dgbuilder/public/red/comms.js

   1 /**
   2  * Copyright 2014 IBM Corp.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  **/
  16
  17 RED.comms = (function() {
  18
  19     var errornotification = null;
  20     var subscriptions = {};
  21     var ws;
  22     function connectWS() {
  23         var path = location.hostname+":"+location.port+document.location.pathname;
  24         path = path+(path.slice(-1) == "/"?"":"/")+"comms";
  25         path = "ws"+(document.location.protocol=="https:"?"s":"")+"://"+path;
  26         ws = new WebSocket(path);
  27         ws.onopen = function() {
  28             if (errornotification) {
  29                 errornotification.close();
  30                 errornotification = null;
  31             }
  32             for (var t in subscriptions) {
  33                 if (subscriptions.hasOwnProperty(t)) {
  34                     ws.send(JSON.stringify({subscribe:t}));
  35                 }
  36             }
  37         }
  38         ws.onmessage = function(event) {
  39             var msg = JSON.parse(event.data);
  40             if (msg.topic) {
  41                 for (var t in subscriptions) {
  42                     if (subscriptions.hasOwnProperty(t)) {
  43                         var re = new RegExp("^"+t.replace(/([\[\]\?\(\)\\\\$\^\*\.|])/g,"\\$1").replace(/\+/g,"[^/]+").replace(/\/#$/,"(\/.*)?")+"$");
  44                         if (re.test(msg.topic)) {
  45                             var subscribers = subscriptions[t];
  46                             if (subscribers) {
  47                                 for (var i=0;i<subscribers.length;i++) {
  48                                     subscribers[i](msg.topic,msg.data);
  49                                 }
  50                             }
  51                         }
  52                     }
  53                 }
  54             }
  55         };
  56         ws.onclose = function() {
  57             if (errornotification == null) {
  58                 errornotification = RED.notify("<b>Error</b>: Lost connection to server","error",true);
  59             }
  60             setTimeout(connectWS,1000);
  61         }
  62     }
  63
  64     function subscribe(topic,callback) {
  65         if (subscriptions[topic] == null) {
  66             subscriptions[topic] = [];
  67         }
  68         subscriptions[topic].push(callback);
  69         if (ws && ws.readyState == 1) {
  70             ws.send(JSON.stringify({subscribe:topic}));
  71         }
  72     }
  73
  74     function unsubscribe(topic,callback) {
  75         if (subscriptions.topic) {
  76             for (var i=0;i<subscriptions.topic.length;i++) {
  77                 if (subscriptions.topic[i] === callback) {
  78                     subscriptions.topic.splice(i,1);
  79                     break;
  80                 }
  81             }
  82             if (subscriptions.topic.length === 0) {
  83                 delete subscriptions.topic;
  84             }
  85         }
  86     }
  87
  88     return {
  89         connect: connectWS,
  90         subscribe: subscribe,
  91         unsubscribe:unsubscribe
  92     }
  93 })();