Switch to tighter Channel scoping...

This is not a normal pattern for setting up ActionCable channels, so it might need some notes. It ensures the broadcasts from the ReportJob are unique not just to the user session but also to the specific tab in the user's browser. Otherwise if the user has two different report pages open in separate tabs with the same session, the broadcast would overwrite the #report-table element in both of them.

app/channels/scoped_channel.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class ScopedChannel < ApplicationCable::Channel
+  class << self
+    def for_id(id)
+      "ScopedChannel:#{id}"
+    end
+  end
+
+  def subscribed
+    stream_from "ScopedChannel:#{params[:id]}"
+  end
+end

app/controllers/admin/reports_controller.rb

@@ -67,7 +67,7 @@ module Admin
       @blob = ReportBlob.create_for_upload_later!(report_filename)
 
       ReportJob.perform_later(
-        report_class, spree_current_user, params, format, @blob, SessionChannel.for_request(request)
+        report_class, spree_current_user, params, format, @blob, ScopedChannel.for_id(params[:uuid])
       )
 
       render cable_ready: cable_car.

app/views/admin/reports/show.html.haml

@@ -6,6 +6,8 @@
 - options = @background_reports ? { data: { remote: "true" } } : {}
 
 = form_for @report.search, { url: url_for }.merge(options) do |f|
+  = hidden_field_tag "uuid", request.uuid
+
   %fieldset.no-border-bottom.print-hidden
     %legend{ align: 'center'}= t(:report_filters)
     = render partial: "admin/reports/filters/#{@report_type}", locals: { f: f }
@@ -27,5 +29,5 @@
 
 = t(@error, link: link_to(t(".report_link_label"), @error_url)) if @error
 
-#report-table
+#report-table{ data: { controller: "scoped-channel", "scoped-channel-id-value": request.uuid } }
   = @table

app/webpacker/controllers/scoped_channel_controller.js

@@ -0,0 +1,22 @@
+import { Controller } from "stimulus";
+import consumer from "../channels/consumer";
+import CableReady from "cable_ready";
+
+export default class extends Controller {
+  static values = { id: String };
+
+  connect() {
+    this.subscription = consumer.subscriptions.create(
+      { channel: "ScopedChannel", id: this.idValue },
+      {
+        received(data) {
+          if (data.cableReady) CableReady.perform(data.operations);
+        },
+      }
+    );
+  }
+
+  disconnect() {
+    consumer.subscriptions.remove(this.subscription);
+  }
+}