I am trying to find out if I can make event tickets (plus) to work so that it is possible to rsvp 1 ticket per registered user.
So far I’ve updated the rsvp.php template so that the attendee info is hidden and automatically filled with the current user’s data (name and email).
I would like to include a check such ad user_has_rsvp() or fetch a list of the user’s ticket. If a user already has a ticket I want to hide the RSVP button and show a message such as ‘You have an RSVP for this event”.
There is a function count_rsvp_attendees( $event_id, $user_id = null ) which might be able to help you. It is defined in the wp-content\plugins\event-tickets\src\Tribe\Tickets-View.php file (line 547).
As an example it is implemented in wp-content\plugins\event-tickets\src\views\tickets\order-links.php.