m2nodehandler

m2nodehandler doubles as a node.js Mongrel2 handler and a lightweight abstraction of ZeroMQ messaging functions. It handles node-application-to-node-application communication and node-application-to-mongrel2 communication.

Getting Started

Install the module with: npm install git+ssh://git@gitlab.openi-ict.eu:m2nodehandler.git

You will need to install the following through macports or aptitude.

sudo port install JsCoverage
sudo port install phantomjs

or

sudo apt-get install JsCoverage
sudo apt-get install phantomjs

To build the project enter the following commands. Note: npm install is only required the first time the module is built or if a new dependency is added. There are a number of grunt tasks that can be executed including: test, cover, default and jenkins. The jenkins task is executed on the build server, if it doesn't pass then the build will fail.

cd m2nodehandler
npm install
grunt jenkins

Documentation

Objects

status - Contains object with human readable text to HTTP status code e.g. status.OK_200 = 200, FORBIDDEN_402 = 402, etc. header_plain - Response objects default headers for plain text. header_json - Response objects default headers for JSON formatted content. header_html - Response objects default headers for HTML content.

Functions

• sender(config) This function sets up a publish or push ZeroMQ socket with the ip address and port supplied in the config parameter.

  • parameters
    config - JavaScript object containing the field spec whose value is the ip address and port that the function should bind to and the id of the connection. e.g. { spec:'tcp://127.0.0.1:49906', bind:false, id:'c', type:'pub', isMongrel2:true }

  {
      spec       : 'Socket IP and Port ',
      bind       : 'Boolean flag for port binding',
      id         : 'Connection ID',
      type       : 'Socket Type: pull, push, pub,. sub',
      isMongrel2 : 'Boolean flag for socket connection to mongrel2',
      subscribe  : 'subscription filter for sub sockets'
  }

  • returns null

• receiver(config, callback) This function sets up a pull or subscription ZeroMQ socket with the ip address and port supplied in the config parameter. It attaches the given callback function to the on message event of the queue. I.e. every time a message is received the callback function is executed.

  • parameters
    config - JavaScript object containing the field spec whose value is the ip address and port that the function should bind to. e.g. { spec:'tcp://127.0.0.1:49906', bind:false, id:'c', type:'sub', subscribe:'' } function (msg) this callback function is attached to the on message event of the incoming queue. Each time a message is recieved from the queue this function is executed. The message is converted to JavaScript object before it is passed to this function e.g. function(msg){console.log(msg)}*
  • returns null

Examples

Example 1: Connect to Mongrel2

This example connects to Mongrel2 instance running on port 49996 and 49997. To configure the Mongrel2 load the configuration file with the following values.

node_handler = Handler(
  send_spec  = 'tcp://127.0.0.1:49997',
  send_ident = '81b7114c-534c-4107-9f17-b317cfd59f62',
  recv_spec  = 'tcp://127.0.0.1:49996',
  recv_ident = ''
)


my_host = Host(name = 'localhost', routes = {
  '/data': node_handler
})


main = Server(
  name         = "my_server",
  port         = 80,
  uuid         = '5dc1fbe7-d9db-4602-8d19-80c7ef2b1b11',
  access_log   = "/logs/access.log",
  error_log    = "/logs/error.log",
  chroot       = ".",
  default_host = "localhost",
  pid_file     = "/run/mongrel2.pid",
  hosts        = [my_host]
)


servers = [main]

Next start the Mongrel2 server.

m2sh load -config my_config_file.conf -db my_mongrel2_conf.db
sudo m2sh start -db my_mongrel2_conf.db -every

Create a file named script.js file and paste the following JavaScript.

'use strict';

var zmq = require('m2nodehandler');

var mongrel2PubQ = zmq.sender({ spec:'tcp://127.0.0.1:49996', id:'test', bind:false, type:'push' })

zmq.receiver( { spec:'tcp://127.0.0.1:49997', id:'test', bind:false, type:'pull' },
   { spec:'tcp://127.0.0.1:49996', id:'test', bind:false, type:'push' }
   function( msg ) {

   console.log("Headers");
   for (var i in msg.headers ){
      console.log("\t" + i + " :" + msg.headers[i]);
   }
   console.log("UUID   : " + msg.uuid);
   console.log("CONNID : " + msg.connId);
   console.log("Path   : " + msg.path);
   console.log("JSON   : " + msg.json);
   console.log();

   var response = zmq.Response( zmq.status.OK_200, zmq.header_json, '{"message":"Hello, World!"}' )

   mongrel2PubQ.send(msg.uuid, msg.connId, response);

});

Finally install this module, start the node application and browse to this URL (http://localhost/data/test).

npm install git+ssh://git@gitlab.openi-ict.eu:m2nodehandler.git
node script.js

Example 2: Node application to node application

Communications between two small node applications via ZeroMQ. The connection isn't request-reply queue but two separate push-pull queues.

Create a file named node1.js and paste the following code.

var zmq   = require('m2nodehandler')

var pushQ = zmq.sender({spec:'tcp://127.0.0.1:49994', id:'nodetest1', bind:false, type:'push'});

zmq.receiver( {spec:'tcp://127.0.0.1:49995', id:'node1', bind:false, type:'pull'}, { spec:'tcp://127.0.0.1:49994', id:'test', bind:false, type:'push' }, function( msg ) {

   msg.count = msg.count + 1;

   pushQ.push(msg)

});

Create another file called node2.js and paste the following JavaScript.

var zmq  = require('m2nodehandler')

var pushQ = zmq.sender({spec:'tcp://127.0.0.1:49995', id:'nodetest2', bind:false, type:'push'});

zmq.receiver( {spec:'tcp://127.0.0.1:49994', id:'node2', bind:false, type:'pull'}, function( msg ) {

   console.log("Count = " + msg.count);

   pushQ.push(msg)

});

pushQ.push({count:0})

Finally install this module, start the two node applications in separate consoles. You should see the counter increase on the second console.

npm install git+ssh://git@gitlab.openi-ict.eu:m2nodehandler.git
node node1.js
node node2.js

Contributors

• Donal McCarthy (dmccarthy@tssg.org)
• David Benson (dbenson@tssg.org)
• Dylan Conway (dconway@tssg.org)

Release History

0.1.0 (23/10/14 dmccarthy@tssg.org, dbenson@tssg.org, dconway@tssg.org) Includes Mongrel2 handler and node-to-node ZMQ communication helpers.

License

Copyright (c) 2013 Licensed under the MIT license.