fix potential crash when users disconnect from client

lib/player_server.js

@@ -73,10 +73,7 @@ PlayerServer.actions = {
         } else {
           key = dbFile.key;
         }
-        // client might have disconnected by now
-        try {
-          client.sendMessage('importUrl', {id: id, key: key});
-        } catch (err) {}
+        client.sendMessage('importUrl', {id: id, key: key});
       });
     },
   },

lib/protocol_parser.js

@@ -10,9 +10,10 @@ function ProtocolParser(options) {
   this.player = options.player;
 
   this.buffer = "";
+  this.alreadyClosed = false;
 }
 
-ProtocolParser.prototype._read = function(size) {}
+ProtocolParser.prototype._read = function(size) {};
 
 ProtocolParser.prototype._write = function(chunk, encoding, callback) {
   var self = this;
@@ -44,15 +45,18 @@ ProtocolParser.prototype._write = function(chunk, encoding, callback) {
     }
     self.emit('message', jsonObject.name, jsonObject.args);
   }
-}
+};
 
 ProtocolParser.prototype.sendMessage = function(name, args) {
+  if (this.alreadyClosed) return;
   var jsonObject = {name: name, args: args};
   this.push(JSON.stringify(jsonObject));
 };
 
 ProtocolParser.prototype.close = function() {
+  if (this.alreadyClosed) return;
   this.push(null);
+  this.alreadyClosed = true;
 };
 
 function extend(o, src) {

lib/web_socket_api_client.js

@@ -11,10 +11,15 @@ function WebSocketApiClient(ws) {
 }
 
 WebSocketApiClient.prototype.sendMessage = function(name, args) {
-  this.ws.send(JSON.stringify({
-    name: name,
-    args: args,
-  }));
+  try {
+    this.ws.send(JSON.stringify({
+      name: name,
+      args: args,
+    }));
+  } catch (err) {
+    // nothing to do
+    // client might have disconnected by now
+  }
 };
 
 WebSocketApiClient.prototype.close = function() {