How to programmatically determine the document root in PHP?

Question

Here\'s a problem that I\'ve been running into lately - a misconfigured apache on a webhost. This means that all scripts that rely on $_SERVER[\'DOCUMENT_ROOT\']

Answer 1

This is one reason why people siphon everything through a bootstrap /index.php using htaccess and/or query strings. You can use the dirname( __FILE__ ) trick noted above and get the public base of your app that way.

If you're too far into it to switch to a single entry point, one thing I've seen people do is have a common header to their script which walks up the directory tree to find a file which is unique to the base dir:

function findAppBase( $dir ) {
    if( file_exists( "$dir/unique_file.txt" ) ) {
        return $dir;

    return findAppBase( dirname( $dir ) );
}

$base = findAppBase( dirname( __FILE__ ) );

That code hasn't been tested, and there might be a slicker way using the vars in $_ENV or $_SERVER that will do what you want...