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node-red/red/comms.js
2014-06-21 22:43:48 +01:00

114 lines
2.9 KiB
JavaScript

/**
* 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.
**/
var ws = require("ws");
var util = require("util");
var server;
var settings;
var wsServer;
var activeConnections = [];
var retained = {};
var heartbeatTimer;
var lastSentTime;
function init(_server,_settings) {
server = _server;
settings = _settings;
}
function start() {
var path = settings.httpAdminRoot || "/";
path = path + (path.slice(-1) == "/" ? "":"/") + "comms";
wsServer = new ws.Server({server:server,path:path});
wsServer.on('connection',function(ws) {
activeConnections.push(ws);
ws.on('close',function() {
for (var i=0;i<activeConnections.length;i++) {
if (activeConnections[i] === ws) {
activeConnections.splice(i,1);
break;
}
}
});
ws.on('message', function(data,flags) {
var msg = JSON.parse(data);
if (msg.subscribe) {
handleRemoteSubscription(ws,msg.subscribe);
}
});
ws.on('error', function(err) {
util.log("[red:comms] error : "+err.toString());
});
});
wsServer.on('error', function(err) {
util.log("[red:comms] server error : "+err.toString());
});
lastSentTime = Date.now();
heartbeatTimer = setInterval(function() {
var now = Date.now();
if (now-lastSentTime > 15000) {
lastSentTime = now;
publish("hb",lastSentTime);
}
}, 15000);
}
function publish(topic,data,retain) {
if (retain) {
retained[topic] = data;
} else {
delete retained[topic];
}
lastSentTime = Date.now();
activeConnections.forEach(function(conn) {
publishTo(conn,topic,data);
});
}
function publishTo(ws,topic,data) {
var msg = JSON.stringify({topic:topic,data:data});
try {
ws.send(msg);
} catch(err) {
util.log("[red:comms] send error : "+err.toString());
}
}
function handleRemoteSubscription(ws,topic) {
var re = new RegExp("^"+topic.replace(/([\[\]\?\(\)\\\\$\^\*\.|])/g,"\\$1").replace(/\+/g,"[^/]+").replace(/\/#$/,"(\/.*)?")+"$");
for (var t in retained) {
if (re.test(t)) {
publishTo(ws,t,retained[t]);
}
}
}
module.exports = {
init:init,
start:start,
publish:publish,
}