Skip to content

Instantly share code, notes, and snippets.

@dunglehome
Forked from scttnlsn/README.md
Created January 14, 2016 21:24
  • Star 0 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
Star You must be signed in to star a gist
Save dunglehome/03d885d781332adb9202 to your computer and use it in GitHub Desktop.
Pub/sub with MongoDB and Node.js

Pub/sub with MongoDB and Node.js

Setup:

$ mongo
> use pubsub
> db.createCollection('messages', { capped: true, size: 100000 })
> db.messages.insert({})

$ npm install mongodb

Subscribe:

$ node subscribe.js

Publish:

$ mongo
> use pubsub
> db.messages.insert({ message: 'Hello world', time: Date.now() })
var mongo = require('mongodb');
var server = new mongo.Server('localhost', 27017);
var db = new mongo.Db('pubsub', server);
db.open(function(err) {
if (err) throw err;
db.collection('messages', function(err, collection) {
if (err) throw err;
var latest = collection.find({}).sort({ $natural: -1 }).limit(1);
latest.nextObject(function(err, doc) {
if (err) throw err;
var query = { _id: { $gt: doc._id }};
var options = { tailable: true, awaitdata: true, numberOfRetries: -1 };
var cursor = collection.find(query, options).sort({ $natural: 1 });
(function next() {
cursor.nextObject(function(err, message) {
if (err) throw err;
console.log(message);
next();
});
})();
});
});
});
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment