Apache rewrite rule .htaccess
Rewrite van http://www.123helpdesk.nl/file/ naar http://www.123helpdesk.nl/file.php

RewriteCond %{REQUEST_URI} !\.
RewriteRule ^(.*)$ $1.php [L]

Uitleg:
accent circonflexe; The caret, ^, betekent het begin van de URL
dollar teken, $, betekent het einde van de te vergelijken string
RewriteCond

The RewriteCond directive defines a rule condition. Preserve a RewriteRule with one or more RewriteCond directives. The following rewriting rule is only used if its pattern matches the current state of the URI and if these additional conditions apply too.

You can set special flags for condition pattern by appending a third argument to the RewriteCond directive. Flags is a comma-separated list of the following flags:

[NC] (No Case)
This makes the condition pattern case insensitive, no difference between 'A-Z' and 'a-z'.

[OR] (OR next condition)
Used to combinate rule conditions with a OR.

RewriteRule

The RewriteRule directive is the real rewriting.

You can set special flags for condition pattern by appending a third argument to the RewriteCond directive. Flags is a comma-separated list of the following flags:

[R] (force Redirect)
Redirect the URL to a external redirection. Send the HTTP response, 302 (MOVED TEMPORARILY).

[F] (force URL to be Forbidden)
Forces the current URL to be forbidden. Send the HTTP response, 403 (FORBIDDEN).

[G] (force URL to be Gone)
Forces the current URL to be gone. Send the HTTP response, 410 (GONE).

[L] (last rule)
Forces the rewriting processing to stop here and don't apply any more rewriting rules.

[P] (force proxy)
This flag forces the current URL as a proxy request and put through the proxy module mod_proxy.
Regular expressions

Some hints about the syntax of regular expressions:

Text:
  . Any single character
  [chars] One  of chars
  [^chars] None of chars
  text1|text2 text1 or text2
Quantifiers:
  ? 0 or 1 of the preceding text
  * 0 or N of the preceding text (N > 0)
  + 1 or N of the preceding text (N > 1)
Grouping:
  (text) Grouping of text
Anchors:
  ^ Start of line anchor
  $ End of line anchor
Escaping:
  \ char escape that particular char

Condition pattern

There are some special variants of CondPatterns. Instead of real regular expression strings you can also use one of the following:

< Condition (is lower than Condition)
Treats the Condition as a string and compares it to String. True if String is lower than Condition.

> Condition (is greater than Condition)
Treats the Condition as a string and compares it to String. True if String is greater than CondPattern.

= Condition (is equal to Condition)
Treats the Condition as a string and compares it to String. True if String is equal to CondPattern.

-d (is directory)
Treats the String as a pathname and tests if it exists and is a directory.

-f (is regular file)
Treats the String as a pathname and tests if it exists and is a regular file.

-s (is regular file with size)
Treats the String as a pathname and tests if it exists and is a regular file with size greater than zero.

-l (is symbolic link)
Treats the String as a pathname and tests if it exists and is a symbolic link.

-F (is existing file via sub request)
Checks if String is a valid file and accessible via all the server's currently configured access controls for that path. Use it with care because it decreases your servers performance!

-U (is existing URL via sub request)
Checks if String is a valid URL and accessible via all the server's currently configured access controls for that path. Use it with care because it decreases your servers performance!

NOTE: You can prefix the pattern string with a '!' character (exclamation mark) to specify a non-matching pattern.

VOORBEELDEN/ EXAMPLES:

Redirect visitor by domain name

DESCRIPTION: In some cases the same web site is accessible by different addresses, like domain.com, www.domain.com, www.domain2.com and we want to redirect it to one address.

RewriteEngine On
RewriteCond %{HTTP_HOST} !^www.domain.com$ [N
RewriteRule ^(.*)$ http://www.domain.com/$1 [R,L]

EXPLAIN: In this case the requested URL http://domain.com/foo.html would redirected to the URL http://www.domain.com/foo.html.


Redirect domains to other directory
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www.domain.com$
RewriteCond %{REQUEST_URI} !^/HTML2/
RewriteRule ^(.*)$ /HTML2/$1

Protecting your images and files from linking

DESCRIPTION: In some cases other webmasters are linking to your download files or using images, hosted on your server as inline-images on their pages.

RewriteEngine On
RewriteCond %{HTTP_REFERER} !^$ [NC]
RewriteCond %{HTTP_REFERER} !^http://domain.com [NC]
RewriteCond %{HTTP_REFERER} !^http://www.domain.com [NC]
RewriteCond %{HTTP_REFERER} !^http://xxx.xxx.xxx.xxx [NC]
RewriteRule ^.*$ http://www.domain.com/ [R,L]

EXPLAIN: In this case are the visitors redirect to http://www.domain.com/ if the hyperlink has not arrived from http://domain.com, http://www.domain.com or http://xxx.xxx.xxx.xxx


Redirect visitor by user agent

DESCRIPTION: For important top level pages it is sometimes necesarry to provide pages dependend on the browser. One has to provide a version for the latest Netscape, a version for the latest Internet Explorer, a version for the Lynx or old browsers and a average feature version for all others.

# MS Internet Explorer - Mozilla v4
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} ^Mozilla/4(.*)MSIE
RewriteRule ^index\.html$ /index.IE.html [L]

# Netscape v6.+ - Mozilla v5
RewriteCond %{HTTP_USER_AGENT} ^Mozilla/5(.*)Gecko
RewriteRule ^index\.html$ /index.NS5.html [L]

# Lynx or Mozilla v1/2
RewriteCond %{HTTP_USER_AGENT} ^Lynx/ [OR]
RewriteCond %{HTTP_USER_AGENT} ^Mozilla/[12]
RewriteRule ^index\.html$ /index.20.html [L]

# All other browsers
RewriteRule ^index\.html$ /index.32.html [L]

EXPLAIN: In this case we have to act on the HTTP header User-Agent. If the User-Agent begins with Mozilla/4 and is MS Internet Explorer (MSIE), the page index.html is rewritten to index.IE.html and the rewriting stops. If the User-Agent begins with Mozilla/5 and is Netscape (Gecko), the page index.html is rewritten to index.NS5.html. If the User-Agent begins with Lynx/ or Mozilla/1,2, the page index.html is rewritten to index.20.html. All other browsers receive page index.32.html