CODEWITHSUNDEEP
ruby-on-railsrubyactioncable
Molfar
Molfar

Reputation: 1501

What is default behavior for actioncable in rails?

When generating a new channel, there is commented out stream_from method call. I understand, that it suits for recognizing streams, like stream_from "comments_#{message.id}".

But if this channel has no such goal and should stream all comments? What is default behavior (of value maybe) of this channel without specifying stream_from?

Upvotes: 0

Views: 167

Answers (1)

Jay-Ar Polidario
Jay-Ar Polidario

Reputation: 6603

Asssuming that your channel is named SomethingChannel

class SomethingChannel < ApplicationCable::Channel
  def subscribed
    # because you do not need stream_from, then remove the stream_from below
    # stream_from "something_channel"

    # and just immediately transmit the data. This should be a hash, and thus I use `as_json`; Change this accordingly as you see fit
    transmit(Comment.all.as_json)
  end

  def unsubscribed
    # Any cleanup needed when channel is unsubscribed
  end
end

Then on the client-side, you just simply invoke the following whenever you already need this.

# ...coffee
App.cable.subscriptions.create 'SomethingChannel',
  connected: ->
    console.log('connected')

  # Called when the WebSocket connection is closed.
  disconnected: ->
    console.log('disconnected')

  # `transmit(Comment.all.as_json)` above will invoke this
  received: (data) ->
    console.log('received')
    console.log(data)

You should see the something like the following in your Google Chrome / Firefox console:

connected
received
▼ [{…}]
  ▶ 0: {id: 1, title: "Hello ", content: "World from Earth! :)", created_at: "2018-02-13T16:15:05.734Z", updated_at: "2018-02-13T16:15:05.734Z"}
  ▶ 1: {id: 2, title: "Lorem ", content: "Ipsum Dolor", created_at: "2018-02-13T16:15:05.734Z", updated_at: "2018-02-13T16:15:05.734Z"}
  length: 2
  ▶ __proto__: Array(0)

P.S. if you are not gonna make use of stream_from or stream_for then perhaps you might not need ActionCable after all, and perhaps you'd be better off retrieving all the comments from an API instead (i.e. GET /comments)

Upvotes: 1

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