simple_pubsub v0.0.4

A Simple PUBSUB Server and Client for Node.js

A publisher publishes a message on a channel which is just a string name. A subscriber subscribed to the channel will be forwarded the published message.

This server is meant for internal/backend use only. Publishers and subscribers talk to a PUBSUB server over TCP/IP.

The NPM package is JavaScript compiled from CoffeeScript. Use the git repository to work with the CoffeeScript version.

Installation

npm install simple_pubsub

Running a PUBSUB Server

simple_pubsub_server [OPTIONS]

--listen <ip:port>      Default: 127.0.0.1:9912
--loglevel <level>      Default: error

Example Publisher

var client = require('simple_pubsub').connect();
var timer_id = setInterval(function () {
  client.publish(new Date(), 'current-time');
}, 1000);
client.on('io-error', function (err) {
  clearInterval(timer_id);
});

Example Subscriber

require('simple_pubsub').connect().subscribe('current-time', function (msg, chan) {
  console.log("The time is " + msg);
});

API

module: simple_pubsub

function: connect(port=9912, host='127.0.0.1')

Returns a SimplePubsubClient object.

object: SimplePubsubClient

event: io-error (err)

An input/output error occurred.

event: protocol-error (err)

Someone wrote a malformed message.

event: message (msg, chan)

All messages that are received due to some subscription.

method: subscribe(chan, cb)

Subscribe to a channel 'chan' and call back function 'cb' with the msg and chan when a message is published to 'chan'.

method: unsubscribe(chan)

Unsubscribe from channel 'chan'.

method: publish(msg, chan)

Publish a message 'msg' to channel 'chan'.

Notes

System messages are published on a reserved channel named simplepubsub. All clients are implicitly subscribed to this channel.

Limitations

Wildcard channel names are unsupported; publishers and subscribers must use literal channel names, not patterns.

Offline storage is unsupported.

Protocol

All messages are encoded as CRLF delimited JSON objects.

Subscribe

A client subscribes to a channel.

{ sub: 'channel' }

Publish

A client publishes a message to one or more channels. The same message is forwarded to subscribers.

{ pub: { msg: value, chan: 'channel' } }

Author

Brian Hammond brian@fictorial.com (http://fictorial.com)

License

MIT