PHP replace delete string after '?'

Question

I have a login function where you submit data in a form on pageA and that data is send to pageB which then redirects you back to pageA with the error messages as a GET.

<?php 
// page B header code
  if(upload_fail) {
    header('Location: ' . $_SERVER['HTTP_REFERER'] . '?err=error_message');
  }
?>

This works fine if you fail the login once, but the second time you fail it appends the '?err=error_message' again, which results in the url being: test.domain/pageA?err=error_message?err=error_message.

so my question is how do I trim the HTTP_REFERER so it clears whatever previous GET it contains and then append the new GET?

Hopefully I've explained myself properly, if I need to clear things up pleas ask. Thanks in advance for your comments :D

Answer 1

<?php

function removeQuery($url, $port = false) {
    $portstring = $port ? ':'.parse_url($url)['port'] : '';
    return parse_url($url)['scheme'].'://'.parse_url($url)['host'] . $portstring . parse_url($url)['path'];
}

// call it like so removeQuery($_SERVER[HTTP_REFERER]);
// If you want the port to be included for instance  on a localhost
// call like so removeQuery($_SERVER[HTTP_REFERER], true);
?>

For anyone that is interested, here's my answer.

It gets the url and and returns only the core elements (Scheme, host, port[optional] and path).

input: http://localhost:8888/index.php?err=error_message

output: http://localhost:8888/index.php (if port is set to true)

I should probably check if each value is set (with isset), but for now it works.