├── app.js
├── README
└── notifications.js


/app.js:
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1 | //console.log(process.env);
2 | 
3 | require("./notifications.js");


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/README:
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 1 | This Node application publishes notifications to the main Greenhouse web application.  It receives messages from a Redis pub/sub topic and then pushes them out to subscribed browser clients via the Socket.IO Node module.
 2 | 
 3 | The app can be started locally (assuming you have NodeJS set up correctly) by executing 'node app.js' from the root directory of the project.
 4 | 
 5 | When running in local mode, it is expected that there is also already a local Redis instance running (on localhost using the default Redis port).
 6 | 
 7 | When running on Cloud Foundry, it is expected that the app has a Redis service bound to it.
 8 | 
 9 | The app will auto-detect its environment on startup, configuring the correct Redis connection based on what is detected.
10 | 
11 | Socket.IO is currently configured to only use the Comet long-polling technique, as Cloud Foundry does not currently allow WebSocket traffic.


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/notifications.js:
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 1 | var http = require('http'),  
 2 |     io = require('socket.io'),
 3 |     redis = require('redis'),
 4 |     redisListener = null,
 5 |     
 6 | server = http.createServer();
 7 | server.listen(process.env.VMC_APP_PORT || 8088);
 8 |     
 9 | //Set up Redis, dynamically discovering and connecting to the bound CloudFoundry service
10 | if (process.env.VCAP_SERVICES) {
11 |     console.log("Bound services detected.");
12 |     var services = JSON.parse(process.env.VCAP_SERVICES);
13 |     for (serviceType in services) {
14 |         console.log("Service: "+serviceType);
15 |         console.log("Service Info: "+JSON.stringify(services[serviceType]));
16 |         if (serviceType.match(/redis*/)) {
17 |             var service = services[serviceType][0];
18 |             console.log("Connecting to Redis service "+service.name+":"+service.credentials.hostname+":"+service.credentials.port);
19 |             redisListener = redis.createClient(service.credentials.port, service.credentials.hostname);
20 |             redisListener.auth(service.credentials.password);
21 |             break;
22 |         }
23 |     }
24 | }
25 | 
26 | //Fall-back Redis connection for local development outside of CloudFoundry
27 | if (!redisListener && !process.env.VCAP_APP_PORT) {
28 |     console.log("Connecting to local Redis service");
29 |     redisListener = redis.createClient();
30 | }
31 | 
32 | if (!redisListener) {
33 |     console.error("Fatal condition - no connection to Redis established");
34 |     process.exit(1);
35 | }
36 | 
37 | redisListener.on("connect", function(){ console.log("Redis listener connection established."); });
38 | 
39 | redisListener.on("error", function(err) { 
40 |     console.log("Error thrown by redis listener connection: "+err);
41 |     process.exit(1);
42 | });
43 |   
44 | // socket.io for pushing messages to the browser
45 | var io = io.listen(server, {transports: ['xhr-polling'], transportOptions: {'xhr-polling': {duration: 10000}} });
46 | 
47 | console.log(io.options);
48 | 
49 | redisListener.subscribe("notifications");
50 | 
51 | redisListener.on("message", function(channel, message){
52 |     io.broadcast(JSON.parse(message));
53 | });


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