Programs & Examples On #.htaccess

Directory-level configuration file used by Apache web servers. Use this tag if and only if .htaccess content is directly involved in the topic. We know many people are using .htaccess, but kindly ask the members of the community to not use this tag, unless you know it is on-topic in your question.

What does $1 [QSA,L] mean in my .htaccess file?

Not the place to give a complete tutorial, but here it is in short;

RewriteCond basically means "execute the next RewriteRule only if this is true". The !-l path is the condition that the request is not for a link (! means not, -l means link)

The RewriteRule basically means that if the request is done that matches ^(.+)$ (matches any URL except the server root), it will be rewritten as index.php?url=$1 which means a request for ollewill be rewritten as index.php?url=olle).

QSA means that if there's a query string passed with the original URL, it will be appended to the rewrite (olle?p=1 will be rewritten as index.php?url=olle&p=1.

L means if the rule matches, don't process any more RewriteRules below this one.

For more complete info on this, follow the links above. The rewrite support can be a bit hard to grasp, but there are quite a few examples on stackoverflow to learn from.

Increase max execution time for php

Try to set a longer max_execution_time:

<IfModule mod_php5.c>
    php_value max_execution_time 300

<IfModule mod_php7.c>
    php_value max_execution_time 300

htaccess Access-Control-Allow-Origin

If your host not at pvn or dedicated, it's dificult to restart server.

Better solution from me, just edit your CSS file (at another domain or your subdomain) that call font eot, woff etc to your origin (your-domain or www yourdomain). it will solve your problem.

I mean, edit relative url on css to absolute url origin domain

Deny all, allow only one IP through htaccess

If you want to use mod_rewrite for access control you can use condition like user agent, http referrer, remote addr etc.


RewriteCond %{REMOTE_ADDR} !=*.*.*.* #you ip address
RewriteRule ^$ - [F]


Remove .php extension with .htaccess

Gumbo's answer in the Stack Overflow question How to hide the .html extension with Apache mod_rewrite should work fine.

Re 1) Change the .html to .php

Re a.) Yup, that's possible, just add #tab to the URL.

Re b.) That's possible using QSA (Query String Append), see below.

This should also work in a sub-directory path:

RewriteCond %{REQUEST_FILENAME}.php -f
RewriteRule !.*\.php$ %{REQUEST_FILENAME}.php [QSA,L]

.htaccess file to allow access to images folder to view pictures?

<Directory /uploads>
   Options +Indexes

How to Specify "Vary: Accept-Encoding" header in .htaccess

I guess it's meant that you enable gzip compression for your css and js files, because that will enable the client to receive both gzip-encoded content and a plain content.

This is how to do it in apache2:

<IfModule mod_deflate.c>
    #The following line is enough for .js and .css
    AddOutputFilter DEFLATE js css

    #The following line also enables compression by file content type, for the following list of Content-Type:s
    AddOutputFilterByType DEFLATE text/html text/plain text/xml application/xml

    #The following lines are to avoid bugs with some browsers
    BrowserMatch ^Mozilla/4 gzip-only-text/html
    BrowserMatch ^Mozilla/4\.0[678] no-gzip
    BrowserMatch \bMSIE !no-gzip !gzip-only-text/html 

And here's how to add the Vary Accept-Encoding header: [src]

<IfModule mod_headers.c>
  <FilesMatch "\.(js|css|xml|gz)$">
    Header append Vary: Accept-Encoding

The Vary: header tells the that the content served for this url will vary according to the value of a certain request header. Here it says that it will serve different content for clients who say they Accept-Encoding: gzip, deflate (a request header), than the content served to clients that do not send this header. The main advantage of this, AFAIK, is to let intermediate caching proxies know they need to have two different versions of the same url because of such change.

Htaccess: add/remove trailing slash from URL

To complement Jon Lin's answer, here is a no-trailing-slash technique that also works if the website is located in a directory (like

RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} (.+)/$
RewriteRule ^ %1 [R=301,L]

For the sake of completeness, here is an alternative emphasizing that REQUEST_URI starts with a slash (at least in .htaccess files):

RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} /(.*)/$
RewriteRule ^ /%1 [R=301,L] <-- added slash here too, don't forget it

Just don't use %{REQUEST_URI} (.*)/$. Because in the root directory REQUEST_URI equals /, the leading slash, and it would be misinterpreted as a trailing slash.

If you are interested in more reading:

(update: this technique is now implemented in Laravel 5.5)

.htaccess: where is located when not in www base dir

The .htaccess is either in the root-directory of your webpage or in the directory you want to protect.

Make sure to make them visible in your filesystem, because AFAIK (I'm no unix expert either) files starting with a period are invisible by default on unix-systems.

How to hide .php extension in .htaccess

1) Are you sure mod_rewrite module is enabled? Check phpinfo()

2) Your above rule assumes the URL starts with "folder". Is this correct? Did you acutally want to have folder in the URL? This would match a URL like:

/folder/thing -> /folder/thing.php

If you actually want

/thing -> /folder/thing.php

You need to drop the folder from the match expression.

I usually use this to route request to page without php (but yours should work which leads me to think that mod_rewrite may not be enabled):

RewriteRule ^([^/\.]+)/?$ $1.php  [L,QSA]

3) Assuming you are declaring your rules in an .htaccess file, does your installation allow for setting Options (AllowOverride) overrides in .htaccess files? Some shared hosts do not.

When the server finds an .htaccess file (as specified by AccessFileName) it needs to know which directives declared in that file can override earlier access information.

htaccess redirect all pages to single page

If your aim is to redirect all pages to a single maintenance page (as the title could suggest also this), then use:

RewriteEngine on
RewriteCond %{REQUEST_URI} !/maintenance.php$ 
RewriteCond %{REMOTE_HOST} !^000\.000\.000\.000
RewriteRule $ /maintenance.php [R=302,L] 

Where 000 000 000 000 should be replaced by your ip adress.


How do I disable directory browsing?

You can place an empty file called index.html into each directory that you don't want listed. This has several advantages:

  • It (usually) requires zero configuration on the server.
  • It will keep working, even if the server administrator decides to use "AllowOverride None" in the the server configuration. (If you use .htaccess files, this can lead to lots of "Error 500 - internal server error" messages for your users!).
  • It also allows you to move your files from one server to the next, again without having to mess with the apache configuration.

Theoretically, the autoindexing might be triggered by a different file (this is controlled by the DirectoryIndex option), but I have yet to encounter this in the real world.

How to prevent http file caching in Apache httpd (MAMP)

<FilesMatch "\.(js|css)$">
  ExpiresActive On
  ExpiresDefault A1
  Header append Cache-Control must-revalidate

htaccess "order" Deny, Allow, Deny

As Gerben suggested, just change:

order deny,allow
deny from all


order allow,deny

And the restrictions will work as you want them to.

Details can be found in Apache's docs.

how to change php version in htaccess in server

just FYI in GoDaddy it's this:

AddHandler x-httpd-php5-3 .php

Https to http redirect using htaccess

RewriteCond %{HTTP:X-Forwarded-Proto} =https

URL rewriting with PHP

You can essentially do this 2 ways:

The .htaccess route with mod_rewrite

Add a file called .htaccess in your root folder, and add something like this:

RewriteEngine on
RewriteRule ^/?Some-text-goes-here/([0-9]+)$ /picture.php?id=$1

This will tell Apache to enable mod_rewrite for this folder, and if it gets asked a URL matching the regular expression it rewrites it internally to what you want, without the end user seeing it. Easy, but inflexible, so if you need more power:

The PHP route

Put the following in your .htaccess instead: (note the leading slash)

FallbackResource /index.php

This will tell it to run your index.php for all files it cannot normally find in your site. In there you can then for example:

$path = ltrim($_SERVER['REQUEST_URI'], '/');    // Trim leading slash(es)
$elements = explode('/', $path);                // Split path on slashes
if(empty($elements[0])) {                       // No path elements means home
} else switch(array_shift($elements))             // Pop off first item and switch
    case 'Some-text-goes-here':
        ShowPicture($elements); // passes rest of parameters to internal function
    case 'more':
        header('HTTP/1.1 404 Not Found');

This is how big sites and CMS-systems do it, because it allows far more flexibility in parsing URLs, config and database dependent URLs etc. For sporadic usage the hardcoded rewrite rules in .htaccess will do fine though.

.htaccess redirect www to non-www with SSL/HTTPS

www to non www with https

RewriteEngine on

RewriteCond %{HTTP_HOST} ^www\.(.*)$ [NC]
RewriteRule ^(.*)$ https://%1/$1 [R=301,L]

RewriteCond %{ENV:HTTPS} !on
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]

Force SSL/https using .htaccess and mod_rewrite

Simple and Easy , just add following

RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

How to automatically redirect HTTP to HTTPS on Apache servers?

I have actually followed this example and it worked for me :)

NameVirtualHost *:80
<VirtualHost *:80>
   Redirect permanent /

<VirtualHost _default_:443>
  DocumentRoot /usr/local/apache2/htdocs
  SSLEngine On
 # etc...

Then do:

/etc/init.d/httpd restart

deny directory listing with htaccess

Try adding this to the .htaccess file in that directory.

Options -Indexes

This has more information.

Getting a 500 Internal Server Error on Laravel 5+ Ubuntu 14.04

Sometimes there is problem with php version. We need to change php version from server. Just write down below string in .htaccess file:

AddHandler application/x-httpd-php5 .php

.htaccess: Invalid command 'RewriteEngine', perhaps misspelled or defined by a module not included in the server configuration

or defined by a module not included in the server configuration

Check to make sure you have mod_rewrite enabled.


  1. Find the httpd.conf file (usually you will find it in a folder called conf, config or something along those lines)
  2. Inside the httpd.conf file uncomment the line LoadModule rewrite_module modules/ (remove the pound '#' sign from in front of the line)
  3. Also find the line ClearModuleList is uncommented then find and make sure that the line AddModule mod_rewrite.c is not commented out.

If the LoadModule rewrite_module modules/ line is missing from the httpd.conf file entirely, just add it.

Sample command

To enable the module in a standard ubuntu do this:

a2enmod rewrite
systemctl restart apache2

Set Memory Limit in htaccess

In your .htaccess you can add:

PHP 5.x

<IfModule mod_php5.c>
    php_value memory_limit 64M

PHP 7.x

<IfModule mod_php7.c>
    php_value memory_limit 64M

If page breaks again, then you are using PHP as mod_php in apache, but error is due to something else.

If page does not break, then you are using PHP as CGI module and therefore cannot use php values - in the link I've provided might be solution but I'm not sure you will be able to apply it.


Tips for debugging .htaccess rewrite rules

Make sure that the syntax of each Regexp is correct

by testing against a set of test patterns to make sure that is a valid syntax and does what you intend with a fully range of test URIs.

See regexpCheck.php below for a simple script that you can add to a private/test directory in your site to help you do this. I've kept this brief rather than pretty. Just past this into a file regexpCheck.php in a test directory to use it on your website. This will help you build up any regexp and test it against a list of test cases as you do so. I am using the PHP PCRE engine here, but having had a look at the Apache source, this is basically identical to the one used in Apache. There are many HowTos and tutorials which provide templates and can help you build your regexp skills.

Listing 1 -- regexpCheck.php

<html><head><title>Regexp checker</title></head><body>
    $a_pattern= isset($_POST['pattern']) ? $_POST['pattern'] : "";
    $a_ntests = isset($_POST['ntests']) ? $_POST['ntests'] : 1;
    $a_test   = isset($_POST['test']) ? $_POST['test'] : array();
    $res = array(); $maxM=-1; 
    foreach($a_test as $t ){
        $rtn = @preg_match('#'.$a_pattern.'#',$t,$m);
        if($rtn == 1){
            $res[]=array_merge( array('matched'),  $m );
        } else {
            $res[]=array(($rtn === FALSE ? 'invalid' : 'non-matched'));
?> <p>&nbsp; </p>
<form method="post" action="<?php echo $_SERVER['SCRIPT_NAME'];?>">
    <label for="pl">Regexp Pattern: </label>
    <input id="p" name="pattern" size="50" value="<?php echo htmlentities($a_pattern,ENT_QUOTES,"UTF-8");;?>" />
    <label for="n">&nbsp; &nbsp; Number of test vectors: </label>
    <input id="n" name="ntests"  size="3" value="<?php echo $a_ntests;?>"/>
    <input type="submit" name="go" value="OK"/><hr/><p>&nbsp;</p>
    <table><thead><tr><td><b>Test Vector</b></td><td>&nbsp; &nbsp; <b>Result</b></td>
    for ( $i=0; $i<$maxM; $i++ ) echo "<td>&nbsp; &nbsp; <b>\$$i</b></td>";
    echo "</tr><tbody>\n";
    for( $i=0; $i<$a_ntests; $i++ ){
        echo '<tr><td>&nbsp;<input name="test[]" value="', 
            htmlentities($a_test[$i], ENT_QUOTES,"UTF-8"),'" /></td>';
        foreach ($res[$i] as $v) { echo '<td>&nbsp; &nbsp; ',htmlentities($v, ENT_QUOTES,"UTF-8"),'&nbsp; &nbsp; </td>';}
        echo "</tr>\n";
?> </table></form></body></html>

Forbidden You don't have permission to access / on this server

This works for me on Mac OS Mojave:

<Directory "/Users/{USERNAME}/Sites/project">
    Options +Indexes +FollowSymLinks +MultiViews
    AllowOverride All
    require all granted

How to debug .htaccess RewriteRule not working

Enter some junk value into your .htaccess e.g. foo bar, sakjnaskljdnas any keyword not recognized by htaccess and visit your URL. If it is working, you should get a

500 Internal Server Error

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request....

I suggest you to put it soon after RewriteEngine on.

Since you are on your machine. I presume you have access to apache .conf file.

open the .conf file, and look for a line similar to:

LoadModule rewrite_module modules/

If it is commented(#), uncomment and restart apache.

To log rewrite

RewriteEngine On
RewriteLog "/path/to/rewrite.log"
RewriteLogLevel 9

Put the above 3 lines in your virtualhost. restart the httpd.

RewriteLogLevel 9 Using a high value for Level will slow down your Apache server dramatically! Use the rewriting logfile at a Level greater than 2 only for debugging! Level 9 will log almost every rewritelog detail.


Things have changed in Apache 2.4:

FROM Upgrading to 2.4 from 2.2

The RewriteLog and RewriteLogLevel directives have been removed. This functionality is now provided by configuring the appropriate level of logging for the mod_rewrite module using the LogLevel directive. See also the mod_rewrite logging section.

For more on LogLevel, refer LogLevel Directive

you can accomplish

RewriteLog "/path/to/rewrite.log"

in this manner now

LogLevel debug rewrite_module:debug

How can I fix the 'Missing Cross-Origin Resource Sharing (CORS) Response Header' webfont issue?

we had similar header issue with Amazon (AWS) S3 presigned Post failing on some browsers.

point was to tell bucket CORS to expose header <ExposeHeader>Access-Control-Allow-Origin</ExposeHeader>

more details in this answer:

htaccess remove index.php from url

I don't have to many bulky code to give out just a little snippet solved the issue for me.

i have rather i want anyone that types it to get error on request event if you type you will still get error since there's this word "index" is contained there will always be an error thrown back though the content of index.php will still be displayed properly

cletus post on "" which solved it

Edit your .htaccess file with the below to redirect people visiting to 404 page

RewriteCond %{THE_REQUEST} \.php[\ /?].*HTTP/
RewriteRule ^.*$ - [R=404,L]

to redirect people visiting to 404 page

RewriteCond %{THE_REQUEST} \index[\ /?].*HTTP/
RewriteRule ^.*$ - [R=404,L]

Not withstanding we have already known that the above code works with already existing codes on stack see where i applied the code above just below the all codes at it end.

# The following will allow you to use URLs such as the following:
# Which will actually serve files such as the following:
# But *only if they exist*, otherwise it will report the usual 404 error.

Options +FollowSymLinks
RewriteEngine On

# Remove trailing slashes.
# e.g. will redirect to
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.+)/$ /$1 [R=permanent,QSA]

# Redirect to HTML if it exists.
# e.g. will display the contents of
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}.html -f
RewriteRule ^(.+)$ $1.html [L,QSA]

# Redirect to PHP if it exists.
# e.g. will display the contents of
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}.php -f
RewriteRule ^(.+)$ $1.php [L,QSA]

RewriteCond %{THE_REQUEST} \.php[\ /?].*HTTP/
RewriteRule ^.*$ - [R=404,L]

RewriteCond %{THE_REQUEST} \index[\ /?].*HTTP/
RewriteRule ^.*$ - [R=404,L]

.htaccess redirect all pages to new domain

Try this methode to redirect all to homepage new domain, Its works for me:

RewriteCond %{HTTP_HOST} ^olddomain\.com$ [OR]
RewriteCond %{HTTP_HOST} ^www\.olddomain\.com$
RewriteRule ^(.*)$ "https\:\/\/newdomain\.com\/" [R=301,L]

Using .htaccess to make all .html pages to run as .php files?

On Dreamhost Servers you can refer to this page that at time of writing indicates you may use the following for php 7.2 with FastCGI:

AddHandler fcgid-script .html
FcgidWrapper "/dh/cgi-system/php72.cgi" .html

Or if you are using php5 cgi (not FastCGI):

AddHandler php5-cgi .html

.htaccess mod_rewrite - how to exclude directory from rewrite rule

We used the following mod_rewrite rule:

RewriteEngine on
RewriteCond %{REQUEST_URI} !^/test/
RewriteCond %{REQUEST_URI} !^/my-folder/
RewriteRule (.*)$1 [R=301,L]

This redirects (permanently with a 301 redirect) all traffic to the site to, except requests to resources in the /test and /my-folder directories. We transfer the user to the exact resource they requested by using the (.*) capture group and then including $1 in the new URL. Mind the spaces.

Laravel 5 not finding css files

You can use one of the following options:

<link href="{{ asset('css/app.css') }}" rel="stylesheet" type="text/css" >

<link href="{{ URL::asset('css/app.css') }}" rel="stylesheet" type="text/css" >

{!! Html::style( asset('css/app.css')) !!}

CodeIgniter 500 Internal Server Error

I know I am late, but this will help someone.

Check if rewrite engine is enabled.

If not, enable rewrite engine and restart server.

sudo a2enmod rewrite
sudo service apache2 restart

Wordpress 403/404 Errors: You don't have permission to access /wp-admin/themes.php on this server

A few years late, but I have a solution for the most recent version of WordPress, which has this same issue (WordPress-generated .htaccess files break sites, reuslting in 403 Forbidden error messages). Here's that it looks like when WordPress creates it:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

# END WordPress

The problem is that the conditional doesn't work. It doesn't work because the module it's looking for isn't .c, it's .so. I think this is a platform-specific, or configuration-specific issue, where Mac OS and Lunix Apache installations are set up for .so AKA 'shared-object' modules. Looking for a .c module shouldn't break the conditional, I think that's a bug, but it's the issue.

Simply change the mod_rewrite.c to and you're all set to go!

# BEGIN WordPress
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

# END WordPress

CodeIgniter htaccess and URL rewrite issues

For those users of wamp server, follow the first 2 steps of @Raul Chipad's solution then:

  1. Click the wamp icon (normally in green), go to "Apache" > "Apache modules" > "rewrite_module". The "rewrite_module" should be ticked! And then it's the way to go!

The requested URL /about was not found on this server

**Solved Permalink Issue Wordpress ** 1) Login to wordpress dashboard > click on settings > premalinks > then select post name. 2) After that login to your hosting server goto .htaccess file and replace the code.

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

htaccess redirect to https://www

I used the below code from this website, it works great

RewriteEngine On_x000D_
RewriteCond %{SERVER_PORT} 80_x000D_
RewriteRule ^(.*)$$1 [R,L]

Hope it helps

Permission denied: /var/www/abc/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable?

If it gets into the selinux arena you've got a much more complicated issue. It's not a good idea to remove the selinux protection but to embrace it and use the tools that were designed to manage it.

If you are serving content out of /var/www/abc, you can verify the selinux permissions with a Z appended to the normal ls -l command. i.e. ls -laZ will give the selinux context.

To add a directory to be served by selinux you can use the semanage command like this. This will change the label on /var/www/abc to httpd_sys_content_t

semanage fcontext -a -t httpd_sys_content_t /var/www/abc

this will update the label for /var/www/abc

restorecon /var/www/abc 

This answer was taken from unixmen and modified to fit this question. I had been searching for this answer for a while and finally found it so felt like I needed to share somewhere. Hope it helps someone.

How to prevent a file from direct URL Access?

rosipov's rule works great!

I use it on live sites to display a blank or special message ;) in place of a direct access attempt to files I'd rather to protect a bit from direct view. I think it's more fun than a 403 Forbidden.

So taking rosipov's rule to redirect any direct request to {gif,jpg,js,txt} files to 'messageforcurious' :

RewriteEngine on 
RewriteCond %{HTTP_REFERER} !^http://(www\.)?domain\.ltd [NC] 
RewriteCond %{HTTP_REFERER} !^http://(www\.)?domain\.ltd.*$ [NC] 
RewriteRule \.(gif|jpg|js|txt)$ /messageforcurious [L]

I see it as a polite way to disallow direct acces to, say, a CMS sensible files like xml, javascript... with security in mind: To all these bots scrawling the web nowadays, I wonder what their algo will make from my 'messageforcurious'.

How to deny access to a file in .htaccess

Strong pattern matching — This is the method that I use here at Perishable Press. Using strong pattern matching, this technique prevents external access to any file containing “.hta”, “.HTA”, or any case-insensitive combination thereof. To illustrate, this code will prevent access through any of the following requests:

  • .htaccess
  • .hTaCcEsS
  • testFILE.htaccess
  • filename.HTACCESS

..etc., etc. Clearly, this method is highly effective at securing your site’s HTAccess files. Further, this technique also includes the fortifying “Satisfy All” directive. Note that this code should be placed in your domain’s root HTAccess file:

<Files ~ "^.*\.([Hh][Tt][Aa])">
order allow,deny
deny from all
satisfy all

Enabling error display in PHP via htaccess only

I feel like adding more details to the existing answer:

# PHP error handling for development servers
php_flag display_startup_errors on
php_flag display_errors on
php_flag html_errors on
php_flag log_errors on
php_flag ignore_repeated_errors off
php_flag ignore_repeated_source off
php_flag report_memleaks on
php_flag track_errors on
php_value docref_root 0
php_value docref_ext 0
php_value error_log /full/path/to/file/php_errors.log
php_value error_reporting -1
php_value log_errors_max_len 0

Give 777 or 755 permission to the log file and then add the code

<Files php_errors.log>
     Order allow,deny
     Deny from all
     Satisfy All

at the end of .htaccess. This will protect your log file.

These options are suited for a development server. For a production server you should not display any error to the end user. So change the display flags to off.

For more information, follow this link: Advanced PHP Error Handling via htaccess

urlencoded Forward slash is breaking URL

In Apache, AllowEncodedSlashes On would prevent the request from being immediately rejected with a 404.

Just another idea on how to fix this.

.htaccess, order allow, deny, deny from all: confused?

This is a quite confusing way of using Apache configuration directives.

Technically, the first bit is equivalent to

Allow From All

This is because Order Deny,Allow makes the Deny directive evaluated before the Allow Directives. In this case, Deny and Allow conflict with each other, but Allow, being the last evaluated will match any user, and access will be granted.

Now, just to make things clear, this kind of configuration is BAD and should be avoided at all cost, because it borders undefined behaviour.

The Limit sections define which HTTP methods have access to the directory containing the .htaccess file.

Here, GET and POST methods are allowed access, and PUT and DELETE methods are denied access. Here's a link explaining what the various HTTP methods are:

However, it's more than often useless to use these limitations as long as you don't have custom CGI scripts or Apache modules that directly handle the non-standard methods (PUT and DELETE), since by default, Apache does not handle them at all.

It must also be noted that a few other methods exist that can also be handled by Limit, namely CONNECT, OPTIONS, PATCH, PROPFIND, PROPPATCH, MKCOL, COPY, MOVE, LOCK, and UNLOCK.

The last bit is also most certainly useless, since any correctly configured Apache installation contains the following piece of configuration (for Apache 2.2 and earlier):

# The following lines prevent .htaccess and .htpasswd files from being 
# viewed by Web clients. 
<Files ~ "^\.ht">
    Order allow,deny
    Deny from all
    Satisfy all

which forbids access to any file beginning by ".ht".

The equivalent Apache 2.4 configuration should look like:

<Files ~ "^\.ht">
    Require all denied

Mobile Redirect using htaccess

Similarly, if you wanted to redirect to a sub-folder instead of a sub-domain, do the following:

Working off of Kevin's great solution you can add this to the .htaccess file in your site's root directory:

    <IfModule mod_rewrite.c>
        RewriteBase /
        RewriteEngine On

        # Check if mobile=1 is set and set cookie 'mobile' equal to 1
        RewriteCond %{QUERY_STRING} (^|&)mobile=1(&|$)
        RewriteRule ^ - [CO=mobile:1:%{HTTP_HOST}]

        # Check if mobile=0 is set and set cookie 'mobile' equal to 0
        RewriteCond %{QUERY_STRING} (^|&)mobile=0(&|$)
        RewriteRule ^ - [CO=mobile:0:%{HTTP_HOST}]

        # cookie can't be set and read in the same request so check
        RewriteCond %{QUERY_STRING} (^|&)mobile=0(&|$)
        RewriteRule ^ - [S=1]

        # Check if this looks like a mobile device
        RewriteCond %{HTTP:x-wap-profile} !^$ [OR]
        RewriteCond %{HTTP_USER_AGENT} "android|blackberry|ipad|iphone|ipod|iemobile|opera mobile|palmos|webos|googlebot-mobile" [NC,OR]
        RewriteCond %{HTTP:Profile}       !^$

        # Check if we're not already on the mobile site
        RewriteCond %{HTTP_HOST}          !^m\.
        # Check to make sure we haven't set the cookie before
        RewriteCond %{HTTP:Cookie}        !\mobile=0(;|$)
        # Now redirect to the mobile site
        RewriteRule ^ [R]

Then, in the /m/ folder, add or create an .htaccess with the following:

    #Begin user agent loop fix

         RewriteEngine Off
         RewriteBase /

    #End user agent loop fix 

I know it's not a direct answer to the question, but somebody (like me) might stumble upon this question and wonder how that method would be accomplished as well.

Deny access to one specific folder in .htaccess

Creating index.php, index.html, index.htm is not secure. Becuse, anyone can get access on your files within specified directory by guessing files name. E.g.: So, recommended method is creating a .htaccess file to deny all visitors ;). Have fun !!

Access-Control-Allow-Origin Multiple Origin Domains?

If you are having trouble with fonts, use:

<FilesMatch "\.(ttf|ttc|otf|eot|woff)$">
    <IfModule mod_headers>
        Header set Access-Control-Allow-Origin "*"

Laravel 5 – Remove Public from URL

Create .htaccess file in root directory and place code something like below.

<IfModule mod_rewrite.c>
    <IfModule mod_negotiation.c>
        Options -MultiViews

    RewriteEngine On

    RewriteCond %{REQUEST_FILENAME} -d [OR]
    RewriteCond %{REQUEST_FILENAME} -f
    RewriteRule ^ ^$1 [N]

    RewriteCond %{REQUEST_URI} (\.\w+$) [NC]
    RewriteRule ^(.*)$ public/$1 

    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^ server.php

htaccess - How to force the client's browser to clear the cache?

You can force browsers to cache something, but

You can't force browsers to clear their cache.

Thus the only (AMAIK) way is to use a new URL for your resources. Something like versioning.

htaccess <Directory> deny from all

You can use from root directory:

RewriteEngine On
RewriteRule ^(?:system)\b.* /403.html


RewriteRule ^(?:system)\b.* /403.php # with header('HTTP/1.0 403 Forbidden');

.htaccess - how to force "www." in a generic way?

This won't work with subdomains. correctly gets redirected to

but gets redirected to

Instead of checking if the subdomain is "not www", check if there are two dots:

RewriteCond %{HTTP_HOST} ^(.*)$ [NC]
RewriteCond %{HTTP_HOST} !^(.*)\.(.*)\. [NC]
RewriteCond %{HTTPS}s ^on(s)|
RewriteRule ^ HTTP%1://www.%{HTTP_HOST}%{REQUEST_URI} [R=301,L]

How can I get Apache gzip compression to work?

In my case append only this line worked

SetOutputFilter DEFLATE

convert htaccess to nginx

You can easily make a Php script to parse your old htaccess, I am using this one for PRestashop rules :

$content = $_POST['content'];

    $lines   = explode(PHP_EOL, $content);
    $results = '';

    foreach($lines as $line)
        $items = explode(' ', $line);

        $q = str_replace("^", "^/", $items[1]);

        if (substr($q, strlen($q) - 1) !== '$') $q .= '$';

        $buffer = 'rewrite "'.$q.'" "'.$items[2].'" last;';

        $results .= $buffer.PHP_EOL;


How to set upload_max_filesize in .htaccess?

If you are getting 500 - Internal server error that means you don't have permission to set these values by .htaccess. You have to contact your web server providers and ask to set AllowOverride Options for your host or to put these lines in their virtual host configuration file.

CodeIgniter removing index.php from url

  Removing index.php from url of codeigniter   

Three steps are require to remove index.php from url in Codeigniter.

1)Create .htacess file in parallel to application holder and just copy past the following code:

RewriteEngine On
RewriteBase /CodeIgniter/
RewriteCond %{REQUEST_URI} ^system.*
RewriteRule ^(.*)$ /index.php/$1 [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L]

2) Change $config['index_page'] to blank in config.php in application folder as below:

$config['index_page'] = '';

3) Enable “rewrite_module” of apache.

How Can I Remove “public/index.php” in the URL Generated Laravel?

1) Check whether mod_rewrite is enabled. Go to /etc/apache2/mods-enabled directory and see whether the rewrite.load is available. If not, enable it using the command sudo a2enmod rewrite.It will enable the rewrite module. If its already enabled, it will show the message Module rewrite already enabled.
2)Create a virtual host for public directory so that instead of giving http://localhost/public/index.php we will be able to use like that [hence public folder name will be hidded]
3)Then create a .htaccess which will hide the index.php from your url which shoul be inside the root directory (public folder)

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /index.php?/$1 [L]

Header set Access-Control-Allow-Origin in .htaccess doesn't work

Be careful on:

 Header add Access-Control-Allow-Origin "*"

This is not judicious at all to grant access to everybody. It's preferable to allow a list of know trusted host only...

Header add Access-Control-Allow-Origin "http://aaa.example"
Header add Access-Control-Allow-Origin "http://bbb.example"
Header add Access-Control-Allow-Origin "http://ccc.example"


.htaccess or .htpasswd equivalent on IIS?

This is the documentation that you want:

I guess the answer is, yes, there is an equivalent that will accomplish the same thing, integrated with Windows security.

Use .htaccess to redirect HTTP to HTTPs

The above final .htaccess and Test A,B,C,D,E did not work for me. I just used below 2 lines code and it works in my WordPress website:

RewriteCond %{SERVER_PORT} 80 
RewriteRule ^(.*)$$1 [R=301,L]

I'm not sure where I was making the mistake but this page helped me out.

.htaccess not working apache

First, note that restarting httpd is not necessary for .htaccess files. .htaccess files are specifically for people who don't have root - ie, don't have access to the httpd server config file, and can't restart the server. As you're able to restart the server, you don't need .htaccess files and can use the main server config directly.

Secondly, if .htaccess files are being ignored, you need to check to see that AllowOverride is set correctly. See for details. You need to also ensure that it is set in the correct scope - ie, in the right block in your configuration. Be sure you're NOT editing the one in the block, for example.

Third, if you want to ensure that a .htaccess file is in fact being read, put garbage in it. An invalid line, such as "INVALID LINE HERE", in your .htaccess file, will result in a 500 Server Error when you point your browser at the directory containing that file. If it doesn't, then you don't have AllowOverride configured correctly.

.htaccess deny from all

A little alternative to @gasp´s answer is to simply put the actual domain name you are running it from. Docs:

In the following example, there is no authentication and all hosts in the domain are allowed access; all other hosts are denied access.

Apache 2.2 configuration:

Order Deny,Allow
Deny from all
Allow from

Apache 2.4 configuration:

Require host

.htaccess not working on localhost with XAMPP

In conf/extra/httpd-vhosts.conf, add the line AllowOverride All for all the websites that you are having problem with

    # rest of the stuff
    <Directory "c:\Projects\">
        Require all granted
         AllowOverride All <-----This line is required

Apache: client denied by server configuration

Here's my symfony 1.4 virtual host file on debian, which works fine.

  <Directory /var/www/sf_project/web/>
    Options All Indexes FollowSymLinks    
    AllowOverride All
    Order allow,deny
    Allow from all

If you wan't to restrict access to a specific ip range, e.g. localhost use this:

Allow from

The mod_authz_host is responsible for filtering ip ranges. You can look up detailed things in there.

But maybe the problem could be related to some kind of misconfiguration in your "apache2.conf".

On what OS is the apache running?

How to redirect all HTTP requests to HTTPS

If you are using Apache, mod_rewrite is the easiest solution, and has a lot of documentation online how to do that. For example:

.htaccess rewrite subdomain to directory

write .htaccess

RewriteEngine On 
RewriteCond %{HTTPS} off 
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

How to increase Maximum Upload size in cPanel?

I have found the answer and solution to this problem. Before, I did not know that php.ini resides where in wordpress files. Now I have found that file in wp-admin directory where I placed the code

post_max_size 33M
upload_max_filesize 32M

then it worked. It increases the upload file size for my worpdress website. But, it is the same 2M as was before on cPanel.

How to check whether mod_rewrite is enable on server?

PHP's perdefined apache_get_modules() function returns a list of enabled modules. To check if mod_rewrite is enabled , you can run the following script on your server :


If the above example fails, you can verify mod-rewrite using your .htaccess file.

Create an htaccess file in the document root and add the following rewriteRule :

RewriteEngine on

RewriteRule ^helloWorld/?$ /index.php [NC,L]

Now visit , You will be internally forwarded to /index.php page of your site. Otherwise, if mod-rewrite is disabled , you will get a 500 Internel server error.

Hope this helps.

enable cors in .htaccess

Should't the .htaccess use add instead of set?

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

Redirect non-www to www in .htaccess

Here's the correct solution which supports https and http:

# Redirect to www
RewriteCond %{HTTP_HOST} ^[^.]+\.[^.]+$
RewriteCond %{HTTPS}s ^on(s)|
RewriteRule ^ http%1://www.%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

UPD.: for domains like, replace

RewriteCond %{HTTP_HOST} ^[^.]+\.[^.]+$


RewriteCond %{HTTP_HOST} ^[^.]+\.[^.]+\.[^.]+$

Server unable to read htaccess file, denying access to be safe

I had the same problem on a rackspeed server after changing the php version in the cpanel. Turned out it also changed the permissions of the folder... I set the permission of the folder to 755 with

chmod 755 folder_name

How to Set AllowOverride all

On Linux, in order to relax access to the document root, you should edit the following file:


And depending on what directory level you want to relax access to, you have to change the directive

AllowOverride None


AllowOverride All

So, assuming you want to allow access to files on the /var/www/html directory, you should change the following lines from:

<Directory "/var/www/html">
 AllowOverride None


<Directory "/var/www/html">
 AllowOverride All

.htaccess 301 redirect of single page

RedirectMatch uses a regular expression that is matched against the URL path. And your regular expression /contact.php just means any URL path that contains /contact.php but not just any URL path that is exactly /contact.php. So use the anchors for the start and end of the string (^ and $):

RedirectMatch 301 ^/contact\.php$ /contact-us.php

HTTP authentication logout via PHP

Mu. No correct way exists, not even one that's consistent across browsers.

This is a problem that comes from the HTTP specification (section 15.6):

Existing HTTP clients and user agents typically retain authentication information indefinitely. HTTP/1.1. does not provide a method for a server to direct clients to discard these cached credentials.

On the other hand, section 10.4.2 says:

If the request already included Authorization credentials, then the 401 response indicates that authorization has been refused for those credentials. If the 401 response contains the same challenge as the prior response, and the user agent has already attempted authentication at least once, then the user SHOULD be presented the entity that was given in the response, since that entity might include relevant diagnostic information.

In other words, you may be able to show the login box again (as @Karsten says), but the browser doesn't have to honor your request - so don't depend on this (mis)feature too much.

How to get htaccess to work on MAMP

Go to httpd.conf on /Applications/MAMP/conf/apache and see if the LoadModule rewrite_module modules/ line is un-commented (without the # at the beginning)

and change these from ...

<VirtualHost *:80>
    ServerName ...
    DocumentRoot /....

To this:

<VirtualHost *:80>
    ServerAdmin ...
    ServerName ...

    DocumentRoot ...
    <Directory ...>
        Options FollowSymLinks
        AllowOverride None
    <Directory ...>
        Options Indexes FollowSymLinks MultiViews
        AllowOverride All
        Order allow,deny
        allow from all

.htaccess File Options -Indexes on Subdirectories

The correct answer is

Options -Indexes

You must have been thinking of

AllowOverride All

.htaccess files (or "distributed configuration files") provide a way to make configuration changes on a per-directory basis. A file, containing one or more configuration directives, is placed in a particular document directory, and the directives apply to that directory, and all subdirectories thereof.

.htaccess rewrite to redirect root URL to subdirectory

This seemed the simplest solution:

RewriteEngine on
RewriteCond %{REQUEST_URI} ^/$
RewriteRule (.*) [R=301,L]

I was getting redirect loops with some of the other solutions.

Make index.html default, but allow index.php to be visited if typed in


Well, I have tried the methods mentioned above! it's working yes, but not exactly the way I wanted. I wanted to redirect the default page extension to the main domain with our further action.

Here how I do that...

# Accesible Index Page
<IfModule dir_module>
 DirectoryIndex index.php index.html
 RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /index\.(html|htm|php|php3|php5|shtml|phtml) [NC]
 RewriteRule ^index\.html|htm|php|php3|php5|shtml|phtml$ / [R=301,L]

The above code simply captures any index.* and redirect it to the main domain.

Thank you

How can I disable notices and warnings in PHP within the .htaccess file?



It is working fine in WordPress' config.php.

Rewrite URL after redirecting 404 error htaccess

In your .htaccess file , if you are using apache you can try with

Rule for Error Page - 404

ErrorDocument 404

How to refresh page on back button click?

You can use the following to refresh the page by clicking the back button:

window.addEventListener('popstate', () => {
}, false);

Redirecting 404 error with .htaccess via 301 for SEO etc

You will need to know something about the URLs, like do they have a specific directory or some query string element because you have to match for something. Otherwise you will have to redirect on the 404. If this is what is required then do something like this in your .htaccess:

ErrorDocument 404 /index.php

An error page redirect must be relative to root so you cannot use

If you have a pattern to match too then use 301 instead of 302 because 301 is permanent and 302 is temporary. A 301 will get the old URLs removed from the search engines and the 302 will not.

Mod Rewrite Reference:

Leverage browser caching, how on apache or .htaccess?

First we need to check if we have enabled mod_headers.c and mod_expires.c.

sudo apache2 -l

If we don't have it, we need to enable them

sudo a2enmod headers

Then we need to restart apache

sudo apache2 restart

At last, add the rules on .htaccess (seen on other answers), for example

ExpiresActive On
ExpiresByType image/gif A2592000
ExpiresByType image/jpeg A2592000
ExpiresByType image/jpg A2592000
ExpiresByType image/png A2592000
ExpiresByType image/x-icon A2592000
ExpiresByType text/css A86400
ExpiresByType text/javascript A86400
ExpiresByType application/x-shockwave-flash A2592000
<FilesMatch "\.(gif|jpe?g|png|ico|css|js|swf)$">
Header set Cache-Control "public"

How do I manually create a file with a . (dot) prefix in Windows? For example, .htaccess

Windows 7, 8 & 10

This is dead easy since Windows 7. In File Explorer, right click anywhere and create a new file. Type the new filename as .something. (notice the appended period) and press enter twice, job done.

Demonstrating how to create a file with no name in File Explorer.

So instead of being prompted with

You must type a file name.

You will instead be prompted with

If you change a file name extension, the file might become unusable.

Note: If you're having issues then please ensure you have "file name extensions" visible, you can activate this under the "View" menu in File Explorer. Also, this method works for folders too.

htaccess redirect if URL contains a certain string

RewriteRule ^(.*)foobar(.*)$ [L,R=301]

(No space inside your website)

Deny direct access to all .php files except index.php

URL rewriting could be used to map a URL to .php files. The following rules can identify whether a .php request was made directly or it was re-written. It forbids the request in the first case:

RewriteEngine On
RewriteCond %{THE_REQUEST} ^.+?\ [^?]+\.php[?\ ]
RewriteRule \.php$ - [F]
RewriteRule test index.php

These rules will forbid all requests that end with .php. However, URLs such as / (which fires index.php), /test (which rewrites to index.php) and /test?f=index.php (which contains index.php in querystring) are still allowed.

THE_REQUEST contains the full HTTP request line sent by the browser to the server (e.g., GET /index.php?foo=bar HTTP/1.1)

Apache 2.4 - Request exceeded the limit of 10 internal redirects due to probable configuration error

This problem can be caused by requests for certain files that don't exist. For example, requests for files in wp-content/uploads/ where the file does not exist.

If this is the situation you're seeing, you can solve the problem by going to .htaccess and changing this line:

RewriteRule ^(wp-(content|admin|includes).*) $1 [L]


RewriteRule ^(wp-(content|admin|includes).*) - [L]

The underlying issue is that the rule above triggers a rewrite to the exact same url with a slash in front and because there was a rewrite, the newly rewritten request goes back through the rules again and the same rule is triggered. By changing that line's "$1" to "-", no rewrite happens and so the rewriting process does not start over again with the same URL.

It's possible that there's a difference in how apache 2.2 and 2.4 handle this situation of only-difference-is-a-slash-in-front and that's why the default rules provided by WordPress aren't working perfectly.

Directory index forbidden by Options directive

Insert this lines:

<Directory "C:/Program Files (x86)/Apache Software Foundation/Apache2.2/htdocs">
        Options  +Indexes

In your C:\Program Files (x86)\Apache Software Foundation\Apache2.2\conf\extra\httpd-vhosts.conf file. I assume you are using Virtual Host for development.

And then, of course, just restart Apache.


How to increase apache timeout directive in .htaccess?

if you have long processing server side code, I don't think it does fall into 404 as you said ("it goes to a webpage is not found error page")

Browser should report request timeout error.

You may do 2 things:

Based on CGI/Server side engine increase timeout there

PHP : - default is 30 seconds

In php.ini:

max_execution_time 60

Increase apache timeout - default is 300 (in version 2.4 it is 60).

In your httpd.conf (in server config or vhost config)

TimeOut 600

Note that first setting allows your PHP script to run longer, it will not interferre with network timeout.

Second setting modify maximum amount of time the server will wait for certain events before failing a request

Sorry, I'm not sure if you are using PHP as server side processing, but if you provide more info I will be more accurate.

Disable PHP in directory (including all sub-directories) with .htaccess

This might be overkill - but be careful doing anything which relies on the extension of PHP files being .php - what if someone comes along later and adds handlers for .php4 or even .html so they're handled by PHP. You might be better off serving files out of those directories from a different instance of Apache or something, which only serves static content.

rewrite a folder name using .htaccess

mod_rewrite can only rewrite/redirect requested URIs. So you would need to request /apple/… to get it rewritten to a corresponding /folder1/….

Try this:

RewriteEngine on
RewriteRule ^apple/(.*) folder1/$1

This rule will rewrite every request that starts with the URI path /apple/… internally to /folder1/….

Edit    As you are actually looking for the other way round:

RewriteCond %{THE_REQUEST} ^GET\ /folder1/
RewriteRule ^folder1/(.*) /apple/$1 [L,R=301]

This rule is designed to work together with the other rule above. Requests of /folder1/… will be redirected externally to /apple/… and requests of /apple/… will then be rewritten internally back to /folder1/….

How to remove index.php from URLs?

Mainly If you are using Linux Based system Like 'Ubuntu' and this is only suggested for localhost user not for the server.

Follow all the steps mentioned in the previous answers. +

Check in Apache configuration for it. (AllowOverride All) If AllowOverride value is none then change it to All and restart apache again.

<Directory /var/www/>
    Options Indexes FollowSymLinks
    AllowOverride All
    Require all granted

Let me know if this step help anyone. As it can save you time if you find it earlier.

enter image description here

I am adding the exact lines from my htaccess file in localhost. for your reference

Around line number 110

<IfModule mod_rewrite.c>

## enable rewrites

Options +FollowSymLinks
RewriteEngine on

## you can put here your magento root folder
## path relative to web root

#RewriteBase /

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

Images are for some user who understand easily from image the from the text:

enter image description here

What is .htaccess file?

It is not so easy to give out specific addresses to people say for a conference or a specific project or product. It could be more secure to prevent hacking such as SQL injection attacks etc.

How to remove .html from URL?

Thanks for your replies. I have already solved my problem. Suppose I have my pages under, the following .htaccess rules apply.

<IfModule mod_rewrite.c>
   RewriteEngine On
   RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /html/(.*).html\ HTTP/
   RewriteRule .* http://localhost/html/%1 [R=301,L]

   RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /html/(.*)\ HTTP/
   RewriteRule .* %1.html [L]

http to https through .htaccess

Try this RewriteCond %{HTTP_HOST} !^www. [NC] RewriteRule ^(.*)$ http://www.%{HTTP_HOST}/$1 [R=301,L]

Redirect all to index.php using htaccess

I just had to face the same kind of issue with my Laravel 7 project, in Debian 10 shared hosting. I have to add RewriteBase / to my .htaccess within /public/ directory. So the .htaccess looks a like

RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^.*$ /index.php [L,QSA]

How to use a RELATIVE path with AuthUserFile in htaccess?

Let's take an example.

Your application is located in /var/www/myApp on some Linux server

.htaccess : /var/www/myApp/.htaccess

htpasswdApp : /var/www/myApp/htpasswdApp. (You're free to use any name for .htpasswd file)

To use relative path in .htaccess:

AuthType Digest
AuthName myApp
AuthUserFile "htpasswdApp"
Require valid-user

But it will search for file in server_root directory. Not in document_root.

In out case, when application is located at /var/www/myApp :

document_root is /var/www/myApp

server_root is /etc/apache2 //(just in our example, because of we using the linux server)

You can redefine it in your apache configuration file ( /etc/apache2/apache2.conf), but I guess it's a bad idea.

So to use relative file path in your /var/www/myApp/.htaccess you should define the password's file in your server_root.

I prefer to do it by follow command:

sudo ln -s /var/www/myApp/htpasswdApp /etc/apache2/htpasswdApp

You're free to copy my command, use a hard link instead of symbol,or copy a file to your server_root.

How can I disable mod_security in .htaccess file?

On some servers and web hosts, it's possible to disable ModSecurity via .htaccess, but be aware that you can only switch it on or off, you can't disable individual rules.

But a good practice that still keeps your site secure is to disable it only on specific URLs, rather than your entire site. You can specify which URLs to match via the regex in the <If> statement below...

### DISABLE mod_security firewall
### Some rules are currently too strict and are blocking legitimate users
### We only disable it for URLs that contain the regex below
### The regex below should be placed between "m#" and "#" 
### (this syntax is required when the string contains forward slashes)
<IfModule mod_security.c>
  <If "%{REQUEST_URI} =~ m#/admin/#">
    SecFilterEngine Off
    SecFilterScanPOST Off

No input file specified

GoDaddy is currently (Feb '13) supporting modification of FastCGI for some accounts using PHP 5.2.x or earlier. See GoDaddy article "Disabling FastCGI in Your Hosting Account".
(In my case, this is apparently necessary to help get the current version of LimeSurvey (2.0) towards a running state.)

How does RewriteBase work in .htaccess

I believe this excerpt from the Apache documentation, complements well the previous answers :

This directive is required when you use a relative path in a substitution in per-directory (htaccess) context unless either of the following conditions are true:

  • The original request, and the substitution, are underneath the DocumentRoot (as opposed to reachable by other means, such as Alias).

  • The filesystem path to the directory containing the RewriteRule, suffixed by the relative substitution is also valid as a URL path on the server (this is rare).

As previously mentioned, in other contexts, it is only useful to make your rule shorter. Moreover, also as previously mentioned, you can achieve the same thing by placing the htaccess file in the subdirectory.

add Shadow on UIView using swift 3

Swift 5 Just call this function and pass your view

public func setViewSettingWithBgShade(view: UIView)
    view.layer.cornerRadius = 8
    view.layer.borderWidth = 1
    view.layer.borderColor = AppTextFieldBorderColor.cgColor

    //MARK:- Shade a view
    view.layer.shadowOpacity = 0.5
    view.layer.shadowOffset = CGSize(width: 1.0, height: 1.0)
    view.layer.shadowRadius = 3.0
    view.layer.shadowColor =
    view.layer.masksToBounds = false

How to create dictionary and add key–value pairs dynamically?

how about the one liner for creating a key value pair?

let result = { ["foo"]: "some value" };

and some iterator function like reduce to dynamically convert an array to a dictionary

var options = [_x000D_
  { key: "foo", value: 1 },_x000D_
  { key: "bar", value: {id: 2, name: "two"} },_x000D_
  { key: "baz", value: {["active"]: true} },_x000D_
var result = options.reduce((accumulator, current) => {_x000D_
  accumulator[current.key] = current.value;_x000D_
  return accumulator;_x000D_
}, {});_x000D_

How do I create a Java string from the contents of a file?

If you're looking for an alternative that doesn't involve a third-party library (e.g. Commons I/O), you can use the Scanner class:

private String readFile(String pathname) throws IOException {

    File file = new File(pathname);
    StringBuilder fileContents = new StringBuilder((int)file.length());        

    try (Scanner scanner = new Scanner(file)) {
        while(scanner.hasNextLine()) {
            fileContents.append(scanner.nextLine() + System.lineSeparator());
        return fileContents.toString();

How to include CSS file in Symfony 2 and Twig?

And you can use %stylesheets% (assetic feature) tag:

{% stylesheets
<link type="text/css" rel="stylesheet" media="all" href="{{ asset_url }}" />
{% endstylesheets %}

You can write path to css as parameter (%parameter_name%).

More about this variant:

How can I scroll a div to be visible in ReactJS?

In you keyup/down handler you just need to set the scrollTop property of the div you want to scroll to make it scroll down (or up).

For example:


<div ref="foo">{content}</div>

keyup/down handler: += 10

If you do something similar to above, your div will scroll down 10 pixels (assuming the div is set to overflow auto or scroll in css, and your content is overflowing of course).

You will need to expand on this to find the offset of the element inside your scrolling div that you want to scroll the div down to, and then modify the scrollTop to scroll far enough to show the element based on it's height.

Have a look at MDN's definitions of scrollTop, and offsetTop here:

How to stop app that node.js express 'npm start'

When I tried the suggested solution I realized that my app name was truncated. I read up on process.title in the nodejs documentation ( and it says

On Linux and OS X, it's limited to the size of the binary name plus the length of the command line arguments because it overwrites the argv memory.

My app does not use any arguments, so I can add this line of code to my app.js

process.title = process.argv[2];

and then add these few lines to my package.json file

  "scripts": {
    "start": "node app.js this-name-can-be-as-long-as-it-needs-to-be",
    "stop": "killall -SIGINT this-name-can-be-as-long-as-it-needs-to-be"

to use really long process names. npm start and npm stop work, of course npm stop will always terminate all running processes, but that is ok for me.

Slide right to left?

or you can use


How to implement a material design circular progress bar in android

android:layout_gravity="center" />

The effect looks like this:


Git - push current branch shortcut

With the help of ceztko's answer I wrote this little helper function to make my life easier:

function gpu()
    if git rev-parse --abbrev-ref --symbolic-full-name @{u} > /dev/null 2>&1; then
        git push origin HEAD
        git push -u origin HEAD

It pushes the current branch to origin and also sets the remote tracking branch if it hasn't been setup yet.

How do I get a computer's name and IP address using VB.NET?

Dim ipAddress As IPAddress
Dim ipHostInfo As IPHostEntry = Dns.Resolve(Dns.GetHostName())
ipAddress = ipHostInfo.AddressList(0)

Unable to find the requested .Net Framework Data Provider in Visual Studio 2010 Professional

I like the other suggestions but I would rather not update the machine.config for a single application. I suggest that you just add it to the web.config / app.config. Here is what I needed to use the MySql Connector/NET that I "bin" deployed.

    <DbProviderFactories >
        <add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data, Version=, Culture=neutral, PublicKeyToken=c5687fc88969c44d" />

How can I set the 'backend' in matplotlib in Python?

You can also try viewing the graph in a browser.

Use the following:


How to run PowerShell in CMD

You need to separate the arguments from the file path:

powershell.exe -noexit "& 'D:\Work\SQLExecutor.ps1 ' -gettedServerName 'MY-PC'"

Another option that may ease the syntax using the File parameter and positional parameters:

powershell.exe -noexit -file "D:\Work\SQLExecutor.ps1" "MY-PC"

Passing parameters to a JDBC PreparedStatement

You should use the setString() method to set the userID. This both ensures that the statement is formatted properly, and prevents SQL injection:

statement =con.prepareStatement("SELECT * from employee WHERE  userID = ?");
statement.setString(1, userID);

There is a nice tutorial on how to use PreparedStatements properly in the Java Tutorials.

accessing a variable from another class

I hope I'm understanding the problem correctly, but it looks like you don't have a reference back to your DrawFrame object from DrawCircle.

Try this:

Change your constructor signature for DrawCircle to take in a DrawFrame object. Within the constructor, set the class variable "d" to the DrawFrame object you just took in. Now add the getWidth/getHeight methods to DrawFrame as mentioned in previous answers. See if that allows you to get what you're looking for.

Your DrawCircle constructor should be changed to something like:

public DrawCircle(DrawFrame frame)
    d = frame;
    w = 400;
    h = 400;
    diBig = 300;
    diSmall = 10;
    maxRad = (diBig/2) - diSmall;
    xSq = 50;
    ySq = 50;
    xPoint = 200;
    yPoint = 200;

The last line of code in DrawFrame should look something like:

contentPane.add(new DrawCircle(this));

Then, try using d.getheight(), d.getWidth() and so on within DrawCircle. This assumes you still have those methods available on DrawFrame to access them, of course.

Error in : figure margins too large, Scatter plot

Just run before plotting your data. This instruction solved my error. So, it's harmless to try it before taking a more complex solution.

struct.error: unpack requires a string argument of length 4

By default, on many platforms the short will be aligned to an offset at a multiple of 2, so there will be a padding byte added after the char.

To disable this, use: struct.unpack("=BH", data). This will use standard alignment, which doesn't add padding:

>>> struct.calcsize('=BH')

The = character will use native byte ordering. You can also use < or > instead of = to force little-endian or big-endian byte ordering, respectively.

How to get a list of MySQL views?

Another way to find all View:

SELECT DISTINCT table_name FROM information_schema.TABLES WHERE table_type = 'VIEW'

'git' is not recognized as an internal or external command

That's because at the time of installation you have selected the default radio button to use "Git" with the "Git bash" only. If you would have chosen "Git and command line tool" than this would not be an issue.

  • Solution#1: as you have already installed Git tool, now navigate to the desired folder and then right click and use "Git bash here" to run your same command and it will run properly.
  • Solution#2: try installing again the Git-scm and select the proper choice.

error running apache after xampp install

After changing main port from 80 to 8080 you have to change the config in XAMPP control panel as I show in the images:

1) enter image description here

2) enter image description here

3) enter image description here

Then restart the service and that's it !

git status shows fatal: bad object HEAD


git remote set-head origin --auto

followed by

git gc

storing user input in array

You're not actually going out after the values. You would need to gather them like this:

var title   = document.getElementById("title").value;
var name    = document.getElementById("name").value;
var tickets = document.getElementById("tickets").value;

You could put all of these in one array:

var myArray = [ title, name, tickets ];

Or many arrays:

var titleArr   = [ title ];
var nameArr    = [ name ];
var ticketsArr = [ tickets ];

Or, if the arrays already exist, you can use their .push() method to push new values onto it:

var titleArr = [];

function addTitle ( title ) {
  titleArr.push( title );
  console.log( "Titles: " + titleArr.join(", ") );

Your save button doesn't work because you refer to this.form, however you don't have a form on the page. In order for this to work you would need to have <form> tags wrapping your fields:

I've made several corrections, and placed the changes on jsbin:

The new form follows:

  <h1>Please enter data</h1>
  <input id="title" type="text" />
  <input id="name" type="text" />
  <input id="tickets" type="text" />
  <input type="button" value="Save" onclick="insert()" />
  <input type="button" value="Show data" onclick="show()" />
<div id="display"></div>

There is still some room for improvement, such as removing the onclick attributes (those bindings should be done via JavaScript, but that's beyond the scope of this question).

I've also made some changes to your JavaScript. I start by creating three empty arrays:

var titles  = [];
var names   = [];
var tickets = [];

Now that we have these, we'll need references to our input fields.

var titleInput  = document.getElementById("title");
var nameInput   = document.getElementById("name");
var ticketInput = document.getElementById("tickets");

I'm also getting a reference to our message display box.

var messageBox  = document.getElementById("display");

The insert() function uses the references to each input field to get their value. It then uses the push() method on the respective arrays to put the current value into the array.

Once it's done, it cals the clearAndShow() function which is responsible for clearing these fields (making them ready for the next round of input), and showing the combined results of the three arrays.

function insert ( ) {
 titles.push( titleInput.value );
 names.push( nameInput.value );
 tickets.push( ticketInput.value );


This function, as previously stated, starts by setting the .value property of each input to an empty string. It then clears out the .innerHTML of our message box. Lastly, it calls the join() method on all of our arrays to convert their values into a comma-separated list of values. This resulting string is then passed into the message box.

function clearAndShow () {
  titleInput.value = "";
  nameInput.value = "";
  ticketInput.value = "";

  messageBox.innerHTML = "";

  messageBox.innerHTML += "Titles: " + titles.join(", ") + "<br/>";
  messageBox.innerHTML += "Names: " + names.join(", ") + "<br/>";
  messageBox.innerHTML += "Tickets: " + tickets.join(", ");

The final result can be used online at

How to check whether Kafka Server is running?

The good option is to use AdminClient as below before starting to produce or consume the messages

private static final int ADMIN_CLIENT_TIMEOUT_MS = 5000;           
 try (AdminClient client = AdminClient.create(properties)) {
            client.listTopics(new ListTopicsOptions().timeoutMs(ADMIN_CLIENT_TIMEOUT_MS)).listings().get();
        } catch (ExecutionException ex) {
            LOG.error("Kafka is not available, timed out after {} ms", ADMIN_CLIENT_TIMEOUT_MS);

Call a Javascript function every 5 seconds continuously

For repeating an action in the future, there is the built in setInterval function that you can use instead of setTimeout.
It has a similar signature, so the transition from one to another is simple:

setInterval(function() {
    // do stuff
}, duration);

How can I use SUM() OVER()

if you are using SQL 2012 you should try

        SUM(Quantity) OVER (PARTITION BY AccountID ORDER BY AccountID rows between unbounded preceding and current row ) AS TopBorcT, 

if available, better order by date column.

AJAX reload page with POST

If you want to refresh the entire page, it makes no sense to use AJAX. Use normal Javascript to post the form element in that page. Make sure the form submits to the same page, or that the form submits to a page which then redirects back to that page

Javascript to be used (always in myForm.php):

function submitform()

Suppose your form is on myForm.php: Method 1:

<form action="./myForm.php" method="post" id="myForm">

Method 2:


<form action="./myFormActor.php" method="post" id="myForm">


    //all code here, no output
    header("Location: ./myForm.php");

What does %>% mean in R

Use ?'%*%' to get the documentation.

%*% is matrix multiplication. For matrix multiplication, you need an m x n matrix times an n x p matrix.

SMTP connect() failed PHPmailer - PHP

 $mail->SMTPOptions = array(
        'ssl' => array(
            'verify_peer' => false,
            'verify_peer_name' => false,
            'allow_self_signed' => true

How to hide a button programmatically?

For "Xamarin Android":

FindViewById<Button>(Resource.Id.Button1).Visibility = ViewStates.Gone;

How do I add multiple conditions to "ng-disabled"?

Make sure you wrap the condition in the correct precedence

ng-disabled="((!product.img) || (!"

Is it possible to override / remove background: none!important with jQuery?

With a <script> right after the <style> that applies the !important things, you should be able to do something like this:

var lastStylesheet = document.styleSheets[document.styleSheets.length - 1];
lastStylesheet.disabled = true;

document.write('<style type="text/css">');
// Call fixBackground for each element that needs fixing

lastStylesheet.disabled = false;

function fixBackground(el) {
    document.write('html #' + + ' { background-image: ' +
        document.defaultView.getComputedStyle(el).backgroundImage +
        ' !important; }');

This probably depends on what kind of browser compatibility you need, though.

Async await in linq select

var inputs = events.Select(async ev => await ProcessEventAsync(ev))
                   .Select(t => t.Result)
                   .Where(i => i != null)

But this seems very weird to me, first of all the use of async and await in the select. According to this answer by Stephen Cleary I should be able to drop those.

The call to Select is valid. These two lines are essentially identical:

events.Select(async ev => await ProcessEventAsync(ev))
events.Select(ev => ProcessEventAsync(ev))

(There's a minor difference regarding how a synchronous exception would be thrown from ProcessEventAsync, but in the context of this code it doesn't matter at all.)

Then the second Select which selects the result. Doesn't this mean the task isn't async at all and is performed synchronously (so much effort for nothing), or will the task be performed asynchronously and when it's done the rest of the query is executed?

It means that the query is blocking. So it is not really asynchronous.

Breaking it down:

var inputs = events.Select(async ev => await ProcessEventAsync(ev))

will first start an asynchronous operation for each event. Then this line:

                   .Select(t => t.Result)

will wait for those operations to complete one at a time (first it waits for the first event's operation, then the next, then the next, etc).

This is the part I don't care for, because it blocks and also would wrap any exceptions in AggregateException.

and is it completely the same like this?

var tasks = await Task.WhenAll(events.Select(ev => ProcessEventAsync(ev)));
var inputs = tasks.Where(result => result != null).ToList();

var inputs = (await Task.WhenAll(events.Select(ev => ProcessEventAsync(ev))))
                                       .Where(result => result != null).ToList();

Yes, those two examples are equivalent. They both start all asynchronous operations (events.Select(...)), then asynchronously wait for all the operations to complete in any order (await Task.WhenAll(...)), then proceed with the rest of the work (Where...).

Both of these examples are different from the original code. The original code is blocking and will wrap exceptions in AggregateException.

Ternary operators in JavaScript without an "else"

You could write

x = condition ? true : x;

So that x is unmodified when the condition is false.

This then is equivalent to

if (condition) x = true


      ? defaults.slideshowWidth = obj.find('img').width()+'px' 
      : null 

There are a couple of alternatives - I'm not saying these are better/worse - merely alternatives

Passing in null as the third parameter works because the existing value is null. If you refactor and change the condition, then there is a danger that this is no longer true. Passing in the exising value as the 2nd choice in the ternary guards against this:

!defaults.slideshowWidth = 
      ? defaults.slideshowWidth = obj.find('img').width()+'px' 
      : defaults.slideshowwidth 

Safer, but perhaps not as nice to look at, and more typing. In practice, I'd probably write

defaults.slideshowWidth = defaults.slideshowWidth 
               || obj.find('img').width()+'px'

ASP.NET MVC JsonResult Date Format

I had a number of issues come up with JSON dates and decided to just get rid of the problem by addressing the date issue in the SQL. Change the date format to a string format

select flddate from tblName

select flddate, convert(varchar(12), flddate, 113) as fldDateStr from tblName

By using the fldDateStr the problem dissappeared and I could still use the date field for sorting or other purposes.

How to read a file line-by-line into a list?

Another option is numpy.genfromtxt, for example:

import numpy as np
data = np.genfromtxt("yourfile.dat",delimiter="\n")

This will make data a NumPy array with as many rows as are in your file.

'System.OutOfMemoryException' was thrown when there is still plenty of memory free

You may want to read this: "“Out Of Memory” Does Not Refer to Physical Memory" by Eric Lippert.

In short, and very simplified, "Out of memory" does not really mean that the amount of available memory is too small. The most common reason is that within the current address space, there is no contiguous portion of memory that is large enough to serve the wanted allocation. If you have 100 blocks, each 4 MB large, that is not going to help you when you need one 5 MB block.

Key Points:

  • the data storage that we call “process memory” is in my opinion best visualized as a massive file on disk.
  • RAM can be seen as merely a performance optimization
  • Total amount of virtual memory your program consumes is really not hugely relevant to its performance
  • "running out of RAM" seldom results in an “out of memory” error. Instead of an error, it results in bad performance because the full cost of the fact that storage is actually on disk suddenly becomes relevant.

How to sort an associative array by its values in Javascript?

Continued discussion & other solutions covered at How to sort an (associative) array by value? with the best solution (for my case) being by saml (quoted below).

Arrays can only have numeric indexes. You'd need to rewrite this as either an Object, or an Array of Objects.

var status = new Array();
status.push({name: 'BOB', val: 10});
status.push({name: 'TOM', val: 3});
status.push({name: 'ROB', val: 22});
status.push({name: 'JON', val: 7});

If you like the status.push method, you can sort it with:

status.sort(function(a,b) {
    return a.val - b.val;

Generate sha256 with OpenSSL and C++

Using OpenSSL's EVP interface (the following is for OpenSSL 1.1):

#include <iomanip>
#include <iostream>
#include <sstream>
#include <string>
#include <openssl/evp.h>

bool computeHash(const std::string& unhashed, std::string& hashed)
    bool success = false;

    EVP_MD_CTX* context = EVP_MD_CTX_new();

    if(context != NULL)
        if(EVP_DigestInit_ex(context, EVP_sha256(), NULL))
            if(EVP_DigestUpdate(context, unhashed.c_str(), unhashed.length()))
                unsigned char hash[EVP_MAX_MD_SIZE];
                unsigned int lengthOfHash = 0;

                if(EVP_DigestFinal_ex(context, hash, &lengthOfHash))
                    std::stringstream ss;
                    for(unsigned int i = 0; i < lengthOfHash; ++i)
                        ss << std::hex << std::setw(2) << std::setfill('0') << (int)hash[i];

                    hashed = ss.str();
                    success = true;


    return success;

int main(int, char**)
    std::string pw1 = "password1", pw1hashed;
    std::string pw2 = "password2", pw2hashed;
    std::string pw3 = "password3", pw3hashed;
    std::string pw4 = "password4", pw4hashed;

    hashPassword(pw1, pw1hashed);
    hashPassword(pw2, pw2hashed);
    hashPassword(pw3, pw3hashed);
    hashPassword(pw4, pw4hashed);

    std::cout << pw1hashed << std::endl;
    std::cout << pw2hashed << std::endl;
    std::cout << pw3hashed << std::endl;
    std::cout << pw4hashed << std::endl;

    return 0;

The advantage of this higher level interface is that you simply need to swap out the EVP_sha256() call with another digest's function, e.g. EVP_sha512(), to use a different digest. So it adds some flexibility.

What do URLs represent?

Replace username with the username of the user that created the repo.

Replace repo-name with the name of the repo.

Replace branch-name with the name of the branch.

Replace path with the path to the file.

To reverse to go to

Can anyone explain what JSONP is, in layman terms?

I have found a useful article that also explains the topic quite clearly and easy language. Link is JSONP

Some of the worth noting points are:

  1. JSONP pre-dates CORS.
  2. It is a pseudo-standard way to retreive data from a different domain,
  3. It has limited CORS features (only GET method)

Working is as follows:

  1. <script src="url?callback=function_name"> is included in the html code
  2. When step 1 gets executed it sens a function with the same function name (as given in the url parameter) as a response.
  3. If the function with the given name exists in the code, it will be executed with the data, if any, returned as an argument to that function.

How do I declare class-level properties in Objective-C?

As seen on WWDC 2016/XCode 8 (what's new in LLVM session @5:05). Class properties can be declared as follows

@interface MyType : NSObject
@property (class) NSString *someString;

NSLog(@"format string %@", MyType.someString);

Note that class properties are never synthesized

static NSString * _someString;
+ (NSString *)someString { return _someString; }
+ (void)setSomeString:(NSString *)newString { _someString = newString; }

How to create a Jar file in Netbeans

Create a Java archive (.jar) file using NetBeans as follows:

  1. Right-click on the Project name
  2. Select Properties
  3. Click Packaging
  4. Check Build JAR after Compiling
  5. Check Compress JAR File
  6. Click OK to accept changes
  7. Right-click on a Project name
  8. Select Build or Clean and Build

Clean and Build will first delete build artifacts (such as .class files), whereas Build will retain any existing .class files, creating new versions necessary. To elucidate, imagine a project with two classes, A and B.

When built the first time, the IDE creates A.class and B.class. Now you delete but don't clear out B.class. Executing Build should leave B.class in the build directory, and bundle it into the JAR. Selecting Clean and Build will delete B.class. Since was deleted, no longer will B.class be bundled.

The JAR file is built. To view it inside NetBeans:

  1. Click the Files tab
  2. Expand Project name >> dist

Ensure files aren't being excluded when building the JAR file.

Set a DateTime database field to "Now"

In SQL you need to use GETDATE():

UPDATE table SET date = GETDATE();

There is no NOW() function.

To answer your question:

In a large table, since the function is evaluated for each row, you will end up getting different values for the updated field.

So, if your requirement is to set it all to the same date I would do something like this (untested):

SET @currDate = GETDATE();

UPDATE table SET date = @currDate;

Trying to get property of non-object MySQLi result

$sql = "SELECT * FROM table";
$result = $conn->query($sql);

if (!$result) {
    trigger_error('Invalid query: ' . $conn->error);

check the error with mysqli_error() function

probably your query has some faults.

Searching for file in directories recursively

Try the following method:

public static IEnumerable<string> GetXMLFiles(string directory)
    List<string> files = new List<string>();

        files.AddRange(Directory.GetFiles(directory, "*.xml", SearchOption.AllDirectories));
    catch (Exception ex)

    return files;

Highlight label if checkbox is checked

I like Andrew's suggestion, and in fact the CSS rule only needs to be:

:checked + label {
   font-weight: bold;

I like to rely on implicit association of the label and the input element, so I'd do something like this:

   <input type="checkbox"/>

with CSS:

:checked + span {
    font-weight: bold;


SQL "between" not inclusive

I find that the best solution to comparing a datetime field to a date field is the following:

DECLARE @StartDate DATE = '5/1/2013', 
        @EndDate   DATE = '5/1/2013' 

FROM   cases 
WHERE  Datediff(day, created_at, @StartDate) <= 0 
       AND Datediff(day, created_at, @EndDate) >= 0 

This is equivalent to an inclusive between statement as it includes both the start and end date as well as those that fall between.

Xcode 9 error: "iPhone has denied the launch request"

Open the App Groups in Capabilities, wait App... effective,then close the App Groups, it worked:

enter image description here

Clearing content of text file using php

To add button you may use either jQuery libraries or simple Javascript script as shown below:

HTML link or button:

<a href="#" onClick="goclear()" id="button">click event</a>


<script type="text/javascript">
var btn = document.getElementById('button');
function goclear() { 
alert("Handler called. Page will redirect to clear.php");
document.location.href = "clear.php";

Use PHP to clear a file content. For instance you can use the fseek($fp, 0); or ftruncate ( resource $file , int $size ) as below:

//open file to write
$fp = fopen("/tmp/file.txt", "r+");
// clear content to 0 bits
ftruncate($fp, 0);
//close file

Redirect PHP - you can use header ( string $string [, bool $replace = true [, int $http_response_code ]] )

header('Location: getbacktoindex.html');

I hope it's help.

How to create an empty file at the command line in Windows?

Yet another method that creates a zero byte file:

break > "file.txt"

Comparison of DES, Triple DES, AES, blowfish encryption for data

                DES                               AES
Developed       1977                              2000
Key Length      56 bits                           128, 192, or 256 bits
Cipher Type     Symmetric                         Symmetric
Block Size      64 bits                           128 bits
Security        inadequate                        secure
Performance     Fast                              Slow

Writing a dictionary to a csv file with one line for every 'key: value'

Can you just do:

for key in mydict.keys():
    f.write(str(key) + ":" + str(mydict[key]) + ",");

So that you can have

key_1: value_1, key_2: value_2

How to remove the last character from a string?

// Remove n last characters  
// System.out.println(removeLast("Hello!!!333",3));

public String removeLast(String mes, int n) {
    return mes != null && !mes.isEmpty() && mes.length()>n
         ? mes.substring(0, mes.length()-n): mes;

// Leave substring before character/string  
// System.out.println(leaveBeforeChar("Hello!!!123", "1"));

public String leaveBeforeChar(String mes, String last) {
    return mes != null && !mes.isEmpty() && mes.lastIndexOf(last)!=-1
         ? mes.substring(0, mes.lastIndexOf(last)): mes;

How to vertically center a <span> inside a div?

Quick answer for single line span

Make the child (in this case a span) the same line-height as the parent <div>'s height

<div class="parent">
  <span class="child">Yes mom, I did my homework lol</span>

You should then add the CSS rules

.parent { height: 20px; }
.child { line-height: 20px; vertical-align: middle; }

Or you can target it with a child selector

.parent { height: 20px; }
.parent > span { line-height: 20px; vertical-align: middle; }

Background on my own use of this

I ran into this similar issue where I needed to vertically center items in a mobile menu. I made the div and spans inside the same line height. Note that this is for a meteor project and therefore not using inline css ;)


<div class="international">        
  <span class="intlFlag">

  <span class="intlCurrent">

  <span class="intlButton">
    <i class="fa fa-globe"></i>

CSS (option for multiple spans in a div)

.international {
  height: 42px;

.international > span {
  line-height: 42px;

In this case if I just had one span I could have added the CSS rule directly to that span.

CSS (option for one specific span)

.intlFlag { line-height: 42px; }

Here is how it displayed for me

enter image description here

NoClassDefFoundError - Eclipse and Android

I got the exact same problem ... To fix it, I just removed my Android Private Libs in "build path" and clicked ok ... and when i opened op the "build path" again eclipse had added them by itself again, and then it worked for me ;)...

loading json data from local file into React JS

I was trying to do the same thing and this is what worked for me (ES6/ES2015):

import myData from './data.json';

I got the solution from this answer on a react-native thread asking the same thing:

How can I get query parameters from a URL in Vue.js?

Try this code

 var vm = new Vue({
       let urlParams = new URLSearchParams(;
           console.log(urlParams.has('yourParam')); // true
           console.log(urlParams.get('yourParam')); // "MyParam"

How to get all of the immediate subdirectories in Python

Why has no one mentioned glob? glob lets you use Unix-style pathname expansion, and is my go to function for almost everything that needs to find more than one path name. It makes it very easy:

from glob import glob
paths = glob('*/')

Note that glob will return the directory with the final slash (as unix would) while most path based solutions will omit the final slash.

Syntax error due to using a reserved word as a table or column name in MySQL

The Problem

In MySQL, certain words like SELECT, INSERT, DELETE etc. are reserved words. Since they have a special meaning, MySQL treats it as a syntax error whenever you use them as a table name, column name, or other kind of identifier - unless you surround the identifier with backticks.

As noted in the official docs, in section 10.2 Schema Object Names (emphasis added):

Certain objects within MySQL, including database, table, index, column, alias, view, stored procedure, partition, tablespace, and other object names are known as identifiers.


If an identifier contains special characters or is a reserved word, you must quote it whenever you refer to it.


The identifier quote character is the backtick ("`"):

A complete list of keywords and reserved words can be found in section 10.3 Keywords and Reserved Words. In that page, words followed by "(R)" are reserved words. Some reserved words are listed below, including many that tend to cause this issue.

  • ADD
  • AND
  • BY
  • CALL
  • CASE
  • DESC
  • FROM
  • IN
  • IS
  • KEY
  • LIKE
  • LONG
  • NOT
  • OR
  • RANK
  • TO

The Solution

You have two options.

1. Don't use reserved words as identifiers

The simplest solution is simply to avoid using reserved words as identifiers. You can probably find another reasonable name for your column that is not a reserved word.

Doing this has a couple of advantages:

  • It eliminates the possibility that you or another developer using your database will accidentally write a syntax error due to forgetting - or not knowing - that a particular identifier is a reserved word. There are many reserved words in MySQL and most developers are unlikely to know all of them. By not using these words in the first place, you avoid leaving traps for yourself or future developers.

  • The means of quoting identifiers differs between SQL dialects. While MySQL uses backticks for quoting identifiers by default, ANSI-compliant SQL (and indeed MySQL in ANSI SQL mode, as noted here) uses double quotes for quoting identifiers. As such, queries that quote identifiers with backticks are less easily portable to other SQL dialects.

Purely for the sake of reducing the risk of future mistakes, this is usually a wiser course of action than backtick-quoting the identifier.

2. Use backticks

If renaming the table or column isn't possible, wrap the offending identifier in backticks (`) as described in the earlier quote from 10.2 Schema Object Names.

An example to demonstrate the usage (taken from 10.3 Keywords and Reserved Words):

mysql> CREATE TABLE interval (begin INT, end INT);
ERROR 1064 (42000): You have an error in your SQL syntax.
near 'interval (begin INT, end INT)'

mysql> CREATE TABLE `interval` (begin INT, end INT); Query OK, 0 rows affected (0.01 sec)

Similarly, the query from the question can be fixed by wrapping the keyword key in backticks, as shown below:

INSERT INTO user_details (username, location, `key`)
VALUES ('Tim', 'Florida', 42)";               ^   ^

What is the minimum length of a valid international phone number?

EDIT 2015-06-27: Minimum is actually 8, including country code. My bad.

Original post

The minimum phone number that I use is 10 digits. International users should always be putting their country code, and as far as I know there are no countries with fewer than ten digits if you count country code.

More info here:

Fastest way to convert Image to Byte array

public static byte[] ReadImageFile(string imageLocation)
        byte[] imageData = null;
        FileInfo fileInfo = new FileInfo(imageLocation);
        long imageFileLength = fileInfo.Length;
        FileStream fs = new FileStream(imageLocation, FileMode.Open, FileAccess.Read);
        BinaryReader br = new BinaryReader(fs);
        imageData = br.ReadBytes((int)imageFileLength);
        return imageData;

Git log to get commits only for a specific branch

BUT I would like to avoid the need of knowing the other branches names.

I don't think this is possible: a branch in Git is always based on another one or at least on another commit, as explained in "git diff doesn't show enough":

enter image description here

You need a reference point for your log to show the right commits.

As mentioned in "GIT - Where did I branch from?":

branches are simply pointers to certain commits in a DAG

So even if git log master..mybranch is one answer, it would still show too many commits, if mybranch is based on myotherbranch, itself based on master.

In order to find that reference (the origin of your branch), you can only parse commits and see in which branch they are, as seen in:

Unable to get provider

I added the following code in proguard file.

-keep public class * extends
-keep public class * extends

and it worked in my case.

Dump a NumPy array into a csv file

I believe you can also accomplish this quite simply as follows:

  1. Convert Numpy array into a Pandas dataframe
  2. Save as CSV

e.g. #1:

    # Libraries to import
    import pandas as pd
    import nump as np

    #N x N numpy array (dimensions dont matter)
    corr_mat    #your numpy array
    my_df = pd.DataFrame(corr_mat)  #converting it to a pandas dataframe

e.g. #2:

    #save as csv 
    my_df.to_csv('foo.csv', index=False)   # "foo" is the name you want to give
                                           # to csv file. Make sure to add ".csv"
                                           # after whatever name like in the code

Center an element in Bootstrap 4 Navbar

from the docs

Navbars may contain bits of text with the help of .navbar-text. This class adjusts vertical alignment and horizontal spacing for strings of text.

i applied the .navbar-text class to my <li> element, so the result is

<li class="nav-item navbar-text">

this centers the links vertically with respect to my navbar-brand img

PopupWindow $BadTokenException: Unable to add window -- token null is not valid

try to show popup like this

new Handler().postDelayed(new Runnable(){

    public void run() {
       popupWindow.showAtLocation(context.getWindow().getDecorView(), Gravity.CENTER,0,0);

}, 200L);

Creating an XmlNode/XmlElement in C# without an XmlDocument?

I would recommend to use XDoc and XElement of System.Xml.Linq instead of XmlDocument stuff. This would be better and you will be able to make use of the LINQ power in querying and parsing your XML:

Using XElement, your ToXml() method will look like the following:

public XElement ToXml()
    XElement element = new XElement("Song",
                        new XElement("Artist", "bla"),
                        new XElement("Title", "Foo"));

    return element;

String.Replace(char, char) method in C#

String.Replace('\n', '') doesn't work because '' is not a valid character literal.

If you use the String.Replace(string, string) override, it should work.

string temp = mystring.Replace("\n", "");

How do I create a list of random numbers without duplicates?

If you wish to ensure that the numbers being added are unique, you could use a Set object

if using 2.7 or greater, or import the sets module if not.

As others have mentioned, this means the numbers are not truly random.

Can I try/catch a warning?

Normaly you should never use @ unless this is the only solution. In that specific case the function dns_check_record should be use first to know if the record exists.

View RDD contents in Python Spark?

If you want to see the contents of RDD then yes collect is one option, but it fetches all the data to driver so there can be a problem

<>.take(<num of elements you want to fetch>)

Better if you want to see just a sample

Running foreach and trying to print, I dont recommend this because if you are running this on cluster then the print logs would be local to the executor and it would print for the data accessible to that executor. print statement is not changing the state hence it is not logically wrong. To get all the logs you will have to do something like

foreach print

But this may result in job failure as collecting all the data on driver may crash it. I would suggest using take command or if u want to analyze it then use sample collect on driver or write to file and then analyze it.

Ruby 'require' error: cannot load such file

This will work nicely if it is in a gem lib directory and this is the tokenizer.rb

require_relative 'tokenizer/main'

How to use executables from a package installed locally in node_modules?

Nice example

You don't have to manipulate $PATH anymore!

From [email protected], npm ships with npx package which lets you run commands from a local node_modules/.bin or from a central cache.

Simply run:

$ npx [options] <command>[@version] [command-arg]...

By default, npx will check whether <command> exists in $PATH, or in the local project binaries, and execute that.

Calling npx <command> when <command> isn't already in your $PATH will automatically install a package with that name from the NPM registry for you, and invoke it. When it's done, the installed package won’t be anywhere in your globals, so you won’t have to worry about pollution in the long-term. You can prevent this behaviour by providing --no-install option.

For npm < 5.2.0, you can install npx package manually by running the following command:

$ npm install -g npx

A component is changing an uncontrolled input of type text to be controlled error in ReactJS

const [name, setName] = useState()

generates error as soon as you type in the text field

const [name, setName] = useState('') // <-- by putting in quotes 

will fix the issue on this string example.

excel - if cell is not blank, then do IF statement

Your formula is wrong. You probably meant something like:


Another equivalent:


Or even shorter:




Error in Swift class: Property not initialized at super.init call

Quote from The Swift Programming Language, which answers your question:

“Swift’s compiler performs four helpful safety-checks to make sure that two-phase initialization is completed without error:”

Safety check 1 “A designated initializer must ensure that all of the “properties introduced by its class are initialized before it delegates up to a superclass initializer.”

Excerpt From: Apple Inc. “The Swift Programming Language.” iBooks.

WPF button click in C# code

// sample C#
public void populateButtons()
    int xPos;
    int yPos;

    Random ranNum = new Random();

    for (int i = 0; i < 50; i++)
        Button foo = new Button();
        Style buttonStyle = Window.Resources["CurvedButton"] as Style;

        int sizeValue = ranNum.Next(50);

        foo.Width = sizeValue;
        foo.Height = sizeValue;
        foo.Name = "button" + i;

        xPos = ranNum.Next(300);
        yPos = ranNum.Next(200);

        foo.HorizontalAlignment = HorizontalAlignment.Left;
        foo.VerticalAlignment = VerticalAlignment.Top;
        foo.Margin = new Thickness(xPos, yPos, 0, 0);

        foo.Style = buttonStyle;

        foo.Click += new RoutedEventHandler(buttonClick);

private void buttonClick(object sender, EventArgs e)
  //do something or...
  Button clicked = (Button) sender;
  MessageBox.Show("Button's name is: " + clicked.Name);

Access And/Or exclusions

Seeing that it appears you are running using the SQL syntax, try with the correct wild card.

SELECT * FROM someTable WHERE (someTable.Field NOT LIKE '%RISK%') AND (someTable.Field NOT LIKE '%Blah%') AND someTable.SomeOtherField <> 4; 

Removing the title text of an iOS UIBarButtonItem

Just entering a single space for the Back button navigation item works!!

Angularjs $http.get().then and binding to a list

$http methods return a promise, which can't be iterated, so you have to attach the results to the scope variable through the callbacks:

$scope.documents = [];
$http.get('/Documents/DocumentsList/' + caseId)
  .then(function(result) {
    $scope.documents =;

Now, since this defines the documents variable only after the results are fetched, you need to initialise the documents variable on scope beforehand: $scope.documents = []. Otherwise, your ng-repeat will choke.

This way, ng-repeat will first return an empty list, because documents array is empty at first, but as soon as results are received, ng-repeat will run again because the `documents``have changed in the success callback.

Also, you might want to alter you ng-repeat expression to:

<li ng-repeat="document in documents" ng-class="IsFiltered(document.Filtered)">

because if your DisplayDocuments() function is making a call to the server, than this call will be executed many times over, due to the $digest cycles.

Merging a lot of data.frames

Put them into a list and use merge with Reduce

Reduce(function(x, y) merge(x, y, all=TRUE), list(df1, df2, df3))
#    id v1 v2 v3
# 1   1  1 NA NA
# 2  10  4 NA NA
# 3   2  3  4 NA
# 4  43  5 NA NA
# 5  73  2 NA NA
# 6  23 NA  2  1
# 7  57 NA  3 NA
# 8  62 NA  5  2
# 9   7 NA  1 NA
# 10 96 NA  6 NA

You can also use this more concise version:

Reduce(function(...) merge(..., all=TRUE), list(df1, df2, df3))

Initialize 2D array

Easy to read/type.

  table = new char[][] {
    , "abcdefghij".toCharArray()

Android Facebook 4.0 SDK How to get Email, Date of Birth and gender of User

Use this snippet for get all profile info

private FacebookCallback<LoginResult> callback = new FacebookCallback<LoginResult>() {
        public void onSuccess(LoginResult loginResult) {
            AccessToken accessToken = loginResult.getAccessToken();
            Profile profile = Profile.getCurrentProfile();

            // Facebook Email address
            GraphRequest request = GraphRequest.newMeRequest(
                    new GraphRequest.GraphJSONObjectCallback() {
                        public void onCompleted(
                                JSONObject object,
                                GraphResponse response) {
                            Log.v("LoginActivity Response ", response.toString());

                            try {
                                Name = object.getString("name");

                                FEmail = object.getString("email");
                                Log.v("Email = ", " " + FEmail);
                                Toast.makeText(getApplicationContext(), "Name " + Name, Toast.LENGTH_LONG).show();

                            } catch (JSONException e) {
            Bundle parameters = new Bundle();
            parameters.putString("fields", "id,name,email,gender, birthday");


        public void onCancel() {


        public void onError(FacebookException e) {


Disable copy constructor

Make SymbolIndexer( const SymbolIndexer& ) private. If you're assigning to a reference, you're not copying.

How to clone a Date object?

This is the cleanest approach

let dat = new Date() _x000D_
let copyOf = new Date(dat.valueOf())_x000D_

Jquery Ajax, return success/error from controller

When you return value from server to jQuery's Ajax call you can also use the below code to indicate a server error:

return StatusCode(500, "My error");


return StatusCode((int)HttpStatusCode.InternalServerError, "My error");


Response.StatusCode = (int)HttpStatusCode.InternalServerError;
return Json(new { responseText = "my error" });

Codes other than Http Success codes (e.g. 200[OK]) will trigger the function in front of error: in client side (ajax).

you can have ajax call like:

        type: "POST",
        url: "/General/ContactRequestPartial",
        data: {
            HashId: id
       success: function (response)  {
            console.log("Custom message : " + response.responseText);
        }, //Is Called when Status Code is 200[OK] or other Http success code
        error: function (jqXHR, textStatus, errorThrown)  {
            console.log("Custom error : " + jqXHR.responseText + " Status: " + textStatus + " Http error:" + errorThrown);
        }, //Is Called when Status Code is 500[InternalServerError] or other Http Error code

Additionally you can handle different HTTP errors from jQuery side like:

        type: "POST",
        url: "/General/ContactRequestPartial",
        data: {
            HashId: id
        statusCode: {
            500: function (jqXHR, textStatus, errorThrown)  {
                console.log("Custom error : " + jqXHR.responseText + " Status: " + textStatus + " Http error:" + errorThrown);
            501: function (jqXHR, textStatus, errorThrown)  {
                console.log("Custom error : " + jqXHR.responseText + " Status: " + textStatus + " Http error:" + errorThrown);

statusCode: is useful when you want to call different functions for different status codes that you return from server.

You can see list of different Http Status codes here:Wikipedia

Additional resources:

  1. Returning Server-Side Errors from AJAX Calls
  2. Returning a JsonResult within the Error function of JQuery Ajax
  3. Handling Ajax errors with jQuery

MYSQL Truncated incorrect DOUBLE value

I did experience this error when I tried doing an WHERE EXIST where the subquery matched 2 columns that accidentially was different types. The two tables was also different storage engines.

One column was a CHAR (90) and the other was a BIGINT (20).

One table was InnoDB and the other was MEMORY.

Part of query:

[...] AND EXISTS (select objectid from temp_objectids where temp_objectids.objectid = items_raw.objectid );

Changing the column type on the one column from BIGINT to CHAR solved the issue.

How to import an existing X.509 certificate and private key in Java keystore to use in SSL?

If you have a PEM file (e.g. server.pem) containing:

  • the trusted certificate
  • the private key

then you can import the certificate and key into a JKS keystore like this:

1) Copy the private key from the PEM file into an ascii file (e.g. server.key)

2) Copy the cert from the PEM file into an ascii file (e.g. server.crt)

3) Export the cert and key into a PKCS12 file:

$ openssl pkcs12 -export -in server.crt -inkey server.key \
                 -out server.p12 -name [some-alias] -CAfile server.pem -caname root
  • the PEM file can be used as the argument to the -CAfile option.
  • you are prompted for an 'export' password.
  • if doing this in git bash then add winpty to the start of the command so the export password can be entered.

4) Convert the PKCS12 file to a JKS keystore:

$ keytool -importkeystore -deststorepass changeit -destkeypass changeit \
          -destkeystore keystore.jks  -srckeystore server.p12 -srcstoretype PKCS12 \
          -srcstorepass changeit
  • the srcstorepass password should match the export password from step 3)


You can use this :

SELECT attname 
FROM pg_attribute,pg_class 
WHERE attrelid=pg_class.oid 
AND relname='TableName' 
AND attstattarget <>0; 

How to align title at center of ActionBar in default theme(Theme.Holo.Light)

This actually works:

  ActionBar.LayoutParams p = new ActionBar.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
        p.gravity = Gravity.CENTER;

You have to define custom_actionbar.xml layout which is as per your requirement e.g. :

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android=""


else & elif statements not working in Python

In IDLE and the interactive python, you entered two consecutive CRLF which brings you out of the if statement. It's the problem of IDLE or interactive python. It will be ok when you using any kind of editor, just make sure your indentation is right.

GitHub authentication failing over https, returning wrong email address

On Windows, you may be silently blocked by your Antivirus or Windows firewall. Temporarily turn off those services and push/pull from remote origin.

How do you declare string constants in C?

Their are a few differences.

#define HELLO "Hello World"

The statement above can be used with preprocessor and can only be change in the preprocessor.

const char *HELLO2 = "Howdy";

The statement above can be changed with c code. Now you can't change the each individual character around like the statement below because its constant.

HELLO2[0] = 'a'

But you what you can do is have it point to a different string like the statement below


It really depends on how you want to be able to change the variable around. With the preprocessor or c code.

Passing a Bundle on startActivity()?

You have a few options:

1) Use the Bundle from the Intent:

Intent mIntent = new Intent(this, Example.class);
Bundle extras = mIntent.getExtras();
extras.putString(key, value);  

2) Create a new Bundle

Intent mIntent = new Intent(this, Example.class);
Bundle mBundle = new Bundle();
mBundle.putString(key, value);

3) Use the putExtra() shortcut method of the Intent

Intent mIntent = new Intent(this, Example.class);
mIntent.putExtra(key, value);

Then, in the launched Activity, you would read them via:

String value = getIntent().getExtras().getString(key)

NOTE: Bundles have "get" and "put" methods for all the primitive types, Parcelables, and Serializables. I just used Strings for demonstrational purposes.

How to find all links / pages on a website

If this is a programming question, then I would suggest you write your own regular expression to parse all the retrieved contents. Target tags are IMG and A for standard HTML. For JAVA,

final String openingTags = "(<a [^>]*href=['\"]?|<img[^> ]* src=['\"]?)";

this along with Pattern and Matcher classes should detect the beginning of the tags. Add LINK tag if you also want CSS.

However, it is not as easy as you may have intially thought. Many web pages are not well-formed. Extracting all the links programmatically that human being can "recognize" is really difficult if you need to take into account all the irregular expressions.

Good luck!

How to refresh page on back button click?

The hidden input solution wasn't working for me in Safari. The solution below works, and came from here.

window.onpageshow = function(event) {
if (event.persisted) {

Centos/Linux setting logrotate to maximum file size for all logs

As mentioned by Zeeshan, the logrotate options size, minsize, maxsize are triggers for rotation.

To better explain it. You can run logrotate as often as you like, but unless a threshold is reached such as the filesize being reached or the appropriate time passed, the logs will not be rotated.

The size options do not ensure that your rotated logs are also of the specified size. To get them to be close to the specified size you need to call the logrotate program sufficiently often. This is critical.

For log files that build up very quickly (e.g. in the hundreds of MB a day), unless you want them to be very large you will need to ensure logrotate is called often! this is critical.

Therefore to stop your disk filling up with multi-gigabyte log files you need to ensure logrotate is called often enough, otherwise the log rotation will not work as well as you want.

on Ubuntu, you can easily switch to hourly rotation by moving the script /etc/cron.daily/logrotate to /etc/cron.hourly/logrotate

Or add

*/5 * * * * /etc/cron.daily/logrotate 

To your /etc/crontab file. To run it every 5 minutes.

The size option ignores the daily, weekly, monthly time options. But minsize & maxsize take it into account.

The man page is a little confusing there. Here's my explanation.

minsize rotates only when the file has reached an appropriate size and the set time period has passed. e.g. minsize 50MB + daily If file reaches 50MB before daily time ticked over, it'll keep growing until the next day.

maxsize will rotate when the log reaches a set size or the appropriate time has passed. e.g. maxsize 50MB + daily. If file is 50MB and we're not at the next day yet, the log will be rotated. If the file is only 20MB and we roll over to the next day then the file will be rotated.

size will rotate when the log > size. Regardless of whether hourly/daily/weekly/monthly is specified. So if you have size 100M - it means when your log file is > 100M the log will be rotated if logrotate is run when this condition is true. Once it's rotated, the main log will be 0, and a subsequent run will do nothing.

So in the op's case. Specficially 50MB max I'd use something like the following:

/var/log/logpath/*.log {
    maxsize 50M
    rotate 8

Which means he'd create 8hrs of logs max. And there would be 8 of them at no more than 50MB each. Since he's saying that he's getting multi gigabytes each day and assuming they build up at a fairly constant rate, and maxsize is used he'll end up with around close to the max reached for each file. So they will be likely close to 50MB each. Given the volume they build, he would need to ensure that logrotate is run often enough to meet the target size.

Since I've put hourly there, we'd need logrotate to be run a minimum of every hour. But since they build up to say 2 gigabytes per day and we want 50MB... assuming a constant rate that's 83MB per hour. So you can imagine if we run logrotate every hour, despite setting maxsize to 50 we'll end up with 83MB log's in that case. So in this instance set the running to every 30 minutes or less should be sufficient.

Ensure logrotate is run every 30 mins.

*/30 * * * * /etc/cron.daily/logrotate 

Can't find bundle for base name

BalusC is right. Version 1.0.13 is current, but 1.0.9 appears to have the required bundles:

$ jar tf lib/jfreechart-1.0.9.jar | grep 

Assign a variable inside a Block to a variable outside a Block

Just a reminder of a mistake I made myself too, the


declaration must be done when first declaring the variable, that is, OUTSIDE of the block, not inside of it. This should resolve problems mentioned in the comments about the variable not retaining its value outside of the block.

Append to string variable

var str1 = "add";
str1 = str1 + " ";

Hope that helps,


Build error: You must add a reference to System.Runtime

The only way that worked for me - add the assembly to web.config

<compilation debug="true" targetFramework="4.5">
    <add assembly="System.Runtime, Version=, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />   

Is there a better way to iterate over two lists, getting one element from each list for each iteration?

in case your Latitude and Longitude lists are large and lazily loaded:

from itertools import izip
for lat, lon in izip(latitudes, longitudes):
    process(lat, lon)

or if you want to avoid the for-loop

from itertools import izip, imap
out = imap(process, izip(latitudes, longitudes))

What does LINQ return when the results are empty

var lst = new List<int>() { 1, 2, 3 };
var ans = lst.Where( i => i > 3 );

(ans == null).Dump();  // False
(ans.Count() == 0 ).Dump();  // True

(Dump is from LinqPad)

How to generate a simple popup using jQuery

I use a jQuery plugin called ColorBox, it is

  1. Very easy to use
  2. lightweight
  3. customizable
  4. the nicest popup dialog I have seen for jQuery yet

Message Queue vs. Web Services?

There's been a fair amount of recent research in considering how REST HTTP calls could replace the message queue concept.

If you introduce the concept of a process and a task as a resource, the need for middle messaging layer starts to evaporate.


POST /task/name
    - Returns a 202 accepted status immediately
    - Returns a resource url for the created task: /task/name/X
    - Returns a resource url for the started process: /process/Y

GET /process/Y
    - Returns status of ongoing process

A task can have multiple steps for initialization, and a process can return status when polled or POST to a callback URL when complete.

This is dead simple, and becomes quite powerful when you realize that you can now subscribe to an rss/atom feed of all running processes and tasks without any middle layer. Any queuing system is going to require some sort of web front end anyway, and this concept has it built in without another layer of custom code.

Your resources exist until you delete them, which means you can view historical information long after the process and task complete.

You have built in service discovery, even for a task that has multiple steps, without any extra complicated protocols.

GET /task/name
    - returns form with required fields

POST (URL provided form's "action" attribute)

Your service discovery is an HTML form - a universal and human readable format.

The entire flow can be used programmatically or by a human, using universally accepted tools. It's a client driven, and therefore RESTful. Every tool created for the web can drive your business processes. You still have alternate message channels by POSTing asynchronously to a separate array of log servers.

After you consider it for a while, you sit back and start to realize that REST may just eliminate the need for a messaging queue and an ESB altogether.

Updating to latest version of CocoaPods?

Below are steps to update cocoapods :

  1. Open terminal (Shortcut : Press cmd + space tab to open Spotlight then text in terminal)
  2. Use command sudo gem install cocoapods. This will ask for system password due to security concern thereafter it installs gems

Screenshot 1

  1. Now, set up pod using pod setup command. This will setup cocoapods master repo.

Screenshot 2

  1. You can check the version of cocoapods using pod --version command.

Screenshot 3

What does "if (" mean?

I'm presuming you're using Java 6 and that the ResultSet that you're using is a java.sql.ResultSet.

The JavaDoc for the method states:

Moves the cursor froward one row from its current position. A ResultSet cursor is initially positioned before the first row; the first call to the method next makes the first row the current row; the second call makes the second row the current row, and so on.

When a call to the next method returns false, the cursor is positioned after the last row. Any invocation of a ResultSet method which requires a current row will result in a SQLException being thrown.

So, if({ //do something } means "If the result set still has results, move to the next result and do something".

As BalusC pointed out, you need to replace

ResultSet rs = stmt.executeQuery(sql);


ResultSet rs = stmt.executeQuery();

Because you've already set the SQL to use in the statement with your previous line

PreparedStatement stmt = conn.prepareStatement(sql);

If you weren't using the PreparedStatement, then ResultSet rs = stmt.executeQuery(sql); would work.

Read input numbers separated by spaces

I would recommend reading in the line into a string, then splitting it based on the spaces. For this, you can use the getline(...) function. The trick is having a dynamic sized data structure to hold the strings once it's split. Probably the easiest to use would be a vector.

#include <string>
#include <vector>
  string rawInput;
  vector<String> numbers;
  while( getline( cin, rawInput, ' ' ) )

So say the input looks like this:

Enter a number, or numbers separated by a space, between 1 and 1000.
10 5 20 1 200 7

You will now have a vector, numbers, that contains the elements: {"10","5","20","1","200","7"}.

Note that these are still strings, so not useful in arithmetic. To convert them to integers, we use a combination of the STL function, atoi(...), and because atoi requires a c-string instead of a c++ style string, we use the string class' c_str() member function.

  string temp = numbers.pop_back();//removes the last element from the string
  num = atoi( temp.c_str() ); //re-used your 'num' variable from your code

  ...//do stuff

Now there's some problems with this code. Yes, it runs, but it is kind of clunky, and it puts the numbers out in reverse order. Lets re-write it so that it is a little more compact:

#include <string>
string rawInput;
cout << "Enter a number, or numbers separated by a space, between 1 and 1000." << endl;
while( getline( cin, rawInput, ' ') )
  num = atoi( rawInput.c_str() );
  ...//do your stuff

There's still lots of room for improvement with error handling (right now if you enter a non-number the program will crash), and there's infinitely more ways to actually handle the input to get it in a usable number form (the joys of programming!), but that should give you a comprehensive start. :)

Note: I had the reference pages as links, but I cannot post more than two since I have less than 15 posts :/

Edit: I was a little bit wrong about the atoi behavior; I confused it with Java's string->Integer conversions which throw a Not-A-Number exception when given a string that isn't a number, and then crashes the program if the exception isn't handled. atoi(), on the other hand, returns 0, which is not as helpful because what if 0 is the number they entered? Let's make use of the isdigit(...) function. An important thing to note here is that c++ style strings can be accessed like an array, meaning rawInput[0] is the first character in the string all the way up to rawInput[length - 1].

#include <string>
#include <ctype.h>
string rawInput;
cout << "Enter a number, or numbers separated by a space, between 1 and 1000." << endl;
while( getline( cin, rawInput, ' ') )
  bool isNum = true;
  for(int i = 0; i < rawInput.length() && isNum; ++i)
    isNum = isdigit( rawInput[i]);

    num = atoi( rawInput.c_str() );
    ...//do your stuff
    cout << rawInput << " is not a number!" << endl;

The boolean (true/false or 1/0 respectively) is used as a flag for the for-loop, which steps through each character in the string and checks to see if it is a 0-9 digit. If any character in the string is not a digit, the loop will break during it's next execution when it gets to the condition "&& isNum" (assuming you've covered loops already). Then after the loop, isNum is used to determine whether to do your stuff, or to print the error message.

Modifying a subset of rows in a pandas dataframe

Starting from pandas 0.20 ix is deprecated. The right way is to use df.loc

here is a working example

>>> import pandas as pd 
>>> import numpy as np 
>>> df = pd.DataFrame({"A":[0,1,0], "B":[2,0,5]}, columns=list('AB'))
>>> df.loc[df.A == 0, 'B'] = np.nan
>>> df
   A   B
0  0 NaN
1  1   0
2  0 NaN


As explained in the doc here, .loc is primarily label based, but may also be used with a boolean array.

So, what we are doing above is applying df.loc[row_index, column_index] by:

  • Exploiting the fact that loc can take a boolean array as a mask that tells pandas which subset of rows we want to change in row_index
  • Exploiting the fact loc is also label based to select the column using the label 'B' in the column_index

We can use logical, condition or any operation that returns a series of booleans to construct the array of booleans. In the above example, we want any rows that contain a 0, for that we can use df.A == 0, as you can see in the example below, this returns a series of booleans.

>>> df = pd.DataFrame({"A":[0,1,0], "B":[2,0,5]}, columns=list('AB'))
>>> df 
   A  B
0  0  2
1  1  0
2  0  5
>>> df.A == 0 
0     True
1    False
2     True
Name: A, dtype: bool

Then, we use the above array of booleans to select and modify the necessary rows:

>>> df.loc[df.A == 0, 'B'] = np.nan
>>> df
   A   B
0  0 NaN
1  1   0
2  0 NaN

For more information check the advanced indexing documentation here.

Convert Map<String,Object> to Map<String,String>

Use the Java 8 way of converting a Map<String, Object> to Map<String, String>. This solution handles null values.

Map<String, String> keysValuesStrings = keysValues.entrySet().stream()
    .filter(entry -> entry.getValue() != null)
    .collect(Collectors.toMap(Entry::getKey, entry -> entry.getValue().toString()));

PHP array: count or sizeof?

I know this is old but just wanted to mention that I tried this with PHP 7.2:

//Creating array with 1 000 000 elements
$a = array();
for ($i = 0; $i < 1000000; ++$i)
    $a[] = 100;

$time = time();
for ($i = 0; $i < 1000000000; ++$i)
    $b = count($a);
print("1 000 000 000 iteration of count() took ".(time()-$time)." sec\n");

$time = time();
for ($i = 0; $i < 1000000000; ++$i)
    $b = sizeof($a);
print("1 000 000 000 iteration of sizeof() took ".(time()-$time)." sec\n");

and the result was:

1 000 000 000 iteration of count() took 414 sec
1 000 000 000 iteration of sizeof() took 1369 sec

So just use count().

Convert a String representation of a Dictionary to a dictionary?

To OP's example:

s = "{'muffin' : 'lolz', 'foo' : 'kitty'}"

We can use Yaml to deal with this kind of non-standard json in string:

>>> import yaml
>>> s = "{'muffin' : 'lolz', 'foo' : 'kitty'}"
>>> s
"{'muffin' : 'lolz', 'foo' : 'kitty'}"
>>> yaml.load(s)
{'muffin': 'lolz', 'foo': 'kitty'}

How to read values from properties file?

Another way is using a ResourceBundle. Basically you get the bundle using its name without the '.properties'

private static final ResourceBundle resource = ResourceBundle.getBundle("config");

And you recover any value using this:

private final String prop = resource.getString("propName");

How to customize the background color of a UITableViewCell?

Here is the most efficient way I have come across to solve this problem, use the willDisplayCell delegate method (this takes care of the white color for the text label background as well when using cell.textLabel.text and/or cell.detailTextLabel.text):

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath { ... }

When this delegate method is called the color of the cell is controlled via the cell rather than the table view, as when you use:

- (UITableViewCell *) tableView: (UITableView *) tableView cellForRowAtIndexPath: (NSIndexPath *) indexPath { ... }

So within the body of the cell delegate method add the following code to alternate colors of cells or just use the function call to make all the cells of the table the same color.

if (indexPath.row % 2)
    [cell setBackgroundColor:[UIColor colorWithRed:.8 green:.8 blue:1 alpha:1]];
else [cell setBackgroundColor:[UIColor clearColor]];

This solution worked well in my circumstance...

In bash, how to store a return value in a variable?

The return value (aka exit code) is a value in the range 0 to 255 inclusive. It's used to indicate success or failure, not to return information. Any value outside this range will be wrapped.

To return information, like your number, use

echo "$value"

To print additional information that you don't want captured, use

echo "my irrelevant info" >&2 

Finally, to capture it, use what you did:


In other words:

echo "enter: "
        read input

        first=`echo $last_two| sed -e 's/\(.\)/\1 /g'|awk '{print $2}'`
        second=`echo $last_two| sed -e 's/\(.\)/\1 /g'|awk '{print $1}'`
        let sum=$first+$second
        echo $second >&2
        echo $sum >&2

        if [ $sum -gt 9 ]

        echo $value
echo "The value is $result"

How to get the response of XMLHttpRequest?

In XMLHttpRequest, using XMLHttpRequest.responseText may raise the exception like below

 Failed to read the \'responseText\' property from \'XMLHttpRequest\': 
 The value is only accessible if the object\'s \'responseType\' is \'\' 
 or \'text\' (was \'arraybuffer\')

Best way to access the response from XHR as follows

function readBody(xhr) {
    var data;
    if (!xhr.responseType || xhr.responseType === "text") {
        data = xhr.responseText;
    } else if (xhr.responseType === "document") {
        data = xhr.responseXML;
    } else {
        data = xhr.response;
    return data;

var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function() {
    if (xhr.readyState == 4) {
}'GET', '', true);

How to get a pixel's x,y coordinate color from an image?

The two previous answers demonstrate how to use Canvas and ImageData. I would like to propose an answer with runnable example and using an image processing framework, so you don't need to handle the pixel data manually.

MarvinJ provides the method image.getAlphaComponent(x,y) which simply returns the transparency value for the pixel in x,y coordinate. If this value is 0, pixel is totally transparent, values between 1 and 254 are transparency levels, finally 255 is opaque.

For demonstrating I've used the image below (300x300) with transparent background and two pixels at coordinates (0,0) and (150,150).

enter image description here

Console output:


image = new MarvinImage();_x000D_
image.load("", imageLoaded);_x000D_
function imageLoaded(){_x000D_
  console.log("(0,0): "+(image.getAlphaComponent(0,0) > 0 ? "NOT_TRANSPARENT" : "TRANSPARENT"));_x000D_
  console.log("(150,150): "+(image.getAlphaComponent(150,150) > 0 ? "NOT_TRANSPARENT" : "TRANSPARENT"));_x000D_
<script src=""></script>

How to know the version of pip itself

Start Python and type import pip pip.__version__ which works for all python packages.

Flask SQLAlchemy query, specify column names


is the same as


for alias, we can use .label()

session.query(SomeModel.col1.label('some alias name'))

How to obtain image size using standard Python class (without using external library)?

Here's a way to get dimensions of a png file without needing a third-party module. From

import struct

def get_image_info(data):
    if is_png(data):
        w, h = struct.unpack('>LL', data[16:24])
        width = int(w)
        height = int(h)
        raise Exception('not a png image')
    return width, height

def is_png(data):
    return (data[:8] == '\211PNG\r\n\032\n'and (data[12:16] == 'IHDR'))

if __name__ == '__main__':
    with open('foo.png', 'rb') as f:
        data =

    print is_png(data)
    print get_image_info(data)

When you run this, it will return:

(x, y)

And another example that includes handling of JPEGs as well:

Android - Spacing between CheckBox and text

I don't know guys, but I tested

<CheckBox android:paddingLeft="8mm" and only moves the text to the right, not entire control.

It suits me fine.

Test credit card numbers for use with PayPal sandbox

It turns out, after messing around with all of the settings in the test business account, that one (or more) of the fraud related settings in the payment receiving preferences / security settings screens were causing the test payments to fail (without any useful error).

jquery to loop through table rows and cells, where checkob is checked, concatenate

Try this:

function createcodes() {

    $('.authors-list tr').each(function () {
        //processing this row
        //how to process each cell(table td) where there is checkbox
        $(this).find('td input:checked').each(function () {

             // it is checked, your code here...

Import PEM into Java Key Store

First, convert your certificate in a DER format :

openssl x509 -outform der -in certificate.pem -out certificate.der

And after, import it in the keystore :

keytool -import -alias your-alias -keystore cacerts -file certificate.der

Correct way to write loops for promise.

First take array of promises(promise array) and after resolve these promise array using Promise.all(promisearray).

var arry=['raju','ram','abdul','kruthika'];

var promiseArry=[];
for(var i=0;i<arry.length;i++) {

  .then((result) => {
  .catch((error) => {

function dbFetchFun(name) {
  // we need to return a  promise
  return db.find({name:name}); // any db operation we can write hear

why should I make a copy of a data frame in pandas

It's necessary to mention that returning copy or view depends on kind of indexing.

The pandas documentation says:

Returning a view versus a copy

The rules about when a view on the data is returned are entirely dependent on NumPy. Whenever an array of labels or a boolean vector are involved in the indexing operation, the result will be a copy. With single label / scalar indexing and slicing, e.g. df.ix[3:6] or df.ix[:, 'A'], a view will be returned.

How to combine two vectors into a data frame

You can use expand.grid( ) function.

x <-c(1,2,3)
y <-c(100,200,300)

Creating a DateTime in a specific Time Zone in c#

Jon's answer talks about TimeZone, but I'd suggest using TimeZoneInfo instead.

Personally I like keeping things in UTC where possible (at least for the past; storing UTC for the future has potential issues), so I'd suggest a structure like this:

public struct DateTimeWithZone
    private readonly DateTime utcDateTime;
    private readonly TimeZoneInfo timeZone;

    public DateTimeWithZone(DateTime dateTime, TimeZoneInfo timeZone)
        var dateTimeUnspec = DateTime.SpecifyKind(dateTime, DateTimeKind.Unspecified);
        utcDateTime = TimeZoneInfo.ConvertTimeToUtc(dateTimeUnspec, timeZone); 
        this.timeZone = timeZone;

    public DateTime UniversalTime { get { return utcDateTime; } }

    public TimeZoneInfo TimeZone { get { return timeZone; } }

    public DateTime LocalTime
            return TimeZoneInfo.ConvertTime(utcDateTime, timeZone); 

You may wish to change the "TimeZone" names to "TimeZoneInfo" to make things clearer - I prefer the briefer names myself.

How does Task<int> become an int?

No requires converting the Task to int. Simply Use The Task Result.

int taskResult = AccessTheWebAndDouble().Result;

public async Task<int> AccessTheWebAndDouble()
    int task = AccessTheWeb();
    return task;

It will return the value if available otherwise it return 0.

Programmatically Check an Item in Checkboxlist where text is equal to what I want

Assuming that the items in your CheckedListBox are strings:

  for (int i = 0; i < checkedListBox1.Items.Count; i++)
    if ((string)checkedListBox1.Items[i] == value)
      checkedListBox1.SetItemChecked(i, true);


  int index = checkedListBox1.Items.IndexOf(value);

  if (index >= 0)
    checkedListBox1.SetItemChecked(index, true);

Iterator invalidation rules

C++17 (All references are from the final working draft of CPP17 - n4659)


Sequence Containers

  • vector: The functions insert, emplace_back, emplace, push_back cause reallocation if the new size is greater than the old capacity. Reallocation invalidates all the references, pointers, and iterators referring to the elements in the sequence. If no reallocation happens, all the iterators and references before the insertion point remain valid. []
    With respect to the reserve function, reallocation invalidates all the references, pointers, and iterators referring to the elements in the sequence. No reallocation shall take place during insertions that happen after a call to reserve() until the time when an insertion would make the size of the vector greater than the value of capacity(). []

  • deque: An insertion in the middle of the deque invalidates all the iterators and references to elements of the deque. An insertion at either end of the deque invalidates all the iterators to the deque, but has no effect on the validity of references to elements of the deque. []

  • list: Does not affect the validity of iterators and references. If an exception is thrown there are no effects. [].
    The insert, emplace_front, emplace_back, emplace, push_front, push_back functions are covered under this rule.

  • forward_list: None of the overloads of insert_after shall affect the validity of iterators and references []

  • array: As a rule, iterators to an array are never invalidated throughout the lifetime of the array. One should take note, however, that during swap, the iterator will continue to point to the same array element, and will thus change its value.

Associative Containers

  • All Associative Containers: The insert and emplace members shall not affect the validity of iterators and references to the container [26.2.6/9]

Unordered Associative Containers

  • All Unordered Associative Containers: Rehashing invalidates iterators, changes ordering between elements, and changes which buckets elements appear in, but does not invalidate pointers or references to elements. [26.2.7/9]
    The insert and emplace members shall not affect the validity of references to container elements, but may invalidate all iterators to the container. [26.2.7/14]
    The insert and emplace members shall not affect the validity of iterators if (N+n) <= z * B, where N is the number of elements in the container prior to the insert operation, n is the number of elements inserted, B is the container’s bucket count, and z is the container’s maximum load factor. [26.2.7/15]

  • All Unordered Associative Containers: In case of a merge operation (e.g., a.merge(a2)), iterators referring to the transferred elements and all iterators referring to a will be invalidated, but iterators to elements remaining in a2 will remain valid. (Table 91 — Unordered associative container requirements)

Container Adaptors

  • stack: inherited from underlying container
  • queue: inherited from underlying container
  • priority_queue: inherited from underlying container


Sequence Containers

  • vector: The functions erase and pop_back invalidate iterators and references at or after the point of the erase. []

  • deque: An erase operation that erases the last element of a deque invalidates only the past-the-end iterator and all iterators and references to the erased elements. An erase operation that erases the first element of a deque but not the last element invalidates only iterators and references to the erased elements. An erase operation that erases neither the first element nor the last element of a deque invalidates the past-the-end iterator and all iterators and references to all the elements of the deque. [ Note: pop_front and pop_back are erase operations. —end note ] []

  • list: Invalidates only the iterators and references to the erased elements. []. This applies to erase, pop_front, pop_back, clear functions.
    remove and remove_if member functions: Erases all the elements in the list referred by a list iterator i for which the following conditions hold: *i == value, pred(*i) != false. Invalidates only the iterators and references to the erased elements [].
    unique member function - Erases all but the first element from every consecutive group of equal elements referred to by the iterator i in the range [first + 1, last) for which *i == *(i-1) (for the version of unique with no arguments) or pred(*i, *(i - 1)) (for the version of unique with a predicate argument) holds. Invalidates only the iterators and references to the erased elements. []

  • forward_list: erase_after shall invalidate only iterators and references to the erased elements. [].
    remove and remove_if member functions - Erases all the elements in the list referred by a list iterator i for which the following conditions hold: *i == value (for remove()), pred(*i) is true (for remove_if()). Invalidates only the iterators and references to the erased elements. [].
    unique member function - Erases all but the first element from every consecutive group of equal elements referred to by the iterator i in the range [first + 1, last) for which *i == *(i-1) (for the version with no arguments) or pred(*i, *(i - 1)) (for the version with a predicate argument) holds. Invalidates only the iterators and references to the erased elements. []

  • All Sequence Containers: clear invalidates all references, pointers, and iterators referring to the elements of a and may invalidate the past-the-end iterator (Table 87 — Sequence container requirements). But for forward_list, clear does not invalidate past-the-end iterators. []

  • All Sequence Containers: assign invalidates all references, pointers and iterators referring to the elements of the container. For vector and deque, also invalidates the past-the-end iterator. (Table 87 — Sequence container requirements)

Associative Containers

  • All Associative Containers: The erase members shall invalidate only iterators and references to the erased elements [26.2.6/9]

  • All Associative Containers: The extract members invalidate only iterators to the removed element; pointers and references to the removed element remain valid [26.2.6/10]

Container Adaptors

  • stack: inherited from underlying container
  • queue: inherited from underlying container
  • priority_queue: inherited from underlying container

General container requirements relating to iterator invalidation:

  • Unless otherwise specified (either explicitly or by defining a function in terms of other functions), invoking a container member function or passing a container as an argument to a library function shall not invalidate iterators to, or change the values of, objects within that container. [26.2.1/12]

  • no swap() function invalidates any references, pointers, or iterators referring to the elements of the containers being swapped. [ Note: The end() iterator does not refer to any element, so it may be invalidated. —end note ] [26.2.1/(11.6)]

As examples of the above requirements:

  • transform algorithm: The op and binary_op functions shall not invalidate iterators or subranges, or modify elements in the ranges [28.6.4/1]

  • accumulate algorithm: In the range [first, last], binary_op shall neither modify elements nor invalidate iterators or subranges [29.8.2/1]

  • reduce algorithm: binary_op shall neither invalidate iterators or subranges, nor modify elements in the range [first, last]. [29.8.3/5]

and so on...

Linking to an external URL in Javadoc?

Taken from the javadoc spec

@see <a href="URL#value">label</a> : Adds a link as defined by URL#value. The URL#value is a relative or absolute URL. The Javadoc tool distinguishes this from other cases by looking for a less-than symbol (<) as the first character.

For example : @see <a href="">Google</a>

pycharm running way slow

In my case, it was very slow and i needed to change inspections settings, i tried everything, the only thing that worked was going from 2018.2 version to 2016.2, sometimes is better to be some updates behind...

Add image in pdf using jspdf

This worked for me in Angular 2:

var img = new Image()
img.src = 'assets/sample.png'
pdf.addImage(img, 'png', 10, 78, 12, 15)

jsPDF version 1.5.3

assets directory is in src directory of the Angular project root

What to do about Eclipse's "No repository found containing: ..." error messages?

Tried to install Google App Engine SDK, and received similar errors.
None of the answers worked for me.
I noticed download hangs around 999K, while the full download was about 100MB.

Somehow after trying for the sixth or seventh time, the problem fixed itself :)
So if none of these work for you.. try at least several times, maybe server is overloaded :)

How to change status bar color to match app in Lollipop? [Android]

Another way to set the status bar color is through the style.xml.

To do that, create a style.xml file under res/values-v21 folder with this content:

<?xml version="1.0" encoding="utf-8"?>
    <style name="AppTheme" parent="android:Theme.Material">
        <!--   darker variant for the status bar and contextual app bars -->
        <item name="android:colorPrimaryDark">@color/blue_dark</item>

Edit: as pointed out in comments, when using AppCompat the code is different. In file res/values/style.xml use instead:

<style name="Theme.MyTheme" parent="Theme.AppCompat.Light">   
    <!-- Set AppCompat’s color theming attrs -->
    <item name="colorPrimary">@color/my_awesome_red</item>
    <item name="colorPrimaryDark">@color/my_awesome_darker_red</item>
    <!-- Other attributes -->

Angular + Material - How to refresh a data source (mat-table)

I did some more research and found this place to give me what I needed - feels clean and relates to update data when refreshed from server:

Most credits to the page above. Below is a sample of how a mat-selector can be used to update a mat-table bound to a datasource on change of selection. I am using Angular 7. Sorry for being extensive, trying to be complete but concise - I have ripped out as many non-needed parts as possible. With this hoping to help someone else getting forward faster!


export class Organization {
    id: number;
    name: String;


import { Observable, empty } from 'rxjs';
import { of } from 'rxjs';

import { Organization } from './organization.model';

export class OrganizationService {
  getConstantOrganizations(filter: String): Observable<Organization[]> {
    if (filter === "All") {
      let Organizations: Organization[] = [
        { id: 1234, name: 'Some data' }
      return of(Organizations);
     } else {
       let Organizations: Organization[] = [
         { id: 5678, name: 'Some other data' }
     return of(Organizations);

  // ...just a sample, other filterings would go here - and of course data instead fetched from server.


import { CollectionViewer, DataSource } from '@angular/cdk/collections';
import { Observable, BehaviorSubject, of } from 'rxjs';
import { catchError, finalize } from "rxjs/operators";

import { OrganizationService } from './organization.service';
import { Organization } from './organization.model';

export class OrganizationDataSource extends DataSource<Organization> {
  private organizationsSubject = new BehaviorSubject<Organization[]>([]);

  private loadingSubject = new BehaviorSubject<boolean>(false);

  public loading$ = this.loadingSubject.asObservable();

  constructor(private organizationService: OrganizationService, ) {

  loadOrganizations(filter: String) {;

    return this.organizationService.getOrganizations(filter).pipe(
      catchError(() => of([])),
      finalize(() =>
    ).subscribe(organization =>;

  connect(collectionViewer: CollectionViewer): Observable<Organization[]> {
    return this.organizationsSubject.asObservable();

  disconnect(collectionViewer: CollectionViewer): void {


<div class="spinner-container" *ngIf="organizationDataSource.loading$ | async">

  <form [formGroup]="formGroup">
    <mat-form-field fxAuto>
      <div fxLayout="row">
        <mat-select formControlName="organizationSelectionControl" (selectionChange)="updateOrganizationSelection()">
          <mat-option *ngFor="let organizationSelectionAlternative of organizationSelectionAlternatives"

<mat-table fxLayout="column" [dataSource]="organizationDataSource">
  <ng-container matColumnDef="name">
    <mat-header-cell *matHeaderCellDef>Name</mat-header-cell>
    <mat-cell *matCellDef="let organization">{{}}</mat-cell>

  <ng-container matColumnDef="number">
    <mat-header-cell *matHeaderCellDef>Number</mat-header-cell>
    <mat-cell *matCellDef="let organization">{{organization.number}}</mat-cell>

  <mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>
  <mat-row *matRowDef="let row; columns: displayedColumns"></mat-row>


.spinner-container {
    height: 360px;
    width: 390px;
    position: fixed;


import { Component, OnInit } from '@angular/core';
import { FormGroup, FormBuilder } from '@angular/forms';
import { Observable } from 'rxjs';

import { OrganizationService } from './organization.service';
import { Organization } from './organization.model';
import { OrganizationDataSource } from './organizationdatasource.model';

  selector: 'organizations',
  templateUrl: './organizations.component.html',
  styleUrls: ['./organizations.component.scss']
export class OrganizationsComponent implements OnInit {
  public displayedColumns: string[];
  public organizationDataSource: OrganizationDataSource;
  public formGroup: FormGroup;

  public organizationSelectionAlternatives = [{
    id: 1,
    name: 'All'
  }, {
    id: 2,
    name: 'With organization update requests'
  }, {
    id: 3,
    name: 'With contact update requests'
  }, {
    id: 4,
    name: 'With order requests'

    private formBuilder: FormBuilder,
    private organizationService: OrganizationService) { }

  ngOnInit() {
    this.formGroup ={
      'organizationSelectionControl': []

    const toSelect = this.organizationSelectionAlternatives.find(c => == 1);

    this.organizationDataSource = new OrganizationDataSource(this.organizationService);
    this.displayedColumns = ['name', 'number' ];

  updateOrganizationSelection() {

Why use argparse rather than optparse?

As of python 2.7, optparse is deprecated, and will hopefully go away in the future.

argparse is better for all the reasons listed on its original page (

  • handling positional arguments
  • supporting sub-commands
  • allowing alternative option prefixes like + and /
  • handling zero-or-more and one-or-more style arguments
  • producing more informative usage messages
  • providing a much simpler interface for custom types and actions

More information is also in PEP 389, which is the vehicle by which argparse made it into the standard library.

How to return values in javascript

I would prefer a callback solution: Working fiddle here:

function myFunction(value1,value2,value3, callback) {

    value2 = 'somevalue2'; //to return
    value3 = 'somevalue3'; //to return

    callback( value2, value3 );


var value1 = 1;
var value2 = 2;
var value3 = 3;

myFunction(value1,value2,value3, function(value2, value3){
    if (value2 && value3) {
        //Do some stuff
        alert( value2 + '-' + value3 );

Error 5 : Access Denied when starting windows service

As the error popup suggests this is related to permission. So run the service as "LocalSystem" account.

To do the same, Right Click on serviceProcessInstaller -> Properties -> Account and set it to "LocalSystem" instead of the default "User". Install the service and voila.

Alternative to Intersect in MySQL

Microsoft SQL Server's INTERSECT "returns any distinct values that are returned by both the query on the left and right sides of the INTERSECT operand" This is different from a standard INNER JOIN or WHERE EXISTS query.

SQL Server

CREATE TABLE table_a (
    value VARCHAR(255)

CREATE TABLE table_b (
    value VARCHAR(255)

INSERT INTO table_a VALUES (1, 'A'), (2, 'B'), (3, 'B');
INSERT INTO table_b VALUES (1, 'B');

SELECT value FROM table_a
SELECT value FROM table_b


(1 rows affected)


CREATE TABLE `table_a` (
  `value` varchar(255),
  PRIMARY KEY (`id`)

CREATE TABLE `table_b` LIKE `table_a`;

INSERT INTO table_a VALUES (1, 'A'), (2, 'B'), (3, 'B');
INSERT INTO table_b VALUES (1, 'B');

SELECT value FROM table_a
INNER JOIN table_b
USING (value);

| value |
| B     |
| B     |
2 rows in set (0.00 sec)

SELECT value FROM table_a
WHERE (value) IN
(SELECT value FROM table_b);

| value |
| B     |
| B     |

With this particular question, the id column is involved, so duplicate values will not be returned, but for the sake of completeness, here's a MySQL alternative using INNER JOIN and DISTINCT:

INNER JOIN table_b
USING (value);

| value |
| B     |

And another example using WHERE ... IN and DISTINCT:

WHERE (value) IN
(SELECT value FROM table_b);

| value |
| B     |

HTML table headers always visible at top of window when viewing a large table

Check out jQuery.floatThead (demos available) which is very cool, can work with DataTables too, and can even work inside an overflow: auto container.

WP -- Get posts by category?

Check here :

Note: The category parameter needs to be the ID of the category, and not the category name.

How to add smooth scrolling to Bootstrap's scroll spy function

What onetrickpony posted is okay, but if you want to have a more general solution, you can just use the code below.

Instead of selecting just the id of the anchor, you can make it bit more standard-like and just selecting the attribute name of the <a>-Tag. This will save you from writing an extra id tag. Just add the smoothscroll class to the navbar element.

What changed

1) $('#nav ul li a[href^="#"]') to $('#nav.smoothscroll ul li a[href^="#"]')

2) $(this.hash) to $('a[name="' + this.hash.replace('#', '') + '"]')

Final Code

/* Enable smooth scrolling on all links with anchors */
$('#nav.smoothscroll ul li a[href^="#"]').on('click', function(e) {

  // prevent default anchor click behavior

  // store hash
  var hash = this.hash;

  // animate
  $('html, body').animate({
    scrollTop: $('a[name="' + this.hash.replace('#', '') + '"]').offset().top
  }, 300, function(){

    // when done, add hash to url
    // (default click behaviour)
    window.location.hash = hash;


Chrome: Uncaught SyntaxError: Unexpected end of input

JSHint is good at finding the location of missing brackets or bad syntax.

How do I get the AM/PM value from a DateTime?

string AM_PM = string.Format("{0:hh:mm:ss tt}", DateTime.Now).Split(new char[]{' '})[1];

Bash command to sum a column of numbers

The following command will add all the lines(first field of the awk output)

awk '{s+=$1} END {print s}' filename

UIScrollView not scrolling

If your scrollView is a subview of a containerView of some type, then make sure that your scrollView is within the frame or bounds of the containerView. I had containerView.clipsToBounds = NO which still allowed me see the scrollView, but because scrollView wasn't within the bounds of containerView it wouldn't detect touch events.

For example:

containerView.frame = CGRectMake(0, 0, 200, 200);
scrollView.frame = CGRectMake(0, 200, 200, 200);
[containerView addSubview:scrollView];
scrollView.userInteractionEnabled = YES;

You will be able to see the scrollView but it won't receive user interactions.

How to make an AlertDialog in Flutter?

You can use this code snippet for creating a two buttoned Alert box,

import 'package:flutter/material.dart';

class BaseAlertDialog extends StatelessWidget {

  //When creating please recheck 'context' if there is an error!

  Color _color = Color.fromARGB(220, 117, 218 ,255);

  String _title;
  String _content;
  String _yes;
  String _no;
  Function _yesOnPressed;
  Function _noOnPressed;

  BaseAlertDialog({String title, String content, Function yesOnPressed, Function noOnPressed, String yes = "Yes", String no = "No"}){
    this._title = title;
    this._content = content;
    this._yesOnPressed = yesOnPressed;
    this._noOnPressed = noOnPressed;
    this._yes = yes;
    this._no = no;

  Widget build(BuildContext context) {
    return AlertDialog(
      title: new Text(this._title),
      content: new Text(this._content),
      backgroundColor: this._color,
          RoundedRectangleBorder(borderRadius: new BorderRadius.circular(15)),
      actions: <Widget>[
        new FlatButton(
          child: new Text(this._yes),
          textColor: Colors.greenAccent,
          onPressed: () {
        new FlatButton(
          child: Text(this._no),
          textColor: Colors.redAccent,
          onPressed: () {

To show the dialog you can have a method that calls it NB after importing BaseAlertDialog class

_confirmRegister() {
var baseDialog = BaseAlertDialog(
    title: "Confirm Registration",
    content: "I Agree that the information provided is correct",
    yesOnPressed: () {},
    noOnPressed: () {},
    yes: "Agree",
    no: "Cancel");
showDialog(context: context, builder: (BuildContext context) => baseDialog);



How are environment variables used in Jenkins with Windows Batch Command?

I know nothing about Jenkins, but it looks like you are trying to access environment variables using some form of unix syntax - that won't work.

If the name of the variable is WORKSPACE, then the value is expanded in Windows batch using
%WORKSPACE%. That form of expansion is performed at parse time. For example, this will print to screen the value of WORKSPACE


If you need the value at execution time, then you need to use delayed expansion !WORKSPACE!. Delayed expansion is not normally enabled by default. Use SETLOCAL EnableDelayedExpansion to enable it. Delayed expansion is often needed because blocks of code within parentheses and/or multiple commands concatenated by &, &&, or || are parsed all at once, so a value assigned within the block cannot be read later within the same block unless you use delayed expansion.

setlocal enableDelayedExpansion
  echo Normal Expansion = %WORKSPACE%
  echo Delayed Expansion = !WORKSPACE!

The output of the above is

Normal Expansion = BEFORE
Delayed Expansion = AFTER

Use HELP SET or SET /? from the command line to get more information about Windows environment variables and the various expansion options. For example, it explains how to do search/replace and substring operations.

How to get Tensorflow tensor dimensions (shape) as int values?

In later versions (tested with TensorFlow 1.14) there's a more numpy-like way to get the shape of a tensor. You can use tensor.shape to get the shape of the tensor.

tensor_shape = tensor.shape

Change Date Format(DD/MM/YYYY) in SQL SELECT Statement

Try like this...

select CONVERT (varchar(10), getdate(), 103) AS [DD/MM/YYYY]

For more info :

How to find tag with particular text with Beautiful Soup?

You could solve this with some simple gazpacho parsing:

from gazpacho import Soup

soup = Soup(html)
tds = soup.find("td", {"class": "pos"})

Which will output:

text I am looking for

Reactjs: Unexpected token '<' Error

I have this error and could not solve this for two days.So the fix of error is very simple. In body ,where you connect your script, add type="text/jsx" and this`ll resolve the problem.

How to append elements into a dictionary in Swift?

There is no function to append the data in dictionary. You just assign the value against new key in existing dictionary. it will automatically add value to the dictionary.

var param  = ["Name":"Aloha","user" : "Aloha 2"]
param["questions"] = "Are you mine?"

The output will be like

["Name":"Aloha","user" : "Aloha 2","questions" : ""Are you mine"?"]

how to refresh page in angular 2

Just in case someone else encounters this problem. You need to call


And you cannot call this from a expression. If you want to call this from a click event you need to put this on a function:


And simply define the function:

reloadPage() {

If you are changing the route, it might not work because the click event seems to happen before the route changes. A very dirty solution is just to add a small delay

reloadPage() {
    }, 100);

Change bullets color of an HTML list without using span

I really liked Marc's answer too - I needed a set of different colored ULs and obviously it would be easier just to use a class. Here is what I used for orange, for example: {
    list-style: none;
    padding: 0px;
} > li:before {
    content: '\25CF ';
    font-size: 15px;
    color: #F00;
    margin-right: 10px;
    padding: 0px;
    line-height: 15px;

Plus, I found that the hex code I used for "content:" was different than Marc's (that hex circle seemed to sit a bit too high). The one I used seems to sit perfectly in the middle. I also found several other shapes (squares, triangles, circles, etc.) right here

Comparing two strings, ignoring case in C#

1st is more efficient (and the best possible option) because val.ToLowerCase() creates a new object since Strings are immutable.

How to find the size of a table in SQL?

Here's a simple query, if you are just trying to find the largest tables.

  -- Find largest table partitions
 SELECT top 20, LTRIM (STR ( sz.in_row_data_page_count * 8, 15, 0) + ' KB') as Size, * FROM sys.dm_db_partition_stats sz
inner join sys.objects obj on obj.object_id = sz.object_id
  order by sz.in_row_data_page_count desc

What is the difference between SQL Server 2012 Express versions?

Scroll down on that page and you'll see:

Express with Tools (with LocalDB) Includes the database engine and SQL Server Management Studio Express)
This package contains everything needed to install and configure SQL Server as a database server. Choose either LocalDB or Express depending on your needs above.

That's the SQLEXPRWT_x64_ENU.exe download.... (WT = with tools)

Express with Advanced Services (contains the database engine, Express Tools, Reporting Services, and Full Text Search)
This package contains all the components of SQL Express. This is a larger download than “with Tools,” as it also includes both Full Text Search and Reporting Services.

That's the SQLEXPRADV_x64_ENU.exe download ... (ADV = Advanced Services)

The SQLEXPR_x64_ENU.exe file is just the database engine - no tools, no Reporting Services, no fulltext-search - just barebones engine.

What is the difference between PUT, POST and PATCH?

Main Difference Between PUT and PATCH Requests:

Suppose we have a resource that holds the first name and last name of a person.

If we want to change the first name then we send a put request for Update

{ "first": "Michael", "last": "Angelo" }

Here, although we are only changing the first name, with PUT request we have to send both parameters first and last.
In other words, it is mandatory to send all values again, the full payload.

When we send a PATCH request, however, we only send the data which we want to update. In other words, we only send the first name to update, no need to send the last name.

How to create a zip archive with PowerShell?

I use this snippet to check my database backups folder for backup files not compressed yet, compress them using 7-Zip, and finally deleting the *.bak files to save some disk space. Notice files are ordered by length (smallest to biggest) before compression to avoid some files not being compressed.

$bkdir = "E:\BackupsPWS"
$7Zip = 'C:\"Program Files"\7-Zip\7z.exe'

get-childitem -path $bkdir | Sort-Object length |
    $_.extension -match ".(bak)" -and
    -not (test-path ($_.fullname -replace "(bak)", "7z"))
} |
    $zipfilename = ($_.fullname -replace "bak", "7z")
    Invoke-Expression "$7Zip a $zipfilename $($_.FullName)"
get-childitem -path $bkdir |
where {
    $_.extension -match ".(bak)" -and
   (test-path ($_.fullname -replace "(bak)", "7z"))
} |
foreach { del $_.fullname }

Here you can check a PowerShell script to backup, compress and transfer those files over FTP.

Replace String in all files in Eclipse

ctrl + H  will show the option to replace in the bottom . 

enter image description here

Once you click on replace it will show as below

enter image description here

JQuery - Get select value

var nationality = $("#dancerCountry").val(); should work. Are you sure that the element selector is working properly? Perhaps you should try:

var nationality = $('select[name="dancerCountry"]').val();

I need a Nodejs scheduler that allows for tasks at different intervals

I would recommend node-cron. It allows to run tasks using Cron patterns e.g.

'* * * * * *' - runs every second
'*/5 * * * * *' - runs every 5 seconds
'10,20,30 * * * * *' - run at 10th, 20th and 30th second of every minute
'0 * * * * *' - runs every minute
'0 0 * * * *' - runs every hour (at 0 minutes and 0 seconds)

But also more complex schedules e.g.

'00 30 11 * * 1-5' - Runs every weekday (Monday through Friday) at 11:30:00 AM. It does not run on Saturday or Sunday.

Sample code: running job every 10 minutes:

var cron = require('cron');
var cronJob = cron.job("0 */10 * * * *", function(){
    // perform operation e.g. GET request http.get() etc.'cron job completed');

You can find more examples in node-cron wiki

More on cron configuration can be found on cron wiki

I've been using that library in many projects and it does the job. I hope that will help.

Why is Spring's ApplicationContext.getBean considered bad?

however, there are still cases where you need the service locator pattern. for example, i have a controller bean, this controller might have some default service beans, which can be dependency injected by configuration. while there could also be many additional or new services this controller can invoke now or later, which then need the service locator to retrieve the service beans.

How to set initial value and auto increment in MySQL?

With CREATE TABLE statement

CREATE TABLE my_table (
  name VARCHAR(100) NOT NULL,

or with ALTER TABLE statement


Where and why do I have to put the "template" and "typename" keywords?

This answer is meant to be a rather short and sweet one to answer (part of) the titled question. If you want an answer with more detail that explains why you have to put them there, please go here.

The general rule for putting the typename keyword is mostly when you're using a template parameter and you want to access a nested typedef or using-alias, for example:

template<typename T>
struct test {
    using type = T; // no typename required
    using underlying_type = typename T::type // typename required

Note that this also applies for meta functions or things that take generic template parameters too. However, if the template parameter provided is an explicit type then you don't have to specify typename, for example:

template<typename T>
struct test {
    // typename required
    using type = typename std::conditional<true, const T&, T&&>::type;
    // no typename required
    using integer = std::conditional<true, int, float>::type;

The general rules for adding the template qualifier are mostly similar except they typically involve templated member functions (static or otherwise) of a struct/class that is itself templated, for example:

Given this struct and function:

template<typename T>
struct test {
    template<typename U>
    void get() const {
        std::cout << "get\n";

template<typename T>
void func(const test<T>& t) {
    t.get<int>(); // error

Attempting to access t.get<int>() from inside the function will result in an error:

main.cpp:13:11: error: expected primary-expression before 'int'
main.cpp:13:11: error: expected ';' before 'int'

Thus in this context you would need the template keyword beforehand and call it like so:

t.template get<int>()

That way the compiler will parse this properly rather than t.get < int.

How do I get a Cron like scheduler in Python?

If you're looking for something lightweight checkout schedule:

import schedule
import time

def job():
    print("I'm working...")


while 1:

Disclosure: I'm the author of that library.

Parsing JSON using C

cJSON has a decent API and is small (2 files, ~700 lines). Many of the other JSON parsers I looked at first were huge... I just want to parse some JSON.

Edit: We've made some improvements to cJSON over the years.

Angular 2 execute script after template render

I've used this method (reported here )

export class AppComponent {

  constructor() {
    var testScript = document.createElement("script");
    testScript.setAttribute("id", "testScript");
    testScript.setAttribute("src", "assets/js/test.js");

it worked for me since I wanted to execute a javascript file AFTER THE COMPONENT RENDERED.

Could not find module FindOpenCV.cmake ( Error in configuration process)

I faced the same error. In my case this "OpenCVConfig.cmake" file is located in /usr/local/share/OpenCV. In CMakeLists.txt add the line

set(OpenCV_DIR /usr/local/share/OpenCV)

as suggested by the error message.

java: run a function after a specific number of seconds

ScheduledThreadPoolExecutor has this ability, but it's quite heavyweight.

Timer also has this ability but opens several thread even if used only once.

Here's a simple implementation with a test (signature close to Android's Handler.postDelayed()):

public class JavaUtil {
    public static void postDelayed(final Runnable runnable, final long delayMillis) {
        final long requested = System.currentTimeMillis();
        new Thread(new Runnable() {
            public void run() {
                // The while is just to ignore interruption.
                while (true) {
                    try {
                        long leftToSleep = requested + delayMillis - System.currentTimeMillis();
                        if (leftToSleep > 0) {
                    } catch (InterruptedException ignored) {


public void testRunsOnlyOnce() throws InterruptedException {
    long delay = 100;
    int num = 0;
    final AtomicInteger numAtomic = new AtomicInteger(num);
    JavaUtil.postDelayed(new Runnable() {
        public void run() {
    }, delay);
    Assert.assertEquals(num, numAtomic.get());
    Thread.sleep(delay + 10);
    Assert.assertEquals(num + 1, numAtomic.get());
    Thread.sleep(delay * 2);
    Assert.assertEquals(num + 1, numAtomic.get());

How to access custom attributes from event object in React?

I think it's recommended to bind all methods where you need to use this.setState method which is defined in the React.Component class, inside the constructor, in your case you constructor should be like

    constructor() {
        //This binding removeTag is necessary to make `this` work in the callback
        this.removeTag = this.removeTag.bind(this)
        //use Object destructuring to fetch all element values''
        const {style, dataset} =
   render() {
      <a data-tag={i} style={showStyle} onClick={this.removeTag.bind(null, i)}></a>

For more reference on Object destructuring

What are the advantages and disadvantages of recursion?

To start:


  • It is the unique way of implementing a variable number of nested loops (and the only elegant way of implementing a big constant number of nested loops).


  • Recursive methods will often throw a StackOverflowException when processing big sets. Recursive loops don't have this problem though. Server returned HTTP response code: 500

I have encountered the same problem and found out the solution.

You may look within the first server response and see if the server sent you a cookie.

To check if the server sent you a cookie, you can use HttpURLConnection#getHeaderFields() and look for headers named "Set-Cookie".

If existing, here's the solution for your problem. 100% Working for this case!

+1 if it worked for you.

How to get a list of all files that changed between two Git commits?

With git show you can get a similar result. For look the commit (like it looks on git log view) with the list of files included in, use:

git show --name-only [commit-id_A]^..[commit-id_B]

Where [commit-id_A] is the initial commit and [commit-id_B] is the last commit than you want to show.

Special attention with ^ symbol. If you don't put that, the commit-id_A information will not deploy.

Phonegap + jQuery Mobile, real world sample or tutorial

These may not solve exactly your "real-world problems", but perhaps something useful ...

Our web site includes PhoneGap and jQuery Mobile tutorials for a media player, barcode scanner, google maps, and OAuth.

Also, my github page has code, but no tutorial, for two apps:

  • AppLaudApp - a run-control, debugging enabling, download complementary app to a cloud IDE
  • NameTrendz - an app developed in at Android Dev Camp to do a bunch of queries about popular name data. The PhoneGap and jQuery Mobile versions are from March 2011.

Python math module


from math import sqrt

Using sqrt(4) works perfectly well. You need to only use math.sqrt(4) when you just use "import math".

What does it mean to write to stdout in C?

@K Scott Piel wrote a great answer here, but I want to add one important point.

Note that the stdout stream is usually line-buffered, so to ensure the output is actually printed and not just left sitting in the buffer waiting to be written you must flush the buffer by either ending your printf statement with a \n


printf("hello world\n");


printf("hello world"); 

or similar, OR you must call fflush(stdout); after your printf call.


printf("hello world"); 

Read more here: Why does printf not flush after the call unless a newline is in the format string?

Dialog with transparent background in Android

This is what I did to achieve translucency with AlertDialog.

Created a custom style:

<style name="TranslucentDialog" parent="@android:style/Theme.DeviceDefault.Dialog.Alert">
    <item name="android:colorBackground">#32FFFFFF</item>

And then create the dialog with:

AlertDialog.Builder builder = new AlertDialog.Builder(getActivity(),;
AlertDialog dialog = builder.create();

How to execute IN() SQL queries with Spring's JDBCTemplate effectively?

You want a parameter source:

Set<Integer> ids = ...;

MapSqlParameterSource parameters = new MapSqlParameterSource();
parameters.addValue("ids", ids);

List<Foo> foo = getJdbcTemplate().query("SELECT * FROM foo WHERE a IN (:ids)",
     parameters, getRowMapper());

This only works if getJdbcTemplate() returns an instance of type NamedParameterJdbcTemplate

Get the list of stored procedures created and / or modified on a particular date?

Here is the "newer school" version.

and CREATED = '20120927'

The type initializer for 'CrystalDecisions.CrystalReports.Engine.ReportDocument' threw an exception

  1. Download cr redist 2005 or 2008(which is your tool) or copy from C:\Program Files\Microsoft Visual Studio 8\SDK\v2.0\BootStrapper\Packages\CrystalReports

  2. Download c++ redist 2005 or 2008(which is your tool)

  3. Install both and restart your system

  4. Problem solved.

How to get current moment in ISO 8601 format with date, hour, and minute?

Java 8:

thisMoment = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mmX")

Pre Java 8:

thisMoment = String.format("%tFT%<tRZ",

From the docs:

'R'    Time formatted for the 24-hour clock as "%tH:%tM"
'F'    ISO 8601 complete date formatted as "%tY-%tm-%td".

push_back vs emplace_back

One more example for lists:

// constructs the elements in place.                                                

// creates a new object and then copies (or moves) that object.

How to Uninstall RVM?

It’s easy; just do the following:

rvm implode


rm -rf ~/.rvm

And don’t forget to remove the script calls in the following files:

  • ~/.bashrc
  • ~/.bash_profile
  • ~/.profile

And maybe others depending on whatever shell you’re using.

Set SSH connection timeout

The problem may be that ssh is trying to connect to all the different IPs that resolves to. For example on my machine:

# ssh -v -o ConnectTimeout=1 -o ConnectionAttempts=1
OpenSSH_5.9p1, OpenSSL 0.9.8t 18 Jan 2012
debug1: Connecting to [] port 22.
debug1: connect to address port 22: Connection timed out
debug1: Connecting to [] port 22.
debug1: connect to address port 22: Connection timed out
debug1: Connecting to [] port 22.
debug1: connect to address port 22: Connection timed out
debug1: Connecting to [] port 22.
debug1: connect to address port 22: Connection timed out
debug1: Connecting to [] port 22.
debug1: connect to address port 22: Connection timed out
ssh: connect to host port 22: Connection timed out

If I run it with a specific IP, it returns much faster.

EDIT: I've timed it (with time) and the results are:

  • - 5.086 seconds
  • - 1.054 seconds

Found a swap file by the name

Accepted answer fails to mention how to delete the .swp file.

Hit "D" when the prompt comes up and it will remove it.

In my case, after I hit D it left the latest saved version intact and deleted the .swp which got created because I exited VIM incorrectly

Passing html values into javascript functions

Here is the JSfiddle Demo

I changed your HTML and give your input textfield an id of value. I removed the passed param for your verifyorder function, and instead grab the content of your textfield by using document.getElementById(); then i convert the str into value with +order so you can check if it's greater than zero:

<input type="text" maxlength="3" name="value" id='value' />
<input type="button" value="submit" onclick="verifyorder()" />
<p id="error"></p>
<p id="detspace"></p> 

function verifyorder() {
        var order = document.getElementById('value').value;
        if (+order > 0) {
            return true;
        else {
            alert("Sorry, you need to enter a positive integer value, try again");
            document.getElementById('error').innerHTML = "Sorry, you need to enter a positive integer value, try again";

Check if a number is odd or even in python

It shouldn't matter if the word has an even or odd amount fo letters:

def is_palindrome(word):
    if word == word[::-1]:
        return True
        return False

E: Unable to locate package npm

This will resolve your error. Run these commands in your terminal. These commands will add the older versions. You can update them later or you can change version here too before running these commands one by one.

sudo apt-get install build-essential
tar -xzf node-v0.8.16.tar.gz
cd node-v0.8.16/
sudo make install

What are App Domains in Facebook Apps?

the app domain is your domain name.

Before you enter your domain, first click on Add Platform, select website, enter your site URL and mobile site url. Save the settings.

Thereafter, you can enter the domain name in the App domains field.

See more at my blog:

Pipe subprocess standard output to a variable

If you are using python 2.7 or later, the easiest way to do this is to use the subprocess.check_output() command. Here is an example:

output = subprocess.check_output('ls')

To also redirect stderr you can use the following:

output = subprocess.check_output('ls', stderr=subprocess.STDOUT)

In the case that you want to pass parameters to the command, you can either use a list or use invoke a shell and use a single string.

output = subprocess.check_output(['ls', '-a'])
output = subprocess.check_output('ls -a', shell=True)

Should jQuery's $(form).submit(); not trigger onSubmit within the form tag?

Sorry, misunderstood your question.

According to Javascript - capturing onsubmit when calling form.submit():

I was recently asked: "Why doesn't the form.onsubmit event get fired when I submit my form using javascript?"

The answer: Current browsers do not adhere to this part of the html specification. The event only fires when it is activated by a user - and does not fire when activated by code.

(emphasis added).

Note: "activated by a user" also includes hitting submit buttons (probably including default submit behaviour from the enter key but I haven't tried this). Nor, I believe, does it get triggered if you (with code) click a submit button.

Session variables not working php

Just talked to the hosting service, it was an issue at their end. he said " your account session.save_path was not set as a result issue arise. I set it for you now."

And it works fine after that :)