TEC > Generate a UID for the event and add it to the iCal feed.

event-uid-to-ical-feed.php

<?php
/**
 * Description:  Generate a UID for the event and add it to the iCal feed.
 * Usage:        Paste the below snippet into your active (child) theme's functions.php file
 *               or use a plugin like Code Snippets.
 *
 * Plugins:      The Events Calendar
 * Author:       Andras Guseo
 * Last updated: 2024-07-22
 */

add_filter( 'tribe_ical_feed_item', 'my_custom_uid', 10, 2 );

/**
 * Add the UID of the event to the feed.
 *
 * @param array   $item       The event data currently being processed.
 * @param WP_Post $event_post The event object.
 *
 * @throws \Random\RandomException
 * @return array The modified event data.
 */
function my_custom_uid( $item, $event_post ) {
	$post_id = $event_post->ID;

	$post_uid = get_post_meta( $post_id, '_eventUID', true );

	// If there is no UID, generate one, save it with the post and use it in the feed.
	if ( ! $post_uid ) {
		$post_uid = generate_uid();
		while ( check_if_uid_exists( $post_uid ) ) {
			$post_uid = generate_uid();
		}

		// Save it with the post.
		add_post_meta( $post_id, '_eventUID', $post_uid, true );
	}

	$item['UID'] = 'UID:' . $post_uid;

	return $item;
}

/**
 * Generate a UID like 5FC53010-1267-4F8E-BC28-1D7AE55A7C99
 *
 * @throws \Random\RandomException
 * @return string
 */
function generate_uid() {
	try {
		// Generate 16 bytes (128 bits) of random data
		$data = random_bytes( 16 );
	}
	catch ( Exception $e ) {
		// Log the exception message or handle it in some way
		error_log( 'Failed to generate random bytes: ' . $e->getMessage() );

		// Rethrow the exception
		throw $e;
	}

	// Set the version to 4 (random UUID).
	$data[6] = chr( ord( $data[6] ) & 0x0f | 0x40 );

	// Set the variant to RFC 4122
	$data[8] = chr( ord( $data[8] ) & 0x3f | 0x80 );

	// Convert the binary data into hexadecimal representation.
	$hex = bin2hex( $data );

	// Format the hex into the UUID format: 8-4-4-4-12.
	$uuid = sprintf( '%s-%s-%s-%s-%s',
		substr( $hex, 0, 8 ),
		substr( $hex, 8, 4 ),
		substr( $hex, 12, 4 ),
		substr( $hex, 16, 4 ),
		substr( $hex, 20, 12 )
	);

	return strtoupper( $uuid );
}

/**
 * Check if UID exists.
 *
 * @param string $uid The UID of the event.
 *
 * @return bool True if post with UID exists.
 */
function check_if_uid_exists( $uid ) {
	$args = [
		'meta_key'    => '_eventUID',
		'meta_value'  => $uid,
		'post_type'   => 'tribe_events',
		'fields'      => 'ids',
		'numberposts' => 1,
	];

	$posts = get_posts( $args );

	return ! empty( $posts );
}