Is there an inbuilt way in PHP to parse a string like this: '/path/to/../../up/something.txt'

Question

So say I have a string like so of a path

$path = '/path/to/../../up/something.txt';

Is there a way built into PHP to parse it and come up with a URL without the directory ups (../) ?

E.g.

$path = parsePath('/path/to/../../up/something.txt'); // /up/something.txt

Answer 1

realpath($path);

Docs

Answer 2

PHP's realpath() is cool, but what if you want to figure it out without accessing the filesystem?

I've written this function that can return a path with ../ and the like calculated to a real path.

It probably doesn't handle all path commands, so let me know if you think I should implement another.

public function resolvePath($path) {

    while (strstr($path, '../')) {
        $path = preg_replace('/\w+\/\.\.\//', '', $path);
    }

    return $path;

}

The regex I borrowed from this user contributed note.