/**
 * @title            Check if Apache's mod_rewrite is installed.
 * 
 * @author           Pierre-Henry Soria <[email protected]>
 * @copyright        (c) 2013, Pierre-Henry Soria. All Rights Reserved.
 * @return           boolean
 */
function isRewriteMod()
{
    if (function_exists('apache_get_modules'))
    {
        $aMods = apache_get_modules();
        $bIsRewrite = in_array('mod_rewrite', $aMods);
    }
    else
    {
        $bIsRewrite = (strtolower(getenv('HTTP_MOD_REWRITE')) == 'on');
    }

    return $bIsRewrite;
}

*Example:* 
        
       if (!isRewriteMod()) exit('Please install Apache mod_rewrite module.');

Check if Apache's mod_rewrite is installed.

server, apache, module, extension

PHP