I have this little piece of code which determines the base URL of PHP:

$root = $_SERVER["SERVER_NAME"];
if(basename(__FILE__) !== trim($_SERVER["PHP_SELF"], "/\\")) {
    $root .= "/" . basename(__DIR__);

This is working for me, but are there other solutions for this "problem," or are there any cases where this would fail?

  • \$\begingroup\$ Can you provide an example of how this works? \$\endgroup\$ – pppp Sep 6 '16 at 8:54

Your code will work for one level deep working directories such as:

  1. servername/admin/index.php
  2. servername/sample/test.php

However, go one level deeper and it will not work. If I have servername/one/two/index.php, I will get a servername/two. It is because the basename() returns the working folder of the file.

I find this code useful for common applications:

$request = explode('/', $_SERVER['SCRIPT_NAME']);
echo $_SERVER['SERVER_NAME'] . implode('/', $request);

It makes use of server's script name. Given the sample servername/one/two/index.php, it will return /one/two/index.php. We then remove the script from the directory using explode and popping the result, and then finally concatenating it to the server name.

  • \$\begingroup\$ Both the OP example and your example will cause a notice in a command line environment, where $_SERVER['SERVER_NAME'] is undefined. \$\endgroup\$ – Conor Mancone Sep 14 '17 at 19:12
  • \$\begingroup\$ Yes, $_SERVER is not available in CLI because no web server is present. \$\endgroup\$ – Edcel Celiz Sep 16 '17 at 1:46

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