MT | ETP | Ties into the Zxing Barcode Scanner app for iOS and Android, allowing one-click scans

tribe_qr_scan_link.php

<?php

/*
 * This adds a fancy one-click scan QR link tie-in to the native zxing Barcode scanner app
 * Android: https://play.google.com/store/apps/details?id=com.google.zxing.client.android&hl=en
 * iOS: https://itunes.apple.com/us/app/barcodes-scanner/id417257150?mt=8
 */
function tribe_qr_scan_link_notice () {
	if ( isset($_GET['page']) && $_GET['page'] === 'tickets-attendees' ) {
		$qr_url = urlencode( site_url().'?event_qr_code={CODE}' );

		echo '<div class="updated" style="border:none;padding:0;background:transparent;box-shadow:none;"><p>';
		echo '<a href="zxing://scan/?ret=' . $qr_url . '" class="button button-primary button-large" style="width:100%;text-align:center;" id="qr-scan-link">Scan a QR Code</a>';
		echo '</p></div>';
	}
}
add_filter( 'admin_notices', 'tribe_qr_scan_link_notice', 100 );

/*
 * This handles the QR submitted data
 */
function tribe_handle_qr_redirects() {

	if ( ! class_exists('Tribe__Tickets_Plus__Main') ) return;

	// Returns a valid URL or an empty string
	$url = isset( $_GET['event_qr_code'] ) ? esc_url( $_GET['event_qr_code'] ) : '';

	// the following code is mostly copied  from the Tribe__Tickets_Plus__QR
	// Had to be copied to avoid private methods :(
	if ( ! empty( $url )  && is_user_logged_in() && current_user_can( 'edit_posts' )) {

		$url_components = parse_url( htmlspecialchars_decode ( $url ) );
		parse_str( $url_components['query'], $query );

		// Check if it's our time to shine.
		// Not as fancy as a custom permalink handler, but way less likely to fail depending on setup and settings
		if ( ! isset( $query['event_qr_code'] ) ) {
			return;
		}

		// Check all the data we need is there
		if ( empty( $query['ticket_id'] ) || empty( $query['event_id'] ) ) {
			return;
		}

		// If the user is the site owner (or similar), Check in the user to the event
		if ( is_user_logged_in() && current_user_can( 'edit_posts' ) ) {

			$modules = Tribe__Tickets__Tickets::modules();

			foreach ( $modules as $class => $module ) {
				if ( ! is_callable( array( $class, 'get_instance' ) ) ) {
					continue;
				}
				$obj = call_user_func( array( $class, 'get_instance' ) );
				$obj->checkin( $query['ticket_id'] );
			}

			$post = get_post( $query['event_id'] );

			if ( empty( $post ) ) {
				return;
			}

			$url = add_query_arg( array(
				'post_type'     => $post->post_type,
				'page'          => Tribe__Tickets__Tickets_Handler::$attendees_slug,
				'event_id'      => $query['event_id'],
				'qr_checked_in' => $query['ticket_id'],
			), admin_url( 'edit.php' ) );
		} else { // Probably just the ticket holder, redirect to the event front end single
			$url = get_permalink( $query['event_id'] );
		}

		wp_redirect( $url );
		exit;
	}
}
add_filter( 'init', 'tribe_handle_qr_redirects', 10 );