new filter hooks on favourite actions #2620

before a favourite action is made, fire a filter hook so plugins can
modify or cancel that action before it takes place.

src/socket.io/posts.js

@@ -168,22 +168,40 @@ function favouriteCommand(socket, command, eventName, notification, data, callba
 			return callback(new Error('[[error:post-deleted]]'));
 		}
 
-		favourites[command](data.pid, socket.uid, function(err, result) {
+		/*
+		hooks:
+			filter.post.upvote
+			filter.post.downvote
+			filter.post.unvote
+			filter.post.favourite
+			filter.post.unfavourite
+		 */
+		plugins.fireHook('filter:post.' + command, data, function(err, filteredData) {
 			if (err) {
 				return callback(err);
 			}
 
-			socket.emit('posts.' + command, result);
+			executeFavouriteCommand(socket, command, eventName, notification, filteredData, callback);
+		});
+	});
+}
 
-			if (result && eventName) {
-				websockets.in(data.room_id).emit('event:' + eventName, result);
-			}
+function executeFavouriteCommand(socket, command, eventName, notification, data, callback) {
+	favourites[command](data.pid, socket.uid, function(err, result) {
+		if (err) {
+			return callback(err);
+		}
 
-			if (notification) {
-				SocketPosts.sendNotificationToPostOwner(data.pid, socket.uid, notification);
-			}
-			callback();
-		});
+		socket.emit('posts.' + command, result);
+
+		if (result && eventName) {
+			websockets.in(data.room_id).emit('event:' + eventName, result);
+		}
+
+		if (notification) {
+			SocketPosts.sendNotificationToPostOwner(data.pid, socket.uid, notification);
+		}
+		callback();
 	});
 }