refactoring

docs/add_your_event_plugin.md

@@ -28,10 +28,10 @@ First you need to add some basic information about your event plugin. Just creat
   final class My_Event_Plugin extends Event_Plugin {
 ```
 
-Then you need to tell the Event Bridge for ActivityPub about that class by adding it to the `EVENT_PLUGIN_CLASSES` constant in the `includes/setup.php` file:
+Then you need to tell the Event Bridge for ActivityPub about that class by adding it to the `EVENT_PLUGIN_INTEGRATIONS` constant in the `includes/setup.php` file:
 
 ```php
-	private const EVENT_PLUGIN_CLASSES = array(
+	private const EVENT_PLUGIN_INTEGRATIONS = array(
 		...
 		'\Event_Bridge_For_ActivityPub\Integrations\My_Event_Plugin',
 	);

includes/activitypub/collection/class-event-sources.php

@@ -31,6 +31,7 @@ class Event_Sources {
 	 */
 	public static function init() {
 		self::register_post_type();
+		\add_filter( 'allowed_redirect_hosts', array( self::class, 'add_event_sources_hosts_to_allowed_redirect_hosts' ) );
 		\add_action( 'event_bridge_for_activitypub_follow', array( self::class, 'activitypub_follow_actor' ), 10, 1 );
 		\add_action( 'event_bridge_for_activitypub_unfollow', array( self::class, 'activitypub_unfollow_actor' ), 10, 1 );
 	}

includes/activitypub/handler/class-update.php

@@ -50,13 +50,12 @@ class Update {
 			return;
 		}
 
-		$transmogrifier_class = Setup::get_transmogrifier();
+		$transmogrifier = Setup::get_transmogrifier();
 
-		if ( ! $transmogrifier_class ) {
+		if ( ! $transmogrifier ) {
 			return;
 		}
 
-		$transmogrifier = new $transmogrifier_class( $activity['object'] );
+		$transmogrifier->save( $activity['object'] );
-		$transmogrifier->save();
 	}
 }

includes/activitypub/transmogrifier/class-base.php

@@ -0,0 +1,339 @@
+<?php
+/**
+ * Base class with common functions for transforming an ActivityPub Event object to a WordPress object.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @since 1.0.0
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub\Activitypub\Transmogrifier;
+
+use Activitypub\Activity\Extended_Object\Event;
+use DateTime;
+use Exception;
+use WP_Error;
+
+use function Activitypub\sanitize_url;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+/**
+ * Base class with common functions for transforming an ActivityPub Event object to a WordPress object.
+ *
+ * @since 1.0.0
+ */
+abstract class Base {
+	/**
+	 * The current GatherPress Event object.
+	 *
+	 * @var Event
+	 */
+	protected $activitypub_event;
+
+	/**
+	 * Internal function to actually save the event.
+	 */
+	abstract protected function save_event();
+
+	/**
+	 * Save the ActivityPub event object as GatherPress Event.
+	 *
+	 * @param array $activitypub_event The ActivityPub event as associative array.
+	 */
+	public function save( $activitypub_event ) {
+		$activitypub_event = Event::init_from_array( $activitypub_event );
+
+		if ( is_wp_error( $activitypub_event ) ) {
+			return;
+		}
+
+		$this->activitypub_event = $activitypub_event;
+		$this->save_event();
+	}
+
+	/**
+	 * Get post.
+	 */
+	protected function get_post_id_from_activitypub_id() {
+		global $wpdb;
+		return $wpdb->get_var(
+			$wpdb->prepare(
+				"SELECT ID FROM $wpdb->posts WHERE guid=%s",
+				esc_sql( $this->activitypub_event->get_id() )
+			)
+		);
+	}
+
+	/**
+	 * Validate a time string if it is according to the ActivityPub specification.
+	 *
+	 * @param string $time_string The time string.
+	 * @return bool
+	 */
+	public static function is_valid_activitypub_time_string( $time_string ) {
+		// Try to create a DateTime object from the input string.
+		try {
+			$date = new DateTime( $time_string );
+		} catch ( Exception $e ) {
+			// If parsing fails, it's not valid.
+			return false;
+		}
+
+		// Ensure the timezone is correctly formatted (e.g., 'Z' or a valid offset).
+		$timezone           = $date->getTimezone();
+		$formatted_timezone = $timezone->getName();
+
+		// Return true only if the time string includes 'Z' or a valid timezone offset.
+		$valid = 'Z' === $formatted_timezone || preg_match( '/^[+-]\d{2}:\d{2}$/ ', $formatted_timezone );
+		return $valid;
+	}
+
+	/**
+	 * Get the image URL and alt-text of an ActivityPub object.
+	 *
+	 * @param array $data The ActivityPub object as ann associative array.
+	 * @return ?array Array containing the images URL and alt-text.
+	 */
+	private static function extract_image_alt_and_url( $data ) {
+		$image = array(
+			'url' => null,
+			'alt' => null,
+		);
+
+		// Check whether it is already simple.
+		if ( ! $data || is_string( $data ) ) {
+			$image['url'] = $data;
+			return $image;
+		}
+
+		if ( ! isset( $data['type'] ) ) {
+			return $image;
+		}
+
+		if ( ! in_array( $data['type'], array( 'Document', 'Image' ), true ) ) {
+			return $image;
+		}
+
+		if ( isset( $data['url'] ) ) {
+			$image['url'] = $data['url'];
+		} elseif ( isset( $data['id'] ) ) {
+			$image['id'] = $data['id'];
+		}
+
+		if ( isset( $data['name'] ) ) {
+			$image['alt'] = $data['name'];
+		}
+
+		return $image;
+	}
+
+	/**
+	 * Returns the URL of the featured image.
+	 *
+	 * @return array
+	 */
+	protected function get_featured_image() {
+		$event = $this->activitypub_event;
+		$image = $event->get_image();
+		if ( $image ) {
+			return self::extract_image_alt_and_url( $image );
+		}
+		$attachment = $event->get_attachment();
+		if ( is_array( $attachment ) && ! empty( $attachment ) ) {
+			$supported_types = array( 'Image', 'Document' );
+			$match           = null;
+
+			foreach ( $attachment as $item ) {
+				if ( in_array( $item['type'], $supported_types, true ) ) {
+					$match = $item;
+					break;
+				}
+			}
+			$attachment = $match;
+		}
+		return self::extract_image_alt_and_url( $attachment );
+	}
+
+	/**
+	 * Given an image URL return an attachment ID. Image will be side-loaded into the media library if it doesn't exist.
+	 *
+	 * Forked from https://gist.github.com/kingkool68/a66d2df7835a8869625282faa78b489a.
+	 *
+	 * @param int    $post_id   The post ID where the image will be set as featured image.
+	 * @param string $url The image URL to maybe sideload.
+	 * @uses media_sideload_image
+	 * @return string|int|WP_Error
+	 */
+	protected static function maybe_sideload_image( $post_id, $url = '' ) {
+		global $wpdb;
+
+		// Include necessary WordPress file for media handling.
+		if ( ! function_exists( 'media_sideload_image' ) ) {
+			require_once ABSPATH . 'wp-admin/includes/media.php';
+			require_once ABSPATH . 'wp-admin/includes/file.php';
+			require_once ABSPATH . 'wp-admin/includes/image.php';
+		}
+
+		// Check to see if the URL has already been fetched, if so return the attachment ID.
+		$attachment_id = $wpdb->get_var(
+			$wpdb->prepare( "SELECT `post_id` FROM {$wpdb->postmeta} WHERE `meta_key` = '_source_url' AND `meta_value` = %s", sanitize_url( $url ) )
+		);
+		if ( ! empty( $attachment_id ) ) {
+			return $attachment_id;
+		}
+
+		$attachment_id = $wpdb->get_var(
+			$wpdb->prepare( "SELECT `ID` FROM {$wpdb->posts} WHERE guid=%s", $url )
+		);
+		if ( ! empty( $attachment_id ) ) {
+			return $attachment_id;
+		}
+
+		// If the URL doesn't exist, sideload it to the media library.
+		return media_sideload_image( sanitize_url( $url ), $post_id, sanitize_url( $url ), 'id' );
+	}
+
+	/**
+	 * Sideload an image_url set it as featured image and add the alt-text.
+	 *
+	 * @param int    $post_id   The post ID where the image will be set as featured image.
+	 * @param string $image_url The image URL.
+	 * @param string $alt_text  The alt-text of the image.
+	 * @return int The attachment ID
+	 */
+	protected static function set_featured_image_with_alt( $post_id, $image_url, $alt_text = '' ) {
+		// Maybe sideload the image or get the Attachment ID of an existing one.
+		$image_id = self::maybe_sideload_image( $post_id, $image_url );
+
+		if ( is_wp_error( $image_id ) ) {
+			// Handle the error.
+			return $image_id;
+		}
+
+		// Set the image as the featured image for the post.
+		set_post_thumbnail( $post_id, $image_id );
+
+		// Update the alt text.
+		if ( ! empty( $alt_text ) ) {
+			update_post_meta( $image_id, '_wp_attachment_image_alt', sanitize_text_field( $alt_text ) );
+		}
+
+		return $image_id; // Return the attachment ID for further use if needed.
+	}
+
+	/**
+	 * Convert a PostalAddress to a string.
+	 *
+	 * @link https://schema.org/PostalAddress
+	 *
+	 * @param array $postal_address The PostalAddress as an associative array.
+	 * @return string
+	 */
+	private static function postal_address_to_string( $postal_address ) {
+		if ( ! is_array( $postal_address ) || 'PostalAddress' !== $postal_address['type'] ) {
+			_doing_it_wrong(
+				__METHOD__,
+				'The parameter postal_address must be an associate array like schema.org/PostalAddress.',
+				esc_html( EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_VERSION )
+			);
+		}
+
+		$address = array();
+
+		$known_attributes = array(
+			'streetAddress',
+			'postalCode',
+			'addressLocality',
+			'addressState',
+			'addressCountry',
+		);
+
+		foreach ( $known_attributes as $attribute ) {
+			if ( isset( $postal_address[ $attribute ] ) && is_string( $postal_address[ $attribute ] ) ) {
+				$address[] = $postal_address[ $attribute ];
+			}
+		}
+
+		$address_string = implode( ' ,', $address );
+
+		return $address_string;
+	}
+
+	/**
+	 * Convert an address to a string.
+	 *
+	 * @param mixed $address The address as an object, string or associative array.
+	 * @return string
+	 */
+	protected static function address_to_string( $address ) {
+		if ( is_string( $address ) ) {
+			return $address;
+		}
+
+		if ( is_object( $address ) ) {
+			$address = (array) $address;
+		}
+
+		if ( ! is_array( $address ) || ! isset( $address['type'] ) ) {
+			return '';
+		}
+
+		if ( 'PostalAddress' === $address['type'] ) {
+			return self::postal_address_to_string( $address );
+		}
+		return '';
+	}
+
+	/**
+	 * Save the ActivityPub event object as GatherPress event.
+	 */
+	public function delete() {
+		$post_id = $this->get_post_id_from_activitypub_id();
+
+		if ( ! $post_id ) {
+			return new WP_Error(
+				'event_bridge_for_activitypub_remote_event_not_found',
+				\__( 'Remote event not found in cache', 'event-bridge-for-activitypub' ),
+				array( 'status' => 404 )
+			);
+		}
+
+		$thumbnail_id = get_post_thumbnail_id( $post_id );
+
+		if ( $thumbnail_id ) {
+			wp_delete_attachment( $thumbnail_id, true );
+		}
+
+		wp_delete_post( $post_id, true );
+	}
+
+	/**
+	 * Return the number of revisions to keep.
+	 *
+	 * @return     int   The number of revisions to keep.
+	 */
+	public static function revisions_to_keep() {
+		return 5;
+	}
+
+	/**
+	 * Returns the URL of the online event link.
+	 *
+	 * @return ?string
+	 */
+	protected function get_online_event_link_from_attachments() {
+		$attachments = $this->activitypub_event->get_attachment();
+
+		if ( ! is_array( $attachments ) || empty( $attachments ) ) {
+			return;
+		}
+
+		foreach ( $attachments as $attachment ) {
+			if ( array_key_exists( 'type', $attachment ) && 'Link' === $attachment['type'] && isset( $attachment['href'] ) ) {
+				return $attachment['href'];
+			}
+		}
+	}
+}

includes/activitypub/transmogrifier/class-gatherpress.php

@@ -11,10 +11,7 @@
 
 namespace Event_Bridge_For_ActivityPub\Activitypub\Transmogrifier;
 
-use Activitypub\Activity\Extended_Object\Event;
 use DateTime;
-use Exception;
-use WP_Error;
 
 use function Activitypub\sanitize_url;
 
@@ -30,224 +27,7 @@ use GatherPress\Core\Event as GatherPress_Event;
  *
  * @since 1.0.0
  */
-class GatherPress {
+class GatherPress extends Base {
-	/**
-	 * The current GatherPress Event object.
-	 *
-	 * @var Event
-	 */
-	protected $activitypub_event;
-
-	/**
-	 * Extend the constructor, to also set the GatherPress objects.
-	 *
-	 * This is a special class object form The Events Calendar which
-	 * has a lot of useful functions, we make use of our getter functions.
-	 *
-	 * @param array $activitypub_event The ActivityPub Event as associative array.
-	 */
-	public function __construct( $activitypub_event ) {
-		$activitypub_event = Event::init_from_array( $activitypub_event );
-
-		if ( is_wp_error( $activitypub_event ) ) {
-			return;
-		}
-
-		$this->activitypub_event = $activitypub_event;
-	}
-
-	/**
-	 * Validate a time string if it is according to the ActivityPub specification.
-	 *
-	 * @param string $time_string The time string.
-	 * @return bool
-	 */
-	public static function is_valid_activitypub_time_string( $time_string ) {
-		// Try to create a DateTime object from the input string.
-		try {
-			$date = new DateTime( $time_string );
-		} catch ( Exception $e ) {
-			// If parsing fails, it's not valid.
-			return false;
-		}
-
-		// Ensure the timezone is correctly formatted (e.g., 'Z' or a valid offset).
-		$timezone           = $date->getTimezone();
-		$formatted_timezone = $timezone->getName();
-
-		// Return true only if the time string includes 'Z' or a valid timezone offset.
-		$valid = 'Z' === $formatted_timezone || preg_match( '/^[+-]\d{2}:\d{2}$/ ', $formatted_timezone );
-		return $valid;
-	}
-
-	/**
-	 * Get a list of Post IDs of events that have ended.
-	 *
-	 * @param int $cache_retention_period Additional time buffer in seconds.
-	 * @return int[]
-	 */
-	public static function get_past_events( $cache_retention_period = 0 ) {
-		global $wpdb;
-
-		$time_limit = gmdate( 'Y-m-d H:i:s', time() - $cache_retention_period );
-
-		$results = $wpdb->get_col(
-			$wpdb->prepare(
-				"SELECT post_id FROM {$wpdb->prefix}gatherpress_events WHERE datetime_end < %s",
-				$time_limit
-			)
-		);
-
-		return $results;
-	}
-
-	/**
-	 * Get post.
-	 */
-	private function get_post_id_from_activitypub_id() {
-		global $wpdb;
-		return $wpdb->get_var(
-			$wpdb->prepare(
-				"SELECT ID FROM $wpdb->posts WHERE guid=%s",
-				esc_sql( $this->activitypub_event->get_id() )
-			)
-		);
-	}
-
-	/**
-	 * Get the image URL and alt-text of an ActivityPub object.
-	 *
-	 * @param array $data The ActivityPub object as ann associative array.
-	 * @return ?array Array containing the images URL and alt-text.
-	 */
-	private static function extract_image_alt_and_url( $data ) {
-		$image = array(
-			'url' => null,
-			'alt' => null,
-		);
-
-		// Check whether it is already simple.
-		if ( ! $data || is_string( $data ) ) {
-			$image['url'] = $data;
-			return $image;
-		}
-
-		if ( ! isset( $data['type'] ) ) {
-			return $image;
-		}
-
-		if ( ! in_array( $data['type'], array( 'Document', 'Image' ), true ) ) {
-			return $image;
-		}
-
-		if ( isset( $data['url'] ) ) {
-			$image['url'] = $data['url'];
-		} elseif ( isset( $data['id'] ) ) {
-			$image['id'] = $data['id'];
-		}
-
-		if ( isset( $data['name'] ) ) {
-			$image['alt'] = $data['name'];
-		}
-
-		return $image;
-	}
-
-	/**
-	 * Returns the URL of the featured image.
-	 *
-	 * @return array
-	 */
-	private function get_featured_image() {
-		$event = $this->activitypub_event;
-		$image = $event->get_image();
-		if ( $image ) {
-			return self::extract_image_alt_and_url( $image );
-		}
-		$attachment = $event->get_attachment();
-		if ( is_array( $attachment ) && ! empty( $attachment ) ) {
-			$supported_types = array( 'Image', 'Document' );
-			$match           = null;
-
-			foreach ( $attachment as $item ) {
-				if ( in_array( $item['type'], $supported_types, true ) ) {
-					$match = $item;
-					break;
-				}
-			}
-			$attachment = $match;
-		}
-		return self::extract_image_alt_and_url( $attachment );
-	}
-
-	/**
-	 * Given an image URL return an attachment ID. Image will be side-loaded into the media library if it doesn't exist.
-	 *
-	 * Forked from https://gist.github.com/kingkool68/a66d2df7835a8869625282faa78b489a.
-	 *
-	 * @param int    $post_id   The post ID where the image will be set as featured image.
-	 * @param string $url The image URL to maybe sideload.
-	 * @uses media_sideload_image
-	 * @return string|int|WP_Error
-	 */
-	public static function maybe_sideload_image( $post_id, $url = '' ) {
-		global $wpdb;
-
-		// Include necessary WordPress file for media handling.
-		if ( ! function_exists( 'media_sideload_image' ) ) {
-			require_once ABSPATH . 'wp-admin/includes/media.php';
-			require_once ABSPATH . 'wp-admin/includes/file.php';
-			require_once ABSPATH . 'wp-admin/includes/image.php';
-		}
-
-		// Check to see if the URL has already been fetched, if so return the attachment ID.
-		$attachment_id = $wpdb->get_var(
-			$wpdb->prepare( "SELECT `post_id` FROM {$wpdb->postmeta} WHERE `meta_key` = '_source_url' AND `meta_value` = %s", sanitize_url( $url ) )
-		);
-		if ( ! empty( $attachment_id ) ) {
-			return $attachment_id;
-		}
-
-		$attachment_id = $wpdb->get_var(
-			$wpdb->prepare( "SELECT `ID` FROM {$wpdb->posts} WHERE guid=%s", $url )
-		);
-		if ( ! empty( $attachment_id ) ) {
-			return $attachment_id;
-		}
-
-		// If the URL doesn't exist, sideload it to the media library.
-		return media_sideload_image( sanitize_url( $url ), $post_id, sanitize_url( $url ), 'id' );
-	}
-
-
-	/**
-	 * Sideload an image_url set it as featured image and add the alt-text.
-	 *
-	 * @param int    $post_id   The post ID where the image will be set as featured image.
-	 * @param string $image_url The image URL.
-	 * @param string $alt_text  The alt-text of the image.
-	 * @return int The attachment ID
-	 */
-	private static function set_featured_image_with_alt( $post_id, $image_url, $alt_text = '' ) {
-		// Maybe sideload the image or get the Attachment ID of an existing one.
-		$image_id = self::maybe_sideload_image( $post_id, $image_url );
-
-		if ( is_wp_error( $image_id ) ) {
-			// Handle the error.
-			return $image_id;
-		}
-
-		// Set the image as the featured image for the post.
-		set_post_thumbnail( $post_id, $image_id );
-
-		// Update the alt text.
-		if ( ! empty( $alt_text ) ) {
-			update_post_meta( $image_id, '_wp_attachment_image_alt', sanitize_text_field( $alt_text ) );
-		}
-
-		return $image_id; // Return the attachment ID for further use if needed.
-	}
-
 	/**
 	 * Add tags to post.
 	 *
@@ -271,94 +51,12 @@ class GatherPress {
 
 		// Add the tags as terms to the post.
 		if ( ! empty( $tag_names ) ) {
-			wp_set_object_terms( $post_id, $tag_names, 'gatherpress_topic', true ); // 'true' appends to existing terms.
+			wp_set_object_terms( $post_id, $tag_names, 'gatherpress_topic', true );
 		}
 
 		return true;
 	}
 
-	/**
-	 * Returns the URL of the online event link.
-	 *
-	 * @return ?string
-	 */
-	protected function get_online_event_link_from_attachments() {
-		$attachments = $this->activitypub_event->get_attachment();
-
-		if ( ! is_array( $attachments ) || empty( $attachments ) ) {
-			return;
-		}
-
-		foreach ( $attachments as $attachment ) {
-			if ( array_key_exists( 'type', $attachment ) && 'Link' === $attachment['type'] && isset( $attachment['href'] ) ) {
-				return $attachment['href'];
-			}
-		}
-	}
-
-	/**
-	 * Convert a PostalAddress to a string.
-	 *
-	 * @link https://schema.org/PostalAddress
-	 *
-	 * @param array $postal_address The PostalAddress as an associative array.
-	 * @return string
-	 */
-	protected static function postal_address_to_string( $postal_address ) {
-		if ( ! is_array( $postal_address ) || 'PostalAddress' !== $postal_address['type'] ) {
-			_doing_it_wrong(
-				__METHOD__,
-				'The parameter postal_address must be an associate array like schema.org/PostalAddress.',
-				esc_html( EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_VERSION )
-			);
-		}
-
-		$address = array();
-
-		$known_attributes = array(
-			'streetAddress',
-			'postalCode',
-			'addressLocality',
-			'addressState',
-			'addressCountry',
-		);
-
-		foreach ( $known_attributes as $attribute ) {
-			if ( isset( $postal_address[ $attribute ] ) && is_string( $postal_address[ $attribute ] ) ) {
-				$address[] = $postal_address[ $attribute ];
-			}
-		}
-
-		$address_string = implode( ' ,', $address );
-
-		return $address_string;
-	}
-
-	/**
-	 * Convert an address to a string.
-	 *
-	 * @param mixed $address The address as an object, string or associative array.
-	 * @return string
-	 */
-	protected static function address_to_string( $address ) {
-		if ( is_string( $address ) ) {
-			return $address;
-		}
-
-		if ( is_object( $address ) ) {
-			$address = (array) $address;
-		}
-
-		if ( ! is_array( $address ) || ! isset( $address['type'] ) ) {
-			return '';
-		}
-
-		if ( 'PostalAddress' === $address['type'] ) {
-			return self::postal_address_to_string( $address );
-		}
-		return '';
-	}
-
 	/**
 	 * Add venue.
 	 *
@@ -421,8 +119,10 @@ class GatherPress {
 
 	/**
 	 * Save the ActivityPub event object as GatherPress Event.
+	 *
+	 * @return void
 	 */
-	public function save() {
+	protected function save_event(): void {
 		// Limit this as a safety measure.
 		add_filter( 'wp_revisions_to_keep', array( self::class, 'revisions_to_keep' ) );
 
@@ -483,36 +183,4 @@ class GatherPress {
 		// Limit this as a safety measure.
 		remove_filter( 'wp_revisions_to_keep', array( self::class, 'revisions_to_keep' ) );
 	}
-
-	/**
-	 * Save the ActivityPub event object as GatherPress event.
-	 */
-	public function delete() {
-		$post_id = $this->get_post_id_from_activitypub_id();
-
-		if ( ! $post_id ) {
-			return new WP_Error(
-				'event_bridge_for_activitypub_remote_event_not_found',
-				\__( 'Remote event not found in cache', 'event-bridge-for-activitypub' ),
-				array( 'status' => 404 )
-			);
-		}
-
-		$thumbnail_id = get_post_thumbnail_id( $post_id );
-
-		if ( $thumbnail_id ) {
-			wp_delete_attachment( $thumbnail_id, true );
-		}
-
-		wp_delete_post( $post_id, true );
-	}
-
-	/**
-	 * Return the number of revisions to keep.
-	 *
-	 * @return     int   The number of revisions to keep.
-	 */
-	public static function revisions_to_keep() {
-		return 5;
-	}
 }

includes/activitypub/transmogrifier/class-the-events-calendar.php

@@ -0,0 +1,59 @@
+<?php
+/**
+ * ActivityPub Transmogrify for the The Events Calendar event plugin.
+ *
+ * Handles converting incoming external ActivityPub events to The Events Calendar Events.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @since 1.0.0
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub\Activitypub\Transmogrifier;
+
+use DateTime;
+
+use function Activitypub\sanitize_url;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use GatherPress\Core\Event as GatherPress_Event;
+
+/**
+ * ActivityPub Transmogrifier for the GatherPress event plugin.
+ *
+ * Handles converting incoming external ActivityPub events to GatherPress Events.
+ *
+ * @since 1.0.0
+ */
+class The_Events_Calendar extends Base {
+	/**
+	 * Get a list of Post IDs of events that have ended.
+	 *
+	 * @param int $cache_retention_period Additional time buffer in seconds.
+	 * @return ?array
+	 */
+	public static function get_past_events( $cache_retention_period = 0 ): ?array {
+		unset( $cache_retention_period );
+
+		$results = array();
+
+		return $results;
+	}
+
+	/**
+	 * Save the ActivityPub event object as GatherPress Event.
+	 *
+	 * @return void
+	 */
+	public function save_event(): void {
+		// Limit this as a safety measure.
+		add_filter( 'wp_revisions_to_keep', array( self::class, 'revisions_to_keep' ) );
+
+		$this->get_post_id_from_activitypub_id();
+
+		// Limit this as a safety measure.
+		remove_filter( 'wp_revisions_to_keep', array( self::class, 'revisions_to_keep' ) );
+	}
+}

includes/admin/class-health-check.php

@@ -97,7 +97,7 @@ class Health_Check {
 		// Call the transformer Factory.
 		$transformer = Transformer_Factory::get_transformer( $event_posts[0] );
 		// Check that we got the right transformer.
-		$desired_transformer_class = $event_plugin::get_activitypub_event_transformer_class();
+		$desired_transformer_class = $event_plugin::get_activitypub_event_transformer( $event_posts[0] );
 		if ( $transformer instanceof $desired_transformer_class ) {
 			return true;
 		}

includes/admin/class-settings-page.php

@@ -19,6 +19,8 @@ use Event_Bridge_For_ActivityPub\ActivityPub\Model\Event_Source;
 use Event_Bridge_For_ActivityPub\Event_Sources;
 use Event_Bridge_For_ActivityPub\ActivityPub\Collection\Event_Sources as Event_Source_Collection;
 use Event_Bridge_For_ActivityPub\Integrations\Event_Plugin;
+use Event_Bridge_For_ActivityPub\Integrations\Event_Plugin_Integration;
+use Event_Bridge_For_ActivityPub\Integrations\Feature_Event_Sources;
 use Event_Bridge_For_ActivityPub\Setup;
 
 /**
@@ -171,15 +173,15 @@ class Settings_Page {
 			case 'settings':
 				$event_terms = array();
 
-				foreach ( $event_plugins as $event_plugin ) {
+				foreach ( $event_plugins as $event_plugin_integration ) {
-					$event_terms = array_merge( $event_terms, self::get_event_terms( $event_plugin ) );
+					$event_terms = array_merge( $event_terms, self::get_event_terms( $event_plugin_integration ) );
 				}
 
 				$supports_event_sources = array();
 
-				foreach ( $event_plugins as $event_plugin ) {
+				foreach ( $event_plugins as $event_plugin_integration ) {
-					if ( $event_plugin->supports_event_sources() ) {
+					if ( $event_plugin_integration instanceof Feature_Event_Sources && $event_plugin_integration instanceof Event_Plugin_Integration ) {
-						$supports_event_sources[ $event_plugin::class ] = $event_plugin->get_plugin_name();
+						$supports_event_sources[ $event_plugin_integration::class ] = $event_plugin_integration::get_plugin_name();
 					}
 				}
 

includes/admin/class-user-interface.php

@@ -9,6 +9,8 @@
 
 namespace Event_Bridge_For_ActivityPub\Admin;
 
+use Event_Bridge_For_ActivityPub\Event_Sources;
+
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
@@ -59,7 +61,7 @@ class User_Interface {
 	 */
 	public static function row_actions( $actions, $post ) {
 		// check if the post is enabled for ActivityPub.
-		if ( ! self::post_is_external_event_post( $post ) ) {
+		if ( ! Event_Sources::is_cached_external_event_post( $post ) ) {
 			return $actions;
 		}
 
@@ -72,19 +74,6 @@ class User_Interface {
 		return $actions;
 	}
 
-	/**
-	 * Check if a post is both an event post and external (from ActivityPub federation).
-	 *
-	 * @param WP_Post $post The post.
-	 * @return bool
-	 */
-	private static function post_is_external_event_post( $post ) {
-		if ( 'gatherpress_event' !== $post->post_type ) {
-			return false;
-		}
-		return str_starts_with( $post->guid, 'https://ga.lan' ) ? true : false;
-	}
-
 	/**
 	 * Modify the user capabilities so that nobody can edit external events.
 	 *
@@ -99,7 +88,7 @@ class User_Interface {
 		if ( 'edit_post' === $cap && isset( $args[0] ) ) {
 			$post_id = $args[0];
 			$post    = get_post( $post_id );
-			if ( $post && self::post_is_external_event_post( $post ) ) {
+			if ( $post && Event_Sources::is_cached_external_event_post( $post ) ) {
 				// Deny editing by returning 'do_not_allow'.
 				return array( 'do_not_allow' );
 			}

includes/class-event-sources.php

@@ -12,6 +12,9 @@ namespace Event_Bridge_For_ActivityPub;
 use Activitypub\Model\Blog;
 use Event_Bridge_For_ActivityPub\ActivityPub\Collection\Event_Sources as Event_Sources_Collection;
 use Event_Bridge_For_ActivityPub\Activitypub\Transmogrifier\GatherPress;
+use Event_Bridge_For_ActivityPub\Activitypub\Handler;
+use Event_Bridge_For_ActivityPub\Admin\User_Interface;
+
 
 use function Activitypub\get_remote_metadata_by_actor;
 use function Activitypub\is_activitypub_request;
@@ -22,6 +25,22 @@ use function Activitypub\is_activitypub_request;
  * @package Event_Bridge_For_ActivityPub
  */
 class Event_Sources {
+	/**
+	 * Init.
+	 */
+	public static function init() {
+		\add_action( 'init', array( Event_Sources_Collection::class, 'init' ) );
+		\add_action( 'activitypub_register_handlers', array( Handler::class, 'register_handlers' ) );
+		\add_action( 'admin_init', array( User_Interface::class, 'init' ) );
+		\add_filter( 'activitypub_is_post_disabled', array( self::class, 'is_cached_external_post' ), 10, 2 );
+		if ( ! \wp_next_scheduled( 'event_bridge_for_activitypub_event_sources_clear_cache' ) ) {
+			\wp_schedule_event( time(), 'daily', 'event_bridge_for_activitypub_event_sources_clear_cache' );
+		}
+		\add_action( 'event_bridge_for_activitypub_event_sources_clear_cache', array( self::class, 'clear_cache' ) );
+		\add_filter( 'activitypub_rest_following', array( self::class, 'add_event_sources_to_following_collection' ), 10, 2 );
+		\add_filter( 'template_include', array( self::class, 'redirect_activitypub_requests_for_cached_external_events' ), 100 );
+	}
+
 	/**
 	 * Get metadata of ActivityPub Actor by ID/URL.
 	 *
@@ -88,10 +107,7 @@ class Event_Sources {
 		if ( $disabled || ! $post ) {
 			return $disabled;
 		}
-		if ( ! str_starts_with( \get_site_url(), $post->guid ) ) {
+		return ! self::is_cached_external_event_post( $post );
-			return true;
-		}
-		return false;
 	}
 
 	/**
@@ -101,13 +117,10 @@ class Event_Sources {
 	 * @return bool
 	 */
 	public static function is_cached_external_event_post( $post ): bool {
-		if ( 'gatherpress_event' !== $post->post_type ) {
+		if ( get_post_meta( $post->id, 'event_bridge_for_activitypub_is_cached', true ) ) {
-			return false;
-		}
-
-		if ( ! str_starts_with( \get_site_url(), $post->guid ) ) {
 			return true;
 		}
+
 		return false;
 	}
 

includes/class-settings.php

@@ -15,6 +15,7 @@ namespace Event_Bridge_For_ActivityPub;
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 use Activitypub\Activity\Extended_Object\Event;
+use Event_Bridge_For_ActivityPub\Integrations\Feature_Event_Sources;
 
 /**
  * Class responsible for the ActivityPui Event Extension related Settings.
@@ -155,7 +156,7 @@ class Settings {
 
 		$valid_options = array();
 		foreach ( $active_event_plugins as $active_event_plugin ) {
-			if ( $active_event_plugin->supports_event_sources() ) {
+			if ( $active_event_plugin instanceof Feature_Event_Sources ) {
 				$full_class      = $active_event_plugin::class;
 				$valid_options[] = substr( $full_class, strrpos( $full_class, '\\' ) + 1 );
 			}

includes/class-setup.php

@@ -15,14 +15,14 @@ namespace Event_Bridge_For_ActivityPub;
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
-use Event_Bridge_For_ActivityPub\ActivityPub\Collection\Event_Sources as Event_Sources_Collection;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transmogrifier\Base as Transmogrifier_Base;
-use Event_Bridge_For_ActivityPub\ActivityPub\Handler;
 use Event_Bridge_For_ActivityPub\Admin\Event_Plugin_Admin_Notices;
 use Event_Bridge_For_ActivityPub\Admin\General_Admin_Notices;
 use Event_Bridge_For_ActivityPub\Admin\Health_Check;
 use Event_Bridge_For_ActivityPub\Admin\Settings_Page;
 use Event_Bridge_For_ActivityPub\Admin\User_Interface;
 use Event_Bridge_For_ActivityPub\Integrations\Event_Plugin;
+use Event_Bridge_For_ActivityPub\Integrations\Feature_Event_Sources;
 
 use function Activitypub\is_user_type_disabled;
 
@@ -127,16 +127,16 @@ class Setup {
 	 *
 	 * @var array
 	 */
-	private const EVENT_PLUGIN_CLASSES = array(
+	private const EVENT_PLUGIN_INTEGRATIONS = array(
-		'\Event_Bridge_For_ActivityPub\Integrations\Events_Manager',
+		\Event_Bridge_For_ActivityPub\Integrations\Events_Manager::class,
-		'\Event_Bridge_For_ActivityPub\Integrations\GatherPress',
+		\Event_Bridge_For_ActivityPub\Integrations\GatherPress::class,
-		'\Event_Bridge_For_ActivityPub\Integrations\The_Events_Calendar',
+		\Event_Bridge_For_ActivityPub\Integrations\The_Events_Calendar::class,
-		'\Event_Bridge_For_ActivityPub\Integrations\VS_Event_List',
+		\Event_Bridge_For_ActivityPub\Integrations\VS_Event_List::class,
-		'\Event_Bridge_For_ActivityPub\Integrations\WP_Event_Manager',
+		\Event_Bridge_For_ActivityPub\Integrations\WP_Event_Manager::class,
-		'\Event_Bridge_For_ActivityPub\Integrations\Eventin',
+		\Event_Bridge_For_ActivityPub\Integrations\Eventin::class,
-		'\Event_Bridge_For_ActivityPub\Integrations\Modern_Events_Calendar_Lite',
+		\Event_Bridge_For_ActivityPub\Integrations\Modern_Events_Calendar_Lite::class,
-		'\Event_Bridge_For_ActivityPub\Integrations\EventPrime',
+		\Event_Bridge_For_ActivityPub\Integrations\EventPrime::class,
-		'\Event_Bridge_For_ActivityPub\Integrations\Event_Organiser',
+		\Event_Bridge_For_ActivityPub\Integrations\Event_Organiser::class,
 	);
 
 	/**
@@ -169,13 +169,18 @@ class Setup {
 		$all_plugins = array_merge( get_plugins(), get_mu_plugins() );
 
 		$active_event_plugins = array();
-		foreach ( self::EVENT_PLUGIN_CLASSES as $event_plugin_class ) {
+		foreach ( self::EVENT_PLUGIN_INTEGRATIONS as $event_plugin_integration ) {
-			$event_plugin_file = call_user_func( array( $event_plugin_class, 'get_relative_plugin_file' ) );
+			// Get the filename of the main plugin file of the event plugin (relative to the plugin dir).
+			$event_plugin_file = $event_plugin_integration::get_relative_plugin_file();
+
+			// This check should not be needed, but does not hurt.
 			if ( ! $event_plugin_file ) {
 				continue;
 			}
+
+			// Check if plugin is present on disk and is activated.
 			if ( array_key_exists( $event_plugin_file, $all_plugins ) && \is_plugin_active( $event_plugin_file ) ) {
-				$active_event_plugins[ $event_plugin_file ] = new $event_plugin_class();
+				$active_event_plugins[ $event_plugin_file ] = new $event_plugin_integration();
 			}
 		}
 		set_transient( 'event_bridge_for_activitypub_active_event_plugins', $active_event_plugins );
@@ -191,12 +196,9 @@ class Setup {
 	public static function detect_event_plugins_supporting_event_sources(): array {
 		$plugins_supporting_event_sources = array();
 
-		foreach ( self::EVENT_PLUGIN_CLASSES as $event_plugin_class ) {
+		foreach ( self::EVENT_PLUGIN_INTEGRATIONS as $event_plugin_integration ) {
-			if ( ! class_exists( $event_plugin_class ) || ! method_exists( $event_plugin_class, 'get_plugin_file' ) ) {
+			if ( $event_plugin_integration instanceof Feature_Event_Sources ) {
-				continue;
+				$plugins_supporting_event_sources[] = new $event_plugin_integration();
-			}
-			if ( call_user_func( array( $event_plugin_class, 'supports_event_sources' ) ) ) {
-				$plugins_supporting_event_sources[] = new $event_plugin_class();
 			}
 		}
 		return $plugins_supporting_event_sources;
@@ -241,39 +243,8 @@ class Setup {
 		}
 
 		if ( ! is_user_type_disabled( 'blog' ) && get_option( 'event_bridge_for_activitypub_event_sources_active' ) ) {
-			add_action( 'init', array( Event_Sources_Collection::class, 'init' ) );
+			Event_Sources::init();
-			add_action( 'activitypub_register_handlers', array( Handler::class, 'register_handlers' ) );
-			add_action( 'admin_init', array( User_Interface::class, 'init' ) );
-			add_filter( 'allowed_redirect_hosts', array( Event_Sources_Collection::class, 'add_event_sources_hosts_to_allowed_redirect_hosts' ) );
-			add_filter( 'activitypub_is_post_disabled', array( Event_Sources::class, 'is_cached_external_post' ), 10, 2 );
-			if ( ! wp_next_scheduled( 'event_bridge_for_activitypub_event_sources_clear_cache' ) ) {
-				wp_schedule_event( time(), 'daily', 'event_bridge_for_activitypub_event_sources_clear_cache' );
 		}
-
-			add_action( 'event_bridge_for_activitypub_event_sources_clear_cache', array( Event_Sources::class, 'clear_cache' ) );
-			add_filter( 'activitypub_rest_following', array( Event_Sources::class, 'add_event_sources_to_following_collection' ), 10, 2 );
-			add_filter(
-				'gatherpress_force_online_event_link',
-				function ( $force_online_event_link ) {
-					// Get the current post object.
-					$post = get_post();
-
-					// Check if we are in a valid context and the post type is 'gatherpress'.
-					if ( $post && 'gatherpress_event' === $post->post_type ) {
-						// Add your custom logic here to decide whether to force the link.
-						// For example, force it only if a specific meta field exists.
-						if ( get_post_meta( $post->ID, 'event_bridge_for_activitypub_is_cached', true ) ) {
-							return true; // Force the online event link.
-						}
-					}
-
-					return $force_online_event_link; // Default behavior.
-				},
-				10,
-				1
-			);
-		}
-		\add_filter( 'template_include', array( \Event_Bridge_For_ActivityPub\Event_Sources::class, 'redirect_activitypub_requests_for_cached_external_events' ), 100 );
 		add_filter( 'activitypub_transformer', array( $this, 'register_activitypub_event_transformer' ), 10, 3 );
 	}
 
@@ -348,10 +319,7 @@ class Setup {
 		// Get the transformer for a specific event plugins event-post type.
 		foreach ( $this->active_event_plugins as $event_plugin ) {
 			if ( $wp_object->post_type === $event_plugin->get_post_type() ) {
-				$transformer_class = $event_plugin::get_activitypub_event_transformer_class();
+				return $event_plugin::get_activitypub_event_transformer( $wp_object, $event_plugin::get_event_category_taxonomy() );
-				if ( class_exists( $transformer_class ) ) {
-					return new $transformer_class( $wp_object, $event_plugin::get_event_category_taxonomy() );
-				}
 			}
 		}
 
@@ -416,9 +384,9 @@ class Setup {
 	/**
 	 * Get the transmogrifier class.
 	 *
-	 * Retrieves the appropriate transmogrifier class based on the active event plugin.
+	 * Retrieves the appropriate transmogrifier class based on the active event plugins and settings.
 	 *
-	 * @return string|null The transmogrifier class name or null if not available.
+	 * @return Transmogrifier_Base|null The transmogrifier class name or null if not available.
 	 */
 	public static function get_transmogrifier() {
 		// Retrieve singleton instance.
@@ -428,7 +396,7 @@ class Setup {
 		$event_sources_active = (bool) get_option( 'event_bridge_for_activitypub_event_sources_active', false );
 		$event_plugin         = get_option( 'event_bridge_for_activitypub_plugin_used_for_event_source_feature', '' );
 
-		// Bail out if event sources are not active or no plugin is specified.
+		// Exit if event sources are not active or no plugin is specified.
 		if ( ! $event_sources_active || empty( $event_plugin ) ) {
 			return null;
 		}
@@ -439,12 +407,12 @@ class Setup {
 		// Loop through active plugins to find a match.
 		foreach ( $active_event_plugins as $active_event_plugin ) {
 			// Retrieve the class name of the active plugin.
-			$active_plugin_class = get_class( $active_event_plugin );
+			$active_plugin_class_name = get_class( $active_event_plugin );
 
 			// Check if the active plugin class name contains the specified event plugin name.
-			if ( false !== strpos( $active_plugin_class, $event_plugin ) ) {
+			if ( false !== strpos( $active_plugin_class_name, $event_plugin ) ) {
 				// Return the transmogrifier class provided by the plugin.
-				return $active_event_plugin->get_transmogrifier_class();
+				return $active_event_plugin->get_transmogrifier();
 			}
 		}
 

includes/integrations/class-event-organiser.php

@@ -11,6 +11,8 @@
 
 namespace Event_Bridge_For_ActivityPub\Integrations;
 
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event_Organiser as Event_Organiser_Transformer;
+
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
@@ -21,7 +23,7 @@ defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
  *
  * @since 1.0.0
  */
-final class Event_Organiser extends Event_Plugin {
+final class Event_Organiser extends Event_Plugin_Integration {
 	/**
 	 * Returns the full plugin file.
 	 *
@@ -49,15 +51,6 @@ final class Event_Organiser extends Event_Plugin {
 		return array( 'event-organiser' );
 	}
 
-	/**
-	 * Returns the ActivityPub transformer class.
-	 *
-	 * @return string
-	 */
-	public static function get_activitypub_transformer_class_name(): string {
-		return 'Event_Organiser';
-	}
-
 	/**
 	 * Returns the taxonomy used for the plugin's event categories.
 	 *
@@ -66,4 +59,14 @@ final class Event_Organiser extends Event_Plugin {
 	public static function get_event_category_taxonomy(): string {
 		return 'event-category';
 	}
+
+	/**
+	 * Returns the ActivityPub transformer for a Event_Organiser event post.
+	 *
+	 * @param WP_Post $post The WordPress post object of the Event.
+	 * @return Event_Organiser_Transformer
+	 */
+	public static function get_activitypub_event_transformer( $post ): Event_Organiser_Transformer {
+		return new Event_Organiser_Transformer( $post, self::get_event_category_taxonomy() );
+	}
 }

includes/integrations/class-event-plugin-integration.php

@@ -11,11 +11,13 @@
 
 namespace Event_Bridge_For_ActivityPub\Integrations;
 
-use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event as Event_Transformer;
+use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event as ActivityPub_Event_Transformer;
 
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
+require_once EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_DIR . 'includes/integrations/interface-feature-event-sources.php';
+
 /**
  * Interface for a supported event plugin.
  *
@@ -23,7 +25,7 @@ defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
  *
  * @since 1.0.0
  */
-abstract class Event_Plugin {
+abstract class Event_Plugin_Integration {
 	/**
 	 * Returns the plugin file relative to the plugins dir.
 	 *
@@ -45,6 +47,14 @@ abstract class Event_Plugin {
 	 */
 	abstract public static function get_event_category_taxonomy(): string;
 
+	/**
+	 * Returns the Activitypub transformer for the event plugins event post type.
+	 *
+	 * @param WP_Post $post The WordPress post object of the Event.
+	 * @return ActivityPub_Event_Transformer
+	 */
+	abstract public static function get_activitypub_event_transformer( $post ): ActivityPub_Event_Transformer;
+
 	/**
 	 * Returns the IDs of the admin pages of the plugin.
 	 *
@@ -54,19 +64,10 @@ abstract class Event_Plugin {
 		return array();
 	}
 
-	/**
-	 * By default event sources are not supported by an event plugin integration.
-	 *
-	 * @return bool True if event sources are supported.
-	 */
-	public static function supports_event_sources(): bool {
-		return false;
-	}
-
 	/**
 	 * Get the plugins name from the main plugin-file's top-level-file-comment.
 	 */
-	final public static function get_plugin_name(): string {
+	public static function get_plugin_name(): string {
 		$all_plugins = array_merge( get_plugins(), get_mu_plugins() );
 		if ( isset( $all_plugins[ static::get_relative_plugin_file() ]['Name'] ) ) {
 			return $all_plugins[ static::get_relative_plugin_file() ]['Name'];
@@ -88,21 +89,4 @@ abstract class Event_Plugin {
 
 		return $is_event_plugins_edit_page || $is_event_plugins_settings_page;
 	}
-
-	/**
-	 * Returns the Activitypub transformer for the event plugins event post type.
-	 */
-	public static function get_activitypub_event_transformer_class(): string {
-		return str_replace( 'Integrations', 'Activitypub\Transformer', static::class );
-	}
-
-	/**
-	 * Returns the class used for transmogrifying an Event (ActivityStreams to Event plugin transformation).
-	 */
-	public static function get_transmogrifier_class(): ?string {
-		if ( ! static::supports_event_sources() ) {
-			return null;
-		}
-		return str_replace( 'Integrations', 'Activitypub\Transmogrifier', static::class );
-	}
 }

includes/integrations/class-eventin.php

@@ -11,6 +11,8 @@
 
 namespace Event_Bridge_For_ActivityPub\Integrations;
 
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Eventin as Eventin_Transformer;
+
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
@@ -21,7 +23,7 @@ defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
  *
  * @since 1.0.0
  */
-final class Eventin extends Event_plugin {
+final class Eventin extends Event_Plugin_Integration {
 	/**
 	 * Returns the full plugin file.
 	 *
@@ -57,4 +59,14 @@ final class Eventin extends Event_plugin {
 	public static function get_event_category_taxonomy(): string {
 		return 'etn_category';
 	}
+
+	/**
+	 * Returns the ActivityPub transformer for a Eventin event post.
+	 *
+	 * @param WP_Post $post The WordPress post object of the Event.
+	 * @return Eventin_Transformer
+	 */
+	public static function get_activitypub_event_transformer( $post ): Eventin_Transformer {
+		return new Eventin_Transformer( $post, self::get_event_category_taxonomy() );
+	}
 }

includes/integrations/class-eventprime.php

@@ -9,6 +9,8 @@
 
 namespace Event_Bridge_For_ActivityPub\Integrations;
 
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\EventPrime as EventPrime_Transformer;
+
 use Activitypub\Signature;
 use Eventprime_Basic_Functions;
 
@@ -20,7 +22,7 @@ defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
  *
  * @since 1.0.0
  */
-final class EventPrime extends Event_Plugin {
+final class EventPrime extends Event_Plugin_Integration {
 	/**
 	 * Add filter for the template inclusion.
 	 */
@@ -56,12 +58,13 @@ final class EventPrime extends Event_Plugin {
 	}
 
 	/**
-	 * Returns the ActivityPub transformer class.
+	 * Returns the ActivityPub transformer for a EventPrime event post.
 	 *
-	 * @return string
+	 * @param WP_Post $post The WordPress post object of the Event.
+	 * @return EventPrime_Transformer
 	 */
-	public static function get_activitypub_transformer_class_name(): string {
+	public static function get_activitypub_event_transformer( $post ): EventPrime_Transformer {
-		return 'EventPrime';
+		return new EventPrime_Transformer( $post, self::get_event_category_taxonomy() );
 	}
 
 	/**

includes/integrations/class-events-manager.php

@@ -11,6 +11,8 @@
 
 namespace Event_Bridge_For_ActivityPub\Integrations;
 
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Events_Manager as Events_Manager_Transformer;
+
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
@@ -21,7 +23,7 @@ defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
  *
  * @since 1.0.0
  */
-final class Events_Manager extends Event_Plugin {
+final class Events_Manager extends Event_Plugin_Integration {
 	/**
 	 * Returns the full plugin file.
 	 *
@@ -57,4 +59,14 @@ final class Events_Manager extends Event_Plugin {
 	public static function get_event_category_taxonomy(): string {
 		return defined( 'EM_TAXONOMY_CATEGORY' ) ? constant( 'EM_TAXONOMY_CATEGORY' ) : 'event-categories';
 	}
+
+	/**
+	 * Returns the ActivityPub transformer for a Events_Manager event post.
+	 *
+	 * @param WP_Post $post The WordPress post object of the Event.
+	 * @return Events_Manager_Transformer
+	 */
+	public static function get_activitypub_event_transformer( $post ): Events_Manager_Transformer {
+		return new Events_Manager_Transformer( $post, self::get_event_category_taxonomy() );
+	}
 }

includes/integrations/class-gatherpress.php

@@ -11,6 +11,9 @@
 
 namespace Event_Bridge_For_ActivityPub\Integrations;
 
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\GatherPress as GatherPress_Transformer;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transmogrifier\GatherPress as GatherPress_Transmogrifier;
+
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
@@ -21,7 +24,7 @@ defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
  *
  * @since 1.0.0
  */
-final class GatherPress extends Event_Plugin {
+final class GatherPress extends Event_Plugin_Integration implements Feature_Event_Sources {
 	/**
 	 * Returns the full plugin file.
 	 *
@@ -49,15 +52,6 @@ final class GatherPress extends Event_Plugin {
 		return array( class_exists( '\GatherPress\Core\Utility' ) ? \GatherPress\Core\Utility::prefix_key( 'general' ) : 'gatherpress_general' );
 	}
 
-	/**
-	 * Returns the ActivityPub transformer class.
-	 *
-	 * @return string
-	 */
-	public static function get_activitypub_transformer_class_name(): string {
-		return 'GatherPress';
-	}
-
 	/**
 	 * Returns the taxonomy used for the plugin's event categories.
 	 *
@@ -68,11 +62,67 @@ final class GatherPress extends Event_Plugin {
 	}
 
 	/**
-	 * GatherPress supports the Event Sources feature.
+	 * Returns the ActivityPub transformer for a GatherPress event post.
 	 *
-	 * @return bool True if event sources are supported.
+	 * @param WP_Post $post The WordPress post object of the Event.
+	 * @return GatherPress_Transformer
 	 */
-	public static function supports_event_sources(): bool {
+	public static function get_activitypub_event_transformer( $post ): GatherPress_Transformer {
-		return true;
+		return new GatherPress_Transformer( $post, self::get_event_category_taxonomy() );
+	}
+
+	/**
+	 * Returns the Transmogrifier for GatherPress.
+	 */
+	public static function get_transmogrifier(): GatherPress_Transmogrifier {
+		return new GatherPress_Transmogrifier();
+	}
+
+	/**
+	 * Get a list of Post IDs of events that have ended.
+	 *
+	 * @param int $ended_before_time Filter: only get events that ended before that datetime as unix-time.
+	 *
+	 * @return array
+	 */
+	public static function get_cached_remote_events( $ended_before_time ): array {
+		global $wpdb;
+
+		$ended_before_time_string = gmdate( 'Y-m-d H:i:s', $ended_before_time );
+
+		$results = $wpdb->get_col(
+			$wpdb->prepare(
+				"SELECT post_id FROM {$wpdb->prefix}gatherpress_events WHERE datetime_end < %s",
+				$ended_before_time_string
+			)
+		);
+
+		return $results;
+	}
+
+	/**
+	 * Init function.
+	 */
+	public static function init() {
+		\add_filter(
+			'gatherpress_force_online_event_link',
+			function ( $force_online_event_link ) {
+				// Get the current post object.
+				$post = get_post();
+
+				// Check if we are in a valid context and the post type is 'gatherpress'.
+				if ( $post && 'gatherpress_event' === $post->post_type ) {
+					// Add your custom logic here to decide whether to force the link.
+					// For example, force it only if a specific meta field exists.
+					if ( get_post_meta( $post->ID, 'event_bridge_for_activitypub_is_cached', true ) ) {
+						return true; // Force the online event link.
+					}
+				}
+
+				return $force_online_event_link; // Default behavior.
+			},
+			10,
+			1
+		);
 	}
 }

includes/integrations/class-modern-events-calendar-lite.php

@@ -11,6 +11,8 @@
 
 namespace Event_Bridge_For_ActivityPub\Integrations;
 
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Modern_Events_Calendar_Lite as Modern_Events_Calendar_Lite_Transformer;
+
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
@@ -21,7 +23,7 @@ defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
  *
  * @since 1.0.0
  */
-final class Modern_Events_Calendar_Lite extends Event_plugin {
+final class Modern_Events_Calendar_Lite extends Event_Plugin_Integration {
 	/**
 	 * Returns the full plugin file.
 	 *
@@ -58,4 +60,14 @@ final class Modern_Events_Calendar_Lite extends Event_plugin {
 	public static function get_event_category_taxonomy(): string {
 		return 'mec_category';
 	}
+
+	/**
+	 * Returns the ActivityPub transformer for a Modern_Events_Calendar_Lite event post.
+	 *
+	 * @param WP_Post $post The WordPress post object of the Event.
+	 * @return Modern_Events_Calendar_Lite_Transformer
+	 */
+	public static function get_activitypub_event_transformer( $post ): Modern_Events_Calendar_Lite_Transformer {
+		return new Modern_Events_Calendar_Lite_Transformer( $post, self::get_event_category_taxonomy() );
+	}
 }

includes/integrations/class-the-events-calendar.php

@@ -11,6 +11,9 @@
 
 namespace Event_Bridge_For_ActivityPub\Integrations;
 
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\The_Events_Calendar as The_Events_Calendar_Transformer;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transmogrifier\The_Events_Calendar as The_Events_Calendar_Transmogrifier;
+
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
@@ -21,7 +24,7 @@ defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
  *
  * @since 1.0.0
  */
-final class The_Events_Calendar extends Event_plugin {
+final class The_Events_Calendar extends Event_plugin_Integration implements Feature_Event_Sources {
 	/**
 	 * Returns the full plugin file.
 	 *
@@ -40,6 +43,25 @@ final class The_Events_Calendar extends Event_plugin {
 		return class_exists( '\Tribe__Events__Main' ) ? \Tribe__Events__Main::POSTTYPE : 'tribe_event';
 	}
 
+	/**
+	 * Returns the taxonomy used for the plugin's event categories.
+	 *
+	 * @return string
+	 */
+	public static function get_event_category_taxonomy(): string {
+		return class_exists( '\Tribe__Events__Main' ) ? \Tribe__Events__Main::TAXONOMY : 'tribe_events_cat';
+	}
+
+	/**
+	 * Returns the ActivityPub transformer for a The_Events_Calendar event post.
+	 *
+	 * @param WP_Post $post The WordPress post object of the Event.
+	 * @return The_Events_Calendar_Transformer
+	 */
+	public static function get_activitypub_event_transformer( $post ): The_Events_Calendar_Transformer {
+		return new The_Events_Calendar_Transformer( $post, self::get_event_category_taxonomy() );
+	}
+
 	/**
 	 * Returns the IDs of the admin pages of the plugin.
 	 *
@@ -55,11 +77,20 @@ final class The_Events_Calendar extends Event_plugin {
 	}
 
 	/**
-	 * Returns the taxonomy used for the plugin's event categories.
+	 * Returns the Transmogrifier for The_Events_Calendar.
-	 *
-	 * @return string
 	 */
-	public static function get_event_category_taxonomy(): string {
+	public static function get_transmogrifier(): The_Events_Calendar_Transmogrifier {
-		return class_exists( '\Tribe__Events__Main' ) ? \Tribe__Events__Main::TAXONOMY : 'tribe_events_cat';
+		return new The_Events_Calendar_Transmogrifier();
+	}
+
+	/**
+	 * Get a list of Post IDs of events that have ended.
+	 *
+	 * @param int $ended_before_time Filter: only get events that ended before that datetime as unix-time.
+	 *
+	 * @return array
+	 */
+	public static function get_cached_remote_events( $ended_before_time ): array {
+		return array();
 	}
 }

includes/integrations/class-vs-event-list.php

@@ -12,7 +12,7 @@
 
 namespace Event_Bridge_For_ActivityPub\Integrations;
 
-use Event_Bridge_For_ActivityPub\Event_Plugins;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\VS_Event_List as VS_Event_List_Transformer;
 
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
@@ -24,7 +24,7 @@ defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
  *
  * @since 1.0.0
  */
-final class VS_Event_List extends Event_Plugin {
+final class VS_Event_List extends Event_Plugin_Integration {
 	/**
 	 * Returns the full plugin file.
 	 *
@@ -52,15 +52,6 @@ final class VS_Event_List extends Event_Plugin {
 		return array( 'settings_page_vsel' );
 	}
 
-	/**
-	 * Returns the ActivityPub transformer class.
-	 *
-	 * @return string
-	 */
-	public static function get_activitypub_transformer_class_name(): string {
-		return 'VS_Event';
-	}
-
 	/**
 	 * Returns the taxonomy used for the plugin's event categories.
 	 *
@@ -69,4 +60,14 @@ final class VS_Event_List extends Event_Plugin {
 	public static function get_event_category_taxonomy(): string {
 		return 'event_cat';
 	}
+
+	/**
+	 * Returns the ActivityPub transformer for a VS_Event_List event post.
+	 *
+	 * @param WP_Post $post The WordPress post object of the Event.
+	 * @return VS_Event_List_Transformer
+	 */
+	public static function get_activitypub_event_transformer( $post ): VS_Event_List_Transformer {
+		return new VS_Event_List_Transformer( $post, self::get_event_category_taxonomy() );
+	}
 }

includes/integrations/class-wp-event-manager.php

@@ -12,7 +12,7 @@
 
 namespace Event_Bridge_For_ActivityPub\Integrations;
 
-use Event_Bridge_For_ActivityPub\Integrations\Event_Plugin;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\WP_Event_Manager as WP_Event_Manager_Transformer;
 
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
@@ -24,7 +24,7 @@ defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
  *
  * @since 1.0.0
  */
-final class WP_Event_Manager extends Event_Plugin {
+final class WP_Event_Manager extends Event_Plugin_Integration {
 	/**
 	 * Returns the full plugin file.
 	 *
@@ -52,15 +52,6 @@ final class WP_Event_Manager extends Event_Plugin {
 		return array( 'event-manager-settings' );
 	}
 
-	/**
-	 * Returns the ActivityPub transformer class.
-	 *
-	 * @return string
-	 */
-	public static function get_activitypub_transformer_class_name(): string {
-		return 'WP_Event_Manager';
-	}
-
 	/**
 	 * Returns the taxonomy used for the plugin's event categories.
 	 *
@@ -69,4 +60,14 @@ final class WP_Event_Manager extends Event_Plugin {
 	public static function get_event_category_taxonomy(): string {
 		return 'event_listing_category';
 	}
+
+	/**
+	 * Returns the ActivityPub transformer for a WP_Event_Manager event post.
+	 *
+	 * @param WP_Post $post The WordPress post object of the Event.
+	 * @return WP_Event_Manager_Transformer
+	 */
+	public static function get_activitypub_event_transformer( $post ): WP_Event_Manager_Transformer {
+		return new WP_Event_Manager_Transformer( $post, self::get_event_category_taxonomy() );
+	}
 }

includes/integrations/interface-feature-event-sources.php

@@ -0,0 +1,42 @@
+<?php
+/**
+ * Interface for defining supported Event Plugins.
+ *
+ * Basic information that each supported event needs for this plugin to work.
+ *
+ * @package Event_Bridge_For_ActivityPub
+ * @since 1.0.0
+ * @license AGPL-3.0-or-later
+ */
+
+namespace Event_Bridge_For_ActivityPub\Integrations;
+
+use Event_Bridge_For_ActivityPub\ActivityPub\Transmogrifier\Base as Transmogrifier;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+/**
+ * Interface for an event plugin integration that supports the Event Sources feature.
+ *
+ * @since 1.0.0
+ */
+interface Feature_Event_Sources {
+	/**
+	 * Returns the plugin file relative to the plugins dir.
+	 *
+	 * @return Transmogrifier
+	 */
+	public static function get_transmogrifier(): Transmogrifier;
+
+	/**
+	 * Retrieves a list of post IDs for cached remote events that have ended.
+	 *
+	 * Filters the events to include only those that ended before the specified timestamp.
+	 *
+	 * @param int $ended_before_time Unix timestamp. Only events ending before this time will be included.
+	 *
+	 * @return int[] List of post IDs for events that match the criteria.
+	 */
+	public static function get_cached_remote_events( $ended_before_time ): array;
+}