful for you

<div class="container">
        <div class="page-header">
                <h1>About Me</h1>
            </div><!--END page-header-->
        <div class="row" id="features">
                <div class="col-sm-6 feature">
                        <img src="http://lorempixel.com/200/200" alt="Web Design" class="img-circle">
                </div><!--END feature-->

                <div class="col-sm-6 feature">
                        <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod
tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam,</p>
                </div><!--END feature-->
            </div><!--end features-->
    </div><!--end container-->

How do I replace text inside a div element?

Use innerText if you can't assume structure - Use Text#data to update existing text Performance Test

Where can I find php.ini?

Best way to find this is: create a php file and add the following code:

<?php phpinfo(); ?>

and open it in browser, it will show the file which is actually being read!

Updates by OP:

  1. The previously accepted answer is likely to be faster and more convenient for you, but it is not always correct. See comments on that answer.
  2. Please also note the more convenient alternative <?php echo php_ini_loaded_file(); ?> mentioned in this answer.

Using jQuery UI sortable with HTML tables

You can call sortable on a <tbody> instead of on the individual rows.

<table>
    <tbody>
        <tr> 
            <td>1</td>
            <td>2</td>
        </tr>
        <tr>
            <td>3</td>
            <td>4</td> 
        </tr>
        <tr>
            <td>5</td>
            <td>6</td>
        </tr>  
    </tbody>    
</table>?

<script>
    $('tbody').sortable();
</script> 

_x000D_
_x000D_
$(function() {_x000D_
  $( "tbody" ).sortable();_x000D_
});
_x000D_
 _x000D_
table {_x000D_
    border-spacing: collapse;_x000D_
    border-spacing: 0;_x000D_
}_x000D_
td {_x000D_
    width: 50px;_x000D_
    height: 25px;_x000D_
    border: 1px solid black;_x000D_
}
_x000D_
 _x000D_
_x000D_
<link href="//code.jquery.com/ui/1.11.1/themes/smoothness/jquery-ui.css" rel="stylesheet">_x000D_
<script src="//code.jquery.com/jquery-1.11.1.js"></script>_x000D_
<script src="//code.jquery.com/ui/1.11.1/jquery-ui.js"></script>_x000D_
_x000D_
<table>_x000D_
    <tbody>_x000D_
        <tr>_x000D_
            <td>1</td>_x000D_
            <td>2</td>_x000D_
        </tr>_x000D_
        <tr>_x000D_
            <td>3</td>_x000D_
            <td>4</td>_x000D_
        </tr>_x000D_
        <tr> _x000D_
            <td>5</td>_x000D_
            <td>6</td>_x000D_
        </tr>_x000D_
        <tr>_x000D_
            <td>7</td>_x000D_
            <td>8</td>_x000D_
        </tr>_x000D_
        <tr>_x000D_
            <td>9</td> _x000D_
            <td>10</td>_x000D_
        </tr>  _x000D_
    </tbody>    _x000D_
</table>
_x000D_
_x000D_
_x000D_

Meaning of 'const' last in a function declaration of a class?

Here const means that at that function any variable's value can not change

class Test{
private:
    int a;
public:
    void test()const{
        a = 10;
    }
};

And like this example, if you try to change the value of a variable in the test function you will get an error.

PHP Email sending BCC

You were setting BCC but then overwriting the variable with the FROM

$to = "[email protected]";
     $subject .= "".$emailSubject."";
 $headers .= "Bcc: ".$emailList."\r\n";
 $headers .= "From: [email protected]\r\n" .
     "X-Mailer: php";
     $headers .= "MIME-Version: 1.0\r\n";
     $headers .= "Content-Type: text/html; charset=ISO-8859-1\r\n";
 $message = '<html><body>';
 $message .= 'THE MESSAGE FROM THE FORM';

     if (mail($to, $subject, $message, $headers)) {
     $sent = "Your email was sent!";
     } else {
      $sent = ("Error sending email.");
     }

Importing from a relative path in Python

EDIT Nov 2014 (3 years later):

Python 2.6 and 3.x supports proper relative imports, where you can avoid doing anything hacky. With this method, you know you are getting a relative import rather than an absolute import. The '..' means, go to the directory above me:

from ..Common import Common

As a caveat, this will only work if you run your python as a module, from outside of the package. For example:

python -m Proj

Original hacky way

This method is still commonly used in some situations, where you aren't actually ever 'installing' your package. For example, it's popular with Django users.

You can add Common/ to your sys.path (the list of paths python looks at to import things):

import sys, os
sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'Common'))
import Common

os.path.dirname(__file__) just gives you the directory that your current python file is in, and then we navigate to 'Common/' the directory and import 'Common' the module.

Check if element is visible in DOM

So what I found is the most feasible method:

function visible(elm) {
  if(!elm.offsetHeight && !elm.offsetWidth) { return false; }
  if(getComputedStyle(elm).visibility === 'hidden') { return false; }
  return true;
}

This is build on these facts:

  • A display: none element (even a nested one) doesn't have a width nor height.
  • visiblity is hidden even for nested elements.

So no need for testing offsetParent or looping up in the DOM tree to test which parent has visibility: hidden. This should work even in IE 9.

You could argue if opacity: 0 and collapsed elements (has a width but no height - or visa versa) is not really visible either. But then again they are not per say hidden.

Hibernate Delete query

instead of using

session.delete(object)

use

getHibernateTemplate().delete(object)

In both place for select query and also for delete use getHibernateTemplate()

In select query you have to use DetachedCriteria or Criteria

Example for select query

List<foo> fooList = new ArrayList<foo>();
DetachedCriteria queryCriteria = DetachedCriteria.forClass(foo.class);
queryCriteria.add(Restrictions.eq("Column_name",restriction));
fooList = getHibernateTemplate().findByCriteria(queryCriteria);

In hibernate avoid use of session,here I am not sure but problem occurs just because of session use

Python function to convert seconds into minutes, hours, and days

I'm not entirely sure if you want it, but I had a similar task and needed to remove a field if it is zero. For example, 86401 seconds would show "1 days, 1 seconds" instead of "1 days, 0 hours, 0 minutes, 1 seconds". THe following code does that.

def secondsToText(secs):
    days = secs//86400
    hours = (secs - days*86400)//3600
    minutes = (secs - days*86400 - hours*3600)//60
    seconds = secs - days*86400 - hours*3600 - minutes*60
    result = ("{} days, ".format(days) if days else "") + \
    ("{} hours, ".format(hours) if hours else "") + \
    ("{} minutes, ".format(minutes) if minutes else "") + \
    ("{} seconds, ".format(seconds) if seconds else "")
    return result

EDIT: a slightly better version that handles pluralization of words.

def secondsToText(secs):
    days = secs//86400
    hours = (secs - days*86400)//3600
    minutes = (secs - days*86400 - hours*3600)//60
    seconds = secs - days*86400 - hours*3600 - minutes*60
    result = ("{0} day{1}, ".format(days, "s" if days!=1 else "") if days else "") + \
    ("{0} hour{1}, ".format(hours, "s" if hours!=1 else "") if hours else "") + \
    ("{0} minute{1}, ".format(minutes, "s" if minutes!=1 else "") if minutes else "") + \
    ("{0} second{1}, ".format(seconds, "s" if seconds!=1 else "") if seconds else "")
    return result

EDIT2: created a gist that does that in several languages

UnicodeDecodeError: 'utf8' codec can't decode bytes in position 3-6: invalid data

Paste this on your command line:

export LC_CTYPE="en_US.UTF-8" 

Nullable type as a generic parameter possible?

Just had to do something incredible similar to this. My code:

public T IsNull<T>(this object value, T nullAlterative)
{
    if(value != DBNull.Value)
    {
        Type type = typeof(T);
        if (type.IsGenericType && 
            type.GetGenericTypeDefinition() == typeof(Nullable<>).GetGenericTypeDefinition())
        {
            type = Nullable.GetUnderlyingType(type);
        }

        return (T)(type.IsEnum ? Enum.ToObject(type, Convert.ToInt32(value)) :
            Convert.ChangeType(value, type));
    }
    else 
        return nullAlternative;
}

Maven:Failed to execute goal org.apache.maven.plugins:maven-resources-plugin:2.7:resources

I had the same error because of character '@' in my resources/application.properties. All I did was replacing the '@' for its unicode value: eureka.client.serviceUrl.defaultZone=http://discUser:discPassword\u0040localhost:8082/eureka/ and it worked like charm. I know the '@' is a perfectly valid character in .properties files and the file was in UTF-8 encoding and it makes me question my career till today but it's worth a shot if you delete content of your resource files to see if you can get pass this error.

how to display full stored procedure code?

SELECT prosrc FROM pg_proc WHERE proname = 'function_name';

This tells the function handler how to invoke the function. It might be the actual source code of the function for interpreted languages, a link symbol, a file name, or just about anything else, depending on the implementation language/call convention

How to extend / inherit components?

just use inheritance,Extend parent class in child class and declare constructor with parent class parameter and this parameter use in super().

1.parent class
@Component({
    selector: 'teams-players-box',
    templateUrl: '/maxweb/app/app/teams-players-box.component.html'
})
export class TeamsPlayersBoxComponent {
    public _userProfile:UserProfile;
    public _user_img:any;
    public _box_class:string="about-team teams-blockbox";
    public fullname:string;
    public _index:any;
    public _isView:string;
    indexnumber:number;
    constructor(
        public _userProfilesSvc: UserProfiles,
        public _router:Router,
    ){}
2.child class
@Component({

    selector: '[teams-players-eligibility]',
    templateUrl: '/maxweb/app/app/teams-players-eligibility.component.html'
})
export class TeamsPlayersEligibilityComponent extends TeamsPlayersBoxComponent{

    constructor (public _userProfilesSvc: UserProfiles,
            public _router:Router) {
            super(_userProfilesSvc,_router);
        }
}

Converting Chart.js canvas chart to image using .toDataUrl() results in blank image

First convert your Chart.js canvas to base64 string.

var url_base64 = document.getElementById('myChart').toDataURL('image/png');

Set it as a href attribute for anchor tag.

link.href = url_base64;

<a id='link' download='filename.png'>Save as Image</a>

Generics in C#, using type of a variable as parameter

The point about generics is to give compile-time type safety - which means that types need to be known at compile-time.

You can call generic methods with types only known at execution time, but you have to use reflection:

// For non-public methods, you'll need to specify binding flags too
MethodInfo method = GetType().GetMethod("DoesEntityExist")
                             .MakeGenericMethod(new Type[] { t });
method.Invoke(this, new object[] { entityGuid, transaction });

Ick.

Can you make your calling method generic instead, and pass in your type parameter as the type argument, pushing the decision one level higher up the stack?

If you could give us more information about what you're doing, that would help. Sometimes you may need to use reflection as above, but if you pick the right point to do it, you can make sure you only need to do it once, and let everything below that point use the type parameter in a normal way.

Scaling a System.Drawing.Bitmap to a given size while maintaining aspect ratio

Target parameters:

float width = 1024;
float height = 768;
var brush = new SolidBrush(Color.Black);

Your original file:

var image = new Bitmap(file);

Target sizing (scale factor):

float scale = Math.Min(width / image.Width, height / image.Height);

The resize including brushing canvas first:

var bmp = new Bitmap((int)width, (int)height);
var graph = Graphics.FromImage(bmp);

// uncomment for higher quality output
//graph.InterpolationMode = InterpolationMode.High;
//graph.CompositingQuality = CompositingQuality.HighQuality;
//graph.SmoothingMode = SmoothingMode.AntiAlias;

var scaleWidth = (int)(image.Width * scale);
var scaleHeight = (int)(image.Height * scale);

graph.FillRectangle(brush, new RectangleF(0, 0, width, height));
graph.DrawImage(image, ((int)width - scaleWidth)/2, ((int)height - scaleHeight)/2, scaleWidth, scaleHeight);

And don't forget to do a bmp.Save(filename) to save the resulting file.

C error: undefined reference to function, but it IS defined

Add the "extern" keyword to the function definitions in point.h

How do I update zsh to the latest version?

If you're not using Homebrew, this is what I just did on MAC OS X Lion (10.7.5):

  1. Get the latest version of the ZSH sourcecode

  2. Untar the download into its own directory then install: ./configure && make && make test && sudo make install

  3. This installs the the zsh binary at /usr/local/bin/zsh.

  4. You can now use the shell by loading up a new terminal and executing the binary directly, but you'll want to make it your default shell...

  5. To make it your default shell you must first edit /etc/shells and add the new path. Then you can either run chsh -s /usr/local/bin/zsh or go to System Preferences > Users & Groups > right click your user > Advanced Options... > and then change "Login shell".

  6. Load up a terminal and check you're now in the correct version with echo $ZSH_VERSION. (I wasn't at first, and it took me a while to figure out I'd configured iTerm to use a specific shell instead of the system default).

How to configure postgresql for the first time?

You probably need to update your pg_hba.conf file. This file controls what users can log in from what IP addresses. I think that the postgres user is pretty locked-down by default.

Height equal to dynamic width (CSS fluid layout)

Using jQuery you can achieve this by doing

var cw = $('.child').width();
$('.child').css({'height':cw+'px'});

Check working example at http://jsfiddle.net/n6DAu/1/

Wait till a Function with animations is finished until running another Function

You can use the javascript Promise and async/await to implement a synchronized call of the functions.

Suppose you want to execute n number of functions in a synchronized manner that are stored in an array, here is my solution for that.

_x000D_
_x000D_
async function executeActionQueue(funArray) {_x000D_
  var length = funArray.length;_x000D_
  for(var i = 0; i < length; i++) {_x000D_
    await executeFun(funArray[i]);_x000D_
  }_x000D_
};_x000D_
_x000D_
function executeFun(fun) {_x000D_
  return new Promise((resolve, reject) => {_x000D_
    _x000D_
    // Execute required function here_x000D_
    _x000D_
    fun()_x000D_
      .then((data) => {_x000D_
        // do required with data _x000D_
        resolve(true);_x000D_
      })_x000D_
      .catch((error) => {_x000D_
      // handle error_x000D_
        resolve(true);_x000D_
      });_x000D_
  })_x000D_
};_x000D_
_x000D_
executeActionQueue(funArray);
_x000D_
_x000D_
_x000D_

Failed to run sdkmanager --list with Java 9

It's very simple, just export the JAVA_HOME environment variable, set to the path of your JDK installation.

I installed Java manually on Ubuntu, and so for me this looks like:

export JAVA_HOME="$HOME/pkg-src/jdk1.8.0_251"

And make sure it exists in your path too...

export PATH="$PATH:$JAVA_HOME"

How to output git log with the first line only?

Does git log --oneline do what you want?

How to grep (search) committed code in the Git history

If you want to browse code changes (see what actually has been changed with the given word in the whole history) go for patch mode - I found a very useful combination of doing:

git log -p
# Hit '/' for search mode.
# Type in the word you are searching.
# If the first search is not relevant, hit 'n' for next (like in Vim ;) )

How to pass parameter to a promise function

You can use .bind() to pass the param(this) to the function.

var someFunction =function(resolve, reject) {
  /* get username, password*/
  var username=this.username;
  var password=this.password;
  if ( /* everything turned out fine */ ) {
    resolve("Stuff worked!");
  } else {
    reject(Error("It broke"));
  }
}
var promise=new Promise(someFunction.bind({username:"your username",password:"your password"}));

How can I scroll up more (increase the scroll buffer) in iTerm2?

There is an option “unlimited scrollback buffer” which you can find under Preferences > Profiles > Terminal or you can just pump up number of lines that you want to have in history in the same place.

How to setup Tomcat server in Netbeans?

I had same issue. No need to re install.

In Netbeans 6.0 , Find RunTime -> Servers - > Add server -> select Tomcat install 'root' directory

In Netbeans 7.x -> Tools -> Servers-> Add server -> select Tomcat install 'root' directory

Here is in Netbeans Wiki.

http://wiki.netbeans.org/AddExternalTomcat

Spring Data JPA and Exists query

You can just return a Boolean like this:

import org.springframework.data.jpa.repository.Query;
import org.springframework.data.jpa.repository.QueryHints;
import org.springframework.data.repository.query.Param;

@QueryHints(@QueryHint(name = org.hibernate.jpa.QueryHints.HINT_FETCH_SIZE, value = "1"))
@Query(value = "SELECT (1=1) FROM MyEntity WHERE ...... :id ....")
Boolean existsIfBlaBla(@Param("id") String id);

Boolean.TRUE.equals(existsIfBlaBla("0815")) could be a solution

How to create batch file in Windows using "start" with a path and command with spaces

Actually, his example won't work (although at first I thought that it would, too). Based on the help for the Start command, the first parameter is the name of the newly created Command Prompt window, and the second and third should be the path to the application and its parameters, respectively. If you add another "" before path to the app, it should work (at least it did for me). Use something like this:

start "" "c:\path with spaces\app.exe" param1 "param with spaces"

You can change the first argument to be whatever you want the title of the new command prompt to be. If it's a Windows app that is created, then the command prompt won't be displayed, and the title won't matter.

Rollback transaction after @Test

You need to run your test with a Spring context and a transaction manager, e.g.,

@RunWith(SpringJUnit4ClassRunner.class)  
@ContextConfiguration(locations = {"/your-applicationContext.xml"})
@TransactionConfiguration(transactionManager="txMgr")
public class StudentSystemTest {

     @Test
     public void testTransactionalService() {
         // test transactional service
     }

     @Test
     @Transactional
     public void testNonTransactionalService() {
         // test non-transactional service
     }
}

See chapter 3.5.8. Transaction Management of the Spring reference for further details.

Questions every good .NET developer should be able to answer?

I found these lists on Scott Hanselman's blog:

Here are what I think are the most important questions from these posts divided into categories. I edited and re-arranged them. Fortunately for most of these questions there is already a good answer on Stack Overflow. Just follow the links (I will update them all ASAP).

Platform independent .NET questions

ASP.NET

Json.NET serialize object with root name

Use anonymous class

Shape your model the way you want using anonymous classes:

var root = new 
{ 
    car = new 
    { 
        name = "Ford", 
        owner = "Henry"
    }
};

string json = JsonConvert.SerializeObject(root);

What does it mean with bug report captured in android tablet?

It's because you have turned on USB debugging in Developer Options. You can create a bug report by holding the power + both volume up and down.

Edit: This is what the forums say:

By pressing Volume up + Volume down + power button, you will feel a vibration after a second or so, that's when the bug reporting initiated.

To disable:

/system/bin/bugmailer.sh must be deleted/renamed.

There should be a folder on your SD card called "bug reports".

Have a look at this thread: http://forum.xda-developers.com/showthread.php?t=2252948

And this one: http://forum.xda-developers.com/showthread.php?t=1405639

How to print a number with commas as thousands separators in JavaScript

function addCommas(nStr) {
    nStr += '';
    var x = nStr.split('.');
    var x1 = x[0];
    var x2 = x.length > 1 ? '.' + x[1] : '';
    var rgx = /(\d+)(\d{3})/;
    while (rgx.test(x1)) {
            x1 = x1.replace(rgx, '$1' + ',' + '$2');
    }
    return x1 + x2;
}

addCommas(parseFloat("1099920.23232").toFixed(2)); //Output  1,099,920.23

Call to undefined function curl_init().?

You have to enable curl with php.

Here is the instructions for same

Calculating time difference between 2 dates in minutes

Try this one:

select * from MyTab T where date_add(T.runTime, INTERVAL 20 MINUTE) < NOW()

NOTE: this should work if you're using MySQL DateTime format. If you're using Unix Timestamp (integer), then it would be even easier:

select * from MyTab T where UNIX_TIMESTAMP() - T.runTime > 20*60

UNIX_TIMESTAMP() function returns you current unix timestamp.

jQuery load first 3 elements, click "load more" to display next 5 elements

Simple and with little changes. And also hide load more when entire list is loaded.

jsFiddle here.

$(document).ready(function () {
    // Load the first 3 list items from another HTML file
    //$('#myList').load('externalList.html li:lt(3)');
    $('#myList li:lt(3)').show();
    $('#showLess').hide();
    var items =  25;
    var shown =  3;
    $('#loadMore').click(function () {
        $('#showLess').show();
        shown = $('#myList li:visible').size()+5;
        if(shown< items) {$('#myList li:lt('+shown+')').show();}
        else {$('#myList li:lt('+items+')').show();
             $('#loadMore').hide();
             }
    });
    $('#showLess').click(function () {
        $('#myList li').not(':lt(3)').hide();
    });
});

Node / Express: EADDRINUSE, Address already in use - Kill server

Just in case check if you have added this line multiple times by mistake

app.listen(3000, function() {
  console.log('listening on 3000')
});

The above code is for express but just check if you are trying to use the same port twice in your code.

Classpath resource not found when running as jar

to get list of data from src/main/resources/data folder --
first of all mention your folder location in properties file as - 
resourceLoader.file.location=data

inside class declare your location. 

@Value("${resourceLoader.file.location}")
    @Setter
    private String location;

    private final ResourceLoader resourceLoader;

public void readallfilesfromresources() {
       Resource[] resources;

        try {
            resources = ResourcePatternUtils.getResourcePatternResolver(resourceLoader).getResources("classpath:" + location + "/*.json");
            for (int i = 0; i < resources.length; i++) {
                try {
                InputStream is = resources[i].getInputStream();
                byte[] encoded = IOUtils.toByteArray(is);
                String content = new String(encoded, Charset.forName("UTF-8"));
                }
            }
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
}

Can anyone confirm that phpMyAdmin AllowNoPassword works with MySQL databases?

After a lot of trials I found the following solution.

This will work if you copied all phpmyadmin files in /var/www

go to your copied location of phpmyadmin folder in /var/www

copy the config.sample.inc.php file as config.inc.php

edit in config.inc.php the following line:

$cfg['Servers'][$i]['AllowNoPassword'] = true;

(In original file it was false, change it as true and save it.)

Then you will be able to login phpmyadmin without password.

Hex colors: Numeric representation for "transparent"?

Very simple: no color, no opacity:

rgba(0, 0, 0, 0);

Upload folder with subfolders using S3 and the AWS console

Normally I use the Enhanced Uploader available via the AWS management console. However, since that requires Java it can cause problems. I found s3cmd to be a great command-line replacement. Here's how I used it:

s3cmd --configure   # enter access keys, enable HTTPS, etc.
s3cmd sync <path-to-folder> s3://<path-to-s3-bucket>/

Using group by on two fields and count in SQL

I think you're looking for: SELECT a, b, COUNT(a) FROM tbl GROUP BY a, b

How do I set the background color of my main screen in Flutter?

I think you can also use a scaffold to do the white background. Here's some piece of code that may help.

import 'package:flutter/material.dart';
void main() => runApp(new MyApp());
class MyApp extends StatelessWidget {
  @override
    Widget build(BuildContext context) {

      return new MaterialApp(
        title: 'Testing',
        home: new Scaffold(
        //Here you can set what ever background color you need.
          backgroundColor: Colors.white,
        ),
      );
    }
}

Hope this helps .

fatal error LNK1169: one or more multiply defined symbols found in game programming

I answered a similar question here.

In the Project’s Settings, add /FORCE:MULTIPLE to the Linker’s Command Line options.

From MSDN: "Use /FORCE:MULTIPLE to create an output file whether or not LINK finds more than one definition for a symbol."

That's what programmers call a "quick and dirty" solution, but sometimes you just want the build to be completed and get to the bottom of the problem later, so that's kind of a ad-hoc solution. To actually avoid this error, provided that you want

int WIDTH = 1024;
int HEIGHT = 800;

to be shared among several source files, just declare them only in a single .c / .cpp file, and refer to them in a header file:

extern int WIDTH;
extern int HEIGHT;

Then include the header in any other source file you wish these global variables to be available.

"Field has incomplete type" error

The problem is that your ui property uses a forward declaration of class Ui::MainWindowClass, hence the "incomplete type" error.

Including the header file in which this class is declared will fix the problem.

EDIT

Based on your comment, the following code:

namespace Ui
{
    class MainWindowClass;
}

does NOT declare a class. It's a forward declaration, meaning that the class will exist at some point, at link time.
Basically, it just tells the compiler that the type will exist, and that it shouldn't warn about it.

But the class has to be defined somewhere.

Note this can only work if you have a pointer to such a type.
You can't have a statically allocated instance of an incomplete type.

So either you actually want an incomplete type, and then you should declare your ui member as a pointer:

namespace Ui
{
    // Forward declaration - Class will have to exist at link time
    class MainWindowClass;
}

class MainWindow : public QMainWindow
{
    private:

        // Member needs to be a pointer, as it's an incomplete type
        Ui::MainWindowClass * ui;
};

Or you want a statically allocated instance of Ui::MainWindowClass, and then it needs to be declared. You can do it in another header file (usually, there's one header file per class).
But simply changing the code to:

namespace Ui
{
    // Real class declaration - May/Should be in a specific header file
    class MainWindowClass
    {};
}


class MainWindow : public QMainWindow
{
    private:

        // Member can be statically allocated, as the type is complete
        Ui::MainWindowClass ui;
};

will also work.

Note the difference between the two declarations. First uses a forward declaration, while the second one actually declares the class (here with no properties nor methods).

How do I initialize a TypeScript Object with a JSON-Object?

the best I found for this purpose is the class-transformer. github.com/typestack/class-transformer

That's how you use it:

Some class:

export class Foo {

    name: string;

    @Type(() => Bar)
    bar: Bar;

    public someFunction = (test: string): boolean => {
        ...
    }
}


import { plainToClass } from 'class-transformer';

export class SomeService {

  anyFunction() {
u = plainToClass(Foo, JSONobj);
 }

If you use the @Type decorator nested properties will be created, too.

How different is Objective-C from C++?

As others have said, Objective-C is much more dynamic in terms of how it thinks of objects vs. C++'s fairly static realm.

Objective-C, being in the Smalltalk lineage of object-oriented languages, has a concept of objects that is very similar to that of Java, Python, and other "standard", non-C++ object-oriented languages. Lots of dynamic dispatch, no operator overloading, send messages around.

C++ is its own weird animal; it mostly skipped the Smalltalk portion of the family tree. In some ways, it has a good module system with support for inheritance that happens to be able to be used for object-oriented programming. Things are much more static (overridable methods are not the default, for example).

How to make a cross-module variable?

Global variables are usually a bad idea, but you can do this by assigning to __builtins__:

__builtins__.foo = 'something'
print foo

Also, modules themselves are variables that you can access from any module. So if you define a module called my_globals.py:

# my_globals.py
foo = 'something'

Then you can use that from anywhere as well:

import my_globals
print my_globals.foo

Using modules rather than modifying __builtins__ is generally a cleaner way to do globals of this sort.

Search for highest key/index in an array

You can get the maximum key this way:

<?php
$arr = array("a"=>"test", "b"=>"ztest");
$max = max(array_keys($arr));
?>

Iterate over a Javascript associative array in sorted order

I really like @luke-schafer's prototype idea, but also hear what he is saying about the issues with prototypes. What about using a simple function?

_x000D_
_x000D_
function sortKeysAndDo( obj, worker ) {_x000D_
  var keys = Object.keys(obj);_x000D_
  keys.sort();_x000D_
  for (var i = 0; i < keys.length; i++) {_x000D_
     worker(keys[i], obj[keys[i]]);_x000D_
  }_x000D_
}_x000D_
_x000D_
function show( key, value ) {_x000D_
  document.write( key + ' : ' + value +'<br>' );_x000D_
}_x000D_
_x000D_
var a = new Array();_x000D_
a['b'] = 1;_x000D_
a['z'] = 1;_x000D_
a['a'] = 1;_x000D_
_x000D_
sortKeysAndDo( a, show);_x000D_
_x000D_
var my_object = { 'c': 3, 'a': 1, 'b': 2 };_x000D_
_x000D_
sortKeysAndDo( my_object, show);
_x000D_
_x000D_
_x000D_

This seems to eliminate the issues with prototypes and still provide a sorted iterator for objects. I am not really a JavaScript guru, though, so I'd love to know if this solution has hidden flaws I missed.

How to get current location in Android

First you need to define a LocationListener to handle location changes.

private final LocationListener mLocationListener = new LocationListener() {
    @Override
    public void onLocationChanged(final Location location) {
        //your code here
    }
};

Then get the LocationManager and ask for location updates

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    mLocationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

    mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, LOCATION_REFRESH_TIME,
            LOCATION_REFRESH_DISTANCE, mLocationListener);
}

And finally make sure that you have added the permission on the Manifest,

For using only network based location use this one

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

For GPS based location, this one

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>

convert a list of objects from one type to another using lambda expression

If you know you want to convert from List<T1> to List<T2> then List<T>.ConvertAll will be slightly more efficient than Select/ToList because it knows the exact size to start with:

target = orig.ConvertAll(x => new TargetType { SomeValue = x.SomeValue });

In the more general case when you only know about the source as an IEnumerable<T>, using Select/ToList is the way to go. You could also argue that in a world with LINQ, it's more idiomatic to start with... but it's worth at least being aware of the ConvertAll option.

In Python, how do you convert a `datetime` object to seconds?

The standard way to find the processing time in ms of a block of code in python 3.x is the following:

import datetime

t_start = datetime.datetime.now()

# Here is the python3 code, you want 
# to check the processing time of

t_end = datetime.datetime.now()
print("Time taken : ", (t_end - t_start).total_seconds()*1000, " ms")

'mat-form-field' is not a known element - Angular 5 & Material2

@NgModule({
  declarations: [
    SearchComponent
  ],
  exports: [
    CommonModule,
    MatInputModule,
    MatButtonModule,
    MatCardModule,
    MatFormFieldModule,
    MatDialogModule,
  ]
})
export class MaterialModule { }

Also, do not forget to import the MaterialModule in the imports array of AppModule.

What is fastest children() or find() in jQuery?

This jsPerf test suggests that find() is faster. I created a more thorough test, and it still looks as though find() outperforms children().

Update: As per tvanfosson's comment, I created another test case with 16 levels of nesting. find() is only slower when finding all possible divs, but find() still outperforms children() when selecting the first level of divs.

children() begins to outperform find() when there are over 100 levels of nesting and around 4000+ divs for find() to traverse. It's a rudimentary test case, but I still think that find() is faster than children() in most cases.

I stepped through the jQuery code in Chrome Developer Tools and noticed that children() internally makes calls to sibling(), filter(), and goes through a few more regexes than find() does.

find() and children() fulfill different needs, but in the cases where find() and children() would output the same result, I would recommend using find().

Spring: Why do we autowire the interface and not the implemented class?

How does spring know which polymorphic type to use.

As long as there is only a single implementation of the interface and that implementation is annotated with @Component with Spring's component scan enabled, Spring framework can find out the (interface, implementation) pair. If component scan is not enabled, then you have to define the bean explicitly in your application-config.xml (or equivalent spring configuration file).

Do I need @Qualifier or @Resource?

Once you have more than one implementation, then you need to qualify each of them and during auto-wiring, you would need to use the @Qualifier annotation to inject the right implementation, along with @Autowired annotation. If you are using @Resource (J2EE semantics), then you should specify the bean name using the name attribute of this annotation.

Why do we autowire the interface and not the implemented class?

Firstly, it is always a good practice to code to interfaces in general. Secondly, in case of spring, you can inject any implementation at runtime. A typical use case is to inject mock implementation during testing stage.

interface IA
{
  public void someFunction();
}


class B implements IA
{
  public void someFunction()
  {
    //busy code block
  }
  public void someBfunc()
  {
     //doing b things
  }
}


class C implements IA
{
  public void someFunction()
  {
    //busy code block
  }
  public void someCfunc()
  {
     //doing C things
  }
}

class MyRunner
{
     @Autowire
     @Qualifier("b") 
     IA worker;

     ....
     worker.someFunction();
}

Your bean configuration should look like this:

<bean id="b" class="B" />
<bean id="c" class="C" />
<bean id="runner" class="MyRunner" />

Alternatively, if you enabled component scan on the package where these are present, then you should qualify each class with @Component as follows:

interface IA
{
  public void someFunction();
}

@Component(value="b")
class B implements IA
{
  public void someFunction()
  {
    //busy code block
  }
  public void someBfunc()
  {
     //doing b things
  }
}


@Component(value="c")
class C implements IA
{
  public void someFunction()
  {
    //busy code block
  }
  public void someCfunc()
  {
     //doing C things
  }
}

@Component    
class MyRunner
{
     @Autowire
     @Qualifier("b") 
     IA worker;

     ....
     worker.someFunction();
}

Then worker in MyRunner will be injected with an instance of type B.

Difference between static and shared libraries?

Shared libraries are .so (or in Windows .dll, or in OS X .dylib) files. All the code relating to the library is in this file, and it is referenced by programs using it at run-time. A program using a shared library only makes reference to the code that it uses in the shared library.

Static libraries are .a (or in Windows .lib) files. All the code relating to the library is in this file, and it is directly linked into the program at compile time. A program using a static library takes copies of the code that it uses from the static library and makes it part of the program. [Windows also has .lib files which are used to reference .dll files, but they act the same way as the first one].

There are advantages and disadvantages in each method:

  • Shared libraries reduce the amount of code that is duplicated in each program that makes use of the library, keeping the binaries small. It also allows you to replace the shared object with one that is functionally equivalent, but may have added performance benefits without needing to recompile the program that makes use of it. Shared libraries will, however have a small additional cost for the execution of the functions as well as a run-time loading cost as all the symbols in the library need to be connected to the things they use. Additionally, shared libraries can be loaded into an application at run-time, which is the general mechanism for implementing binary plug-in systems.

  • Static libraries increase the overall size of the binary, but it means that you don't need to carry along a copy of the library that is being used. As the code is connected at compile time there are not any additional run-time loading costs. The code is simply there.

Personally, I prefer shared libraries, but use static libraries when needing to ensure that the binary does not have many external dependencies that may be difficult to meet, such as specific versions of the C++ standard library or specific versions of the Boost C++ library.

How can I require at least one checkbox be checked before a form can be submitted?

<ul>
    <li><input class="checkboxes" name="BoxSelect[]" type="checkbox" value="Box 1" required><label>Box 1</label></li>
    <li><input class="checkboxes" name="BoxSelect[]" type="checkbox" value="Box 2" required><label>Box 2</label></li>
    <li><input class="checkboxes" name="BoxSelect[]" type="checkbox" value="Box 3" required><label>Box 3</label></li>
    <li><input class="checkboxes" name="BoxSelect[]" type="checkbox" value="Box 4" required><label>Box 4</label></li>
</ul>

<script type="text/javascript">
$(document).ready(function(){
    var checkboxes = $('.checkboxes');
    checkboxes.change(function(){
        if($('.checkboxes:checked').length>0) {
            checkboxes.removeAttr('required');
        } else {
            checkboxes.attr('required', 'required');
        }
    });
});
</script>

How do I truly reset every setting in Visual Studio 2012?

1) Run Visual Studio Installer

2) Click More on your Installed version and select Repair

3) Restart

Worked on Visual Studio 2017 Community

Open window in JavaScript with HTML inserted

You can also create an "example.html" page which has your desired html and give that page's url as parameter to window.open

var url = '/example.html';
var myWindow = window.open(url, "", "width=800,height=600");

How can I use break or continue within for loop in Twig template?

From @NHG comment — works perfectly

{% for post in posts|slice(0,10) %}

How can I iterate over files in a given directory?

Original answer:

import os

for filename in os.listdir(directory):
    if filename.endswith(".asm") or filename.endswith(".py"): 
         # print(os.path.join(directory, filename))
        continue
    else:
        continue

Python 3.6 version of the above answer, using os - assuming that you have the directory path as a str object in a variable called directory_in_str:

import os

directory = os.fsencode(directory_in_str)
    
for file in os.listdir(directory):
     filename = os.fsdecode(file)
     if filename.endswith(".asm") or filename.endswith(".py"): 
         # print(os.path.join(directory, filename))
         continue
     else:
         continue

Or recursively, using pathlib:

from pathlib import Path

pathlist = Path(directory_in_str).glob('**/*.asm')
for path in pathlist:
     # because path is object not string
     path_in_str = str(path)
     # print(path_in_str)
  • Use rglob to replace glob('**/*.asm') with rglob('*.asm')
    • This is like calling Path.glob() with '**/' added in front of the given relative pattern:
from pathlib import Path

pathlist = Path(directory_in_str).rglob('*.asm')
for path in pathlist:
     # because path is object not string
     path_in_str = str(path)
     # print(path_in_str)

Google Maps Android API v2 - Interactive InfoWindow (like in original android google maps)

I see that this question is already old but still...

We made a sipmle library at our company for achieving what is desired - An interactive info window with views and everything. You can check it out on github.

I hope it helps :)

How to check if a view controller is presented modally or pushed on a navigation stack?

To detect your controller is pushed or not just use below code in anywhere you want:

if ([[[self.parentViewController childViewControllers] firstObject] isKindOfClass:[self class]]) {

    // Not pushed
}
else {

    // Pushed
}

I hope this code can help anyone...

CronJob not running

Finally I found the solution. Following is the solution:-

  1. Never use relative path in python scripts to be executed via crontab. I did something like this instead:-

    import os
    import sys
    import time, datetime
    
    CLASS_PATH = '/srv/www/live/mainapp/classes'
    SETTINGS_PATH = '/srv/www/live/foodtrade'
    sys.path.insert(0, CLASS_PATH)
    sys.path.insert(1,SETTINGS_PATH)
    
    import other_py_files
    
  2. Never supress the crontab code instead use mailserver and check the mail for the user. That gives clearer insights of what is going.

What happened to console.log in IE8?

Here is my "IE please don't crash"

typeof console=="undefined"&&(console={});typeof console.log=="undefined"&&(console.log=function(){});

Convert IQueryable<> type object to List<T> type?

System.Linq has ToList() on IQueryable<> and IEnumerable<>. It will cause a full pass through the data to put it into a list, though. You loose your deferred invoke when you do this. Not a big deal if it is the consumer of the data.

How can I view array structure in JavaScript with alert()?

If what you want is to show with an alert() the content of an array of objects, i recomend you to define in the object the method toString() so with a simple alert(MyArray); the full content of the array will be shown in the alert.

Here is an example:

//-------------------------------------------------------------------
// Defininf the Point object
function Point(CoordenadaX, CoordenadaY) {
    // Sets the point coordinates depending on the parameters defined
    switch (arguments.length) {
        case 0:
            this.x = null;
            this.y = null;
            break;
        case 1:
            this.x = CoordenadaX;
            this.y = null;
            break;
        case 2:
            this.x = CoordenadaX;
            this.y = CoordenadaY;
            break;
    }
    // This adds the toString Method to the point object so the 
    // point can be printed using alert();
    this.toString = function() {
        return " (" + this.x + "," + this.y + ") ";
    };
 }

Then if you have an array of points:

var MyArray = [];
MyArray.push ( new Point(5,6) );
MyArray.push ( new Point(7,9) );

You can print simply calling:

alert(MyArray);

Hope this helps!

How to connect SQLite with Java?

You have to download and add the SQLite JDBC driver to your classpath.
You can download from here https://bitbucket.org/xerial/sqlite-jdbc/downloads

If you use Gradle, you will only have to add the SQLite dependency:

dependencies {
    compile 'org.xerial:sqlite-jdbc:3.8.11.2'
} 

Next thing you have to do is to initialize the driver:

try {
    Class.forName("org.sqlite.JDBC");
} catch (ClassNotFoundException eString) {
    System.err.println("Could not init JDBC driver - driver not found");
}

How to change colour of blue highlight on select box dropdown

i just found this site that give a cool themes for the select box http://gregfranko.com/jquery.selectBoxIt.js/

and you can try this themes if your problem with the overall look blue - yellow - grey

Read HttpContent in WebApi controller

By design the body content in ASP.NET Web API is treated as forward-only stream that can be read only once.

The first read in your case is being done when Web API is binding your model, after that the Request.Content will not return anything.

You can remove the contact from your action parameters, get the content and deserialize it manually into object (for example with Json.NET):

[HttpPut]
public HttpResponseMessage Put(int accountId)
{
    HttpContent requestContent = Request.Content;
    string jsonContent = requestContent.ReadAsStringAsync().Result;
    CONTACT contact = JsonConvert.DeserializeObject<CONTACT>(jsonContent);
    ...
}

That should do the trick (assuming that accountId is URL parameter so it will not be treated as content read).

How to check whether a string contains a substring in JavaScript?

There is a String.prototype.includes in ES6:

"potato".includes("to");
> true

Note that this does not work in Internet Explorer or some other old browsers with no or incomplete ES6 support. To make it work in old browsers, you may wish to use a transpiler like Babel, a shim library like es6-shim, or this polyfill from MDN:

if (!String.prototype.includes) {
  String.prototype.includes = function(search, start) {
    'use strict';
    if (typeof start !== 'number') {
      start = 0;
    }

    if (start + search.length > this.length) {
      return false;
    } else {
      return this.indexOf(search, start) !== -1;
    }
  };
}

How to create a regex for accepting only alphanumeric characters?

[a-zA-Z0-9] will only match ASCII characters, it won't match

String target = new String("A" + "\u00ea" + "\u00f1" +
                             "\u00fc" + "C");

If you also want to match unicode characters:

String pat = "^[\\p{L}0-9]*$";

Multiple axis line chart in excel

Best and Free ( maybe only) solution for this is google sheets. i don't know whether it plots as u expected or not but certainly you can draw multiple axes.

Regards

keerthan

How to compile .c file with OpenSSL includes?

You need to include the library path (-L/usr/local/lib/)

gcc -o Opentest Opentest.c -L/usr/local/lib/ -lssl -lcrypto

It works for me.

How to get bitmap from a url in android?

This is a simple one line way to do it:

    try {
        URL url = new URL("http://....");
        Bitmap image = BitmapFactory.decodeStream(url.openConnection().getInputStream());
    } catch(IOException e) {
        System.out.println(e);
    }

PHP not displaying errors even though display_errors = On

You also need to make sure you have your php.ini file include the following set or errors will go only to the log that is set by default or specified in the virtual host's configuration.

display_errors = On

The php.ini file is where base settings for all PHP on your server, however these can easily be overridden and altered any place in the PHP code and effect everything following that change. A good check is to add the display_errors directive to your php.ini file. If you don't see an error, but one is being logged, insert this at the top of the file causing the error:

ini_set('display_errors', 1);
error_reporting(E_ALL);

If this works then something earlier in your code is disabling error display.

Reading a file line by line in Go

In the code bellow, I read the interests from the CLI until the user hits enter and I'm using Readline:

interests := make([]string, 1)
r := bufio.NewReader(os.Stdin)
for true {
    fmt.Print("Give me an interest:")
    t, _, _ := r.ReadLine()
    interests = append(interests, string(t))
    if len(t) == 0 {
        break;
    }
}
fmt.Println(interests)

Pure css close button

I spent more time on this than I should have, and haven't tested in IE for obvious reasons. That being said, it's pretty much identical.

http://jsfiddle.net/adzFe/14/

a.boxclose{
    float:right;
    margin-top:-30px;
    margin-right:-30px;
    cursor:pointer;
    color: #fff;
    border: 1px solid #AEAEAE;
    border-radius: 30px;
    background: #605F61;
    font-size: 31px;
    font-weight: bold;
    display: inline-block;
    line-height: 0px;
    padding: 11px 3px;       
}

.boxclose:before {
    content: "×";
}

Switch to selected tab by name in Jquery-UI Tabs

Only this code real works!

$('#tabs').tabs();
$('#tabs').tabs('select', '#sample-tab-2');

Clear android application user data

Afaik the Browser application data is NOT clearable for other apps, since it is store in private_mode. So executing this command could probalby only work on rooted devices. Otherwise you should try another approach.

Simple DatePicker-like Calendar

No need to include JQuery or any other third party library.

Specify your input date format in title tag.

HTML:

<script type="text/javascript" src="http://services.iperfect.net/js/IP_generalLib.js">

Body

<input type="text" name="date1" id="date1" alt="date" class="IP_calendar" title="d/m/Y">

How to conditional format based on multiple specific text in Excel

You can use MATCH for instance.

  1. Select the column from the first cell, for example cell A2 to cell A100 and insert a conditional formatting, using 'New Rule...' and the option to conditional format based on a formula.

  2. In the entry box, put:

    =MATCH(A2, 'Sheet2'!A:A, 0)
    
  3. Pick the desired formatting (change the font to red or fill the cell background, etc) and click OK.

MATCH takes the value A2 from your data table, looks into 'Sheet2'!A:A and if there's an exact match (that's why there's a 0 at the end), then it'll return the row number.

Note: Conditional formatting based on conditions from other sheets is available only on Excel 2010 onwards. If you're working on an earlier version, you might want to get the list of 'Don't check' in the same sheet.

EDIT: As per new information, you will have to use some reverse matching. Instead of the above formula, try:

=SUM(IFERROR(SEARCH('Sheet2'!$A$1:$A$44, A2),0))

How to make my layout able to scroll down?

For using scroll view along with Relative layout :

<ScrollView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:fillViewport="true"> <!--IMPORTANT otherwise backgrnd img. will not fill the whole screen -->

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingBottom="@dimen/activity_vertical_margin"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        android:paddingTop="@dimen/activity_vertical_margin"
        android:background="@drawable/background_image"
    >

    <!-- Bla Bla Bla i.e. Your Textviews/Buttons etc. -->
    </RelativeLayout>
</ScrollView>

Parsing a JSON string in Ruby

Just to extend the answers a bit with what to do with the parsed object:

# JSON Parsing example
require "rubygems" # don't need this if you're Ruby v1.9.3 or higher
require "json"

string = '{"desc":{"someKey":"someValue","anotherKey":"value"},"main_item":{"stats":{"a":8,"b":12,"c":10}}}'
parsed = JSON.parse(string) # returns a hash

p parsed["desc"]["someKey"]
p parsed["main_item"]["stats"]["a"]

# Read JSON from a file, iterate over objects
file = open("shops.json")
json = file.read

parsed = JSON.parse(json)

parsed["shop"].each do |shop|
  p shop["id"]
end

Field 'id' doesn't have a default value?

I was getting error while ExecuteNonQuery() resolved with adding AutoIncrement to Primary Key of my table. In your case if you don't want to add primary key then we must need to assign value to primary key.

ALTER TABLE `t1` 
CHANGE COLUMN `id` `id` INT(11) NOT NULL AUTO_INCREMENT ;

How can I comment a single line in XML?

It is the same as the HTML or JavaScript block comments:

<!-- The to-be-commented XML block goes here. -->

What is %2C in a URL?

Simple & Easy answer,

The %2C means , comma in URL. when you add the String "abc,defg" in the url as parameter then that comma in the string which is abc , defg is changed to abc%2Cdefg .There is no need to worry about it.

How to make a button redirect to another page using jQuery or just Javascript

You can use this simple JavaScript code to make search button to link to a sample search results page. Here I have redirected to '/search' of my home page, If you want to search from Google search engine, You can use "https://www.google.com/search" in form action.

<form action="/search"> Enter your search text: 
<input type="text" id="searchtext" name="q"> &nbsp;
<input onclick="myFunction()" type="submit" value="Search It" />
</form> 
<script> function myFunction() 
{ 
var search = document.getElementById("searchtext").value; 
window.location = '/search?q='+search; 
} 
</script>

Replace an element into a specific position of a vector

See an example here: http://www.cplusplus.com/reference/stl/vector/insert/ eg.:



...
vector::iterator iterator1;

  iterator1= vec1.begin();
  vec1.insert ( iterator1+i , vec2[i] );

// This means that at position "i" from the beginning it will insert the value from vec2 from position i

Your first approach was replacing the values from vec1[i] with the values from vec2[i]