Add server (web/socket), create socket system, better helper loader.

- The Magic Mirror is now hosted via a express server, allowing you to
load it from an external client (for debugging.)
- It now includes a socket system to communicate between the
node_helper and the client module.
- node_helpers are now only loaded if the module is configured in the
config.

modules/newsfeed/node_helper.js

@@ -1,17 +1,142 @@
-// Configuration.
-var config = {
-	port: 8080
-};
 
 // Load modules.
-var express = require('express');
 var request = require('request'); 
 var FeedMe = require('feedme');
 var validUrl = require('valid-url');
-var app = express();
+var MMSocket = require('../../js/socketclient.js');
+var socket = new MMSocket('newsfeed');
 
-// Create NewsFetcher.
-var NewsFetcher = (function() {
+var fetchers = {};
+
+// Register the notification callback.
+socket.setNotificationCallback(function(notification, payload) {
+	if(notification === 'ADD_FEED') {
+		createFetcher(payload.url, payload.reloadInterval);
+	}
+});
+
+/* createFetcher(url, reloadInterval)
+ * Creates a fetcher for a new url if it doesn't exsist yet.
+ * Otherwise it reoses the exsisting one.
+ *
+ * attribute url string - URL of the news feed.
+ * attribute reloadInterval number - Reload interval in milliseconds.
+ */
+
+var createFetcher = function(url, reloadInterval) {
+	if (!validUrl.isUri(url)){
+        socket.sendNotification('INCORRECT_URL', url);
+        return;
+    }
+
+    var fetcher;
+    if (typeof fetchers[url] === 'undefined') {
+    	console.log('Create new news fetcher for url: ' + url + ' - Interval: ' + reloadInterval);
+    	fetcher = new Fetcher(url, reloadInterval);
+    	fetchers[url] = fetcher;
+    } else {
+    	console.log('Use exsisting news fetcher for url: ' + url);
+    	fetcher = fetchers[url];
+    	fetcher.setReloadInterval(reloadInterval);
+    	fetcher.broadcastItems();
+    }
+
+    fetcher.startFetch();
+};
+
+
+/* Fetcher
+ * Responsible for requesting an update on the set interval and broadcasting the data.
+ *
+ * attribute url string - URL of the news feed.
+ * attribute reloadInterval number - Reload interval in milliseconds.
+ */
+
+var Fetcher = function(url, reloadInterval) {
+	var self = this;
+	var newsFetcher = new NewsFetcher();
+	if (reloadInterval < 1000) {
+		reloadInterval = 1000;
+	}
+	
+	var reloadTimer = null;
+	var items = [];
+
+	/* private methods */
+
+	/* fetchNews()
+	 * Request the new items from the newsFetcher.
+	 */
+
+	var fetchNews = function() {
+		//console.log('Fetch news.');
+		clearTimeout(reloadTimer);
+		reloadTimer = null;
+		newsFetcher.fetchNews(url, function(fetchedItems) {
+			//console.log(fetchedItems.length + ' items received.');
+			items = fetchedItems;
+			self.broadcastItems();
+			scheduleTimer();
+		}, function(error) {
+			//console.log('Unable to load news: ' + error);
+			socket.sendNotification('UNABLE_TO_LOAD_NEWS', {url:url, error:error});
+			scheduleTimer();
+		});
+	};
+
+	/* scheduleTimer()
+	 * Schedule the timer for the next update.
+	 */
+
+	var scheduleTimer = function() {
+		//console.log('Schedule update timer.');
+		clearTimeout(reloadTimer);
+		reloadTimer = setTimeout(function() {
+			fetchNews();
+		}, reloadInterval);
+	};
+
+	/* public methods */
+
+	/* setReloadInterval()
+	 * Update the reload interval, but only if we need to increase the speed.
+	 *
+	 * attribute interval number - Interval for the update in milliseconds.
+	 */
+	this.setReloadInterval = function(interval) {
+		if (interval > 1000 && interval < reloadInterval) {
+			reloadInterval = interval;
+		}
+	};
+
+	/* startFetch()
+	 * Initiate fetchNews();
+	 */
+	this.startFetch = function() {
+		fetchNews();
+	};
+
+	/* broadcastItems()
+	 * Broadcast the exsisting items.
+	 */
+	this.broadcastItems = function() {
+		if (items.length <= 0) {
+			//console.log('No items to broadcast yet.');
+			return;
+		}
+		//console.log('Broadcasting ' + items.length + ' items.');
+		socket.sendNotification('NEWS_ITEMS', {
+			url: url,
+			items: items
+		});
+	};
+};
+
+/* NewsFetcher
+ * Responsible for requesting retrieving the data.
+ */
+
+var NewsFetcher = function() {
 	var self = this;
 
 	self.successCallback = function(){};
@@ -33,41 +158,27 @@ var NewsFetcher = (function() {
 		self.successCallback(self.items);
 	});
 
-	parser.on('error', function(item) {
-		self.errorCallback();
+	parser.on('error', function(error) {
+		self.errorCallback(error);
 	});
 
-	return {
-		fetchNews: function(url, success, error) {
-			self.successCallback = success;
-			self.errorCallback = error;
-			request(url).pipe(parser);
-		}
+	/* public methods */
+
+	/* fetchNews()
+	 * Fetch the new news items.
+	 *
+	 * attribute url string - The url to fetch.
+	 * attribute success function(items) - Callback on succes. 
+	 * attribute error function(error) - Callback on error. 
+	 */
+	self.fetchNews = function(url, success, error) {
+		self.successCallback = success;
+		self.errorCallback = error;
+		request(url).pipe(parser);
 	};
-})();
+};
 
-// Create route for fetcher.
-app.get('/', function (req, res) {
 
-	if (!validUrl.isUri(req.query.url)){
-        res.status(404).send('No valid feed URL.');
-        return;
-    }
-
-	NewsFetcher.fetchNews(req.query.url, function(items) {
-		res.send(items);
-	}, function() {
-		res.status(400).send('Could not parse feed.');
-	});
-});
-
-// Listen on port.
-app.listen(config.port, function () {
-  console.log('Feed proxy is running on port: ' + config.port);
-});
-
-console.log('Starting feed proxy on port: ' + config.port);
-