[php] Beautiful way to remove GET-variables with PHP?

I have a string with a full URL including GET variables. Which is the best way to remove the GET variables? Is there a nice way to remove just one of them?

This is a code that works but is not very beautiful (I think):

$current_url = explode('?', $current_url);
echo $current_url[0];

The code above just removes all the GET variables. The URL is in my case generated from a CMS so I don't need any information about server variables.

How about:

preg_replace('/\\?.*/', '', $str)

just use echo'd javascript to rid the URL of any variables with a self-submitting, blank form:

    <?
    if (isset($_GET['your_var'])){
    //blah blah blah code
    echo "<script type='text/javascript'>unsetter();</script>"; 
    ?> 

Then make this javascript function:

    function unsetter() {
    $('<form id = "unset" name = "unset" METHOD="GET"><input type="submit"></form>').appendTo('body');
    $( "#unset" ).submit();
    }

Couldn't you use the server variables to do this?

Or would this work?:

unset($_GET['page']);
$url = $_SERVER['SCRIPT_NAME'] ."?".http_build_query($_GET);

Just a thought.

@list($url) = explode("?", $url, 2);

basename($_SERVER['REQUEST_URI']) returns everything after and including the '?',

In my code sometimes I need only sections, so separate it out so I can get the value of what I need on the fly. Not sure on the performance speed compared to other methods, but it's really useful for me.

$urlprotocol = 'http'; if ($_SERVER["HTTPS"] == "on") {$urlprotocol .= "s";} $urlprotocol .= "://";
$urldomain = $_SERVER["SERVER_NAME"];
$urluri = $_SERVER['REQUEST_URI'];
$urlvars = basename($urluri);
$urlpath = str_replace($urlvars,"",$urluri);

$urlfull = $urlprotocol . $urldomain . $urlpath . $urlvars;

You can use the server variables for this, for example $_SERVER['REQUEST_URI'], or even better: $_SERVER['PHP_SELF'].

If the URL that you are trying to remove the query string from is the current URL of the PHP script, you can use one of the previously mentioned methods. If you just have a string variable with a URL in it and you want to strip off everything past the '?' you can do:

$pos = strpos($url, "?");
$url = substr($url, 0, $pos);

How about a function to rewrite the query string by looping through the $_GET array

! Rough outline of a suitable function

function query_string_exclude($exclude, $subject = $_GET, $array_prefix=''){
   $query_params = array;
   foreach($subject as $key=>$var){
      if(!in_array($key,$exclude)){
         if(is_array($var)){ //recursive call into sub array
            $query_params[]  = query_string_exclude($exclude, $var, $array_prefix.'['.$key.']');
         }else{
            $query_params[] = (!empty($array_prefix)?$array_prefix.'['.$key.']':$key).'='.$var;
         }
      }
   }

   return implode('&',$query_params);
}

Something like this would be good to keep handy for pagination links etc.

<a href="?p=3&<?= query_string_exclude(array('p')) ?>" title="Click for page 3">Page 3</a>

Another solution... I find this function more elegant, it will also remove the trailing '?' if the key to remove is the only one in the query string.

/**
 * Remove a query string parameter from an URL.
 *
 * @param string $url
 * @param string $varname
 *
 * @return string
 */
function removeQueryStringParameter($url, $varname)
{
    $parsedUrl = parse_url($url);
    $query = array();

    if (isset($parsedUrl['query'])) {
        parse_str($parsedUrl['query'], $query);
        unset($query[$varname]);
    }

    $path = isset($parsedUrl['path']) ? $parsedUrl['path'] : '';
    $query = !empty($query) ? '?'. http_build_query($query) : '';

    return $parsedUrl['scheme']. '://'. $parsedUrl['host']. $path. $query;
}

Tests:

$urls = array(
    'http://www.example.com?test=test',
    'http://www.example.com?bar=foo&test=test2&foo2=dooh',
    'http://www.example.com',
    'http://www.example.com?foo=bar',
    'http://www.example.com/test/no-empty-path/?foo=bar&test=test5',
    'https://www.example.com/test/test.test?test=test6',
);

foreach ($urls as $url) {
    echo $url. '<br/>';
    echo removeQueryStringParameter($url, 'test'). '<br/><br/>';
}

Will output:

http://www.example.com?test=test
http://www.example.com

http://www.example.com?bar=foo&test=test2&foo2=dooh
http://www.example.com?bar=foo&foo2=dooh

http://www.example.com
http://www.example.com

http://www.example.com?foo=bar
http://www.example.com?foo=bar

http://www.example.com/test/no-empty-path/?foo=bar&test=test5
http://www.example.com/test/no-empty-path/?foo=bar

https://www.example.com/test/test.test?test=test6
https://www.example.com/test/test.test

» Run these tests on 3v4l

Inspired by the comment of @MitMaro, I wrote a small benchmark to test the speed of solutions of @Gumbo, @Matt Bridges and @justin the proposal in the question:

function teststrtok($number_of_tests){
    for($i = 0; $i < $number_of_tests; $i++){
      $str = "http://www.example.com?test=test";
      $str = strtok($str,'?');
    }
}
function testexplode($number_of_tests){
    for($i = 0; $i < $number_of_tests; $i++){
      $str = "http://www.example.com?test=test";
      $str = explode('?', $str);
    }
}
function testregexp($number_of_tests){
    for($i = 0; $i < $number_of_tests; $i++){
      $str = "http://www.example.com?test=test";
      preg_replace('/\\?.*/', '', $str);
    }
}
function teststrpos($number_of_tests){
    for($i = 0; $i < $number_of_tests; $i++){
      $str = "http://www.example.com?test=test";
      $qPos = strpos($str, "?");
      $url_without_query_string = substr($str, 0, $qPos);
    }
}

$number_of_runs = 10;
for($runs = 0; $runs < $number_of_runs; $runs++){

  $number_of_tests = 40000;
  $functions = array("strtok", "explode", "regexp", "strpos");
  foreach($functions as $func){
    $starttime = microtime(true);
    call_user_func("test".$func, $number_of_tests);
    echo $func.": ". sprintf("%0.2f",microtime(true) - $starttime).";";
  }
  echo "<br />";
}

strtok: 0.12;explode: 0.19;regexp: 0.31;strpos: 0.18;
strtok: 0.12;explode: 0.19;regexp: 0.31;strpos: 0.18;
strtok: 0.12;explode: 0.19;regexp: 0.31;strpos: 0.18;
strtok: 0.12;explode: 0.19;regexp: 0.31;strpos: 0.18;
strtok: 0.12;explode: 0.19;regexp: 0.31;strpos: 0.18;
strtok: 0.12;explode: 0.19;regexp: 0.31;strpos: 0.18;
strtok: 0.12;explode: 0.19;regexp: 0.31;strpos: 0.18;
strtok: 0.12;explode: 0.19;regexp: 0.31;strpos: 0.18;
strtok: 0.12;explode: 0.19;regexp: 0.31;strpos: 0.18;
strtok: 0.12;explode: 0.19;regexp: 0.31;strpos: 0.18;

Result: @justin's strtok is the fastest.

Note: tested on a local Debian Lenny system with Apache2 and PHP5.

In my opinion, the best way would be this:

<? if(isset($_GET['i'])){unset($_GET['i']); header('location:/');} ?>

It checks if there is an 'i' GET parameter, and removes it if there is.