PERF: Move user-tips and narrative to per-user messagebus channels (#19773)

Using a shared channel with per-message permissions means that every client is updated with the channel's 'last_id', even if there are no messages available to them. Per-user channel names avoid this problem - the last_id will only be incremented when there is a message for the given user.

plugins/discourse-narrative-bot/assets/javascripts/initializers/new-user-narrative.js

@@ -15,9 +15,9 @@ export default {
     this.appEvents = container.lookup("service:app-events");
 
     withPluginApi("0.8.7", (api) => {
-      const currentUser = api.getCurrentUser();
+      this.currentUser = api.getCurrentUser();
 
-      if (!currentUser) {
+      if (!this.currentUser) {
         return;
       }
 
@@ -41,17 +41,19 @@ export default {
       );
 
       this.messageBus.subscribe(
-        "/new_user_narrative/tutorial_search",
+        `/new_user_narrative/tutorial_search/${this.currentUser.id}`,
         this.onMessage
       );
     });
   },
 
   teardown() {
-    this.messageBus?.unsubscribe(
-      "/new_user_narrative/tutorial_search",
-      this.onMessage
-    );
+    if (this.currentUser) {
+      this.messageBus?.unsubscribe(
+        `/new_user_narrative/tutorial_search/${this.currentUser.id}`,
+        this.onMessage
+      );
+    }
   },
 
   @bind

plugins/discourse-narrative-bot/lib/discourse_narrative_bot/new_user_narrative.rb

@@ -173,7 +173,11 @@ module DiscourseNarrativeBot
       topic = @post.topic
       post = topic.first_post
 
-      MessageBus.publish("/new_user_narrative/tutorial_search", {}, user_ids: [@user.id])
+      MessageBus.publish(
+        "/new_user_narrative/tutorial_search/#{@user.id}",
+        {},
+        user_ids: [@user.id],
+      )
 
       raw = <<~MD
       #{post.raw}