turbo_custom_cable_stream

application_helper.rb

module ApplicationHelper
  def turbo_custom_stream_from(*streamables, **attributes)
    attributes[:channel] = attributes[:channel]&.to_s || "Turbo::StreamsChannel"
    attributes[:"signed-stream-name"] = Turbo::StreamsChannel.signed_stream_name(streamables)

    tag.turbo_custom_cable_stream_source(**attributes)
  end
end

custom_cable_stream_source_element.js

import { Turbo, cable } from "@hotwired/turbo-rails";

const { connectStreamSource, disconnectStreamSource } = Turbo;
const { subscribeTo } = cable;

class TurboCustomCableStreamSource extends HTMLElement {
  async connectedCallback() {
    connectStreamSource(this);
    this.subscription = await subscribeTo(this.channel, {
      initialized() {
      },

      connected() {
      },

      received(data) {
      },

      disconnected() {
      },
      
      received: this.dispatchMessageEvent.bind(this)
    });
  }

  disconnectedCallback() {
    disconnectStreamSource(this);
    if (this.subscription) this.subscription.unsubscribe();
  }

  dispatchMessageEvent(data) {
    const event = new MessageEvent("message", { data });
    return this.dispatchEvent(event);
  }

  get channel() {
    const channel = this.getAttribute("channel");
    const signed_stream_name = this.getAttribute("signed-stream-name");
    return { channel, signed_stream_name };
  }
}

customElements.define("turbo-custom-cable-stream-source", TurboCustomCableStreamSource);

custom_channel.rb

class CustomChannel < ActionCable::Channel::Base
  extend Turbo::Streams::Broadcasts, Turbo::Streams::StreamName
  include Turbo::Streams::StreamName::ClassMethods

  def subscribed
    if stream_name = verified_stream_name_from_params
      stream_from stream_name
    else
      reject
    end
  end

  def unsubscribed
  end
end

example.html.erb

<%= turbo_custom_stream_from "example", channel: CustomChannel %>