FIX: Avoid publishing a gigantic payload.

* Certain sites have way too many categories.

app/assets/javascripts/discourse/initializers/subscribe-user-notifications.js.es6

@@ -95,6 +95,10 @@ export default {
 
       bus.subscribe("/client_settings", data => Ember.set(siteSettings, data.name, data.value));
 
+      bus.subscribe("/refresh_client", data => {
+        Discourse.set("assetVersion", data);
+      });
+
       if (!Ember.testing) {
         if (!site.mobileView) {
           bus.subscribe(alertChannel(user), data => onNotification(data, user));

app/models/group.rb

@@ -414,12 +414,18 @@ class Group < ActiveRecord::Base
     users.pluck(:username).join(",")
   end
 
+  PUBLISH_CATEGORIES_LIMIT = 10
+
   def add(user)
     self.users.push(user) unless self.users.include?(user)
 
-    MessageBus.publish('/categories', {
-      categories: ActiveModel::ArraySerializer.new(self.categories).as_json
-    }, user_ids: [user.id])
+    if self.categories.count < PUBLISH_CATEGORIES_LIMIT
+      MessageBus.publish('/categories', {
+        categories: ActiveModel::ArraySerializer.new(self.categories).as_json
+      }, user_ids: [user.id])
+    else
+      Discourse.request_refresh!(user_ids: [user.id])
+    end
 
     self
   end

lib/discourse.rb

@@ -296,12 +296,16 @@ module Discourse
     last_read_only[$redis.namespace] = nil
   end
 
-  def self.request_refresh!
+  def self.request_refresh!(user_ids: nil)
     # Causes refresh on next click for all clients
     #
     # This is better than `MessageBus.publish "/file-change", ["refresh"]` because
     # it spreads the refreshes out over a time period
-    MessageBus.publish '/global/asset-version', 'clobber'
+    if user_ids
+      MessageBus.publish("/refresh_client", 'clobber', user_ids: user_id)
+    else
+      MessageBus.publish('/global/asset-version', 'clobber')
+    end
   end
 
   def self.git_version

spec/models/group_spec.rb

@@ -539,6 +539,20 @@ describe Group do
         expect(message.data[:categories].first[:id]).to eq(category.id)
         expect(message.user_ids).to eq([user.id])
       end
+
+      describe "when group belongs to more than #{Group::PUBLISH_CATEGORIES_LIMIT} categories" do
+        it "should publish a message to refresh the user's client" do
+          (Group::PUBLISH_CATEGORIES_LIMIT + 1).times do
+            group.categories << Fabricate(:category)
+          end
+
+          message = MessageBus.track_publish { group.add(user) }.first
+
+          expect(message.data).to eq('clobber')
+          expect(message.channel).to eq('/refresh_client')
+          expect(message.user_ids).to eq([user.id])
+        end
+      end
     end
   end