teensy-audio/gui/red/comms.js

/** Modified from original Node-Red source, for audio system visualization
 * vim: set ts=4:
 * Copyright 2014 IBM Corp.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 **/
 
RED.comms = (function() {
	
	var errornotification = null;
	var subscriptions = {};
	var ws;
	function connectWS() {
		var path = location.hostname+":"+location.port+document.location.pathname;
		path = path+(path.slice(-1) == "/"?"":"/")+"comms";
		path = "ws"+(document.location.protocol=="https:"?"s":"")+"://"+path;
		ws = new WebSocket(path);
		ws.onopen = function() {
			if (errornotification) {
				errornotification.close();
				errornotification = null;
			}
			for (var t in subscriptions) {
				if (subscriptions.hasOwnProperty(t)) {
					ws.send(JSON.stringify({subscribe:t}));
				}
			}
		}
		ws.onmessage = function(event) {
			var msg = JSON.parse(event.data);
			if (msg.topic) {
				for (var t in subscriptions) {
					if (subscriptions.hasOwnProperty(t)) {
						var re = new RegExp("^"+t.replace(/([\[\]\?\(\)\\\\$\^\*\.|])/g,"\\$1").replace(/\+/g,"[^/]+").replace(/\/#$/,"(\/.*)?")+"$");
						if (re.test(msg.topic)) {
							var subscribers = subscriptions[t];
							if (subscribers) {
								for (var i=0;i<subscribers.length;i++) {
									subscribers[i](msg.topic,msg.data);
								}
							}
						}
					}
				}
			}
		};
		ws.onclose = function() {
			if (errornotification == null) {
				//errornotification = RED.notify("<b>Error</b>: Lost connection to server","error",true);
			}
			setTimeout(connectWS,1000);
		}
	}
	
	function subscribe(topic,callback) {
		if (subscriptions[topic] == null) {
			subscriptions[topic] = [];
		}
		subscriptions[topic].push(callback);
		if (ws && ws.readyState == 1) {
			ws.send(JSON.stringify({subscribe:topic}));
		}
	}
	
	
	return {
		connect: connectWS,
		subscribe: subscribe
	}
})();