CODEWITHSUNDEEP
ruby-on-railsrubyactioncable
Alexandre
Alexandre

Reputation: 641

Rails 5 ActionCable When is a connection is started?

I have discovered ActionCable today and I have created a very simple chat. Now I want to add this into my current project.

When is a connection with a channel established? In my simple chat, I have a controller named Welcome with an index method and a channel named Demo. On the index page, you can write/see messages. I deduce when we access any page of the app, we are automatically connected to the channel? (if i don't add any instructions in connection.rb)

Upvotes: 2

Views: 397

Answers (1)

DiegoSalazar
DiegoSalazar

Reputation: 13531

Short answer

When you load the web page.

Long anwser

The client opens the connection to the actioncable channel. According to the docs in the client side section:

http://edgeguides.rubyonrails.org/action_cable_overview.html#client-side-components

When you load the web page (in your case, the welcome controller's index action) javascript such as this will execute:

// app/assets/javascripts/cable.js
//= require action_cable
//= require_self
//= require_tree ./channels

(function() {
  this.App || (this.App = {});

  App.cable = ActionCable.createConsumer();
}).call(this);

Followed by a subscription function such as:

# app/assets/javascripts/cable/subscriptions/chat.coffee
App.cable.subscriptions.create { channel: "ChatChannel", room: "Best Room" }

That is what opens the connection to your channel which is defined (as in this example in the server side channels section): http://edgeguides.rubyonrails.org/action_cable_overview.html#channels

# app/channels/chat_channel.rb
class ChatChannel < ApplicationCable::Channel
  # Called when the consumer has successfully
  # become a subscriber of this channel.
  def subscribed
  end
end

When the client side javascript subscribes, the connection will eventually lead to the subscribed method of your channel object.

Upvotes: 2

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