rpc-events

An rpc-engine subclass that makes doing pub-sub things super easy.

Why

Making a remote procedure call to an EventEmitter's on or removeListener methods doesn't really do what you want.

How

JSON-RPC style notifications + wrappers for on and removeListener. See the API section below.

Example

var Rpc = require('rpc-events')
 
var a = new Rpc()
var b = new Rpc()
 
a.send = b.receive
b.send = a.receive
 
a.subscribe('event', handler)
 
function handler (evt) {
  console.log(evt) // => 42
  a.unsubscribe('event', handler)
}
 
b.getInterface().emit('event', 42)

Test

$ npm run test

API

See rpc-engine for the superclass API.

Methods

rpc.setInterface(path[, iface])

rpc.setInterface(iface)

Same as superclass, but iface must implement on and removeListener (see EventEmitter API).

rpc.subscribe(eventName, handler[, onerror])

Subscribe to a remote event.

• eventName A String.
• handler A Function.
• onerror A Function. Will be called if the remote side removes the interface before the local side has called unsubscribe.

rpc.unsubscribe(eventName, handler)

Unsubscribe from a remote event.

• eventName A String.
• handler A Function.

rpc.open()

This method will reinform the remote about the currently active subscriptions. This is useful for implementing persistent connections where transports may come and go transparently.

rpc.close()

This method extends the superclass implementation to ensure all local and remote subscriptions are torn down before cancelling outstanding requests.

rpc.closeLocal()

rpc.closeRemote()

These methods are invoked by rpc.close but can be useful independently. Closing the local side removes everything created by calls to rpc.subscribe, and closing the remote side removes all subscriptions created by the remote peer. rpc.closeRemote is useful in situations where you plan to reopen the connection at some point without losing track of your subscriptions, but can't be sure if the remote plans to do the same.

Releases

• 2.1
  • Add open method
  • Split close out into its local and remote components
• 2.0
  • rpc-engine@6.0.0
  • Alter API to support scenario where remote side removes the interface a local subscription is associated with.
  • Try to ensure local behavior is correct even if remote side misses messages or receives them out of order.
• 1.0
  • First release

License

MIT