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rails--rails/actioncable/app/assets/javascripts/action_cable/subscription.coffee

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CoffeeScript

# A new subscription is created through the ActionCable.Subscriptions instance available on the consumer.
# It provides a number of callbacks and a method for calling remote procedure calls on the corresponding
# Channel instance on the server side.
#
# An example demonstrates the basic functionality:
#
# App.appearance = App.cable.subscriptions.create "AppearanceChannel",
# connected: ->
# # Called once the subscription has been successfully completed
#
# appear: ->
# @perform 'appear', appearing_on: @appearingOn()
#
# away: ->
# @perform 'away'
#
# appearingOn: ->
# $('main').data 'appearing-on'
#
# The methods #appear and #away forward their intent to the remote AppearanceChannel instance on the server
# by calling the `@perform` method with the first parameter being the action (which maps to AppearanceChannel#appear/away).
# The second parameter is a hash that'll get JSON encoded and made available on the server in the data parameter.
#
# This is how the server component would look:
#
# class AppearanceChannel < ApplicationActionCable::Channel
# def subscribed
# current_user.appear
# end
#
# def unsubscribed
# current_user.disappear
# end
#
# def appear(data)
# current_user.appear on: data['appearing_on']
# end
#
# def away
# current_user.away
# end
# end
#
# The "AppearanceChannel" name is automatically mapped between the client-side subscription creation and the server-side Ruby class name.
# The AppearanceChannel#appear/away public methods are exposed automatically to client-side invocation through the @perform method.
class ActionCable.Subscription
constructor: (@subscriptions, params = {}, mixin) ->
@identifier = JSON.stringify(params)
extend(this, mixin)
@subscriptions.add(this)
@consumer = @subscriptions.consumer
# Perform a channel action with the optional data passed as an attribute
perform: (action, data = {}) ->
data.action = action
@send(data)
send: (data) ->
@consumer.send(command: "message", identifier: @identifier, data: JSON.stringify(data))
unsubscribe: ->
@subscriptions.remove(this)
extend = (object, properties) ->
if properties?
for key, value of properties
object[key] = value
object