websocket-rails Chat Rooms

Question

I am trying to create sort of Whatsapp like messaging app server side in Rails, with private conversations. now, I am trying to implement the realtime part of the app - I am using websocket-rails - and I am not sure how to send a message only to the users in the private message - I saw a feature called private channels in websocket-rails - but after reading the documentation, I got under the impression that each private channel needs to be defined statically, and I cannot create channels realtime. Do you know how can I implement private conversations in websocket-rails, like a guide or a direction? or any other websocket service I can use to implement it?

Answer 1

You can pass parameters from the client side to the server side when creating a subscription. For example:

# app/channels/chat_channel.rb
class ChatChannel < ApplicationCable::Channel
  def subscribed
    stream_from "chat_#{params[:room]}"
  end
end

An object passed as the first argument to subscriptions.create becomes the params hash in the cable channel. The keyword channel is required:

# app/assets/javascripts/cable/subscriptions/chat.coffee
App.cable.subscriptions.create { channel: "ChatChannel", room: "Best Room" },
  received: (data) ->
    @appendLine(data)

  appendLine: (data) ->
    html = @createLine(data)
    $("[data-chat-room='Best Room']").append(html)

  createLine: (data) ->
    """
    <article class="chat-line">
      <span class="speaker">#{data["sent_by"]}</span>
      <span class="body">#{data["body"]}</span>
    </article>
    """

Somewhere in your app this is called, perhaps

ActionCable.server.broadcast(
  "chat_#{room}",
  sent_by: 'Paul',
  body: 'This is a cool chat app.'
)