exorelay

Exosphere Communication Relay for JavaScript

Communication relay between JavaScript code bases and the Exosphere environment

This library allows you to add Exosphere communication to any Node.JS codebase. It is intended to be used in your web or API server, or with legacy Node code bases. If you want to write a new micro-service in Node, please use ExoService-JS, which uses this library internally.

Add an ExoRelay to your application

Each code base should have only one ExoRelay instance.

ExoRelay = require 'exorelay'

exoRelay = new ExoRelay exocomPort: <port>, serviceName: <name of the service using ExoRelay>
exoRelay.on 'online', (port) ->  # yay, we are online!
exoRelay.on 'error', (err) ->    # examine, print, or log the error here
exoRelay.listen 4000

More details and how to customize the port is described in the spec.

Events

ExoRelay instances are EventEmitters. They emit the following events to signal state changes:

online	The instance is completely online now. Provides the port it listens on.
offline	The instance is offline now.
error	An error has occurred. The instance is in an invalid state, your application should crash.

Handle incoming messages

Let's say we build a service that greets users. Here is how to register a handler for incoming "hello" messages:

exoRelay.registerHandler 'hello', (name) -> console.log "hello #{name}!"

More details on how to define message listeners are here.

Send outgoing messages

Send a message to Exosphere:

exoRelay.send 'hello', name: 'world'

Sending a message is fire-and-forget, i.e. you don't have to wait for the sending process to finish before you can do the next thing. More details on how to send various data are here.

Send outgoing replies to incoming messages

If you are implementing services, you want to send outgoing replies to incoming messages:

exoRelay.registerHandler 'user.create', (userData, {reply}) ->
  # on this line we would save userData in the database
  reply 'user.created', id: 456, name: userData.name

More details and a working example of how to send replies is here.

Handle incoming replies

If a message you send expects a reply, you can provide the handler for it right when you send it:

exoRelay.send 'users.create', name: 'Will Riker', (createdUser) ->
  console.log "the remove service has finished creating user #{createdUser.id}"

More examples for handling incoming replies are here.

Development

See our developer guidelines