Wordpress - Get Permalink without domain (i.e. get relative permalink)

I use

str_replace(home_url(), '', get_permalink()); 

If site root is not /

Use $_SERVER['REQUEST_URI'] instead of get_permalink() to grab the current URL. get_permalink will give you the full address of the current post, not the address of the URL visited.

e.g. for example.com/test/page echo $_SERVER['REQUEST_URI']; prints /test/page

Note that this doesn't include the hashtag, as that part never gets sent to the server, and it also doesn't include ?foo=bar type parameters, those are in the $_GET array.

This works for me:

function force_relative_url ($url)
{
    return preg_replace ('/^(http)?s?:?\/\/[^\/]*(\/?.*)$/i', '$2', '' . $url);
}

To use it on a permalink:

$relative_permalink = force_relative_url (get_permalink ($post->ID));