Eventonomy

Recipe: Custom RSVP Field

Goal: Add a custom field to the RSVP form, persist the submitted value against the RSVP record using the Meta API, and expose it in the attendee admin table.

Seams Used

Seam Type Purpose
evnm_register_meta Action Register the meta key with type + sanitizer so it is typed and REST-accessible.
evnm_registration_fields Filter Add the field definition to the RSVP form.
evnm_after_create_rsvp Action Persist the submitted value from the REST payload.
evnm_get_meta / evnm_update_meta Functions Read/write against evnm_meta (public Meta API).

The Code

<?php
// my-addon/my-addon.php

// 1. Register the meta key so it is typed and optionally REST-exposed.
add_action( 'evnm_register_meta', function () {
    evnm_register_meta( 'rsvp', 'tshirt_size', [
        'type'              => 'string',
        'sanitize_callback' => 'sanitize_text_field',
        'show_in_rest'      => true,   // surfaced in GET /rsvps/{id} responses
    ] );
} );

// 2. Add the field to the RSVP form.
add_filter( 'evnm_registration_fields', function ( array $fields, array $event ): array {
    $fields[] = [
        'id'       => 'tshirt_size',
        'label'    => __( 'T-shirt size', 'my-addon' ),
        'type'     => 'select',
        'options'  => [ 'XS', 'S', 'M', 'L', 'XL', 'XXL' ],
        'required' => false,
    ];
    return $fields;
}, 10, 2 );

// 3. Persist the submitted value after the RSVP is created.
//    $rsvp['meta'] is populated by Free from the REST payload for registered fields.
add_action( 'evnm_after_create_rsvp', function ( array $rsvp, array $context ) {
    $size = isset( $rsvp['meta']['tshirt_size'] )
        ? sanitize_text_field( (string) $rsvp['meta']['tshirt_size'] )
        : '';

    if ( '' !== $size ) {
        evnm_update_meta( 'rsvp', $rsvp['id'], 'tshirt_size', $size );
    }
}, 10, 2 );

// 4. (Optional) Show the value in the attendee list via the REST prepare filter.
add_filter( 'evnm_rest_prepare_rsvp', function ( array $data, array $rsvp, $request ): array {
    $data['tshirt_size'] = evnm_get_meta( 'rsvp', $rsvp['id'], 'tshirt_size', '' );
    return $data;
}, 10, 3 );

Supported Field Types

The evnm_registration_fields filter accepts these type values, which the block renders as native form controls:

Type Renders as
text <input type="text">
textarea <textarea>
select <select> with options array
checkbox <input type="checkbox">

Verify It Worked

  1. Visit a published event's single-event page.
  2. Submit an RSVP - the T-shirt size field should appear in the form.
  3. After submission, run in WP-CLI:
    wp eval 'echo evnm_get_meta("rsvp", RSVP_ID, "tshirt_size");'
  4. Confirm the selected size is returned.
  5. Check GET /wp-json/eventonomy/v1/events/{id}/rsvps - each RSVP object should include tshirt_size if show_in_rest: true was set.

Related