I have a page called event and set the bellow rewrite rule to store the event ID in the URL:

add_action('init', function () {

add_filter('query_vars', function ($vars) {
    $vars[] = 'event_id';
    return $vars;

e.g. mysite.com/event/37/

Works fine until user clicks on Review button and CiviCRM removes the id from URL:

e.g. mysite.com/event/?civiwp=CiviCRM&q=civicrm%2Fevent%2Fregister&_qf_Register_display=true&qfKey=CRMEventControllerRegistration...

Is there a way to keep the ID or get the event ID using other solution?

  • Depends upon how you using it. Are you using Civi hooks or wp hooks? Commented Nov 14, 2023 at 15:18
  • @PradeepNayak You mean to render the event form? I'm using shortcode and set the Shortcode Display Mode to "Remain in Shortcode Mode". Commented Nov 14, 2023 at 15:20
  • any reason you want to retain the id? What you trying to achieve by adding id in the URL? Commented Nov 14, 2023 at 15:46
  • @PradeepNayak the layout of the event page is very customized. I need the event ID to get things like the event title. Commented Nov 14, 2023 at 15:49
  • Have you tried civicrm hooks to alter the pages? like buildForm or preProcess Commented Nov 14, 2023 at 15:56

2 Answers 2


I would suggest using CiviCRM buildForm or preProcess hook to alter the event registration pages

  • I'm using civicrm_buildForm to add a hidden field with the event id and I'm able to get this value using $_POST when user click on Review button. However, I'm not able to do the same when user click on Go Back button. Commented Nov 14, 2023 at 16:05
  • you can use $form->getVar('_id'); to get the event id, if you want to store that id somewhere so that you can access it in any function you can use Civi::$statics['myCustomPluginName']['eventId'] = $form->getVar('_id'); Commented Nov 14, 2023 at 16:32
  • I'm using civicrm_buildForm to store the event form ID, but it seems like the trigger fires too late and I can't use it inside a WordPress template. Commented Nov 14, 2023 at 17:42

My solution for this issue was to use the filter page_link, called (indirectly) by get_permalink function. This way, the URL used on form action attribute is correct.

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