Added some features that I wanted for my app.

bbp-api.php

@@ -152,4 +152,93 @@
 		'methods' => WP_REST_Server::READABLE,
 		'callback' => 'bbp_api_stats',
 	) );
+
+	// SUBSCRIBE 
+	$args = array(
+		array(
+			'args' => array(
+				'forum_id' => array(
+					'required' => True,
+					'description' => 'ID of the forum.',
+					'type' => 'integer',
+				),
+				'user_id' => array(
+					'required' => True,
+					'description' => 'ID of the user.',
+					'type' => 'integer',
+				),
+			),
+			'methods' => WP_REST_Server::CREATABLE,
+			'callback' => 'bbp_api_subscribe_forum',
+		),
+	);
+	// register /forum/subscribe
+	register_rest_route( 'bbp-api/v1', '/forum/subscribe/', $args );
+
+
+	$args = array(
+		array(
+			'args' => array(
+				'topic_id' => array(
+					'required' => True,
+					'description' => 'ID of the topic.',
+					'type' => 'integer',
+				),
+				'user_id' => array(
+					'required' => True,
+					'description' => 'ID of the user.',
+					'type' => 'integer',
+				),
+			),
+			'methods' => WP_REST_Server::CREATABLE,
+			'callback' => 'bbp_api_subscribe_topic',
+		),
+	);
+	// register /topic/subscribe
+	register_rest_route( 'bbp-api/v1', '/topic/subscribe/', $args );
+
+	// UNSUBSCRIBE 
+	$args = array(
+		array(
+			'args' => array(
+				'forum_id' => array(
+					'required' => True,
+					'description' => 'ID of the forum.',
+					'type' => 'integer',
+				),
+				'user_id' => array(
+					'required' => True,
+					'description' => 'ID of the user.',
+					'type' => 'integer',
+				),
+			),
+			'methods' => WP_REST_Server::CREATABLE,
+			'callback' => 'bbp_api_unsubscribe_forum',
+		),
+	);
+	// register /forum/unsubscribe
+	register_rest_route( 'bbp-api/v1', '/forum/unsubscribe/', $args );
+
+
+	$args = array(
+		array(
+			'args' => array(
+				'topic_id' => array(
+					'required' => True,
+					'description' => 'ID of the topic.',
+					'type' => 'integer',
+				),
+				'user_id' => array(
+					'required' => True,
+					'description' => 'ID of the user.',
+					'type' => 'integer',
+				),
+			),
+			'methods' => WP_REST_Server::CREATABLE,
+			'callback' => 'bbp_api_unsubscribe_topic',
+		),
+	);
+	// register /topic/unsubscribe
+	register_rest_route( 'bbp-api/v1', '/topic/unsubscribe/', $args );
+
 } );

inc/forums.php

@@ -1,99 +1,207 @@
 <?php
+
 /*
+
  * /bbp-api/forums
+
 */
+
 function bbp_api_forums() {
+
 	$all_forums_data = $all_forums_ids = array();
+
 	if ( bbp_has_forums() ) {
+
 		// Get root list of forums
+
 		while ( bbp_forums() ) {
+
 			bbp_the_forum();
+
 			$forum_id = bbp_get_forum_id();
+
 			$all_forums_ids[] = $forum_id;
+
 				if ( $sublist = bbp_forum_get_subforums() ) {
+
 					foreach ( $sublist as $sub_forum ) {
+
 							$all_forums_ids[] = (int)$sub_forum->ID;
+
 					}
+
 				}
+
 		} // while
+
 		$i = 0;
+
 		foreach ( $all_forums_ids as $forum_id ) {
+
 			$all_forums_data[$i]['id'] = $forum_id;
+
 			$all_forums_data[$i]['title'] = bbp_get_forum_title( $forum_id );
+
 			$all_forums_data[$i]['parent'] = bbp_get_forum_parent_id( $forum_id );
+
 			$all_forums_data[$i]['topic_count'] = bbp_get_forum_topic_count( $forum_id );
+
 			$all_forums_data[$i]['reply_count'] = bbp_get_forum_reply_count( $forum_id );
+
 			$all_forums_data[$i]['permalink'] = bbp_get_forum_permalink( $forum_id );
+
 			$all_forums_data[$i]['content'] = bbp_get_forum_content( $forum_id );
+
 			$all_forums_data[$i]['type'] = bbp_get_forum_type( $forum_id );
+
 			$i++;
+
 		}
+
 	} // if()
+	return new WP_REST_Response($all_forums_data, 200);  
+
 	if ( empty( $all_forums_data ) ) {
+
 		return null;
+
 	}
+
 	return $all_forums_data;
+
 }
+
 /*
+
  * /bbp-api/forums/<id>
+
  *
+
  * per_page and page are following https://developer.wordpress.org/rest-api/using-the-rest-api/pagination/#pagination-parameters
+
  * including the 100 maximum records
+
 */
+
 function bbp_api_forums_one( $data ) {
+
 	$all_forum_data = array();
+
 	$forum_id = bbp_get_forum_id( $data['id'] );
+
 	if ($forum_id) {
+
 		$per_page = !isset($_GET['per_page']) ? 20 : $_GET['per_page'];
+
 		if ($per_page > 100) $per_page = 100;
+
 		$page = !isset($_GET['page']) ? 1 : $_GET['page'];
 
+		if(isset($_GET['user_id'])) {
+
+			$user_id = $_GET['user_id'];
+
+			$all_forum_data['subscribed'] = bbp_is_user_subscribed_to_forum (  $user_id,  $forum_id);
+
+		}
+
 		$all_forum_data['id'] = $forum_id;
+
 		$all_forum_data['title'] = bbp_get_forum_title( $forum_id );
+
 		$all_forum_data['parent'] = bbp_get_forum_parent_id( $forum_id );
+
 		$all_forum_data['topic_count'] = bbp_get_forum_topic_count( $forum_id );
+
 		$all_forum_data['reply_count'] = bbp_get_forum_reply_count( $forum_id );
+
 		$all_forum_data['permalink'] = bbp_get_forum_permalink( $forum_id );
+
 		$all_forum_data['content'] = bbp_get_forum_content( $forum_id );
+
 		$all_forum_data['type'] = bbp_get_forum_type( $forum_id );
+
 		$all_forum_data['subforums'] = array();
+
 		$subforums = bbp_forum_query_subforum_ids( $forum_id );
+
 		$i = 0;
+
 		foreach ($subforums as $subforum_id) {
+
 			$all_forum_data['subforums'][$i]['id'] = $subforum_id;
+
 			$all_forum_data['subforums'][$i]['title'] = bbp_get_forum_title( $subforum_id );
+
 			$all_forum_data['subforums'][$i]['topic_count'] = bbp_get_forum_topic_count( $subforum_id );
+
 			$all_forum_data['subforums'][$i]['reply_count'] = bbp_get_forum_reply_count( $subforum_id );
+
 			$all_forum_data['subforums'][$i]['permalink'] = bbp_get_forum_permalink( $subforum_id );
+
 			$all_forum_data['subforums'][$i]['content'] = bbp_get_forum_content( $subforum_id );
+
 			$all_forum_data['subforums'][$i]['type'] = bbp_get_forum_type( $subforum_id );
+
 			$i++;
+
 		}
+
 
+
 		if ( ( $per_page * $page ) > $all_forum_data['topic_count'] ) {
+
 			// This is the last page
+
 			$all_forum_data['next_page'] = 0;
+
 		} else {
+
 			$all_forum_data['next_page'] = $page + 1;
+
 			$all_forum_data['next_page_url'] = get_site_url() . '/wp-json/bbp-api/v1/forums' . $forum_id . '?page=' . $all_forum_data['next_page'] . '&per_page=' . $per_page;
+
 		}
+
 
+
 		$i = 0;
+
 		if ( bbp_has_topics ( array( 'orderby' => 'date', 'order' => 'DESC', 'posts_per_page' => $per_page, 'paged' => $page, 'post_parent' => $forum_id ) ) );
+
 		while ( bbp_topics() ) : bbp_the_topic();
+
 			$topic_id = bbp_get_topic_id();
+
 			$all_forum_data['topics'][$i]['id'] = $topic_id;
+
 			$all_forum_data['topics'][$i]['title'] = bbp_get_topic_title( $topic_id );
+
 			$all_forum_data['topics'][$i]['reply_count'] = bbp_get_topic_reply_count( $topic_id );
+			$all_forum_data['topics'][$i]['voice_count'] = bbp_get_topic_voice_count( $topic_id );
+
+
 			$all_forum_data['topics'][$i]['permalink'] = bbp_get_topic_permalink( $topic_id );
+
 			$all_forum_data['topics'][$i]['author_name'] = bbp_get_topic_author_display_name( $topic_id );
+
 			$all_forum_data['topics'][$i]['author_avatar'] = bbp_get_topic_author_avatar( $topic_id );
+
 			$all_forum_data['topics'][$i]['post_date'] = bbp_get_topic_post_date( $topic_id );
+
 			$i++;
+
 		endwhile;
+
 	}
+	return new WP_REST_Response($all_forum_data, 200);  
+
 	if ( empty( $all_forum_data ) ) {
+
 		return null;
+
 	}
+
 	return $all_forum_data;
-}
+
+}