Alpaca

UPDATE - I've since decided that a full EIP like Camel for Node.js is too heavyweight and we are better off focusing on microservices so I've stopped work on this project. I'd recommend using the async library (https://github.com/caolan/async) for pipelines and writing small functions, I'm not convinced node projects should be any bigger than that.

Cheers

@superaking

Key Concepts

Exchange

Object passed between routes and processors, contains a Message.

Message

Object that contains content and headers.

Endpoint

URI that identifies an input or an output

Processor

A function(exchange, callback) or an object with a process(exchange, callback) function, if object is passed then it binds to the object

Route

Input endpoint, a pipeline and an optional output endpoint

Pipeline

A list of processors that the exchange is passed through sequentially

Core Processors

When

contains a truthy expression (usually checking something on the exchange)
wraps a processor / endpoint

Choice

a list of When processors
loops through and sends to the first When processor whose expression is true

To

sends to an endpoint
calls back to the exchange

Multicast

sends to multiple endpoints or processors

Filter

filters based on an expression

Splitter

Aggregator

Wiretap

Basic Useage with Route Builder

var Alpaca = require('alpaca'),
    Context = Alpaca.Context,
    RouteBuilder = Alpaca.RouteBuilder,
    Exchange = Alpaca.Exchange,
    Message = Alpaca.Message,

// basic processor that processes an exchange, appending a string to the body
function TextAppender(textToAppend) {
  this.textToAppend = textToAppend;
}

// processors should provide a process method that takes an exchange
// and a callback
TextAppender.prototype.process = function(exchange, callback) {

  // process the exchange
  exchange.message.body += this.textToAppend;

  // callback (err, exchange)
  callback(null, exchange);
};


var cx = new Context();

cx.addRoute(new RouteBuilder(cx).from("direct:one")
                               .process(new TextAppender(' 1!'))
                               .build());

cx.addRoute(new RouteBuilder(cx).from("direct:two")
                               .process(new TextAppender(' 2!'))
                               .build());

cx.addRoute(new RouteBuilder(cx).from("direct:three")
                               .process(new TextAppender(' 3!'))
                               .to('direct:outbound')
                               .build());

cx.addRoute(new RouteBuilder(cx).from("direct:multicast")
                                .process(new TextAppender('Hello'))
                                .multicast('direct:one', 'direct:two', 'direct:three')
                                .build());

cx.on('direct:outbound', function(exchange) {
  // exchange.message.body == 'Hello 3!'
  done();
});

cx.send('direct:multicast', new Exchange());

alexanderjamesking/alpaca-js