I am building a PHP application in CodeIgniter. CodeIgniter sends all requests to the main controller: index.php. However, I don't like to see index.php in the URI. For example, http://www.example.com/faq/whatever will route to http://www.example.com/index.php/faq/whatever. I need a reliable way for a script to know what it's address is, so it will know what to do with the navigation. I've used mod_rewrite, as per CodeIgniter documentation.
The rule is as follows:
RewriteEngine on
RewriteCond $1 !^(images|inc|favicon\.ico|index\.php|robots\.txt)
RewriteRule ^(.*)$ /index.php/$1 [L]
Normally, I would just check php_self, but in this case it's always index.php. I can get it from REQUEST_URI, PATH_INFO, etc., but I'm trying to decide which will be most reliable. Does anyone know (or know where to find) the real difference between PHP_SELF, PATH_INFO, SCRIPT_NAME, and REQUEST_URI? Thanks for your help!
Note: I've had to add spaces, as SO sees the underscore, and makes it italic for some reason.
Updated: Fixed the spaces.
The PHP documentation can tell you the difference:
'PHP_SELF'
The filename of the currently executing script, relative to the document root. For instance, $_SERVER['PHP_SELF'] in a script at the address http://example.com/test.php/foo.bar would be /test.php/foo.bar. The __FILE__ constant contains the full path and filename of the current (i.e. included) file. If PHP is running as a command-line processor this variable contains the script name since PHP 4.3.0. Previously it was not available.
'SCRIPT_NAME'
Contains the current script's path. This is useful for pages which need to point to themselves. The __FILE__ constant contains the full path and filename of the current (i.e. included) file.
'REQUEST_URI'
The URI which was given in order to access this page; for instance, '/index.html'.
PATH_INFO doesn't seem to be documented...
Some practical examples of the differences between these variables:
Example 1.
PHP_SELF is different from SCRIPT_NAME only when requested url is in form:
http://example.com/test.php/foo/bar
[PHP_SELF] => /test.php/foo/bar
[SCRIPT_NAME] => /test.php
(this seems to be the only case when PATH_INFO contains sensible information [PATH_INFO] => /foo/bar) Note: this used to be different in some older PHP versions (<= 5.0 ?).
Example 2.
REQUEST_URI is different from SCRIPT_NAME when a non-empty query string is entered:
http://example.com/test.php?foo=bar
[SCRIPT_NAME] => /test.php
[REQUEST_URI] => /test.php?foo=bar
Example 3. REQUEST_URI is different from SCRIPT_NAME when server-side redirecton is in effect (for example mod_rewrite on apache):
[REQUEST_URI] => /test.php
[SCRIPT_NAME] => /test2.php
Example 4.
REQUEST_URI is different from SCRIPT_NAME when handling HTTP errors with scripts.
Using apache directive ErrorDocument 404 /404error.php
http://example.com/test.php
[REQUEST_URI] => /test.php
[SCRIPT_NAME] => /404error.php
On IIS server using custom error pages
http://example.com/test.php
[SCRIPT_NAME] => /404error.php
[REQUEST_URI] => /404error.php?404;http://example.com/test.php