Question

In php I’m adding an extra URL segment ?sort to sort posts by ascending or descending.

    <?php
    //get current URL
    $url = "http://" . $_SERVER['HTTP_HOST']  . $_SERVER['REQUEST_URI'];

    //filter URL and create sorting links
    if(filter_var($url, FILTER_VALIDATE_URL))
    { ?>         
      <a href="<?php echo $url; ?>?sort=asc">Small</a>
      <a href="<?php echo $url; ?>?sort=desc">Large</a>
    <?php } ?>

The problem: every time I click a link the url segment repeats in the URL.

Example: http://mysite.com/another_segment/?sort=asc?sort=asc?sort=asc

To disallow repetition, how I replace the URL segment whenever I click one of the two sorting link? I don’t need to separate parameters with & symbols. I’m expecting just one delimiter. I’m using it in a pagination script so the parameter needs to stay in the URL when I browse pages.

I’m trying to avoid javascript as well

Answer 1

You should use the following function to remove the “sort” key in the existing URL and then append.

function remove_querystring_var($url, $key) { 
  $url = preg_replace('/(.*)(?|&)' . $key . '=[^&]+?(&)(.*)/i', '$1$2$4', $url . '&'); 
  $url = substr($url, 0, -1); 
  return $url; 
}

Your code should modify this way

   <?php
    //get current URL
    $url = "http://" . $_SERVER['HTTP_HOST']  . $_SERVER['REQUEST_URI'];
     $url = remove_querystring_var($url, "sort");
    //filter URL and create sorting links
    if(filter_var($url, FILTER_VALIDATE_URL))
    { ?>         
      <a href="<?php echo $url; ?>?sort=asc">Small</a>
      <a href="<?php echo $url; ?>?sort=desc">Large</a>
    <?php } ?>