Ignore favicon requests. Output error to http stream if no system found

lib/sonos-http-api.js

@@ -6,10 +6,9 @@ const logger = require('sonos-discovery/lib/helpers/logger');
 
 function HttpAPI(discovery, settings) {
 
-  var port = settings.port;
-  var webroot = settings.webroot;
-  var actionsDir = __dirname + '/actions';
-  var actions = {};
+  const port = settings.port;
+  const webroot = settings.webroot;
+  const actions = {};
 
   this.getWebRoot = function () {
     return webroot;
@@ -48,18 +47,23 @@ function HttpAPI(discovery, settings) {
   });
 
   this.requestHandler = function (req, res) {
-    if (discovery.zones.length === 0) {
-      res.writeHead(500, 'No system has been found yet.');
+    if (req.url === '/favicon.ico') {
       res.end();
-      logger.error('No system has yet been discovered. Please see https://github.com/jishi/node-sonos-http-api/issues/77 if it doesn\'t resolve itself in a few seconds.');
       return;
     }
 
-    var params = req.url.substring(1).split('/');
+    if (discovery.zones.length === 0) {
+      const msg = 'No system has yet been discovered. Please see https://github.com/jishi/node-sonos-http-api/issues/77 if it doesn\'t resolve itself in a few seconds.';
+      logger.error(msg);
+      sendResponse(500, { status: 'error', error: msg });
+      return;
+    }
+
+    const params = req.url.substring(1).split('/');
 
-    var player = discovery.getPlayer(decodeURIComponent(params[0]));
+    let player = discovery.getPlayer(decodeURIComponent(params[0]));
 
-    var opt = {};
+    const opt = {};
 
     if (player) {
       opt.action = (params[1] || '').toLowerCase();