node-pub-sub v1.3.3

node-pub-sub

Implements Publish/Subscribe messaging paradigm in a very simple way.

V1.3

Some Wiki

In software architecture, publish–subscribe is a messaging pattern where senders of messages, called publishers, do not program the messages to be sent directly to specific receivers, called subscribers. Instead, published messages are characterized into classes, without knowledge of what, if any, subscribers there may be. Similarly, subscribers express interest in one or more classes, and only receive messages that are of interest, without knowledge of what, if any, publishers there are.

Pub/sub is a sibling of the message queue paradigm, and is typically one part of a larger message-oriented middleware system.

Most messaging systems support both the pub/sub and message queue models in their API, e.g. Java Message Service (JMS).

API

All communication/messages it's done in JSON.

Publish

require('node-pub-sub').Publish
  
Publish([port], [host], [options])
  
 port: default to 5000
 host: default to localhost
 options: {timeout: 120000, encoding: 'ascii'}
      timeout: put a timeout like 1 hour or 6 hours because if spend much 
          time without publish messages the server will close the 
          connection, default to 3600000
      
  
events:
      ('ready', callback)
      ('error', callback (err))
      ('end', callback)


// publish messages
pub.publish('some channel', 'some message', [callback])

// end
pub.end()

Subscribe

require('node-pub-sub').Publish

Publish(port, [host], [options])

  host: default to localhost
  port: default to 5000
  options: {timeout: 120000, encoding: 'ascii'}
      timeout: put a timeout like 1 hour or 6 hours because if spend much
          time without publish messages the server will close the connection,
          default to 3600000
      

// subscribe to a channel      
sub.start('some channel', callback ('error/warn message', 'message - json object'))

// unsubscribe, for now unsubscribe to all channels
sub.end()

Examples

**Publish**

var Publish = require('node-pub-sub').Publish;

var pub = new Publish(5000, {timeout: 120000});

pub.on('ready', function () { console.log('publish ready'); });
pub.on('error', function (err) { console.log(err); });
pub.on('end', function () { console.log('publish ended'); });


pub.publish('some channel', 'some message', function () {
    // some acknowledgement
});

// close Publish    
pub.end();


Message format:
{"n":990,"tmx":1392154487968,"msg":"Hello World"}

create by Publish
n   => message counter 
tmx => message timestamp


**Subscribe**

var Subscribe = require('node-pub-sub').Subscribe;

var sub = new Subscribe(5000, {timeout: 120000});

sub.start(channel, function (err, message) {
    if (err) throw err;
    
    // JSON object 
    console.log(message);
});

// unsubscribe when you want
setTimeout(function () {
    sub.end();
}, 60000);