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Getting Started

With the Eve library for Node.js, one can create software agents in Javascript and run them in Node.js or in the browser.

This tutorial contains the following steps:


To run Eve on Node.js, Node.js must be installed on your system. Node.js can be downloaded from the website There are installers available for Windows, Mac.


Install the module via npm:

npm install evejs


An agent basically has a methods send, receive, connect and disconnect. An agent can be extended with modules like pattern and request. There is a central configuration eve.system which can be used to load transports. The loaded transports can be used by agents to communicate with each other.

To set up a system with eve agents:

var eve = require('evejs');
  function MyAgent(id) {, id);
    // ...
  MyAgent.prototype = Object.create(eve.Agent.prototype);
  MyAgent.prototype.constructor = MyAgent;
  MyAgent.prototype.receive = function (from, message) {
    // ...
  module.exports = MyAgent;
    transports: [
        type: 'distribus'
var agent1 = new MyAgent('agent1');
agent1.send('distribus://networkId/agent2', 'hello agent2!');
  agent1.send('agent2', 'hello agent2!'); // send via the default transport

The networkId of a transport can be found at transport.networkId.


To create a simple agent class, create a file HelloAgent.js with the following code:

var eve = require('evejs');

function HelloAgent(id) {
  // execute super constructor, id);

  // connect to all transports configured by the system

// extend the eve.Agent prototype
HelloAgent.prototype = Object.create(eve.Agent.prototype);
HelloAgent.prototype.constructor = HelloAgent;

HelloAgent.prototype.sayHello = function(to) {
  this.send(to, 'Hello ' + to + '!');

HelloAgent.prototype.receive = function(from, message) {
  console.log(from + ' said: ' + JSON.stringify(message));

  if (message.indexOf('Hello') === 0) {
    // reply to the greeting
    this.send(from, 'Hi ' + from + ', nice to meet you!');

module.exports = HelloAgent;

This agent class can be used as follows. Note that the agents talk to each other via a LocalTransport which is instantiated in eve.system by default.

var HelloAgent = require('./HelloAgent');

// create two agents
var agent1 = new HelloAgent('agent1');
var agent2 = new HelloAgent('agent2');

// send a message to agent1
agent2.send('agent1', 'Hello agent1!');



The Node.js application can be deployed on any of the available hosting solutions for Node.js:


To use evejs in the browser, one can browserify the library and load it into any browser.

Site last rendered 30 March 2015