I am trying to intercept the GET request of a post and add a value to it.

function foo($request) {
    $request['vid'] = wp_generate_uuid4();

    return $request;
add_filter( 'request', 'foo' );

and hope that it would be available later with


but no access so far any ideas?

  • WordPress doesn't add vid to the $_REQUEST array. Use get_query_var( 'vid' ) to access the vid value.. – Sally CJ May 15 at 13:10
  • @SallyCJ 10x man it works. Put in an answer I will accept it – Bat Man May 15 at 13:20
  • Done, @BatMan.. – Sally CJ May 15 at 13:40

WordPress doesn't add the vid to the $_REQUEST array. Instead, it's saved in a class property — see WP::$query_vars which is an array.

And to access the value of items in that array, use get_query_var() like so in your case:

$vid = get_query_var( 'vid' );
echo "vid value is $vid";
  • Is it possible if 2 requests happen almost simultaneously that the second one overrides the value returned by get_query_var( 'vid' ) if using it in functions.php when serving a post ? – Bat Man May 16 at 13:25
  • I don't really understand your question, but plugins, themes and custom code can change the value at anytime during the same page load/request. E.g. Using set_query_var( 'vid', 'value' ). – Sally CJ May 16 at 17:56
  • Ok Can second page load/request change it for the first being in process for it should trigger the same filter hook? Or they stack 1 after another? – Bat Man May 17 at 11:13
  • 1
    They stack 1 after another - you get a fresh value on each page load because the data is persistent in the same request only. – Sally CJ May 17 at 19:03

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