Determine base URL of PHP app

Question

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?

• pppp: Can you provide an example of how this works?

Answer 1

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('/', $_SERVER['SCRIPT_NAME']);
array_pop($request);
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.

• Conor Mancone: Both the OP example and your example will cause a notice in a command line environment, where $_SERVER['SERVER_NAME'] is undefined.
• Edcel Celiz: Yes, $_SERVER is not available in CLI because no web server is present.