adamringhede / node-amqp-sub

Multicasting on AMQP topic exchanges with WebSockets

This is a layer between WebSockets and a message queue using AMQP for building fault tolerant, scalable, and reliable notification systems with a layer of security.

How to use it

Example usage

const sub = require('@adamringhede/amqp-sub')

sub.start({
  handler: req => `my.routes.*`,
  path: '/subscribe',
  amqpUri: 'amqp://localhost',
  exchange: 'updates',
  port: 8001
})

Parameters

• handler: req -> Promise<String>|String A function which is called when a new connection is established. It should perfrom any necessary authorization logic and return or resolve a route key as a string. If it returns anything other than a valid route key, the connection will be rejected. The req arguments includes both path and query parameters as objects under the properties req.params and req.query respectively.

• path: String (optional) A url path used for incomming request. If it is specified, then requests that does not match it will be rejected. The path can include parameters which will be available in the handler function by prefixing the parameter with a colon as in /my/path/:my_param.

• amqpUri: String A uri for AMQP. Read more at https://www.rabbitmq.com/uri-spec.html

• exchange: String The name of the topic exchange to use for routing messages.

• httpServer: http.Server (optional) An instance of an HTTP server to bind the WebSocket server to. If one is not specified, a new one will be created with the specified port.

• port: Number (optional) The port to use if a httpServer is not specified. If neither port or httpServer is specified, a server will be created using port 8001.

Publishing messages

Messages are published to the exchange created when starting the server according to the AMQP protocol. The package also includes a publisher class for convenience.

Using the built in publisher

const sub = require('@adamringhede/amqp-sub')

const pub = new sub.Publisher({ exchange: 'updates', amqpUri: 'amqp://localhost' })
pub.publish('my.routes.123', "Hello World!")