Question

I have a piece of PHP software that does beautifull things with mod_rewrite. But the same software should run on a server where mod_rewrite isn’t installed. Can I check in my php code if mod_rewrite is installed AND if a certain rule is applied?

For example, something like this:

    if ((mod_rewrite is enabled) and (mod_rewrite_rule is OK)){
        return  createBeautifullLink();
    }else{
        return createUglyLink();
    }

Thanks in advance

Answer 1

use this:

in .htaccess

<IfModule mod_rewrite.c>
   # inform php that mod_rewrite is enabled
   SetEnv HTTP_MOD_REWRITE on
   ...

in PHP:

$mod_rewrite = FALSE;
if (function_exists("apache_get_modules")) {
   $modules = apache_get_modules();
   $mod_rewrite = in_array("mod_rewrite",$modules);
}
if (!isset($mod_rewrite) && isset($_SERVER["HTTP_MOD_REWRITE"])) {
   $mod_rewrite = ($_SERVER["HTTP_MOD_REWRITE"]=="on" ? TRUE : FALSE); 
}
if (!isset($mod_rewrite)) {
   // last solution; call a specific page as "mod-rewrite" have been enabled; based on result, we decide.
   $result = file_get_contents("http://somepage.com/test_mod_rewrite");
   $mod_rewrite  = ($result=="ok" ? TRUE : FALSE);
}

The first (apache) can be disabled by server, the second custom one will exist in $_SERVER only if mod_env is installed.
So what i think as best solution is to create a fake url redirection in your .htaccess that points to some file of yours (that return simply an “ok”) and call that with the redirection from a .php; if returns “ok”, you can use clean urls…
The redirection code in .htaccess might looks like:

<IfModule mod_rewrite.c>
   ...
   RewriteEngine on
   # fake rule to verify if mod rewriting works (if there are unbearable restrictions..)
   RewriteRule ^test_mod_rewrite/?$    index.php?type=test_mod_rewrite [NC,L]