sugo-hub/lib/connectors/observer_connector.js

Hub server of SUGOS

/**
 * Connector for observers
 * @augments Connector
 * @class ObserverConnector
 */
'use strict'

const Connector = require('./connector')

const {ReservedEvents, ObservingEvents} = require('sg-socket-constants')
const {START, STOP, CHANGE} = ObservingEvents
const {DISCONNECT} = ReservedEvents

const {ActorEvents, CallerEvents} = require('sugo-constants')
const {SETUP, UPDATE, TEARDOWN} = ActorEvents
const {JOIN, LEAVE} = CallerEvents

const debug = require('debug')('sg:hub:observer')

/** @lends ObserverConnector */
class ObserverConnector extends Connector {

  /**
   * @override
   */
  handleConnection (socket, scope) {
    const s = this

    let {
      observerService,
      actorService,
      callerService
    } = scope

    let {socketPipe, registerListeners, deregisterListeners} = ObserverConnector

    let {id} = socket

    let actorListeners = socketPipe(socket, [SETUP, UPDATE, TEARDOWN])
    let callerListeners = socketPipe(socket, [JOIN, LEAVE])

    // Handle connect request form observer
    socket.on(START, s.ack(async function startObserving (data) {
      const observer = await observerService.startObserving(id)

      debug(`Start observing on socket: ${observer.socketId}`)

      registerListeners(actorService, actorListeners)
      registerListeners(callerService, callerListeners)

      return [{key: observer.key}]
    }))

    // Handle disconnect request from observer
    socket.on(STOP, s.ack(async function teardownActor (data) {
      const observer = await observerService.stopObserving(id)

      debug(`Stop observing on socket: ${observer.socketId}`)

      deregisterListeners(actorService, actorListeners)
      deregisterListeners(callerService, callerListeners)

      return [{key: observer.key}]
    }))

    // Cleanup sockets
    socket.on(DISCONNECT, async () => {
      const observer = await observerService.findBySocketId(id)
      if (observer) {
        await observerService.destroy(observer.key)
      }
    })
  }
}

Object.assign(ObserverConnector, {
  socketPipe (socket, events) {
    let handlers = {}
    for (let event of events) {
      handlers[event] = (data) => socket.emit(CHANGE, {event, data})
    }
    return handlers
  },
  registerListeners (emitter, listeners) {
    for (let event of Object.keys(listeners)) {
      emitter.addListener(event, listeners[event])
    }
  },
  deregisterListeners (emitter, listeners) {
    for (let event of Object.keys(listeners)) {
      emitter.removeListener(event, listeners[event])
    }
  }

})

module.exports = ObserverConnector