Mongoose Pub/Sub

This node module implements pub/sub messaging using the "tailable cursor" feature of MongoDB capped collections.

Features

• Easily implement pub/sub without adding new infrastructure
• Sub-millisecond messaging
• Send javascript objects as messages

Installation

npm install mongoose-pubsub

Use

var MessageQueue = require('mongoose-pubsub');
var messenger = new MessageQueue();
 
//channel names are used as filters
var channelName = 'news';
messenger.subscribe(channelName, true); //subscribe
messenger.subscribe(channelName, false); //unsubscribe
 
// connect() begins "tailing" the collection
messenger.connect(function(){
  // emits events for each new message on the channel
  messenger.on(channelName, function(message){
    console.log(channelName, message);
  });
});
 
// you can send without connect() first.
messenger.send(channelName, {some: 'message'}, function(err){
  console.log('Sent message');
});

See the test directory for more information.

Note: The best way to use this in your application is to create a file like the following that exports a singleton. Then, when you require this in multiple files in your app, you always get the same instance.

// in lib/messenger.js ...
var MessageQueue = require('mongoose-pubsub');
module.exports = new MessageQueue({retryInterval: 100});
 
// in other files in your app ...
var messenger = require('./lib/messenger');
messenger.on(...

Tests

npm test
npm run lint
npm run coverage