Custom event page not keep event ID when click on Review button

Question

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_rewrite_rule(
        '^event/(\d+)/?$',
        'index.php?pagename=event&event_id=$matches[1]',
        'top'
    );
});

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?

Answer 1

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

Answer 2

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.