Programs & Examples On #Ftps

An extension to the commonly used File Transfer Protocol (FTP) that adds support for the Transport Layer Security (TLS) and the Secure Sockets Layer (SSL) cryptographic protocols.

curl: (35) error:1408F10B:SSL routines:ssl3_get_record:wrong version number

If anyone is getting this error using Nginx, try adding the following to your server config:

server {
    listen 443 ssl;

The issue stems from Nginx serving an HTTP server to a client expecting HTTPS on whatever port you're listening on. When you specify ssl in the listen directive, you clear this up on the server side.

TypeError: expected str, bytes or os.PathLike object, not _io.BufferedReader

I think it has to do with your second element in storbinary. You are trying to open file, but it is already a pointer to the file you opened in line file = open(local_path,'rb'). So, try to use ftp.storbinary("STOR " + i, file).

curl: (35) SSL connect error

curl 7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.19.1 Basic ECC zlib/1.2.3 libidn/1.18 libssh2/1.4.2

You are using a very old version of curl. My guess is that you run into the bug described 6 years ago. Fix is to update your curl.

Curl: Fix CURL (51) SSL error: no alternative certificate subject name matches

Editor's note: this is a very dangerous approach, if you are using a version of PHP old enough to use it. It opens your code to man-in-the-middle attacks and removes one of the primary purposes of an encrypted connection. The ability to do this has been removed from modern versions of PHP because it is so dangerous. The only reason this has been upvoted 70 time is because people are lazy. DO NOT DO THIS.

I know it's a (very) old question and it's about command line, but when I searched Google for "SSL: no alternative certificate subject name matches target host name", this was the first hit.

It took me a good while to figure out the answer so hope this saves someone a lot of time! In PHP add this to your cUrl setopts:

curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, FALSE);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, FALSE);

p.s: this should be a temporary solution. Since this is a certificate error, best thing is to have the certificate fixed ofcourse!

PowerShell Connect to FTP server and get files

Remote pick directory path should be the exact path on the ftp server you are tryng to access.. here is the script to download files from the server.. you can add or modify with SSLMode..

#ftp server 
$ftp = "" 
$user = "XX" 
$pass = "XXX"
$SetType = "bin"  
$remotePickupDir = Get-ChildItem 'c:\test' -recurse
$webclient = New-Object System.Net.WebClient 

$webclient.Credentials = New-Object System.Net.NetworkCredential($user,$pass)  
foreach($item in $remotePickupDir){ 
    $uri = New-Object System.Uri($ftp+$item.Name) 

phpinfo() is not working on my CentOS server

I accidentally set the wrong file permissions. After chmod 644 phpinfo.php the info indeed showed up as expected.

"com.jcraft.jsch.JSchException: Auth fail" with working passwords

Try to add auth method explicitly as below, because sometimes it is required:

session.setConfig("PreferredAuthentications", "password");

cURL not working (Error #77) for SSL connections on CentOS for non-root users

If you recently reached here as I did when searching for the same error in vain you may find it to be an update to NSS causing failure on CentOS. Test by running yum update and see if you get errors, curl also creates this error. Solution is simple enough just install NSS manually.

Read on...

If you're like me it threw up an error similar to this:

curl: (77) Problem with the SSL CA cert (path? access rights?)

This took some time to solve but found that it wasn't the CA cert because by recreating them and checking all the configuration I had ruled it out. It could have been libcurl so I went in search of updates.

As mentioned I recreated CA certs. You can do this also but it may be a waste of time.

The next step (probably should of been my first) was to check that everything was up-to-date by simply running yum.

$ yum update
$ yum upgrade

This gave me an affirmative answer that there was a bigger problem at play: Downloading Packages: error: rpmts_HdrFromFdno: Header V3 RSA/SHA1 Signature, key ID c105b9de: BAD Problem opening package nss-softokn-freebl-3.14.3–19.el6_6.x86_64.rpm I started reading about Certificate Verification with NSS and how this new update may be related to my problems. So yum is broken. This is because nss-softokn-* needs nss-softokn-freebl-* need each other to function. The problem is they don't check each others version for compatibility and in some cases it ends up breaking yum. Lets go fix things:

$ wget
$ rpm -Uvh nss-softokn-freebl-3.14.3–19.el6_6.x86_64.rpm
$ yum update

You should of course download from your nearest mirror and check for the correct version / OS etc. We basically download and install the update from the rpm to fix yum. As @grumpysysadmin pointed out you can shorten the commands down. @cwgtex contributed that you should install the upgrade using the RPM command making the process even simplier.

To fix things with wordpress you need to restart your http server.

$ service httpd restart

Try again and success!

Secure FTP using Windows batch script

First, make sure you understand, if you need to use Secure FTP (=FTPS, as per your text) or SFTP (as per tag you have used).

Neither is supported by Windows command-line ftp.exe. As you have suggested, you can use WinSCP. It supports both FTPS and SFTP.

Using WinSCP, your batch file would look like (for SFTP):

echo open sftp://ftp_user:[email protected] -hostkey="server's hostkey" >> ftpcmd.dat
echo put c:\directory\%1-export-%date%.csv >> ftpcmd.dat
echo exit >> ftpcmd.dat /script=ftpcmd.dat
del ftpcmd.dat

And the batch file: /log=ftpcmd.log /script=ftpcmd.dat /parameter %1 %date%

Though using all capabilities of WinSCP (particularly providing commands directly on command-line and the %TIMESTAMP% syntax), the batch file simplifies to: /log=ftpcmd.log /command ^
    "open sftp://ftp_user:[email protected] -hostkey=""server's hostkey""" ^
    "put c:\directory\%1-export-%%TIMESTAMP#yyyymmdd%%.csv" ^

For the purpose of -hostkey switch, see verifying the host key in script.

Easier than assembling the script/batch file manually is to setup and test the connection settings in WinSCP GUI and then have it generate the script or batch file for you:

Generate batch file

All you need to tweak is the source file name (use the %TIMESTAMP% syntax as shown previously) and the path to the log file.

For FTPS, replace the sftp:// in the open command with ftpes:// (explicit TLS/SSL) or ftps:// (implicit TLS/SSL). Remove the -hostkey switch. /log=ftpcmd.log /command ^
    "open ftps://ftp_user:[email protected] -explicit" ^
    "put c:\directory\%1-export-%%TIMESTAMP#yyyymmdd%%.csv" ^

You may need to add the -certificate switch, if your server's certificate is not issued by a trusted authority.

Again, as with the SFTP, easier is to setup and test the connection settings in WinSCP GUI and then have it generate the script or batch file for you.

See a complete conversion guide from ftp.exe to WinSCP.

You should also read the Guide to automating file transfers to FTP server or SFTP server.

Note to using %TIMESTAMP#yyyymmdd% instead of %date%: A format of %date% variable value is locale-specific. So make sure you test the script on the same locale you are actually going to use the script on. For example on my Czech locale the %date% resolves to ct 06. 11. 2014, what might be problematic when used as a part of a file name.

For this reason WinSCP supports (locale-neutral) timestamp formatting natively. For example %TIMESTAMP#yyyymmdd% resolves to 20170515 on any locale.

(I'm the author of WinSCP)

downloading all the files in a directory with cURL

Here is how I did to download quickly with cURL (I'm not sure how many files it can download though) :

setlocal EnableDelayedExpansion

cd where\to\download

set STR=
for /f "skip=2 delims=" %%F in ('P:\curl -l -u user:password') do set STR=-O "" !STR!
path\to\curl.exe -v -u user:password !STR!

Why skip=2 ? To get ride of . and ..

Why delims= ? To support names with spaces

PHP fopen() Error: failed to open stream: Permission denied

[function.fopen]: failed to open stream

If you have access to your php.ini file, try enabling Fopen. Find the respective line and set it to be "on": & if in wp e.g localhost/wordpress/function.fopen in the php.ini :

allow_url_fopen = off
should bee this 
allow_url_fopen = On

And add this line below it:
allow_url_include = off
should bee this 
allow_url_include = on

Unable to find the wrapper "https" - did you forget to enable it when you configured PHP?

I got this error while attempting to install composer using php cli on Windows. To solve it, I just needed to change the extension directory in php.ini. I had to uncomment this line:

; On windows:
extension_dir = "ext"

Then this one and all things worked

; Dynamic Extensions ;

Accessing a Shared File (UNC) From a Remote, Non-Trusted Domain With Credentials

For people looking for a quick solution, you can use the NetworkShareAccesser I wrote recently (based on this answer (thanks so much!)):


    File.Copy(@"C:\Some\File\To\copy.txt", @"\\REMOTE-COMPUTER\My\Shared\Target\file.txt");

WARNING: Please make absolutely sure, that Dispose of the NetworkShareAccesser is called (even if you app crashes!), otherwise an open connection will remain on Windows. You can see all open connections by opening the cmd prompt and enter net use.

The Code:

/// <summary>
/// Provides access to a network share.
/// </summary>
public class NetworkShareAccesser : IDisposable
    private string _remoteUncName;
    private string _remoteComputerName;

    public string RemoteComputerName
            return this._remoteComputerName;
            this._remoteComputerName = value;
            this._remoteUncName = @"\\" + this._remoteComputerName;

    public string UserName
    public string Password

    #region Consts

    private const int RESOURCE_CONNECTED = 0x00000001;
    private const int RESOURCE_GLOBALNET = 0x00000002;
    private const int RESOURCE_REMEMBERED = 0x00000003;

    private const int RESOURCETYPE_ANY = 0x00000000;
    private const int RESOURCETYPE_DISK = 0x00000001;
    private const int RESOURCETYPE_PRINT = 0x00000002;

    private const int RESOURCEDISPLAYTYPE_GENERIC = 0x00000000;
    private const int RESOURCEDISPLAYTYPE_DOMAIN = 0x00000001;
    private const int RESOURCEDISPLAYTYPE_SERVER = 0x00000002;
    private const int RESOURCEDISPLAYTYPE_SHARE = 0x00000003;
    private const int RESOURCEDISPLAYTYPE_FILE = 0x00000004;
    private const int RESOURCEDISPLAYTYPE_GROUP = 0x00000005;

    private const int RESOURCEUSAGE_CONNECTABLE = 0x00000001;
    private const int RESOURCEUSAGE_CONTAINER = 0x00000002;

    private const int CONNECT_INTERACTIVE = 0x00000008;
    private const int CONNECT_PROMPT = 0x00000010;
    private const int CONNECT_REDIRECT = 0x00000080;
    private const int CONNECT_UPDATE_PROFILE = 0x00000001;
    private const int CONNECT_COMMANDLINE = 0x00000800;
    private const int CONNECT_CMD_SAVECRED = 0x00001000;

    private const int CONNECT_LOCALDRIVE = 0x00000100;


    #region Errors

    private const int NO_ERROR = 0;

    private const int ERROR_ACCESS_DENIED = 5;
    private const int ERROR_ALREADY_ASSIGNED = 85;
    private const int ERROR_BAD_DEVICE = 1200;
    private const int ERROR_BAD_NET_NAME = 67;
    private const int ERROR_BAD_PROVIDER = 1204;
    private const int ERROR_CANCELLED = 1223;
    private const int ERROR_EXTENDED_ERROR = 1208;
    private const int ERROR_INVALID_ADDRESS = 487;
    private const int ERROR_INVALID_PARAMETER = 87;
    private const int ERROR_INVALID_PASSWORD = 1216;
    private const int ERROR_MORE_DATA = 234;
    private const int ERROR_NO_MORE_ITEMS = 259;
    private const int ERROR_NO_NET_OR_BAD_PATH = 1203;
    private const int ERROR_NO_NETWORK = 1222;

    private const int ERROR_BAD_PROFILE = 1206;
    private const int ERROR_CANNOT_OPEN_PROFILE = 1205;
    private const int ERROR_DEVICE_IN_USE = 2404;
    private const int ERROR_NOT_CONNECTED = 2250;
    private const int ERROR_OPEN_FILES = 2401;


    #region PInvoke Signatures

    private static extern int WNetUseConnection(
        IntPtr hwndOwner,
        NETRESOURCE lpNetResource,
        string lpPassword,
        string lpUserID,
        int dwFlags,
        string lpAccessName,
        string lpBufferSize,
        string lpResult

    private static extern int WNetCancelConnection2(
        string lpName,
        int dwFlags,
        bool fForce

    private class NETRESOURCE
        public int dwScope = 0;
        public int dwType = 0;
        public int dwDisplayType = 0;
        public int dwUsage = 0;
        public string lpLocalName = "";
        public string lpRemoteName = "";
        public string lpComment = "";
        public string lpProvider = "";


    /// <summary>
    /// Creates a NetworkShareAccesser for the given computer name. The user will be promted to enter credentials
    /// </summary>
    /// <param name="remoteComputerName"></param>
    /// <returns></returns>
    public static NetworkShareAccesser Access(string remoteComputerName)
        return new NetworkShareAccesser(remoteComputerName);

    /// <summary>
    /// Creates a NetworkShareAccesser for the given computer name using the given domain/computer name, username and password
    /// </summary>
    /// <param name="remoteComputerName"></param>
    /// <param name="domainOrComuterName"></param>
    /// <param name="userName"></param>
    /// <param name="password"></param>
    public static NetworkShareAccesser Access(string remoteComputerName, string domainOrComuterName, string userName, string password)
        return new NetworkShareAccesser(remoteComputerName,
                                        domainOrComuterName + @"\" + userName,

    /// <summary>
    /// Creates a NetworkShareAccesser for the given computer name using the given username (format: domainOrComputername\Username) and password
    /// </summary>
    /// <param name="remoteComputerName"></param>
    /// <param name="userName"></param>
    /// <param name="password"></param>
    public static NetworkShareAccesser Access(string remoteComputerName, string userName, string password)
        return new NetworkShareAccesser(remoteComputerName, 

    private NetworkShareAccesser(string remoteComputerName)
        RemoteComputerName = remoteComputerName;               

        this.ConnectToShare(this._remoteUncName, null, null, true);

    private NetworkShareAccesser(string remoteComputerName, string userName, string password)
        RemoteComputerName = remoteComputerName;
        UserName = userName;
        Password = password;

        this.ConnectToShare(this._remoteUncName, this.UserName, this.Password, false);

    private void ConnectToShare(string remoteUnc, string username, string password, bool promptUser)
            dwType = RESOURCETYPE_DISK,
            lpRemoteName = remoteUnc

        int result;
        if (promptUser)
            result = WNetUseConnection(IntPtr.Zero, nr, "", "", CONNECT_INTERACTIVE | CONNECT_PROMPT, null, null, null);
            result = WNetUseConnection(IntPtr.Zero, nr, password, username, 0, null, null, null);

        if (result != NO_ERROR)
            throw new Win32Exception(result);

    private void DisconnectFromShare(string remoteUnc)
        int result = WNetCancelConnection2(remoteUnc, CONNECT_UPDATE_PROFILE, false);
        if (result != NO_ERROR)
            throw new Win32Exception(result);

    /// <summary>
    /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
    /// </summary>
    /// <filterpriority>2</filterpriority>
    public void Dispose()

How to retrieve a file from a server via SFTP?

Andy, to delete file on remote system you need to use (channelExec) of JSch and pass unix/linux commands to delete it.

How to search for a part of a word with ElasticSearch

While there are a lot of answers which focuses on solving the issue at hand but don't talk much about the various trade-off which someone needs to make before choosing a particular answer. So let me try to add a few more details on this perspective.

Partial search is now a day a very common and important feature and if not implemented properly can lead to poor user experience and bad performance, so first know your application function and non-function requirement related to this feature which I talked about in my this detailed SO answer.

Now there are various approaches, like query time, index time, completion suggester and search as you type data-types added in recent version of elasticsarch.

Now people who quickly want to just implement a solution can use below end to end working solution.

Index mapping

  "settings": {
    "analysis": {
      "filter": {
        "autocomplete_filter": {
          "type": "ngram",
          "min_gram": 1,
          "max_gram": 10
      "analyzer": {
        "autocomplete": { 
          "type": "custom",
          "tokenizer": "standard",
          "filter": [
    "index.max_ngram_diff" : 10
  "mappings": {
    "properties": {
      "title": {
        "type": "text",
        "analyzer": "autocomplete", 
        "search_analyzer": "standard" 

Index given sample docs

  "title" : "John Doeman"

  "title" : "Jane Doewoman"

  "title" : "Jimmy Jackal"

And search query

    "query": {
        "match": {
            "title": "Doe"

which returns expected search results

 "hits": [
                "_index": "6467067",
                "_type": "_doc",
                "_id": "1",
                "_score": 0.76718915,
                "_source": {
                    "title": "John Doeman"
                "_index": "6467067",
                "_type": "_doc",
                "_id": "2",
                "_score": 0.76718915,
                "_source": {
                    "title": "Jane Doewoman"

How to get the first column of a pandas DataFrame as a Series?

You can get the first column as a Series by following code:


How to add form validation pattern in Angular 2?

Now, you don't need to use FormBuilder and all this complicated valiation angular stuff. I put more details from this (Angular 2.0.8 - 3march2016):

Example from repo :

<input [ngControl]="fullName" pattern="[a-zA-Z ]*">

I test it and it works :) - here is my code:

<form (ngSubmit)="onSubmit(room)" #roomForm='ngForm'  >

Alternative approach (UPDATE June 2017)

Validation is ONLY on server side. If something is wrong then server return error code e.g HTTP 400 and following json object in response body (as example):

this.err = { 
    "capacity" : "too_small"
    "filed_name" : "error_name", 
    "field2_name" : "other_error_name",

In html template I use separate tag (div/span/small etc.)

<input [(ngModel)]='room.capacity' ...>
<small *ngIf="err.capacity" ...>{{ translate(err.capacity) }}</small>

If in 'capacity' is error then tag with msg translation will be visible. This approach have following advantages:

  • it is very simple
  • avoid backend validation code duplication on frontend (for regexp validation this can either prevent or complicate ReDoS attacks)
  • control on way the error is shown (e.g. <small> tag)
  • backend return error_name which is easy to translate to proper language in frontend

Of course sometimes I make exception if validation is needed on frontend side (e.g. retypePassword field on registration is never send to server).

How to invoke a Linux shell command from Java

exec does not execute a command in your shell


Process p = Runtime.getRuntime().exec(new String[]{"csh","-c","cat /home/narek/pk.txt"});


EDIT:: I don't have csh on my system so I used bash instead. The following worked for me

Process p = Runtime.getRuntime().exec(new String[]{"bash","-c","ls /home/XXX"});

What does "#pragma comment" mean?

#pragma comment is a compiler directive which indicates Visual C++ to leave a comment in the generated object file. The comment can then be read by the linker when it processes object files.

#pragma comment(lib, libname) tells the linker to add the 'libname' library to the list of library dependencies, as if you had added it in the project properties at Linker->Input->Additional dependencies

See #pragma comment on MSDN

What is the difference between the remap, noremap, nnoremap and vnoremap mapping commands in Vim?

remap is an option that makes mappings work recursively. By default it is on and I'd recommend you leave it that way. The rest are mapping commands, described below:

:map and :noremap are recursive and non-recursive versions of the various mapping commands. For example, if we run:

:map j gg           (moves cursor to first line)
:map Q j            (moves cursor to first line)
:noremap W j        (moves cursor down one line)


  • j will be mapped to gg.
  • Q will also be mapped to gg, because j will be expanded for the recursive mapping.
  • W will be mapped to j (and not to gg) because j will not be expanded for the non-recursive mapping.

Now remember that Vim is a modal editor. It has a normal mode, visual mode and other modes.

For each of these sets of mappings, there is a mapping that works in normal, visual, select and operator modes (:map and :noremap), one that works in normal mode (:nmap and :nnoremap), one in visual mode (:vmap and :vnoremap) and so on.

For more guidance on this, see:

:help :map
:help :noremap
:help recursive_mapping
:help :map-modes

How to calculate age (in years) based on Date of Birth and getDate()

I've done a lot of thinking and searching about this and I have 3 solutions that

  • calculate age correctly
  • are short (mostly)
  • are (mostly) very understandable.

Here are testing values:

DECLARE @NOW DATETIME = '2013-07-04 23:59:59' 
DECLARE @DOB DATETIME = '1986-07-05' 

Solution 1: I found this approach in one js library. It's my favourite.


It's actually adding difference in years to DOB and if it is bigger than current date then subtracts one year. Simple right? The only thing is that difference in years is duplicated here.

But if you don't need to use it inline you can write it like this:

SET @AGE = @AGE - 1

Solution 2: This one I originally copied from @bacon-bits. It's the easiest to understand but a bit long.


It's basically calculating age as we humans do.

Solution 3: My friend refactored it into this:

  CEILING(0.5 * SIGN((MONTH(@DOB) - MONTH(@NOW)) * 50 + DAY(@DOB) - DAY(@NOW)))

This one is the shortest but it's most difficult to understand. 50 is just a weight so the day difference is only important when months are the same. SIGN function is for transforming whatever value it gets to -1, 0 or 1. CEILING(0.5 * is the same as Math.max(0, value) but there is no such thing in SQL.

jQuery AutoComplete Trigger Change Event

I was trying to do the same, but without keeping a variable of autocomplete. I walk throught this calling change handler programatically on the select event, you only need to worry about the actual value of input.

    source: context.companies, 
    change: handleCompanyChanged,
    select: function(event,ui){

How to pass optional arguments to a method in C++?

An important rule with respect to default parameter usage:
Default parameters should be specified at right most end, once you specify a default value parameter you cannot specify non default parameter again. ex:

int DoSomething(int x, int y = 10, int z) -----------> Not Allowed

int DoSomething(int x, int z, int y = 10) -----------> Allowed 

When to use cla(), clf() or close() for clearing a plot in matplotlib?

They all do different things, since matplotlib uses a hierarchical order in which a figure window contains a figure which may consist of many axes. Additionally, there are functions from the pyplot interface and there are methods on the Figure class. I will discuss both cases below.

pyplot interface

pyplot is a module that collects a couple of functions that allow matplotlib to be used in a functional manner. I here assume that pyplot has been imported as import matplotlib.pyplot as plt. In this case, there are three different commands that remove stuff:

plt.cla() clears an axes, i.e. the currently active axes in the current figure. It leaves the other axes untouched.

plt.clf() clears the entire current figure with all its axes, but leaves the window opened, such that it may be reused for other plots.

plt.close() closes a window, which will be the current window, if not specified otherwise.

Which functions suits you best depends thus on your use-case.

The close() function furthermore allows one to specify which window should be closed. The argument can either be a number or name given to a window when it was created using figure(number_or_name) or it can be a figure instance fig obtained, i.e., usingfig = figure(). If no argument is given to close(), the currently active window will be closed. Furthermore, there is the syntax close('all'), which closes all figures.

methods of the Figure class

Additionally, the Figure class provides methods for clearing figures. I'll assume in the following that fig is an instance of a Figure:

fig.clf() clears the entire figure. This call is equivalent to plt.clf() only if fig is the current figure.

fig.clear() is a synonym for fig.clf()

Note that even del fig will not close the associated figure window. As far as I know the only way to close a figure window is using plt.close(fig) as described above.

How to install pip for Python 3.6 on Ubuntu 16.10?

Let's suppose that you have a system running Ubuntu 16.04, 16.10, or 17.04, and you want Python 3.6 to be the default Python.

If you're using Ubuntu 16.04 LTS, you'll need to use a PPA:

sudo add-apt-repository ppa:jonathonf/python-3.6  # (only for 16.04 LTS)

Then, run the following (this works out-of-the-box on 16.10 and 17.04):

sudo apt update
sudo apt install python3.6
sudo apt install python3.6-dev
sudo apt install python3.6-venv
sudo python3.6
sudo ln -s /usr/bin/python3.6 /usr/local/bin/python3
sudo ln -s /usr/local/bin/pip /usr/local/bin/pip3

# Do this only if you want python3 to be the default Python
# instead of python2 (may be dangerous, esp. before 2020):
# sudo ln -s /usr/bin/python3.6 /usr/local/bin/python

When you have completed all of the above, each of the following shell commands should indicate Python 3.6.1 (or a more recent version of Python 3.6):

python --version   # (this will reflect your choice, see above)
python3 --version
$(head -1 `which pip` | tail -c +3) --version
$(head -1 `which pip3` | tail -c +3) --version

How to install easy_install in Python 2.7.1 on Windows 7

That tool is part of the setuptools (now called Distribute) package. Install Distribute. Of course you'll have to fetch that one manually.

I need to get all the cookies from the browser

You cannot. By design, for security purpose, you can access only the cookies set by your site. StackOverflow can't see the cookies set by UserVoice nor those set by Amazon.

How to manage a redirect request after a jQuery Ajax call

You can also hook XMLHttpRequest send prototype. This will work for all sends (jQuery/dojo/etc) with one handler.

I wrote this code to handle a 500 page expired error, but it should work just as well to trap a 200 redirect. Ready the wikipedia entry on XMLHttpRequest onreadystatechange about the meaning of readyState.

// Hook XMLHttpRequest
var oldXMLHttpRequestSend = XMLHttpRequest.prototype.send;

XMLHttpRequest.prototype.send = function() {
  //console.dir( this );

  this.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 500 && this.responseText.indexOf("Expired") != -1) {
      try {
        document.documentElement.innerHTML = this.responseText;
      } catch(error) {
        // IE makes document.documentElement read only
        document.body.innerHTML = this.responseText;

  oldXMLHttpRequestSend.apply(this, arguments);

python list in sql query as parameter

To run a select from where field is in list of strings (instead of int), as per this question use repr(tuple(map(str, l))). Full example:

l = ['a','b','c']
sql = f'''

select name 
from students 
where id in {repr(tuple(map(str, l)))}

Returns: select name from students where id in ('a', 'b', 'c')

For a list of dates in Oracle, this worked

dates_str = ','.join([f'DATE {repr(s)}' for s in ['2020-11-24', '2020-12-28']])
dates_str = f'({dates_str})'

sql_cmd = f'''
select *
from students 
and date in {dates_str}

Returns: select * from students where and date in (DATE '2020-11-24',DATE '2020-12-28')

How do I localize the jQuery UI Datepicker?

This solution may help.

$(document).ready(function () {_x000D_
  var userLang = navigator.language || navigator.userLanguage;_x000D_
  var options = $.extend({},_x000D_
    $.datepicker.regional["ja"], {_x000D_
      dateFormat: "yy/mm/dd",_x000D_
      changeMonth: true,_x000D_
      changeYear: true,_x000D_
      highlightWeek: true_x000D_
#ui-datepicker-div {_x000D_
  font-size: 14px;_x000D_
<!DOCTYPE html>_x000D_
    <meta charset="UTF-8">_x000D_
    <link rel="stylesheet" type="text/css"_x000D_
    <script src=""></script>_x000D_
    <script src=""></script>_x000D_
    <script src=""></script>_x000D_
<h3>Japanese JQuery UI Datepicker</h3>_x000D_
<input type="text" id="japaneseCalendar"/>_x000D_

Installing tkinter on ubuntu 14.04

First, make sure you have Tkinter module installed.

sudo apt-get install python-tk

In python 2 the package name is Tkinter not tkinter.

from Tkinter import *


Convert .pfx to .cer

Might be irrelevant for OP's Q, but I've tried all openssl statements with all the different flags, while trying to connect with PHP \SoapClient(...) and after 3 days I finally found a solution that worked for me.


$ cd path/to/certificate/
$ openssl pkcs12 -in personal_certificate.pfx -out public_key.pem -clcerts

First you have to enter YOUR_CERT_PASSWORD once, then DIFFERENT_PASSWORD! twice. The latter will possibly be available to everyone with access to code.



$wsdlUrl   = "";
$publicKey = "rel/path/to/certificate/public_key.pem";
$password  = "DIFFERENT_PASSWORD!";

$params = [
    'local_cert' => $publicKey,
    'passphrase' => $password,
    'trace' => 1,
    'exceptions' => 0

$soapClient = new \SoapClient($wsdlUrl, $params);


window.location.href and () methods in JavaScript

  • will open a new browser with the specified URL.

  • window.location.href will open the URL in the window in which the code is called.

Note also that is a function on the window object itself whereas window.location is an object that exposes a variety of other methods and properties.

Use of Finalize/Dispose method in C#

Using lambdas instead of IDisposable.

I have never been thrilled with the whole using/IDisposable idea. The problem is that it requires the caller to:

  • know that they must use IDisposable
  • remember to use 'using'.

My new preferred method is to use a factory method and a lambda instead

Imagine I want to do something with a SqlConnection (something that should be wrapped in a using). Classically you would do

using (Var conn = Factory.MakeConnection())

New way


In the first case the caller could simply not use the using syntax. IN the second case the user has no choice. There is no method that creates a SqlConnection object, the caller must invoke DoWithConnection.

DoWithConnection looks like this

void DoWithConnection(Action<SqlConnection> action)
   using (var conn = MakeConnection())

MakeConnection is now private

"int cannot be dereferenced" in Java

Basically, you're trying to use int as if it was an Object, which it isn't ('s complicated)


Should be...

id == list[pos].getItemNumber()

How to trigger an event in input text after I stop typing/writing?

You can use underscore.js "debounce"

$('input#username').keypress( _.debounce( function(){<your ajax call here>}, 500 ) );

This means that your function call will execute after 500ms of pressing a key. But if you press another key (another keypress event is fired) before the 500ms, the previous function execution will be ignored (debounced) and the new one will execute after a fresh 500ms timer.

For extra info, using _.debounce(func,timer,true) would mean that the first function will execute and all other keypress events withing subsequent 500ms timers would be ignored.

Where is the <conio.h> header file on Linux? Why can't I find <conio.h>?

conio.h is a C header file used in old MS-DOS compilers to create text user interfaces. Compilers that targeted non-DOS operating systems, such as Linux, Win32 and OS/2, provided different implementations of these functions.

The #include <curses.h> will give you almost all the functionalities that was provided in conio.h

nucurses need to be installed at the first place

In deb based Distros use

sudo apt-get install libncurses5-dev libncursesw5-dev

And in rpm based distros use

sudo yum install ncurses-devel ncurses

For getch() class of functions, you can try this

UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 23: ordinal not in range(128)

You are encoding to UTF-8, then re-encoding to UTF-8. Python can only do this if it first decodes again to Unicode, but it has to use the default ASCII codec:

>>> u'ñ'
>>> u'ñ'.encode('utf8')
>>> u'ñ'.encode('utf8').encode('utf8')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 0: ordinal not in range(128)

Don't keep encoding; leave encoding to UTF-8 to the last possible moment instead. Concatenate Unicode values instead.

You can use str.join() (or, rather, unicode.join()) here to concatenate the three values with dashes in between:

nombre = u'-'.join(fabrica, sector, unidad)
return nombre.encode('utf-8')

but even encoding here might be too early.

Rule of thumb: decode the moment you receive the value (if not Unicode values supplied by an API already), encode only when you have to (if the destination API does not handle Unicode values directly).

What does the 'Z' mean in Unix timestamp '120314170138Z'?

"Z" doesn't stand for "Zulu"

I don't have any more information than the Wikipedia article cited by the two existing answers, but I believe the interpretation that "Z" stands for "Zulu" is incorrect. UTC time is referred to as "Zulu time" because of the use of Z to identify it, not the other way around. The "Z" seems to have been used to mark the time zone as the "zero zone", in which case "Z" unsurprisingly stands for "zero" (assuming the following information from Wikipedia is accurate):

Around 1950, a letter suffix was added to the zone description, assigning Z to the zero zone, and A–M (except J) to the east and N–Y to the west (J may be assigned to local time in non-nautical applications — zones M and Y have the same clock time but differ by 24 hours: a full day). These can be vocalized using the NATO phonetic alphabet which pronounces the letter Z as Zulu, leading to the use of the term "Zulu Time" for Greenwich Mean Time, or UT1 from January 1, 1972 onward.

Jquery UI datepicker. Disable array of Dates

If you want to disable particular date(s) in jquery datepicker then here is the simple demo for you.

<script type="text/javascript">
    var arrDisabledDates = {};
    arrDisabledDates[new Date("08/28/2017")] = new Date("08/28/2017");
    arrDisabledDates[new Date("12/23/2017")] = new Date("12/23/2017");
        dateFormat: "dd/mm/yy",
        beforeShowDay: function (date) {
            var day = date.getDay(),
                    bDisable = arrDisabledDates[date];
            if (bDisable)
                return [false, "", ""]

Squaring all elements in a list

you can do

square_list =[i**2 for i in start_list]

which returns

[25, 9, 1, 4, 16]  

or, if the list already has values

square_list.extend([i**2 for i in start_list])  

which results in a list that looks like:

[25, 9, 1, 4, 16]  

Note: you don't want to do

square_list.append([i**2 for i in start_list])

as it literally adds a list to the original list, such as:

[_original_, _list_, _data_, [25, 9, 1, 4, 16]]

How to link to specific line number on github

For a line in a pull request.
90 <- PR number
ce6bf647d5a531e54ef0502c7fe799de <- MD5 has of file name from repo root
R <- Which side of the diff to reference (merge-base or head). Can be L or R.
27 <- Line number

This will take you to a line as long as L and R are correct. I am not sure if there is a way to visit L OR R. I.e If the PR adds a line you must use R. If it removes a line you must use L.

From: Generate line pointer URL into Github Pull Request

Best way to implement keyboard shortcuts in a Windows Forms application?

You probably forgot to set the form's KeyPreview property to True. Overriding the ProcessCmdKey() method is the generic solution:

protected override bool ProcessCmdKey(ref Message msg, Keys keyData) {
  if (keyData == (Keys.Control | Keys.F)) {
    MessageBox.Show("What the Ctrl+F?");
    return true;
  return base.ProcessCmdKey(ref msg, keyData);

Adding a column to an existing table in a Rails migration

You can also do

rake db:rollback

if you have not added any data to the tables.Then edit the migration file by adding the email column to it and then call

rake db:migrate

This will work if you have rails 3.1 onwards installed in your system.

Much simpler way of doing it is change let the change in migration file be as it is. use

$rake db:migrate:redo

This will roll back the last migration and migrate it again.

Get the number of rows in a HTML table

In the DOM, a tr element is (implicitly or explicitly) a child of tbody, thead, or tfoot, not a child of table (hence the 0 you got). So a general answer is:

var count = $('#gvPerformanceResult > * > tr').length;

This includes the rows of the table but excludes rows of any inner table.

What is the difference between find(), findOrFail(), first(), firstOrFail(), get(), list(), toArray()

  1. find($id) takes an id and returns a single model. If no matching model exist, it returns null.

  2. findOrFail($id) takes an id and returns a single model. If no matching model exist, it throws an error1.

  3. first() returns the first record found in the database. If no matching model exist, it returns null.

  4. firstOrFail() returns the first record found in the database. If no matching model exist, it throws an error1.

  5. get() returns a collection of models matching the query.

  6. pluck($column) returns a collection of just the values in the given column. In previous versions of Laravel this method was called lists.

  7. toArray() converts the model/collection into a simple PHP array.

Note: a collection is a beefed up array. It functions similarly to an array, but has a lot of added functionality, as you can see in the docs.

Unfortunately, PHP doesn't let you use a collection object everywhere you can use an array. For example, using a collection in a foreach loop is ok, put passing it to array_map is not. Similarly, if you type-hint an argument as array, PHP won't let you pass it a collection. Starting in PHP 7.1, there is the iterable typehint, which can be used to accept both arrays and collections.

If you ever want to get a plain array from a collection, call its all() method.

1 The error thrown by the findOrFail and firstOrFail methods is a ModelNotFoundException. If you don't catch this exception yourself, Laravel will respond with a 404, which is what you want most of the time.

How do I retrieve an HTML element's actual width and height?

NOTE: this answer was written in 2008. At the time the best cross-browser solution for most people really was to use jQuery. I'm leaving the answer here for posterity and, if you're using jQuery, this is a good way to do it. If you're using some other framework or pure JavaScript the accepted answer is probably the way to go.

As of jQuery 1.2.6 you can use one of the core CSS functions, height and width (or outerHeight and outerWidth, as appropriate).

var height = $("#myDiv").height();
var width = $("#myDiv").width();

var docHeight = $(document).height();
var docWidth = $(document).width();

Create an application setup in visual studio 2013

Microsoft has listened to the cry for supporting installers (MSI) in Visual Studio and release the Visual Studio Installer Projects Extension. You can now create installers in VS2013, download the extension here from the visualstudiogallery.


How to remove item from a python list in a loop?

hymloth and sven's answers work, but they do not modify the list (the create a new one). If you need the object modification you need to assign to a slice:

x[:] = [value for value in x if len(value)==2]

However, for large lists in which you need to remove few elements, this is memory consuming, but it runs in O(n).

glglgl's answer suffers from O(n²) complexity, because list.remove is O(n).

Depending on the structure of your data, you may prefer noting the indexes of the elements to remove and using the del keywork to remove by index:

to_remove = [i for i, val in enumerate(x) if len(val)==2]
for index in reversed(to_remove): # start at the end to avoid recomputing offsets
    del x[index]

Now del x[i] is also O(n) because you need to copy all elements after index i (a list is a vector), so you'll need to test this against your data. Still this should be faster than using remove because you don't pay for the cost of the search step of remove, and the copy step cost is the same in both cases.

[edit] Very nice in-place, O(n) version with limited memory requirements, courtesy of @Sven Marnach. It uses itertools.compress which was introduced in python 2.7:

from itertools import compress

selectors = (len(s) == 2 for s in x)
for i, s in enumerate(compress(x, selectors)): # enumerate elements of length 2
    x[i] = s # move found element to beginning of the list, without resizing
del x[i+1:]  # trim the end of the list

Postgres FOR LOOP

Below is example you can use:

create temp table test2 (
  id1  numeric,
  id2  numeric,
  id3  numeric,
  id4  numeric,
  id5  numeric,
  id6  numeric,
  id7  numeric,
  id8  numeric,
  id9  numeric,
  id10 numeric) 
with (oids = false);

     i int;
for  i in 1..100000
    insert into test2  values (random(), i * random(), i / random(), i + random(), i * random(), i / random(), i + random(), i * random(), i / random(), i + random());
end loop;

Is there a java setting for disabling certificate validation?

On my Mac that I'm sure I'm not going to allow java anyplace other than a specific site, I was able to use Preferences->Java to bring up the Java control panel and turned the checking off. If DLink ever fixes their certificate, I'll turn it back on.

Java control panel - Advanced

Single TextView with multiple colored text

I have write down some code for other question which is similar to this one, but that question got duplicated so i can't answer there so i am just putting my code here if someone looking for same requirement.

It's not fully working code, you need to make some minor changes to get it worked.

Here is the code:

I've used @Graeme idea of using spannable text.

String colorfulText = "colorfulText";       
    Spannable span = new SpannableString(colorfulText);             

    for ( int i = 0, len = colorfulText.length(); i < len; i++ ){
        span.setSpan(new ForegroundColorSpan(getRandomColor()), i, i+1,Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);                     


Random Color Method:

  private int getRandomColor(){
        Random rnd = new Random();
        return Color.argb(255, rnd.nextInt(256), rnd.nextInt(256), rnd.nextInt(256));

How to get the last element of a slice?

For just reading the last element of a slice:


For removing it:

sl = sl[:len(sl)-1]

See this page about slice tricks

Animate visibility modes, GONE and VISIBLE

Visibility change itself can be easy animated by overriding setVisibility method. Look at complete code:

public class SimpleViewAnimator extends FrameLayout
    private Animation inAnimation;
    private Animation outAnimation;

    public SimpleViewAnimator(Context context)

    public void setInAnimation(Animation inAnimation)
        this.inAnimation = inAnimation;

    public void setOutAnimation(Animation outAnimation)
        this.outAnimation = outAnimation;

    public void setVisibility(int visibility)
        if (getVisibility() != visibility)
            if (visibility == VISIBLE)
                if (inAnimation != null) startAnimation(inAnimation);
            else if ((visibility == INVISIBLE) || (visibility == GONE))
                if (outAnimation != null) startAnimation(outAnimation);


Java - ignore exception and continue

You could catch the NullPointerException explicitly and ignore it - though its generally not recommended. You should not, however, ignore all exceptions as you're currently doing.

UserInfo ui = new UserInfo();
try {
    DirectoryUser du = LDAPService.findUser(username);
    if (du!=null) {
} catch (NullPointerException npe) {
    // Lulz @ your NPE
    Logger.log("No user info for " +username+ ", will find some way to cope");

Difference between == and ===

The right shift logical operator (>>> N) shifts bits to the right by N positions, discarding the sign bit and padding the N left-most bits with 0's. For example:

-1 (in 32-bit): 11111111111111111111111111111111

after a >>> 1 operation becomes:

2147483647: 01111111111111111111111111111111

The right shift arithmetic operator (>> N) also shifts bits to the right by N positions, but preserves the sign bit and pads the N left-most bits with 1's. For example:

-2 (in 32-bit): 11111111111111111111111111111110

after a >> 1 operation becomes:

-1: 11111111111111111111111111111111

Callback to a Fragment from a DialogFragment

I solved this in an elegant way with RxAndroid. Receive an observer in the constructor of the DialogFragment and suscribe to observable and push the value when the callback being called. Then, in your Fragment create an inner class of the Observer, create an instance and pass it in the constructor of the DialogFragment. I used WeakReference in the observer to avoid memory leaks. Here is the code:

import java.lang.ref.WeakReference;

import io.reactivex.Observer;

public class BaseDialogFragment<O> extends DialogFragment {

    protected WeakReference<Observer<O>> observerRef;

    protected BaseDialogFragment(Observer<O> observer) {
        this.observerRef = new WeakReference<>(observer);

    protected Observer<O> getObserver() {
    return observerRef.get();

public class DatePickerFragment extends BaseDialogFragment<Integer>
    implements DatePickerDialog.OnDateSetListener {

public DatePickerFragment(Observer<Integer> observer) {

public Dialog onCreateDialog(Bundle savedInstanceState) {
    // Use the current date as the default date in the picker
    final Calendar c = Calendar.getInstance();
    int year = c.get(Calendar.YEAR);
    int month = c.get(Calendar.MONTH);
    int day = c.get(Calendar.DAY_OF_MONTH);

    // Create a new instance of DatePickerDialog and return it
    return new DatePickerDialog(getActivity(), this, year, month, day);

public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) {
        if (getObserver() != null) {

//Show the dialog fragment when the button is clicked
void onDateClick() {
    DialogFragment newFragment = new DatePickerFragment(new OnDateSelectedObserver());, "datePicker");
 //Observer inner class
 private class OnDateSelectedObserver implements Observer<Integer> {

    public void onSubscribe(Disposable d) {


    public void onNext(Integer integer) {
       //Here you invoke the logic


    public void onError(Throwable e) {


    public void onComplete() {


You can see the source code here:

What is a CSRF token? What is its importance and how does it work?

The Cloud Under blog has a good explanation of CSRF tokens. (archived)

Imagine you had a website like a simplified Twitter, hosted on Signed in users can enter some text (a tweet) into a form that’s being sent to the server as a POST request and published when they hit the submit button. On the server the user is identified by a cookie containing their unique session ID, so your server knows who posted the Tweet.

The form could be as simple as that:

 <form action="" method="POST">
   <input type="text" name="tweet">
   <input type="submit">

Now imagine, a bad guy copies and pastes this form to his malicious website, let’s say The form would still work. As long

as a user is signed in to your Twitter (i.e. they’ve got a valid session cookie for, the POST request would be sent to and processed as usual when the user clicks the submit button.

So far this is not a big issue as long as the user is made aware about what the form exactly does, but what if our bad guy tweaks the form like this:

 <form action="" method="POST">
   <input type="hidden" name="tweet" value="Buy great products at">
   <input type="submit" value="Click to win!">

Now, if one of your users ends up on the bad guy’s website and hits the “Click to win!” button, the form is submitted to

your website, the user is correctly identified by the session ID in the cookie and the hidden Tweet gets published.

If our bad guy was even worse, he would make the innocent user submit this form as soon they open his web page using JavaScript, maybe even completely hidden away in an invisible iframe. This basically is cross-site request forgery.

A form can easily be submitted from everywhere to everywhere. Generally that’s a common feature, but there are many more cases where it’s important to only allow a form being submitted from the domain where it belongs to.

Things are even worse if your web application doesn’t distinguish between POST and GET requests (e.g. in PHP by using $_REQUEST instead of $_POST). Don’t do that! Data altering requests could be submitted as easy as <img src="">, embedded in a malicious website or even an email.

How do I make sure a form can only be submitted from my own website? This is where the CSRF token comes in. A CSRF token is a random, hard-to-guess string. On a page with a form you want to protect, the server would generate a random string, the CSRF token, add it to the form as a hidden field and also remember it somehow, either by storing it in the session or by setting a cookie containing the value. Now the form would look like this:

    <form action="" method="POST">
      <input type="hidden" name="csrf-token" value="nc98P987bcpncYhoadjoiydc9ajDlcn">
      <input type="text" name="tweet">
      <input type="submit">

When the user submits the form, the server simply has to compare the value of the posted field csrf-token (the name doesn’t

matter) with the CSRF token remembered by the server. If both strings are equal, the server may continue to process the form. Otherwise the server should immediately stop processing the form and respond with an error.

Why does this work? There are several reasons why the bad guy from our example above is unable to obtain the CSRF token:

Copying the static source code from our page to a different website would be useless, because the value of the hidden field changes with each user. Without the bad guy’s website knowing the current user’s CSRF token your server would always reject the POST request.

Because the bad guy’s malicious page is loaded by your user’s browser from a different domain ( instead of, the bad guy has no chance to code a JavaScript, that loads the content and therefore our user’s current CSRF token from your website. That is because web browsers don’t allow cross-domain AJAX requests by default.

The bad guy is also unable to access the cookie set by your server, because the domains wouldn’t match.

When should I protect against cross-site request forgery? If you can ensure that you don’t mix up GET, POST and other request methods as described above, a good start would be to protect all POST requests by default.

You don’t have to protect PUT and DELETE requests, because as explained above, a standard HTML form cannot be submitted by a browser using those methods.

JavaScript on the other hand can indeed make other types of requests, e.g. using jQuery’s $.ajax() function, but remember, for AJAX requests to work the domains must match (as long as you don’t explicitly configure your web server otherwise).

This means, often you do not even have to add a CSRF token to AJAX requests, even if they are POST requests, but you will have to make sure that you only bypass the CSRF check in your web application if the POST request is actually an AJAX request. You can do that by looking for the presence of a header like X-Requested-With, which AJAX requests usually include. You could also set another custom header and check for its presence on the server side. That’s safe, because a browser would not add custom headers to a regular HTML form submission (see above), so no chance for Mr Bad Guy to simulate this behaviour with a form.

If you’re in doubt about AJAX requests, because for some reason you cannot check for a header like X-Requested-With, simply pass the generated CSRF token to your JavaScript and add the token to the AJAX request. There are several ways of doing this; either add it to the payload just like a regular HTML form would, or add a custom header to the AJAX request. As long as your server knows where to look for it in an incoming request and is able to compare it to the original value it remembers from the session or cookie, you’re sorted.

Setting up enviromental variables in Windows 10 to use java and javac

Its still the same concept, you'll need to setup path variable so that windows is aware of the java executable and u can run it from command prompt conveniently

Details from the java's own page: That article applies to: •Platform(s): Solaris SPARC, Solaris x86, Red Hat Linux, SUSE Linux, Windows 8, Windows 7, Vista, Windows XP, Windows 10

How can I create a small color box using html and css?

You can create these easily using the floating ability of CSS, for example. I have created a small example on Jsfiddle over here, all the related css and html is also provided there.

.foo {_x000D_
  float: left;_x000D_
  width: 20px;_x000D_
  height: 20px;_x000D_
  margin: 5px;_x000D_
  border: 1px solid rgba(0, 0, 0, .2);_x000D_
.blue {_x000D_
  background: #13b4ff;_x000D_
.purple {_x000D_
  background: #ab3fdd;_x000D_
.wine {_x000D_
  background: #ae163e;_x000D_
<div class="foo blue"></div>_x000D_
<div class="foo purple"></div>_x000D_
<div class="foo wine"></div>

onclick="location.href='link.html'" does not load page in Safari

I had the same error. Make sure you don't have any <input>, <select>, etc. name="location".

How to convert hex to ASCII characters in the Linux shell?

You can use this command (python script) for larger inputs:

echo 58595a | python -c "import sys; import binascii; print(binascii.unhexlify("

The result will be:


And for more simplicity, define an alias:

alias hexdecoder='python -c "import sys; import binascii; print(binascii.unhexlify("'

echo 58595a | hexdecoder

How to execute an .SQL script file using c#

I tried this solution with Microsoft.SqlServer.Management but it didn't work well with .NET 4.0 so I wrote another solution using .NET libs framework only.

string script = File.ReadAllText(@"E:\someSqlScript.sql");

// split script on GO command
IEnumerable<string> commandStrings = Regex.Split(script, @"^\s*GO\s*$", RegexOptions.Multiline | RegexOptions.IgnoreCase);

foreach (string commandString in commandStrings)
    if (!string.IsNullOrWhiteSpace(commandString.Trim()))
        using(var command = new SqlCommand(commandString, Connection))

Get public/external IP address?

using System.Net;

private string GetWorldIP()
    String url = "";
    String result = null;

        WebClient client = new WebClient();
        result = client.DownloadString(url);
        return result;
    catch (Exception ex) { return ""; }

Used loopback as fallback just so things don't fatally break.

Structure of a PDF file?

Here is a link to Adobe's reference material

You should know though that PDF is only about presentation, not structure. Parsing will not come easy.

Get error message if ModelState.IsValid fails?

It is sample extension

public class GetModelErrors
    //Usage return Json to View :
    //return Json(new { state = false, message = new GetModelErrors(ModelState).MessagesWithKeys() });
    public class KeyMessages
        public string Key { get; set; }
        public string Message { get; set; }
    private readonly ModelStateDictionary _entry;
    public GetModelErrors(ModelStateDictionary entry)
        _entry = entry;

    public int Count()
        return _entry.ErrorCount;
    public string Exceptions(string sp = "\n")
        return string.Join(sp, _entry.Values
            .SelectMany(v => v.Errors)
            .Select(e => e.Exception));
    public string Messages(string sp = "\n")
        string msg = string.Empty;
        foreach (var item in _entry)
            if (item.Value.ValidationState == ModelValidationState.Invalid)
                msg += string.Join(sp, string.Join(",", item.Value.Errors.Select(i => i.ErrorMessage)));
        return msg;

    public List<KeyMessages> MessagesWithKeys(string sp = "<p> ? ")
        List<KeyMessages> list = new List<KeyMessages>();
        foreach (var item in _entry)
            if (item.Value.ValidationState == ModelValidationState.Invalid)
                list.Add(new KeyMessages
                    Key = item.Key,
                    Message = string.Join(null, item.Value.Errors.Select(i => sp + i.ErrorMessage))
        return list;

Fatal error: "No Target Architecture" in Visual Studio

Another cause of this can be including a header that depends on windows.h, before including windows.h.

In my case I included xinput.h before windows.h and got this error. Swapping the order solved the problem.

Camera access through browser

I think this one is working. Recording a video or audio;

<input type="file" accept="video/*;capture=camcorder">
<input type="file" accept="audio/*;capture=microphone">

or (new method)

<device type="media" onchange="update("></device>
<video autoplay></video>
  function update(stream) {
    document.querySelector('video').src = stream.url;

If it is not, probably will work on ios6, more detail can be found at get user media

Hidden property of a button in HTML

<script src=""></script>

function showButtons () { $('#b1, #b2, #b3').show(); }

<style type="text/css">
#b1, #b2, #b3 {
display: none;


<a href="#" onclick="showButtons();">Show me the money!</a>

<input type="submit" id="b1" value="B1" />
<input type="submit" id="b2" value="B2"/>
<input type="submit" id="b3" value="B3" />


PHP Remove elements from associative array

The way to do this to take your nested target array and copy it in single step to a non-nested array. Delete the key(s) and then assign the final trimmed array to the nested node of the earlier array. Here is a code to make it simple:

$temp_array = $list['resultset'][0];


$list['resultset'][0] = $temp_array;

SQL MAX of multiple columns?

If you are using SQL Server 2005, you can use the UNPIVOT feature. Here is a complete example:

create table dates 
  number int,
  date1 datetime,
  date2 datetime,
  date3 datetime 

insert into dates values (1, '1/1/2008', '2/4/2008', '3/1/2008')
insert into dates values (1, '1/2/2008', '2/3/2008', '3/3/2008')
insert into dates values (1, '1/3/2008', '2/2/2008', '3/2/2008')
insert into dates values (1, '1/4/2008', '2/1/2008', '3/4/2008')

select max(dateMaxes)
from (
    (select max(date1) from dates) date1max, 
    (select max(date2) from dates) date2max,
    (select max(date3) from dates) date3max
) myTable
unpivot (dateMaxes For fieldName In (date1max, date2max, date3max)) as tblPivot

drop table dates

Compare 2 JSON objects

Simply parsing the JSON and comparing the two objects is not enough because it wouldn't be the exact same object references (but might be the same values).

You need to do a deep equals.

From - which seems the use jQuery.

Object.extend(Object, {
   deepEquals: function(o1, o2) {
     var k1 = Object.keys(o1).sort();
     var k2 = Object.keys(o2).sort();
     if (k1.length != k2.length) return false;
     return, function(keyPair) {
       if(typeof o1[keyPair[0]] == typeof o2[keyPair[1]] == "object"){
         return deepEquals(o1[keyPair[0]], o2[keyPair[1]])
       } else {
         return o1[keyPair[0]] == o2[keyPair[1]];


var anObj = JSON.parse(jsonString1);
var anotherObj= JSON.parse(jsonString2);

if (Object.deepEquals(anObj, anotherObj))

Set scroll position

Note that if you want to scroll an element instead of the full window, elements don't have the scrollTo and scrollBy methods. You should:

var el = document.getElementById("myel"); // Or whatever method to get the element

// To set the scroll
el.scrollTop = 0;
el.scrollLeft = 0;

// To increment the scroll
el.scrollTop += 100;
el.scrollLeft += 100;

You can also mimic the window.scrollTo and window.scrollBy functions to all the existant HTML elements in the webpage on browsers that don't support it natively:

Object.defineProperty(HTMLElement.prototype, "scrollTo", {
    value: function(x, y) {
        el.scrollTop = y;
        el.scrollLeft = x;
    enumerable: false

Object.defineProperty(HTMLElement.prototype, "scrollBy", {
    value: function(x, y) {
        el.scrollTop += y;
        el.scrollLeft += x;
    enumerable: false

so you can do:

var el = document.getElementById("myel"); // Or whatever method to get the element, again

// To set the scroll
el.scrollTo(0, 0);

// To increment the scroll
el.scrollBy(100, 100);

NOTE: Object.defineProperty is encouraged, as directly adding properties to the prototype is a breaking bad habit (When you see it :-).

First Heroku deploy failed `error code=H10`

I had this issue, the only problem was my Procfile was like this

web : node index.js

and I changed to

web:node index.js

the only problem was spaces

How to compile and run C/C++ in a Unix console/Mac terminal?

All application execution in a Unix (Linux, Mac OS X, AIX, etc.) environment depends on the executable search path.

You can display this path in the terminal with this command:

echo $PATH

On Mac OS X (by default) this will display the following colon separated search path:


So any executable in the listed directories can by run just by typing in their name. For example:

cat mytextfile.txt

This runs /bin/cat and displays mytextfile.txt to the terminal.

To run any other command that is not in the executable search path requires that you qualify the path to the executable. So say I had an executable called MyProgram in my home directory on Mac OS X I can fully qualify it like so:


If you are in a location that is near the program you wished to execute you can qualify the name with a partial path. For example, if MyProgram was in the directory /Users/oliver/MyProject I and I was in my home directory I can qualify the executable name like this, and have it execute:


Or say I was in the directory /Users/oliver/MyProject2 and I wanted to execute /Users/oliver/MyProject/MyProgram I can use a relative path like this, to execute it:


Similarly if I am in the same directory as MyProgram I need to use a "current directory" relative path. The current directory you are in is the period character followed by a slash. For example:


To determine which directory you are currently in use the pwd command.

If you are commonly putting programs in a place on your hard disk that you wish to run without having to qualify their names. For example, if you have a "bin" directory in your home directory for regularly used shell scripts of other programs it may be wise to alter your executable search path.

This can be does easily by either creating or editing the existing .bash_profile file in your home directory and adding the lines:

export PATH=$PATH:~/bin

Here the tilde (~) character is being used as a shortcut for /Users/oliver. Also note that the hash bang (#!) line needs to be the first line of the file (if it doesn't already exist). Note also that this technique requires that your login shell be bash (the default on Mac OS X and most Linux distributions). Also note that if you want your programs installed in ~/bin to be used in preference to system executables your should reorder the export statement as follows:

export PATH=~/bin:$PATH

Convert digits into words with JavaScript

var inWords = function(totalRent){
var a = ['','one ','two ','three ','four ', 'five ','six ','seven ','eight ','nine ','ten ','eleven ','twelve ','thirteen ','fourteen ','fifteen ','sixteen ','seventeen ','eighteen ','nineteen '];
var b = ['', '', 'twenty','thirty','forty','fifty', 'sixty','seventy','eighty','ninety'];
var number = parseFloat(totalRent).toFixed(2).split(".");
var num = parseInt(number[0]);
var digit = parseInt(number[1]);
if ((num.toString()).length > 9)  return 'overflow';
var n = ('000000000' + num).substr(-9).match(/^(\d{2})(\d{2})(\d{2})(\d{1})(\d{2})$/);
var d = ('00' + digit).substr(-2).match(/^(\d{2})$/);;
if (!n) return; var str = '';
str += (n[1] != 0) ? (a[Number(n[1])] || b[n[1][0]] + ' ' + a[n[1][1]]) + 'crore ' : '';
str += (n[2] != 0) ? (a[Number(n[2])] || b[n[2][0]] + ' ' + a[n[2][1]]) + 'lakh ' : '';
str += (n[3] != 0) ? (a[Number(n[3])] || b[n[3][0]] + ' ' + a[n[3][1]]) + 'thousand ' : '';
str += (n[4] != 0) ? (a[Number(n[4])] || b[n[4][0]] + ' ' + a[n[4][1]]) + 'hundred ' : '';
str += (n[5] != 0) ? (a[Number(n[5])] || b[n[5][0]] + ' ' + a[n[5][1]]) + 'Rupee ' : '';
str += (d[1] != 0) ? ((str != '' ) ? "and " : '') + (a[Number(d[1])] || b[d[1][0]] + ' ' + a[d[1][1]]) + 'Paise ' : 'Only!';
return str;

This is modified code supports for Indian Rupee with 2 decimal place.

Memory errors and list limits?

The MemoryError exception that you are seeing is the direct result of running out of available RAM. This could be caused by either the 2GB per program limit imposed by Windows (32bit programs), or lack of available RAM on your computer. (This link is to a previous question).

You should be able to extend the 2GB by using 64bit copy of Python, provided you are using a 64bit copy of windows.

The IndexError would be caused because Python hit the MemoryError exception before calculating the entire array. Again this is a memory issue.

To get around this problem you could try to use a 64bit copy of Python or better still find a way to write you results to file. To this end look at numpy's memory mapped arrays.

You should be able to run you entire set of calculation into one of these arrays as the actual data will be written disk, and only a small portion of it held in memory.

Using quotation marks inside quotation marks

When you have several words like this which you want to concatenate in a string, I recommend using format or f-strings which increase readability dramatically (in my opinion).

To give an example:

s = "a word that needs quotation marks"
s2 = "another word"

Now you can do

print('"{}" and "{}"'.format(s, s2))

which will print

"a word that needs quotation marks" and "another word"

As of Python 3.6 you can use:

print(f'"{s}" and "{s2}"')

yielding the same output.

Object passed as parameter to another class, by value or reference?

In general, an "object" is an instance of a class, which is an "image"/"fingerprint" of a class created in memory (via New keyword).
The variable of object type refers to this memory location, that is, it essentially contains the address in memory.
So a parameter of object type passes a reference/"link" to an object, not a copy of the whole object.

private final static attribute vs private final attribute

As already Jon said, a static variable, also referred to as a class variable, is a variable which exists across instances of a class.

I found an example of this here:

public class StaticVariable
  static int noOfInstances;
  public static void main(String[] args)
    StaticVariable sv1 = new StaticVariable();
    System.out.println("No. of instances for sv1 : " + sv1.noOfInstances);

    StaticVariable sv2 = new StaticVariable();
    System.out.println("No. of instances for sv1 : "  + sv1.noOfInstances);
    System.out.println("No. of instances for st2 : "  + sv2.noOfInstances);

    StaticVariable sv3 = new StaticVariable();
    System.out.println("No. of instances for sv1 : "  + sv1.noOfInstances);
    System.out.println("No. of instances for sv2 : "  + sv2.noOfInstances);
    System.out.println("No. of instances for sv3 : "  + sv3.noOfInstances);

Output of the program is given below:

As we can see in this example each object has its own copy of class variable.

C:\java>java StaticVariable
No. of instances for sv1 : 1
No. of instances for sv1 : 2
No. of instances for st2 : 2
No. of instances for sv1 : 3
No. of instances for sv2 : 3
No. of instances for sv3 : 3

Accessing dictionary value by index in python

Standard Python dictionaries are inherently unordered, so what you're asking to do doesn't really make sense.

If you really, really know what you're doing, use

value_at_index = dic.values()[index]

Bear in mind that adding or removing an element can potentially change the index of every other element.

How to capture the browser window close event?

As of jQuery 1.7, the .live() method is deprecated. Use .on() to attach event handlers. Users of older versions of jQuery should use .delegate() in preference to .live()

$(window).bind("beforeunload", function() {
    return true || confirm("Do you really want to close?"); 

on complete or link


Allow scroll but hide scrollbar

Try this:


<div id="container">
    <div id="content">
        // Content here


    height: 100%;
    width: 100%;
    overflow: hidden;

    width: 100%;
    height: 99%;
    overflow: auto;
    padding-right: 15px;

html, body{
    height: 99%;

JSFiddle Demo

Tested on FF and Safari.

IIS7: Setup Integrated Windows Authentication like in IIS6

So do you want them to get the IE password-challenge box, or should they be directed to your login page and enter their information there? If it's the second option, then you should at least enable Anonymous access to your login page, since the site won't know who they are yet.

If you want the first option, then the login page they're getting forwarded to will need to read the currently logged-in user and act based on that, since they would have had to correctly authenticate to get this far.

Remove URL parameters without refreshing page

These are all misleading, you never want to add to the browser history unless you want to go to a different page in a single page app. If you want to remove the parameters without a change in the page, you must use:

window.history.replaceState(null, null, window.location.pathname);

How to position absolute inside a div?

The absolute divs are taken out of the flow of the document so the containing div does not have any content except for the padding. Give #box a height to fill it out.

#box {
    background-color: #000;
    position: relative;
    padding: 10px;
    width: 220px;

JavaScript checking for null vs. undefined and difference between == and ===

Ad 1. null is not an identifier for a property of the global object, like undefined can be

let x;      // undefined_x000D_
let y=null; // null_x000D_
let z=3;    // has value_x000D_
// 'w'      // is undeclared_x000D_
if(!x) console.log('x is null or undefined');_x000D_
if(!y) console.log('y is null or undefined');_x000D_
if(!z) console.log('z is null or undefined');_x000D_
try { if(w) 0 } catch(e) { console.log('w is undeclared') }_x000D_
// typeof not throw exception for undelared variabels_x000D_
if(typeof w === 'undefined') console.log('w is undefined');

Ad 2. The === check values and types. The == dont require same types and made implicit conversion before comparison (using .valueOf() and .toString()). Here you have all (src):


enter image description here

== (its negation !=)

enter image description here

=== (its negation !==)

enter image description here

How to apply a CSS class on hover to dynamically generated submit buttons?

The most efficient selector you can use is an attribute selector.

 input[name="btnPage"]:hover {/*your css here*/}

Here's a live demo:

How to find Current open Cursors in Oracle

I use something like this:

  count(*) as "OPEN CURSORS" 
group by 

How to install Python packages from the tar.gz file without using pip install

You can install a tarball without extracting it first. Just navigate to the directory containing your .tar.gz file from your command prompt and enter this command:

pip install my-tarball-file-name.tar.gz

I am running python 3.4.3 and this works for me. I can't tell if this would work on other versions of python though.

How to get the selected item of a combo box to a string variable in c#

Try this:

string selected = this.ComboBox.GetItemText(this.ComboBox.SelectedItem);

How can I pretty-print JSON using node.js?

I think this might be useful... I love example code :)

var fs = require('fs');

var myData = {

var outputFilename = '/tmp/my.json';

fs.writeFile(outputFilename, JSON.stringify(myData, null, 4), function(err) {
    if(err) {
    } else {
      console.log("JSON saved to " + outputFilename);

How to pad a string to a fixed length with spaces in Python?

string = ""
name = raw_input() #The value at the field
length = input() #the length of the field
string += name
string += " "*(length-len(name)) # Add extra spaces

This will add the number of spaces needed, provided the field has length >= the length of the name provided

You have to be inside an angular-cli project in order to use the build command after reinstall of angular-cli

Just include this in the package.json in devDependencies section

"angular-cli": "1.0.0-beta.25.5"

Not compulsory to install it if you have another vresion of cli installed globally.

I got this issue when I worked with angular2 & 4 at a time with different project. So angular4 - need angular-cli@latest and angular2 need angular-cli the above version.

Rails 4: assets not loading in production

I was able to solve this problem by changing: config.assets.compile = false to
config.assets.compile = true in /config/environments/production.rb

Update (June 24, 2018): This method creates a security vulnerability if the version of Sprockets you're using is less than 2.12.5, 3.7.2, or 4.0.0.beta8

App.Config Transformation for projects which are not Web Projects in Visual Studio?

This works now with the Visual Studio AddIn treated in this article: SlowCheetah - Web.config Transformation Syntax now generalized for any XML configuration file.

You can right-click on your web.config and click "Add Config Transforms." When you do this, you'll get a web.debug.config and a web.release.config. You can make a web.whatever.config if you like, as long as the name lines up with a configuration profile. These files are just the changes you want made, not a complete copy of your web.config.

You might think you'd want to use XSLT to transform a web.config, but while they feels intuitively right it's actually very verbose.

Here's two transforms, one using XSLT and the same one using the XML Document Transform syntax/namespace. As with all things there's multiple ways in XSLT to do this, but you get the general idea. XSLT is a generalized tree transformation language, while this deployment one is optimized for a specific subset of common scenarios. But, the cool part is that each XDT transform is a .NET plugin, so you can make your own.

<?xml version="1.0" ?>
<xsl:stylesheet xmlns:xsl="" version="1.0">
<xsl:template match="@*|node()">
    <xsl:apply-templates select="@*|node()"/>
<xsl:template match="/configuration/appSettings">
    <xsl:apply-templates select="node()|@*"/>
    <xsl:element name="add">
      <xsl:attribute name="key">NewSetting</xsl:attribute>
      <xsl:attribute name="value">New Setting Value</xsl:attribute>

Or the same thing via the deployment transform:

<configuration xmlns:xdt="">
      <add name="NewSetting" value="New Setting Value" xdt:Transform="Insert"/>

Selecting and manipulating CSS pseudo-elements such as ::before and ::after using javascript (or jQuery)

You could also pass the content to the pseudo element with a data attribute and then use jQuery to manipulate that:



In jQuery:



span:after {
    content: attr(data-content) ' any other text you may want';

If you want to prevent the 'other text' from showing up, you could combine this with seucolega's solution like this:



In jQuery:



span.change:after {
    content: attr(data-content) ' any other text you may want';

Add space between HTML elements only using CSS

You can take advantage of the fact that span is an inline element


However, this solution will break if you have more than one word of text in your span

How to start nginx via different port(other than 80)

You have to go to the /etc/nginx/sites-enabled/ and if this is the default configuration, then there should be a file by name: default.

Edit that file by defining your desired port; in the snippet below, we are serving the Nginx instance on port 81.

server {
    listen 81;

To start the server, run the command line below;

sudo service nginx start

You may now access your application on port 81 (for localhost, http://localhost:81).

Android, How to create option Menu

Change your onCreateOptionsMenu method to return true. To quote the docs:

You must return true for the menu to be displayed; if you return false it will not be shown.

Jquery - Uncaught TypeError: Cannot use 'in' operator to search for '324' in

You have a JSON string, not an object. Tell jQuery that you expect a JSON response and it will parse it for you. Either use $.getJSON instead of $.get, or pass the dataType argument to $.get:

        $.each(data, function(key, value){
            console.log(key + ":" + value)

What is the difference between UTF-8 and Unicode?

UTF-8 is one possible encoding scheme for Unicode text.

Unicode is a broad-scoped standard which defines over 140,000 characters and allocates each a numerical code (a code point). It also defines rules for how to sort this text, normalise it, change its case, and more. A character in Unicode is represented by a code point from zero up to 0x10FFFF inclusive, though some code points are reserved and cannot be used for characters.

There is more than one way that a string of Unicode code points can be encoded into a binary stream. These are called "encodings". The most straightforward encoding is UTF-32, which simply stores each code point as a 32-bit integer, with each being 4 bytes wide.

UTF-8 is another encoding, and is becoming the de-facto standard, due to a number of advantages over UTF-32 and others. UTF-8 encodes each code point as a sequence of either 1, 2, 3 or 4 byte values. Code points in the ASCII range are encoded as a single byte value, to be compatible with ASCII. Code points outside this range use either 2, 3, or 4 bytes each, depending on what range they are in.

UTF-8 has been designed with these properties in mind:

  • ASCII characters are encoded exactly as they are in ASCII, such that an ASCII string is also a valid UTF-8 string representing the same characters.

  • Binary sorting: Sorting UTF-8 strings using a binary sort will still result in all code points being sorted in numerical order.

  • When a code point uses multiple bytes, none of those bytes contain values in the ASCII range, ensuring that no part of them could be mistaken for an ASCII character. This is also a security feature.

  • UTF-8 can be easily validated, and distinguished from other character encodings by a validator. Text in other 8-bit or multi-byte encodings will very rarely also validate as UTF-8 due to the very specific structure of UTF-8.

  • Random access: At any point in a UTF-8 string it is possible to tell if the byte at that position is the first byte of a character or not, and to find the start of the next or current character, without needing to scan forwards or backwards more than 3 bytes or to know how far into the string we started reading from.

Export to csv in jQuery

I recently posted a free software library for this: "html5csv.js" -- GitHub

It is intended to help streamline the creation of small simulator apps in Javascript that might need to import or export csv files, manipulate, display, edit the data, perform various mathematical procedures like fitting, etc.

After loading "html5csv.js" the problem of scanning a table and creating a CSV is a one-liner:


Here is a JSFiddle demo of your example with this code.

Internally, for Firefox/Chrome this is a data URL oriented solution, similar to that proposed by @italo, @lepe, and @adeneo (on another question). For IE

The CSV.begin() call sets up the system to read the data into an internal array. That fetch then occurs. Then the .download() generates a data URL link internally and clicks it with a link-clicker. This pushes a file to the end user.

According to caniuse IE10 doesn't support <a download=...>. So for IE my library calls navigator.msSaveBlob() internally, as suggested by @Manu Sharma

javax.mail.AuthenticationFailedException: failed to connect, no password specified?

This error may be about password characters. If your password contains special characters and also you add your password into Transport class methods;

For Example

Transport transport = session.getTransport("smtp");


Transport.send(msg, "user", "passw%rd");

you may get that error. Because Transport class' methods may not handle special characters. If you add your username and password into your message using javax.mail.PasswordAuthentication class, i hope you will escape that error;

For Example

Session session = Session.getInstance(props, new javax.mail.Authenticator()
  protected PasswordAuthentication getPasswordAuthentication()
    return new PasswordAuthentication("user", "pas$w@r|d");

Message message = new MimeMessage(session);

How to use PHP's password_hash to hash and verify passwords

Yes you understood it correctly, the function password_hash() will generate a salt on its own, and includes it in the resulting hash-value. Storing the salt in the database is absolutely correct, it does its job even if known.

// Hash a new password for storing in the database.
// The function automatically generates a cryptographically safe salt.
$hashToStoreInDb = password_hash($_POST['password'], PASSWORD_DEFAULT);

// Check if the hash of the entered login password, matches the stored hash.
// The salt and the cost factor will be extracted from $existingHashFromDb.
$isPasswordCorrect = password_verify($_POST['password'], $existingHashFromDb);

The second salt you mentioned (the one stored in a file), is actually a pepper or a server side key. If you add it before hashing (like the salt), then you add a pepper. There is a better way though, you could first calculate the hash, and afterwards encrypt (two-way) the hash with a server-side key. This gives you the possibility to change the key when necessary.

In contrast to the salt, this key should be kept secret. People often mix it up and try to hide the salt, but it is better to let the salt do its job and add the secret with a key.

Vim autocomplete for Python

Try Jedi! There's a Vim plugin at

It works just much better than anything else for Python in Vim. It even has support for renaming, goto, etc. The best part is probably that it really tries to understand your code (decorators, generators, etc. Just look at the feature list).

Trying to fire the onload event on script tag

I faced a similar problem, trying to test if jQuery is already present on a page, and if not force it's load, and then execute a function. I tried with @David Hellsing workaround, but with no chance for my needs. In fact, the onload instruction was immediately evaluated, and then the $ usage inside this function was not yet possible (yes, the huggly "$ is not a function." ^^).

So, I referred to this article : and attached a event listener to my script object.

var script = document.createElement('script');
script.type = "text/javascript";
script.addEventListener("load", function(event) {
    console.log("script loaded :)");
script.src = "";

For my needs, it works fine now. Hope this can help others :)

How to remove leading whitespace from each line in a file

You can use AWK:

$ awk '{$1=$1}1' file
for (i = 0; i < 100; i++)
for (i = 0; i < 100; i++)
for (i = 0; i < 100; i++)
for (i = 0; i < 100; i++)
for (i = 0; i < 100; i++)
for (i = 0; i < 100; i++)
for (i = 0; i < 100; i++)


$ sed 's|^[[:blank:]]*||g' file
for (i = 0; i < 100; i++)
for (i = 0; i < 100; i++)
for (i = 0; i < 100; i++)
for (i = 0; i < 100; i++)
for (i = 0; i < 100; i++)
for (i = 0; i < 100; i++)
for (i = 0; i < 100; i++)

The shell's while/read loop

while read -r line
    echo $line
done <"file"

How do I use Safe Area Layout programmatically?

For those of you who use SnapKit, just like me, the solution is anchoring your constraints to view.safeAreaLayoutGuide like so:

yourView.snp.makeConstraints { (make) in
    if #available(iOS 11.0, *) {
        //Bottom guide
        //Top guide
        //Leading guide
        //Trailing guide

     } else {

Resolving IP Address from hostname with PowerShell

This worked well for my purpose

$ping = ping -4 $env:COMPUTERNAME
$ip = $ping.Item(2)
$ip = $ip.Substring(11,11)

Connection attempt failed with "ECONNREFUSED - Connection refused by server"

I solved this error

A connection attempt failed with "ECONNREFUSED - Connection refused by server"

by changing my port to 22 that was successful

How do I pass a string into subprocess.Popen (using the stdin argument)?

Popen.communicate() documentation:

Note that if you want to send data to the process’s stdin, you need to create the Popen object with stdin=PIPE. Similarly, to get anything other than None in the result tuple, you need to give stdout=PIPE and/or stderr=PIPE too.

Replacing os.popen*

    pipe = os.popen(cmd, 'w', bufsize)
    # ==>
    pipe = Popen(cmd, shell=True, bufsize=bufsize, stdin=PIPE).stdin

Warning Use communicate() rather than stdin.write(), or to avoid deadlocks due to any of the other OS pipe buffers filling up and blocking the child process.

So your example could be written as follows:

from subprocess import Popen, PIPE, STDOUT

p = Popen(['grep', 'f'], stdout=PIPE, stdin=PIPE, stderr=STDOUT)    
grep_stdout = p.communicate(input=b'one\ntwo\nthree\nfour\nfive\nsix\n')[0]
# -> four
# -> five
# ->

On Python 3.5+ (3.6+ for encoding), you could use, to pass input as a string to an external command and get its exit status, and its output as a string back in one call:

#!/usr/bin/env python3
from subprocess import run, PIPE

p = run(['grep', 'f'], stdout=PIPE,
        input='one\ntwo\nthree\nfour\nfive\nsix\n', encoding='ascii')
# -> 0
# -> four
# -> five
# -> 

Purpose of installing Twitter Bootstrap through npm?

  1. Use npm/bower to install bootstrap if you want to recompile it/change less files/test. With grunt it would be easier to do this, as shown on If you only want to add precompiled libraries feel free to manually include files to project.

  2. No, you have to do this by yourself or use separate grunt tool. For example 'grunt-contrib-concat' How to concatenate and minify multiple CSS and JavaScript files with Grunt.js (0.3.x)

How do I search within an array of hashes by hash values in ruby?

this will return first match

@fathers.detect {|f| f["age"] > 35 }

How does Facebook Sharer select Images and other metadata when sharing my URL?

This is what worked for me: I placed the desired thumbnail image on the page right after the tag and making it too small to see..

<img src="imagename.jpg" width="1" height="1" />

I have not tested it with height 0 and width 0 but it probably will still work.. This does not guarantee the user will select this image..

ALSO it seems like Facebook caches the thumbnails on your page and doesnt always check it for new ones.. try adding this to another page on your site and you'll see that it works.

Express.js: how to get remote client address

I know this question has been answered, but here's how I got mine to work.

let ip = req.connection.remoteAddress.split(`:`).pop();

Strip Leading and Trailing Spaces From Java String

To trim specific char, you can use:

String s = s.replaceAll("^(,|\\s)*|(,|\\s)*$", "")

Here will strip leading and trailing space and comma.

Get attribute name value of <input>

A better way could be using 'this', it takes whatever the name of the 'id' is and uses that. As long as you add the class name called 'mytarget'.

Whenever any of the fields that have target change then it will show an alert box with the name of that field. Just cut and past whole script for it to work!

<script src="//" type="text/javascript"></script>
$(document).ready(function() {
 $('.mytarget').change(function() {
var name1 = $(this).attr("name");

Name: <input type="text" name="myname" id="myname" class="mytarget"><br />
Age: <input type="text" name="myage" id="myage" class="mytarget"><br />

Change text color with Javascript?

innerHTML is a string representing the contents of the element.

You want to modify the element itself. Drop the .innerHTML part.

REACT - toggle class onclick

using React you can add toggle class to any id/element, try


    display: none !important;
    /* transition: 2s all ease-in 0.9s; */
    transition: all ease-in 0.4s;
    width: 240px;
    min-width: 240px;
    /* transition: all ease-in 0.4s; */
    width: 88px;
    transition: all ease-in 0.4s;


                isActive: !this.state.isActive
        render() {
            return (
                <div className={this.state.isActive===true ? "left-panel leftbar-open" : "left-panel leftbar-close"} id="leftPanel">
                    <div className="top-logo-container"  onClick={this.ToggleMenu}>
                            <span className={this.state.isActive===true ? "left-menu-main-link hide-from-menu" : "hide-text"}>Welcome!</span>

                    <div className="welcome-member">
                        <span className={this.state.isActive===true ? "left-menu-main-link hide-from-menu" : "hide-text"}>Welcome<br/>SDO Rizwan</span>

How do I rename a Git repository?

With Github As Your Remote

Renaming the Remote Repo on Github

Regarding the remote repository, if you are using Github or Github Enterprise as the server location for saving/distributing your repository remotely, you can simply rename the repository directly in the repo settings.

From the main repo page, the settings tab is on the right, and the repo name is the first item on the page:

enter image description here

Github will redirect requests to the new URL

One very nice feature in Github when you rename a repo, is that Github will save the old repo name and all the related URLs and redirect traffic to the new URLs. Since your username/org and repo name are a part of the URL, a rename will change the URL.

Since Github saves the old repo name and redirects requests to the new URLs, if anyone uses links based on the old repo name when trying to access issues, wiki, stars, or followers they will still arrive at the new location on the Github website. Github also redirects lower level Git commands like git clone, git fetch, etc.

More information is in the Github Help for Renaming a Repo

Renaming the Local Repo Name

As others have mentioned, the local "name" of your repo is typically considered to be the root folder/directory name, and you can change that, move, or copy the folder to any location and it will not affect the repo at all.

Git is designed to only worry about files inside the root folder.

What is @ModelAttribute in Spring MVC?

This is used for data binding purposes in Spring MVC. Let you have a jsp having a form element in it e.g

on JSP

<form:form action="test-example" method="POST" commandName="testModelAttribute"> </form:form>

(Spring Form method, Simple form element can also be used)

On Controller Side

@RequestMapping(value = "/test-example", method = RequestMethod.POST)
public ModelAndView testExample(@ModelAttribute("testModelAttribute") TestModel testModel, Map<String, Object> map,...) {


Now when you will submit the form the form fields values will be available to you.

How to deselect all selected rows in a DataGridView control?

i found out why my first row was default selected and found out how to not select it by default.

By default my datagridview was the object with the first tab-stop on my windows form. Making the tab stop first on another object (maybe disabling tabstop for the datagrid at all will work to) disabled selecting the first row

How can I get the value of a registry key from within a batch script?

With regedit:

@echo off
::if the scrit is not ran as administrator
::  and the key does not require admin permissions
set __COMPAT_LAYER=RunAsInvoker

set "key=%~1"
set "value=%~2"

regedit /e "#.reg" "%key%"

for /f "tokens=1,* delims==" %%a in ('find  """%value%""=" "#.reg"') do if "%%~b" neq "" echo %%~b
del /q #.reg



call regreader.bat "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v3.0\Setup\1033\" Version



How can I tell when a MySQL table was last updated?

I would create a trigger that catches all updates/inserts/deletes and write timestamp in custom table, something like tablename | timestamp

Just because I don't like the idea to read internal system tables of db server directly

Why do I always get the same sequence of random numbers with rand()?

To quote from man rand :

The srand() function sets its argument as the seed for a new sequence of pseudo-random integers to be returned by rand(). These sequences are repeatable by calling srand() with the same seed value.

If no seed value is provided, the rand() function is automatically seeded with a value of 1.

So, with no seed value, rand() assumes the seed as 1 (every time in your case) and with the same seed value, rand() will produce the same sequence of numbers.

How to convert a column of DataTable to a List

Try this:

static void Main(string[] args)
    var dt = new DataTable
        Columns = { { "Lastname",typeof(string) }, { "Firstname",typeof(string) } }
    dt.Rows.Add("Lennon", "John");
    dt.Rows.Add("McCartney", "Paul");
    dt.Rows.Add("Harrison", "George");
    dt.Rows.Add("Starr", "Ringo");

    List<string> s = dt.AsEnumerable().Select(x => x[0].ToString()).ToList();

    foreach(string e in s)


Getting the text that follows after the regex match

You just need to put "group(1)" instead of "group()" in the following line and the return will be the one you expected:

System.out.println("I found the text: " +**1**).toString());

What does it mean to "call" a function in Python?

I'll give a slightly advanced answer. In Python, functions are first-class objects. This means they can be "dynamically created, destroyed, passed to a function, returned as a value, and have all the rights as other variables in the programming language have."

Calling a function/class instance in Python means invoking the __call__ method of that object. For old-style classes, class instances are also callable but only if the object which creates them has a __call__ method. The same applies for new-style classes, except there is no notion of "instance" with new-style classes. Rather they are "types" and "objects".

As quoted from the Python 2 Data Model page, for function objects, class instances(old style classes), and class objects(new-style classes), "x(arg1, arg2, ...) is a shorthand for x.__call__(arg1, arg2, ...)".

Thus whenever you define a function with the shorthand def funcname(parameters): you are really just creating an object with a method __call__ and the shorthand for __call__ is to just name the instance and follow it with parentheses containing the arguments to the call. Because functions are first class objects in Python, they can be created on the fly with dynamic parameters (and thus accept dynamic arguments). This comes into handy with decorator functions/classes which you will read about later.

For now I suggest reading the Official Python Tutorial.

jQuery - What are differences between $(document).ready and $(window).load?

This three function are the same.









here $ is used for define jQuery like $ = jQuery.

Now difference is that

$(document).ready is jQuery event that is fired when DOM is loaded, so it’s fired when the document structure is ready.

$(window).load event is fired after whole content is loaded like page contain images,css etc.

How to make Java 6, which fails SSL connection with "SSL peer shut down incorrectly", succeed like Java 7?

It seems that in the debug log for Java 6 the request is send in SSLv2 format.

main, WRITE: SSLv2 client hello message, length = 110

This is not mentioned as enabled by default in Java 7.
Change the client to use SSLv3 and above to avoid such interoperability issues.

Look for differences in JSSE providers in Java 7 and Java 6

Go To Definition: "Cannot navigate to the symbol under the caret."

I also faced with the same problem and "Find all references" for selected class has solved this issue.

What is a "bundle" in an Android application

I have to add that bundles are used by activities to pass data to themselves in the future.

When the screen rotates, or when another activity is started, the method protected void onSaveInstanceState(Bundle outState) is invoked, and the activity is destroyed. Later, another instance of the activity is created, and public void onCreate(Bundle savedInstanceState) is called. When the first instance of activity is created, the bundle is null; and if the bundle is not null, the activity continues some business started by its predecessor.

Android automatically saves the text in text fields, but it does not save everything, and subtle bugs sometimes appear.

The most common anti-pattern, though, is assuming that onCreate() does just initialization. It is wrong, because it also must restore the state.

There is an option to disable this "re-create activity on rotation" behavior, but it will not prevent restart-related bugs, it will just make them more difficult to mention.

Note also that the only method whose call is guaranteed when the activity is going to be destroyed is onPause(). (See the activity life cycle graph in the docs.)

how to prevent adding duplicate keys to a javascript array

Generally speaking, this is better accomplished with an object instead since JavaScript doesn't really have associative arrays:

var foo = { bar: 0 };

Then use in to check for a key:

if ( !( 'bar' in foo ) ) {
    foo['bar'] = 42;

As was rightly pointed out in the comments below, this method is useful only when your keys will be strings, or items that can be represented as strings (such as numbers).

Conversion between UTF-8 ArrayBuffer and String

The main problem of programmers looking for conversion from byte array into a string is UTF-8 encoding (compression) of unicode characters. This code will help you:

var getString = function (strBytes) {

    var MAX_SIZE = 0x4000;
    var codeUnits = [];
    var highSurrogate;
    var lowSurrogate;
    var index = -1;

    var result = '';

    while (++index < strBytes.length) {
        var codePoint = Number(strBytes[index]);

        if (codePoint === (codePoint & 0x7F)) {

        } else if (0xF0 === (codePoint & 0xF0)) {
            codePoint ^= 0xF0;
            codePoint = (codePoint << 6) | (strBytes[++index] ^ 0x80);
            codePoint = (codePoint << 6) | (strBytes[++index] ^ 0x80);
            codePoint = (codePoint << 6) | (strBytes[++index] ^ 0x80);
        } else if (0xE0 === (codePoint & 0xE0)) {
            codePoint ^= 0xE0;
            codePoint = (codePoint << 6) | (strBytes[++index] ^ 0x80);
            codePoint = (codePoint << 6) | (strBytes[++index] ^ 0x80);
        } else if (0xC0 === (codePoint & 0xC0)) {
            codePoint ^= 0xC0;
            codePoint = (codePoint << 6) | (strBytes[++index] ^ 0x80);

        if (!isFinite(codePoint) || codePoint < 0 || codePoint > 0x10FFFF || Math.floor(codePoint) != codePoint)
            throw RangeError('Invalid code point: ' + codePoint);

        if (codePoint <= 0xFFFF)
        else {
            codePoint -= 0x10000;
            highSurrogate = (codePoint >> 10) | 0xD800;
            lowSurrogate = (codePoint % 0x400) | 0xDC00;
            codeUnits.push(highSurrogate, lowSurrogate);
        if (index + 1 == strBytes.length || codeUnits.length > MAX_SIZE) {
            result += String.fromCharCode.apply(null, codeUnits);
            codeUnits.length = 0;

    return result;

All the best !

How to import keras from tf.keras in Tensorflow?

Use the keras module from tensorflow like this:

import tensorflow as tf

Import classes

from tensorflow.python.keras.layers import Input, Dense

or use directly

dense = tf.keras.layers.Dense(...)

EDIT Tensorflow 2

from tensorflow.keras.layers import Input, Dense

and the rest stays the same.

Javascript Image Resize

To modify an image proportionally, simply only alter one of the width/height css properties, leave the other set to auto. = '50%' = 'auto'

This will ensure that its aspect ratio remains the same.

Bear in mind that browsers tend to suck at resizing images nicely - you'll probably find that your resized image looks horrible.

Checking to see if one array's elements are in another array in PHP

Performance test for in_array vs array_intersect:

$a1 = array(2,4,8,11,12,13,14,15,16,17,18,19,20);

$a2 = array(3,20);

$intersect_times = array();
$in_array_times = array();
for($j = 0; $j < 10; $j++)
    /***** TEST ONE array_intersect *******/
    $t = microtime(true);
    for($i = 0; $i < 100000; $i++)
        $x = array_intersect($a1,$a2);
        $x = empty($x);
    $intersect_times[] = microtime(true) - $t;

    /***** TEST TWO in_array *******/
    $t2 = microtime(true);
    for($i = 0; $i < 100000; $i++)
        $x = false;
        foreach($a2 as $v){
                $x = true;
    $in_array_times[] = microtime(true) - $t2;

echo '<hr><br>'.implode('<br>',$intersect_times).'<br>array_intersect avg: '.(array_sum($intersect_times) / count($intersect_times));
echo '<hr><br>'.implode('<br>',$in_array_times).'<br>in_array avg: '.(array_sum($in_array_times) / count($in_array_times));

Here are the results:

array_intersect avg: 0.16692011356354

in_array avg: 0.029640197753906

in_array is at least 5 times faster. Note that we "break" as soon as a result is found.

Display current path in terminal only

If you just want to get the information of current directory, you can type:


and you don't need to use the Nautilus, or you can use a teamviewer software to remote connect to the computer, you can get everything you want.

Use placeholders in yaml

I suppose would be an acceptable solution to your problem

How can I make a Python script standalone executable to run without ANY dependency?

Use Cython to convert to C, compile, and link with GCC.

Another could be, make the core functions in C (the ones you want to make hard to reverse), compile them and use Boost.Python to import the compiled code (plus you get a much faster code execution). Then use any tool mentioned to distribute.

How to hide form code from view code/inspect element browser?

While I don't think there is a way to fully do this you can take a few measures to stop almost everyone from viewing the HTML.

You can first of all try and stop the inspect menu by doing the following:

I would also suggest using the method that Jonas gave of using his javascript and putting what you don't want people to see in a div with id="element-to-hide" and his given js script to furthermore stop people from inspecting.

I'm pretty sure that it's quite hard to get past that. But then someone can just type and that will show them the source. So you will then probably want to encrypt the HTML(I would advise using a website that gives you an extended security option). There are plenty of good websites that do this for free (eg: and use extended security which you can't usually unencrypt through HTML un encryptors.

This will basically encrypt your HTML so if you view the source using the method I showed above you will just get encrypted HTML(that is also extremely difficult to unencrypt if you used the extended security option). But you can view the unencrypted HTML through inspecting but we have already blocked that(to a very reasonable extent)

SQL Server stored procedure creating temp table and inserting value

A SELECT INTO statement creates the table for you. There is no need for the CREATE TABLE statement before hand.

What is happening is that you create #ivmy_cash_temp1 in your CREATE statement, then the DB tries to create it for you when you do a SELECT INTO. This causes an error as it is trying to create a table that you have already created.

Either eliminate the CREATE TABLE statement or alter your query that fills it to use INSERT INTO SELECT format.

If you need a unique ID added to your new row then it's best to use SELECT INTO... since IDENTITY() only works with this syntax.

JDK on OSX 10.7 Lion

You can download the 10.7 Lion JDK from

  1. Sign in and click the java section on the right.

  2. The jdk is installed into a different location then previous. This will result in IDEs (such as Eclipse) being unable to locate source code and javadocs.

  3. At the time of writing the JDK ended up here:


  4. Open up eclipse preferences and go to Java --> Installed JREs page

  5. Rather than use the "JVM Contents (MacOS X Default) we will need to use the JDK location

  6. At the time of writing Search is not aware of the new JDK location; we we will need to click on the Add button

  7. From the Add JRE wizard choose "MacOS X VM" for the JRE Type

  8. For the JRE Definition Page we need to fill in the following:

    • JRE Home: /Library/Java/JavaVirtualMachines/1.6.0_26-b03-383.jdk/Contents/Home
  9. The other fields will now auto fill, with the default JRE name being "Home". You can quickly correct this to something more meaningful:

    • JRE name: System JDK
  10. Finish the wizard and return to the Installed JREs page

  11. Choose "System JDK" from the list

  12. You can now develop normally with:

    • javadocs correctly shown for base classes
    • source code correctly shown when debugging

MYSQL query between two timestamps


FROM eventList 


FROM eventList WHERE  `date` 
BETWEEN '2013-03-26 00:00:01' AND '2013-03-26 23:59:59'

Mean Squared Error in Numpy?

Even more numpy

np.square(np.subtract(A, B)).mean()

VBA: Convert Text to Number

For large datasets a faster solution is required.

Making use of 'Text to Columns' functionality provides a fast solution.

Example based on column F, starting range at 25 to LastRow

Sub ConvTxt2Nr()

Dim SelectR As Range
Dim sht As Worksheet
Dim LastRow As Long

Set sht = ThisWorkbook.Sheets("DumpDB")

LastRow = sht.Cells(sht.Rows.Count, "F").End(xlUp).Row

Set SelectR = ThisWorkbook.Sheets("DumpDB").Range("F25:F" & LastRow)

SelectR.TextToColumns Destination:=Range("F25"), DataType:=xlDelimited, _
    TextQualifier:=xlDoubleQuote, ConsecutiveDelimiter:=False, Tab:=True, _
    Semicolon:=False, Comma:=False, Space:=False, Other:=False, FieldInfo _
    :=Array(1, 1), TrailingMinusNumbers:=True

End Sub

Why is using "" for array iteration a bad idea?

Using the loop for an array is not wrong, although I can guess why someone told you that:

1.) There is already a higher order function, or method, that has that purpose for an array, but has more functionality and leaner syntax, called 'forEach': Array.prototype.forEach(function(element, index, array) {} );

2.) Arrays always have a length, but and forEach do not execute a function for any value that is 'undefined', only for the indexes that have a value defined. So if you only assign one value, these loops will only execute a function once, but since an array is enumerated, it will always have a length up to the highest index that has a defined value, but that length could go unnoticed when using these loops.

3.) The standard for loop will execute a function as many times as you define in the parameters, and since an array is numbered, it makes more sense to define how many times you want to execute a function. Unlike the other loops, the for loop can then execute a function for every index in the array, whether the value is defined or not.

In essence, you can use any loop, but you should remember exactly how they work. Understand the conditions upon which the different loops reiterate, their separate functionalities, and realize they will be more or less appropriate for differing scenarios.

Also, it may be considered a better practice to use the forEach method than the loop in general, because it is easier to write and has more functionality, so you may want to get in the habit of only using this method and standard for, but your call.

See below that the first two loops only execute the console.log statements once, while the standard for loop executes the function as many times as specified, in this case, array.length = 6.

var arr = [];
arr[5] = 'F';

for (var index in arr) {
// 5
// 'F'
// => (6) [undefined x 5, 6]

arr.forEach(function(element, index, arr) {
// 5
// 'F'
// => Array (6) [undefined x 5, 6]

for (var index = 0; index < arr.length; index++) {
// 0
// undefined
// => Array (6) [undefined x 5, 6]

// 1
// undefined
// => Array (6) [undefined x 5, 6]

// 2
// undefined
// => Array (6) [undefined x 5, 6]

// 3
// undefined
// => Array (6) [undefined x 5, 6]

// 4
// undefined
// => Array (6) [undefined x 5, 6]

// 5
// 'F'
// => Array (6) [undefined x 5, 6]

iOS 6 apps - how to deal with iPhone 5 screen size?


if ([[UIScreen mainScreen] bounds].size.height > 960)

on iPhone 5 is wrong

if ([[UIScreen mainScreen] bounds].size.height == 568)

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:


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

  -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:

  -ms-grid-column: 1;
  -ms-grid-row: 1;

  -ms-grid-column: 2;
  -ms-grid-row: 1;

Docker how to change repository name or rename image?

docker image tag #imageId myname/server:latest

This works for me

How do I write dispatch_after GCD in Swift 3, 4, and 5?

Swift 4

You can create a extension on DispatchQueue and add function delay which uses DispatchQueue asyncAfter function internally

extension DispatchQueue {
   static func delay(_ delay: DispatchTimeInterval, closure: @escaping () -> ()) {
      DispatchQueue.main.asyncAfter(deadline: .now() + delay, execute: closure)

and use

DispatchQueue.delay(.milliseconds(10)) {
   print("task to be done")

How to convert JSON data into a Python object

Expanding on DS's answer a bit, if you need the object to be mutable (which namedtuple is not), you can use the recordclass library instead of namedtuple:

import json
from recordclass import recordclass

data = '{"name": "John Smith", "hometown": {"name": "New York", "id": 123}}'

# Parse into a mutable object
x = json.loads(data, object_hook=lambda d: recordclass('X', d.keys())(*d.values()))

The modified object can then be converted back to json very easily using simplejson: = "John Doe"
new_json = simplejson.dumps(x)

Wait for Angular 2 to load/resolve model before rendering view/template

Implement the routerOnActivate in your @Component and return your promise:

EDIT: This explicitly does NOT work, although the current documentation can be a little hard to interpret on this topic. See Brandon's first comment here for more information:

EDIT: The related information on the otherwise-usually-accurate Auth0 site is not correct:

EDIT: The angular team is planning a @Resolve decorator for this purpose.

JWT (JSON Web Token) automatic prolongation of expiration

Today, lots of people opt for doing session management with JWTs without being aware of what they are giving up for the sake of perceived simplicity. My answer elaborates on the 2nd part of the questions:

What is the real benefit then? Why not have only one token (not JWT) and keep the expiration on the server?

Are there other options? Is using JWT not suited for this scenario?

JWTs are capable of supporting basic session management with some limitations. Being self-describing tokens, they don't require any state on the server-side. This makes them appealing. For instance, if the service doesn't have a persistence layer, it doesn't need to bring one in just for session management.

However, statelessness is also the leading cause of their shortcomings. Since they are only issued once with fixed content and expiration, you can't do things you would like to with a typical session management setup.

Namely, you can't invalidate them on-demand. This means you can't implement a secure logout as there is no way to expire already issued tokens. You also can't implement idle timeout for the same reason. One solution is to keep a blacklist, but that introduces state.

I wrote a post explaining these drawbacks in more detail. To be clear, you can work around these by adding more complexity (sliding sessions, refresh tokens, etc.)

As for other options, if your clients only interact with your service via a browser, I strongly recommend using a cookie-based session management solution. I also compiled a list authentication methods currently widely used on the web.

MIT vs GPL license

It seems to me that the chief difference between the MIT license and GPL is that the MIT doesn't require modifications be open sourced whereas the GPL does.

True - in general. You don't have to open-source your changes if you're using GPL. You could modify it and use it for your own purpose as long as you're not distributing it. BUT... if you DO distribute it, then your entire project that is using the GPL code also becomes GPL automatically. Which means, it must be open-sourced, and the recipient gets all the same rights as you - meaning, they can turn around and distribute it, modify it, sell it, etc. And that would include your proprietary code which would then no longer be proprietary - it becomes open source.

The difference with MIT is that even if you actually distribute your proprietary code that is using the MIT licensed code, you do not have to make the code open source. You can distribute it as a closed app where the code is encrypted or is a binary. Including the MIT-licensed code can be encrypted, as long as it carries the MIT license notice.

is the GPL is more restrictive than the MIT license?

Yes, very much so.

Find the files existing in one directory but not in the other

Meld ( does a great job at comparing directories and the files within.

Meld comparing directories

Change the current directory from a Bash script

In light of the unreadability and overcomplication of answers, i believe this is what the requestor should do

  1. add that script to the PATH
  2. run the script as . scriptname

The . (dot) will make sure the script is not run in a child shell.

Webpack not excluding node_modules

From your config file, it seems like you're only excluding node_modules from being parsed with babel-loader, but not from being bundled.

In order to exclude node_modules and native node libraries from bundling, you need to:

  1. Add target: 'node' to your webpack.config.js. This will exclude native node modules (path, fs, etc.) from being bundled.
  2. Use webpack-node-externals in order to exclude other node_modules.

So your result config file should look like:

var nodeExternals = require('webpack-node-externals');
module.exports = {
    target: 'node', // in order to ignore built-in modules like path, fs, etc. 
    externals: [nodeExternals()], // in order to ignore all modules in node_modules folder 

"Unorderable types: int() < str()"

Just a side note, in Python 2.0 you could compare anything to anything (int to string). As this wasn't explicit, it was changed in 3.0, which is a good thing as you are not running into the trouble of comparing senseless values with each other or when you forget to convert a type.

Creating files in C++

use c methods FILE *fp =fopen("filename","mode"); fclose(fp); mode means a for appending r for reading ,w for writing

   / / using ofstream constructors.
      #include <iostream>
       #include <fstream>  
      std::string input="some text to write"
     std::ofstream outfile ("test.txt");

    outfile <<input << std::endl;


u'\ufeff' in Python string

Here is based on the answer from Mark Tolonen. The string included different languages of the word 'test' that's separated by '|', so you can see the difference.

u = u'ABCtestß???másbêta|test|??????|??|??|???|???????|???????|????????|ki?m tra|Ölçek|'
e8 = u.encode('utf-8')        # encode without BOM
e8s = u.encode('utf-8-sig')   # encode with BOM
e16 = u.encode('utf-16')      # encode with BOM
e16le = u.encode('utf-16le')  # encode without BOM
e16be = u.encode('utf-16be')  # encode without BOM
print('utf-8     %r' % e8)
print('utf-8-sig %r' % e8s)
print('utf-16    %r' % e16)
print('utf-16le  %r' % e16le)
print('utf-16be  %r' % e16be)
print('utf-8  w/ BOM decoded with utf-8     %r' % e8s.decode('utf-8'))
print('utf-8  w/ BOM decoded with utf-8-sig %r' % e8s.decode('utf-8-sig'))
print('utf-16 w/ BOM decoded with utf-16    %r' % e16.decode('utf-16'))
print('utf-16 w/ BOM decoded with utf-16le  %r' % e16.decode('utf-16le'))

Here is a test run:

>>> u = u'ABCtestß???másbêta|test|??????|??|??|???|???????|???????|????????|ki?m tra|Ölçek|'
>>> e8 = u.encode('utf-8')        # encode without BOM
>>> e8s = u.encode('utf-8-sig')   # encode with BOM
>>> e16 = u.encode('utf-16')      # encode with BOM
>>> e16le = u.encode('utf-16le')  # encode without BOM
>>> e16be = u.encode('utf-16be')  # encode without BOM
>>> print('utf-8     %r' % e8)
utf-8     b'ABCtest\xce\xb2\xe8\xb2\x9d\xe5\xa1\x94\xec\x9c\x84m\xc3\xa1sb\xc3\xaata|test|\xd8\xa7\xd8\xae\xd8\xaa\xd8\xa8\xd8\xa7\xd8\xb1|\xe6\xb5\x8b\xe8\xaf\x95|\xe6\xb8\xac\xe8\xa9\xa6|\xe3\x83\x86\xe3\x82\xb9\xe3\x83\x88|\xe0\xa4\xaa\xe0\xa4\xb0\xe0\xa5\x80\xe0\xa4\x95\xe0\xa5\x8d\xe0\xa4\xb7\xe0\xa4\xbe|\xe0\xb4\xaa\xe0\xb4\xb0\xe0\xb4\xbf\xe0\xb4\xb6\xe0\xb5\x8b\xe0\xb4\xa7\xe0\xb4\xa8|\xd7\xa4\xd6\xbc\xd7\xa8\xd7\x95\xd7\x91\xd7\x99\xd7\xa8\xd7\x9f|ki\xe1\xbb\x83m tra|\xc3\x96l\xc3\xa7ek|'
>>> print('utf-8-sig %r' % e8s)
utf-8-sig b'\xef\xbb\xbfABCtest\xce\xb2\xe8\xb2\x9d\xe5\xa1\x94\xec\x9c\x84m\xc3\xa1sb\xc3\xaata|test|\xd8\xa7\xd8\xae\xd8\xaa\xd8\xa8\xd8\xa7\xd8\xb1|\xe6\xb5\x8b\xe8\xaf\x95|\xe6\xb8\xac\xe8\xa9\xa6|\xe3\x83\x86\xe3\x82\xb9\xe3\x83\x88|\xe0\xa4\xaa\xe0\xa4\xb0\xe0\xa5\x80\xe0\xa4\x95\xe0\xa5\x8d\xe0\xa4\xb7\xe0\xa4\xbe|\xe0\xb4\xaa\xe0\xb4\xb0\xe0\xb4\xbf\xe0\xb4\xb6\xe0\xb5\x8b\xe0\xb4\xa7\xe0\xb4\xa8|\xd7\xa4\xd6\xbc\xd7\xa8\xd7\x95\xd7\x91\xd7\x99\xd7\xa8\xd7\x9f|ki\xe1\xbb\x83m tra|\xc3\x96l\xc3\xa7ek|'
>>> print('utf-16    %r' % e16)
utf-16    b"\xff\xfeA\x00B\x00C\x00t\x00e\x00s\x00t\x00\xb2\x03\x9d\x8cTX\x04\xc7m\x00\xe1\x00s\x00b\x00\xea\x00t\x00a\x00|\x00t\x00e\x00s\x00t\x00|\x00'\x06.\x06*\x06(\x06'\x061\x06|\x00Km\xd5\x8b|\x00,nf\x8a|\x00\xc60\xb90\xc80|\x00*\t0\t@\t\x15\tM\t7\t>\t|\x00*\r0\r?\r6\rK\r'\r(\r|\x00\xe4\x05\xbc\x05\xe8\x05\xd5\x05\xd1\x05\xd9\x05\xe8\x05\xdf\x05|\x00k\x00i\x00\xc3\x1em\x00 \x00t\x00r\x00a\x00|\x00\xd6\x00l\x00\xe7\x00e\x00k\x00|\x00"
>>> print('utf-16le  %r' % e16le)
utf-16le  b"A\x00B\x00C\x00t\x00e\x00s\x00t\x00\xb2\x03\x9d\x8cTX\x04\xc7m\x00\xe1\x00s\x00b\x00\xea\x00t\x00a\x00|\x00t\x00e\x00s\x00t\x00|\x00'\x06.\x06*\x06(\x06'\x061\x06|\x00Km\xd5\x8b|\x00,nf\x8a|\x00\xc60\xb90\xc80|\x00*\t0\t@\t\x15\tM\t7\t>\t|\x00*\r0\r?\r6\rK\r'\r(\r|\x00\xe4\x05\xbc\x05\xe8\x05\xd5\x05\xd1\x05\xd9\x05\xe8\x05\xdf\x05|\x00k\x00i\x00\xc3\x1em\x00 \x00t\x00r\x00a\x00|\x00\xd6\x00l\x00\xe7\x00e\x00k\x00|\x00"
>>> print('utf-16be  %r' % e16be)
utf-16be  b"\x00A\x00B\x00C\x00t\x00e\x00s\x00t\x03\xb2\x8c\x9dXT\xc7\x04\x00m\x00\xe1\x00s\x00b\x00\xea\x00t\x00a\x00|\x00t\x00e\x00s\x00t\x00|\x06'\x06.\x06*\x06(\x06'\x061\x00|mK\x8b\xd5\x00|n,\x8af\x00|0\xc60\xb90\xc8\x00|\t*\t0\t@\t\x15\tM\t7\t>\x00|\r*\r0\r?\r6\rK\r'\r(\x00|\x05\xe4\x05\xbc\x05\xe8\x05\xd5\x05\xd1\x05\xd9\x05\xe8\x05\xdf\x00|\x00k\x00i\x1e\xc3\x00m\x00 \x00t\x00r\x00a\x00|\x00\xd6\x00l\x00\xe7\x00e\x00k\x00|"
>>> print()

>>> print('utf-8  w/ BOM decoded with utf-8     %r' % e8s.decode('utf-8'))
utf-8  w/ BOM decoded with utf-8     '\ufeffABCtestß???másbêta|test|??????|??|??|???|???????|???????|????????|ki?m tra|Ölçek|'
>>> print('utf-8  w/ BOM decoded with utf-8-sig %r' % e8s.decode('utf-8-sig'))
utf-8  w/ BOM decoded with utf-8-sig 'ABCtestß???másbêta|test|??????|??|??|???|???????|???????|????????|ki?m tra|Ölçek|'
>>> print('utf-16 w/ BOM decoded with utf-16    %r' % e16.decode('utf-16'))
utf-16 w/ BOM decoded with utf-16    'ABCtestß???másbêta|test|??????|??|??|???|???????|???????|????????|ki?m tra|Ölçek|'
>>> print('utf-16 w/ BOM decoded with utf-16le  %r' % e16.decode('utf-16le'))
utf-16 w/ BOM decoded with utf-16le  '\ufeffABCtestß???másbêta|test|??????|??|??|???|???????|???????|????????|ki?m tra|Ölçek|'

It's worth to know that only both utf-8-sig and utf-16 get back the original string after both encode and decode.

How can I multiply and divide using only bit shifting and adding?

To multiply in terms of adding and shifting you want to decompose one of the numbers by powers of two, like so:

21 * 5 = 10101_2 * 101_2             (Initial step)
       = 10101_2 * (1 * 2^2  +  0 * 2^1  +  1 * 2^0)
       = 10101_2 * 2^2 + 10101_2 * 2^0 
       = 10101_2 << 2 + 10101_2 << 0 (Decomposed)
       = 10101_2 * 4 + 10101_2 * 1
       = 10101_2 * 5
       = 21 * 5                      (Same as initial expression)

(_2 means base 2)

As you can see, multiplication can be decomposed into adding and shifting and back again. This is also why multiplication takes longer than bit shifts or adding - it's O(n^2) rather than O(n) in the number of bits. Real computer systems (as opposed to theoretical computer systems) have a finite number of bits, so multiplication takes a constant multiple of time compared to addition and shifting. If I recall correctly, modern processors, if pipelined properly, can do multiplication just about as fast as addition, by messing with the utilization of the ALUs (arithmetic units) in the processor.

Extract column values of Dataframe as List in Apache Spark

List<String> whatever_list = df.toJavaRDD().map(new Function<Row, String>() {
    public String call(Row row) {
        return row.getAs("column_name").toString();
}).collect();"list is %s",whatever_list)); //verification

Since no one has given any solution in java(Real Programming Language) Can thank me later

How to disable action bar permanently

You can force hide the action bar simply:

ActionBar  actionbar = getSupportActionBar();

Just use your default theme, it will work good if fullscreen is set

How do I use Bash on Windows from the Visual Studio Code integrated terminal?

For scoop users:

"": "C:\\Users\\[YOUR-NAME]\\scoop\\apps\\git\\current\\usr\\bin\\bash.exe",
"": [

HTTP could not register URL http://+:8000/HelloWCF/. Your process does not have access rights to this namespace

Unfortunately the link in the exception text,, is broken. However, it used to lead to which explains how to set the permissions.

It basically informs you to use the following command:

netsh http add urlacl url=http://+:80/MyUri user=DOMAIN\user

You can get more help on the details using the help of netsh

For example: netsh http add ?

Gives help on the http add command.

How to represent the double quotes character (") in regex?

you need to use backslash before ". like \"

From the doc here you can see that

A character preceded by a backslash ( \ ) is an escape sequence and has special meaning to the compiler.

and " (double quote) is a escacpe sequence

When an escape sequence is encountered in a print statement, the compiler interprets it accordingly. For example, if you want to put quotes within quotes you must use the escape sequence, \", on the interior quotes. To print the sentence

She said "Hello!" to me.

you would write

System.out.println("She said \"Hello!\" to me.");

How to change theme for AlertDialog

I"m not sure how Arve's solution would work in a custom Dialog with builder where the view is inflated via a LayoutInflator.

The solution should be to insert the the ContextThemeWrapper in the inflator through cloneInContext():

View sensorView = LayoutInflater.from(context).cloneInContext(
     new ContextThemeWrapper(context,
).inflate(R.layout.dialog_fingerprint, null);

check if a string matches an IP address pattern in python?

If you use Python3, you can use ipaddress module Example:

>>> import ipaddress

>>> ipv6 = "2001:0db8:0a0b:12f0:0000:0000:0000:0001"
>>> ipv4 = ""
>>> ipv4invalid = ""
>>> str = "Tay Tay"

>>> ipaddress.ip_address(ipv6)

>>> ipaddress.ip_address(ipv4)

>>> ipaddress.ip_address(ipv4invalid)
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/usr/lib/python3.4/", line 54, in ip_address
ValueError: '' does not appear to be an IPv4 or IPv6 address

>>> ipaddress.ip_address(str)
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/usr/lib/python3.4/", line 54, in ip_address
ValueError: 'Tay Tay' does not appear to be an IPv4 or IPv6 address

How do you copy the contents of an array to a std::vector in C++ without looping?

int dataArray[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };//source

unsigned dataArraySize = sizeof(dataArray) / sizeof(int);

std::vector<int> myvector (dataArraySize );//target

std::copy ( myints, myints+dataArraySize , myvector.begin() );

//myvector now has 1,2,3,...10 :-)

Mixing a PHP variable with a string literal

echo "{$test}y";

You can use braces to remove ambiguity when interpolating variables directly in strings.

Also, this doesn't work with single quotes. So:

echo '{$test}y';

will output


Regular expression to remove HTML tags from a string

You should not attempt to parse HTML with regex. HTML is not a regular language, so any regex you come up with will likely fail on some esoteric edge case. Please refer to the seminal answer to this question for specifics. While mostly formatted as a joke, it makes a very good point.

The following examples are Java, but the regex will be similar -- if not identical -- for other languages.

String target = someString.replaceAll("<[^>]*>", "");

Assuming your non-html does not contain any < or > and that your input string is correctly structured.

If you know they're a specific tag -- for example you know the text contains only <td> tags, you could do something like this:

String target = someString.replaceAll("(?i)<td[^>]*>", "");

Edit: Omega brought up a good point in a comment on another post that this would result in multiple results all being squished together if there were multiple tags.

For example, if the input string were <td>Something</td><td>Another Thing</td>, then the above would result in SomethingAnother Thing.

In a situation where multiple tags are expected, we could do something like:

String target = someString.replaceAll("(?i)<td[^>]*>", " ").replaceAll("\\s+", " ").trim();

This replaces the HTML with a single space, then collapses whitespace, and then trims any on the ends.

How to run multiple DOS commands in parallel?

You can execute commands in parallel with start like this:

start "" ping myserver
start "" nslookup myserver
start "" morecommands

They will each start in their own command prompt and allow you to run multiple commands at the same time from one batch file.

Hope this helps!

ImportError: DLL load failed: %1 is not a valid Win32 application

I just hit this and the problem was that the package had at one point been installed in the per-user packages directory. (On Windows.) aka %AppData%\Python. So Python was looking there first, finding an old 32-bit version of the .pyd file, and failing with the listed error. Unfortunately pip uninstall by itself wasn't enough to clean this, and at this time pip 10.0.1 doesn't seem to have a --user parameter for uninstall, only for install.

tl;dr Deleting the old .pyd from %AppData%\python\python27\site-packages resolved this problem for me.

How to copy to clipboard using Access/VBA?

I couldn't figure out how to use the API using the first Google results. Fortunately a thread somewhere pointed me to this link:

Which works nicely. :)

How to create a directive with a dynamic template in AngularJS?

i've used the $templateCache to accomplish something similar. i put several ng-templates in a single html file, which i reference using the directive's templateUrl. that ensures the html is available to the template cache. then i can simply select by id to get the ng-template i want.


<script type="text/ng-template" id=“foo”>

<script type="text/ng-template" id=“bar”>


myapp.directive(‘foobardirective’, ['$compile', '$templateCache', function ($compile, $templateCache) {

    var getTemplate = function(data) {
        // use data to determine which template to use
        var templateid = 'foo';
        var template = $templateCache.get(templateid);
        return template;

    return {
        templateUrl: 'views/partials/template.html',
        scope: {data: '='},
        restrict: 'E',
        link: function(scope, element) {
            var template = getTemplate(;


App can't be opened because it is from an unidentified developer

I had the same problem, Eclipse would not start. Found this link and it worked like a charm:

Can't click Menu Bar Items in Eclipse

Java is messed-up on Maverick, need to download and install from here:

Is it safe to store a JWT in localStorage with ReactJS?

Isn't neither localStorage or httpOnly cookie acceptable? In regards to a compromised 3rd party library, the only solution I know of that will reduce / prevent sensitive information from being stolen would be enforced Subresource Integrity.

Subresource Integrity (SRI) is a security feature that enables browsers to verify that resources they fetch (for example, from a CDN) are delivered without unexpected manipulation. It works by allowing you to provide a cryptographic hash that a fetched resource must match.

As long as the compromised 3rd party library is active on your website, a keylogger can start collecting info like username, password, and whatever else you input into the site.

An httpOnly cookie will prevent access from another computer but will do nothing to prevent the hacker from manipulating the user's computer.

Convert char to int in C#

This converts to an integer and handles unicode


You can read more here.

MySQL & Java - Get id of the last inserted value (JDBC)

Alternatively you can do:

Statement stmt = db.prepareStatement(query, Statement.RETURN_GENERATED_KEYS);
numero = stmt.executeUpdate();

ResultSet rs = stmt.getGeneratedKeys();
if ({

But use Sean Bright's answer instead for your scenario.

Escape double quote in VB string

Did you try using double-quotes? Regardless, no one in 2011 should be limited by the native VB6 shell command. Here's a function that uses ShellExecuteEx, much more versatile.

Option Explicit

Private Const SEE_MASK_DEFAULT = &H0

Public Enum EShellShowConstants
        essSW_HIDE = 0
        essSW_SHOWNORMAL = 1
        essSW_SHOWMINIMIZED = 2
        essSW_MAXIMIZE = 3
        essSW_SHOWMAXIMIZED = 3
        essSW_SHOWNOACTIVATE = 4
        essSW_SHOW = 5
        essSW_MINIMIZE = 6
        essSW_SHOWNA = 8
        essSW_RESTORE = 9
        essSW_SHOWDEFAULT = 10
End Enum

        cbSize        As Long
        fMask         As Long
        hwnd          As Long
        lpVerb        As String
        lpFile        As String
        lpParameters  As String
        lpDirectory   As String
        nShow         As Long
        hInstApp      As Long
        lpIDList      As Long     'Optional
        lpClass       As String   'Optional
        hkeyClass     As Long     'Optional
        dwHotKey      As Long     'Optional
        hIcon         As Long     'Optional
        hProcess      As Long     'Optional
End Type

Private Declare Function ShellExecuteEx Lib "shell32.dll" Alias "ShellExecuteExA" (lpSEI As SHELLEXECUTEINFO) As Long

Public Function ExecuteProcess(ByVal FilePath As String, ByVal hWndOwner As Long, ShellShowType As EShellShowConstants, Optional EXEParameters As String = "", Optional LaunchElevated As Boolean = False) As Boolean

    On Error GoTo Err

    'Fill the SEI structure
    With SEI
        .cbSize = Len(SEI)                  ' Bytes of the structure
        .fMask = SEE_MASK_DEFAULT           ' Check MSDN for more info on Mask
        .lpFile = FilePath                  ' Program Path
        .nShow = ShellShowType              ' How the program will be displayed
        .lpDirectory = PathGetFolder(FilePath)
        .lpParameters = EXEParameters       ' Each parameter must be separated by space. If the lpFile member specifies a document file, lpParameters should be NULL.
        .hwnd = hWndOwner                   ' Owner window handle

        ' Determine launch type (would recommend checking for Vista or greater here also)
        If LaunchElevated = True Then ' And m_OpSys.IsVistaOrGreater = True
            .lpVerb = "runas"
            .lpVerb = "Open"
        End If
    End With

     ExecuteProcess = ShellExecuteEx(SEI)   ' Execute the program, return success or failure

    Exit Function
    ' TODO: Log Error
    ExecuteProcess = False
End Function

Private Function PathGetFolder(psPath As String) As String
    On Error Resume Next
    Dim lPos As Long
    lPos = InStrRev(psPath, "\")
    PathGetFolder = Left$(psPath, lPos - 1)
End Function

What is the meaning of the word logits in TensorFlow?

Personal understanding, in TensorFlow domain, logits are the values to be used as input to softmax. I came to this understanding based on this tensorflow tutorial.

Although it is true that logit is a function in maths(especially in statistics), I don't think that's the same 'logit' you are looking at. In the book Deep Learning by Ian Goodfellow, he mentioned,

The function s-1(x) is called the logit in statistics, but this term is more rarely used in machine learning. s-1(x) stands for the inverse function of logistic sigmoid function.

In TensorFlow, it is frequently seen as the name of last layer. In Chapter 10 of the book Hands-on Machine Learning with Scikit-learn and TensorFLow by Aurélien Géron, I came across this paragraph, which stated logits layer clearly.

note that logits is the output of the neural network before going through the softmax activation function: for optimization reasons, we will handle the softmax computation later.

That is to say, although we use softmax as the activation function in the last layer in our design, for ease of computation, we take out logits separately. This is because it is more efficient to calculate softmax and cross-entropy loss together. Remember that cross-entropy is a cost function, not used in forward propagation.

Can I invoke an instance method on a Ruby module without including it?

If you want to call these methods without including module in another class then you need to define them as module methods:

module UsefulThings
  def self.get_file; ...
  def self.delete_file; ...

  def self.format_text(x); ...

and then you can call them with




But anyway I would recommend that you put just related methods in one module or in one class. If you have problem that you want to include just one method from module then it sounds like a bad code smell and it is not good Ruby style to put unrelated methods together.

Python: SyntaxError: keyword can't be an expression

sum.up is not a valid keyword argument name. Keyword arguments must be valid identifiers. You should look in the documentation of the library you are using how this argument really is called – maybe sum_up?

How to check Network port access and display useful message?

Great answer by mshutov & Salselvaprabu. I needed something a little bit more robust, and that checked all IPAddresses that was provided instead of checking only the first one.

I also wanted to replicate some of the parameter names and functionality than the Test-Connection function.

This new function allows you to set a Count for the number of retries, and the Delay between each try. Enjoy!

function Test-Port {

    Param (
        [string] $ComputerName,
        [int] $Port,
        [int] $Delay = 1,
        [int] $Count = 3

    function Test-TcpClient ($IPAddress, $Port) {

        $TcpClient = New-Object Net.Sockets.TcpClient
        Try { $TcpClient.Connect($IPAddress, $Port) } Catch {}

        If ($TcpClient.Connected) { $TcpClient.Close(); Return $True }
        Return $False


    function Invoke-Test ($ComputerName, $Port) {

        Try   { [array]$IPAddress = [System.Net.Dns]::GetHostAddresses($ComputerName) | Select-Object -Expand IPAddressToString } 
        Catch { Return $False }

        [array]$Results = $IPAddress | % { Test-TcpClient -IPAddress $_ -Port $Port }
        If ($Results -contains $True) { Return $True } Else { Return $False }


    for ($i = 1; ((Invoke-Test -ComputerName $ComputerName -Port $Port) -ne $True); $i++)
        if ($i -ge $Count) {
            Write-Warning "Timed out while waiting for port $Port to be open on $ComputerName!"
            Return $false

        Write-Warning "Port $Port not open, retrying..."
        Sleep $Delay

    Return $true


how to increase MaxReceivedMessageSize when calling a WCF from C#

Change the customBinding in the web.config to use larger defaults. I picked 2MB as it is a reasonable size. Of course setting it to 2GB (as your code suggests) will work but it does leave you more vulnerable to attacks. Pick a size that is larger than your largest request but isn't overly large.

Check this : Using Large Message Requests in Silverlight with WCF

       <behavior name="TestLargeWCF.Web.MyServiceBehavior">
         <serviceMetadata httpGetEnabled="true"/>
         <serviceDebug includeExceptionDetailInFaults="false"/>
       <binding name="customBinding0">
         <binaryMessageEncoding />
         <!-- Start change -->
         <httpTransport maxReceivedMessageSize="2097152"
         <!-- Stop change -->
   <serviceHostingEnvironment aspNetCompatibilityEnabled="true"/>
     <service behaviorConfiguration="Web.MyServiceBehavior" name="TestLargeWCF.Web.MyService">
       <endpoint address=""
       <endpoint address="mex"

How can I group data with an Angular filter?

In addition to the accepted answer you can use this if you want to group by multiple columns:

<ul ng-repeat="(key, value) in players | groupBy: '[team,name]'">

Run an Ansible task only when the variable contains a specific string

I used

failed_when: not(promtool_version.stdout.find('1.5.2') != -1)

means - failed only when the previously registered variable "promtool_version" doesn't contains string '1.5.2'.

Regex for allowing alphanumeric,-,_ and space

Try this regex

*Updated regex


This will allow only single space or - or _ between the text

Ex: this-some abc123_regex

To learn :

*Note: I have updated the regex based on Toto question

Quicksort: Choosing the pivot

Ideally the pivot should be the middle value in the entire array. This will reduce the chances of getting worst case performance.

Get data from fs.readFile

const fs = require('fs')
function readDemo1(file1) {
    return new Promise(function (resolve, reject) {
        fs.readFile(file1, 'utf8', function (err, dataDemo1) {
            if (err)
async function copyFile() {

    try {
        let dataDemo1 = await readDemo1('url')
        dataDemo1 += '\n' +  await readDemo1('url')

        await writeDemo2(dataDemo1)
    } catch (error) {

function writeDemo2(dataDemo1) {
    return new Promise(function(resolve, reject) {
      fs.writeFile('text.txt', dataDemo1, 'utf8', function(err) {
        if (err)
          resolve("Promise Success!");

Excel formula to reference 'CELL TO THE LEFT'

Instead of writing the very long:


You can simply write:

=OFFSET(*Name of your Cell*,0,-1)

Thus for example you can write into Cell B2:


to reference to cell B1

Still thanks Jason Young!! I would have never come up with this solution without your answer!

Setting user agent of a java URLConnection

Off hand, setting the http.agent system property to "" might do the trick (I don't have the code in front of me).

You might get away with:

 System.setProperty("http.agent", "");

but that might require a race between you and initialisation of the URL protocol handler, if it caches the value at startup (actually, I don't think it does).

The property can also be set through JNLP files (available to applets from 6u10) and on the command line:


Or for wrapper commands:


Proper use of const for defining functions in JavaScript

There's no problem with what you've done, but you must remember the difference between function declarations and function expressions.

A function declaration, that is:

function doSomething () {}

Is hoisted entirely to the top of the scope (and like let and const they are block scoped as well).

This means that the following will work:

doSomething() // works!
function doSomething() {}

A function expression, that is:

[const | let | var] = function () {} (or () =>

Is the creation of an anonymous function (function () {}) and the creation of a variable, and then the assignment of that anonymous function to that variable.

So the usual rules around variable hoisting within a scope -- block-scoped variables (let and const) do not hoist as undefined to the top of their block scope.

This means:

if (true) {
    doSomething() // will fail
    const doSomething = function () {}

Will fail since doSomething is not defined. (It will throw a ReferenceError)

If you switch to using var you get your hoisting of the variable, but it will be initialized to undefined so that block of code above will still not work. (This will throw a TypeError since doSomething is not a function at the time you call it)

As far as standard practices go, you should always use the proper tool for the job.

Axel Rauschmayer has a great post on scope and hoisting including es6 semantics: Variables and Scoping in ES6

Changing ImageView source

Just write a method for changing imageview

public void setImage(final Context mContext, final ImageView imageView, int picture)
    if (mContext != null && imageView != null)
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP)
                imageView.setImageDrawable(mContext.getResources().getDrawable(picture, mContext.getApplicationContext().getTheme()));
            } else
        } catch (Exception e)

Creating a range of dates in Python

Marginally better...

base =
date_list = [base - datetime.timedelta(days=x) for x in range(numdays)]

jQuery: what is the best way to restrict "number"-only input for textboxes? (allow decimal points)

    $(".numeric").keypress(function(event) {
  // Backspace, tab, enter, end, home, left, right
  // We don't support the del key in Opera because del == . == 46.
  var controlKeys = [8, 9, 13, 35, 36, 37, 39];
  // IE doesn't support indexOf
  var isControlKey = controlKeys.join(",").match(new RegExp(event.which));
  // Some browsers just don't raise events for control keys. Easy.
  // e.g. Safari backspace.
  if (!event.which || // Control keys in most browsers. e.g. Firefox tab is 0
      (49 <= event.which && event.which <= 57) || // Always 1 through 9
      (48 == event.which && $(this).attr("value")) || // No 0 first digit
      isControlKey) { // Opera assigns values for control keys.
  } else {

This code worked pretty good on me, I just had to add the 46 in the controlKeys array to use the period, though I don't thinks is the best way to do it ;)

How do you get the string length in a batch file?

You can do it in two lines, fully in a batch file, by writing the string to a file and then getting the length of the file. You just have to subtract two bytes to account for the automatic CR+LF added to the end.

Let's say your string is in a variable called strvar:

ECHO %strvar%> tempfile.txt
FOR %%? IN (tempfile.txt) DO ( SET /A strlength=%%~z? - 2 )

The length of the string is now in a variable called strlength.

In slightly more detail:

  • FOR %%? IN (filename) DO ( ... : gets info about a file
  • SET /A [variable]=[expression] : evaluate the expression numerically
  • %%~z? : Special expression to get the length of the file

To mash the whole command in one line:

ECHO %strvar%>x&FOR %%? IN (x) DO SET /A strlength=%%~z? - 2&del x

How can I revert multiple Git commits (already pushed) to a published repository?

The Problem

There are a number of work-flows you can use. The main point is not to break history in a published branch unless you've communicated with everyone who might consume the branch and are willing to do surgery on everyone's clones. It's best not to do that if you can avoid it.

Solutions for Published Branches

Your outlined steps have merit. If you need the dev branch to be stable right away, do it that way. You have a number of tools for Debugging with Git that will help you find the right branch point, and then you can revert all the commits between your last stable commit and HEAD.

Either revert commits one at a time, in reverse order, or use the <first_bad_commit>..<last_bad_commit> range. Hashes are the simplest way to specify the commit range, but there are other notations. For example, if you've pushed 5 bad commits, you could revert them with:

# Revert a series using ancestor notation.
git revert --no-edit

# Revert a series using commit hashes.
git revert --no-edit ffffffff..12345678

This will apply reversed patches to your working directory in sequence, working backwards towards your known-good commit. With the --no-edit flag, the changes to your working directory will be automatically committed after each reversed patch is applied.

See man 1 git-revert for more options, and man 7 gitrevisions for different ways to specify the commits to be reverted.

Alternatively, you can branch off your HEAD, fix things the way they need to be, and re-merge. Your build will be broken in the meantime, but this may make sense in some situations.

The Danger Zone

Of course, if you're absolutely sure that no one has pulled from the repository since your bad pushes, and if the remote is a bare repository, then you can do a non-fast-forward commit.

git reset --hard <last_good_commit>
git push --force

This will leave the reflog intact on your system and the upstream host, but your bad commits will disappear from the directly-accessible history and won't propagate on pulls. Your old changes will hang around until the repositories are pruned, but only Git ninjas will be able to see or recover the commits you made by mistake.

Foreign Key naming scheme

This is probably over-kill, but it works for me. It helps me a great deal when I am dealing with VLDBs especially. I use the following:

CONSTRAINT [FK_ChildTableName_ChildColName_ParentTableName_PrimaryKeyColName]

Of course if for some reason you are not referencing a primary key you must be referencing a column contained in a unique constraint, in this case:

CONSTRAINT [FK_ChildTableName_ChildColumnName_ParentTableName_ColumnInUniqueConstaintName]

Can it be long, yes. Has it helped keep info clear for reports, or gotten me a quick jump on that the potential issue is during a prod-alert 100% would love to know peoples thoughts on this naming convention.

How to secure the ASP.NET_SessionId cookie?

If the entire site uses HTTPS, your sessionId cookie is as secure as the HTTPS encryption at the very least. This is because cookies are sent as HTTP headers, and when using SSL, the HTTP headers are encrypted using the SSL when being transmitted.

Curl command line for consuming webServices?

Posting a string:

curl -d "String to post" ""

Posting the contents of a file:

curl -d @soap.xml ""

"detached entity passed to persist error" with JPA/EJB code

if you use to generate the id = GenerationType.AUTO strategy in your entity.

Replaces user.setId (1) by user.setId (null), and the problem is solved.

Benefits of EBS vs. instance-store (and vice-versa)

We like instance-store. It forces us to make our instances completely recyclable, and we can easily automate the process of building a server from scratch on a given AMI. This also means we can easily swap out AMIs. Also, EBS still has performance problems from time to time.

How to change the Eclipse default workspace?

In Eclipse, go to File -> Switch Workspace, choose or create a new workspace.

What can cause a “Resource temporarily unavailable” on sock send() command

"Resource temporarily unavailable" is the error message corresponding to EAGAIN, which means that the operation would have blocked but nonblocking operation was requested. For send(), that could be due to any of:

  • explicitly marking the file descriptor as nonblocking with fcntl(); or
  • passing the MSG_DONTWAIT flag to send(); or
  • setting a send timeout with the SO_SNDTIMEO socket option.

Trying to merge 2 dataframes but get ValueError

In one of your dataframes the year is a string and the other it is an int64 you can convert it first and then join (e.g. df['year']=df['year'].astype(int) or as RafaelC suggested df.year.astype(int))

Edit: Also note the comment by Anderson Zhu: Just in case you have None or missing values in one of your dataframes, you need to use Int64 instead of int. See the reference here.

How to drop a database with Mongoose?

beforeEach((done) => {
      mongoose.connection.dropCollection('products',(error ,result) => {
      if (error) {
        console.log('Products Collection is not dropped')
      } else {