FEATURE: Add support for user badge revocation webhook events (#21204)

Currently, only user badge grants emit webhook events. This change
extends the `user_badge` webhook to emit user badge revocation events.

A new `user_badge_revoked` event has been introduced instead of relying
on the existing `user_badge_removed` event. `user_badge_removed` emitted
just the `badge_id` and `user_id` which aren't helpful for generating a
meaningful webhook payload for revoked(deleted) user badges.

The new event emits  the user badge object.

app/models/user_badge.rb

@@ -48,7 +48,10 @@ class UserBadge < ActiveRecord::Base
     Badge.decrement_counter "grant_count", self.badge_id
     UserStat.update_distinct_badge_count self.user_id
     UserBadge.update_featured_ranks! self.user_id
+
+    # TODO: Follow up with a deprecation notice for `user_badge_removed`
     DiscourseEvent.trigger(:user_badge_removed, self.badge_id, self.user_id)
+    DiscourseEvent.trigger(:user_badge_revoked, user_badge: self)
   end
 
   def self.ensure_consistency!

config/initializers/012-web_hook_events.rb

@@ -55,12 +55,18 @@ end
   DiscourseEvent.on(event) { |tag| WebHook.enqueue_object_hooks(:tag, tag, event, TagSerializer) }
 end
 
-%i[user_badge_granted].each do |event|
-  # user_badge_revoked
-  DiscourseEvent.on(event) do |badge, user_id|
-    ub = UserBadge.find_by(badge: badge, user_id: user_id)
-    WebHook.enqueue_object_hooks(:user_badge, ub, event, UserBadgeSerializer)
-  end
+DiscourseEvent.on(:user_badge_granted) do |badge_id, user_id|
+  ub = UserBadge.find_by(badge_id: badge_id, user_id: user_id)
+  WebHook.enqueue_object_hooks(:user_badge, ub, :user_badge_granted, UserBadgeSerializer)
+end
+
+DiscourseEvent.on(:user_badge_revoked) do |args|
+  WebHook.enqueue_object_hooks(
+    :user_badge,
+    args[:user_badge],
+    :user_badge_revoked,
+    UserBadgeSerializer,
+  )
 end
 
 %i[reviewable_created reviewable_score_updated].each do |event|

config/locales/client.en.yml

@@ -4867,8 +4867,8 @@ en:
           name: "User Promoted Event"
           details: "When a user is promoted from one trust level to another."
         user_badge_event:
-          name: "Badge Grant Event"
-          details: "When a user receives a badge."
+          name: "Badge Event"
+          details: "When a badge is granted or revoked."
         group_user_event:
           name: "Group User Event"
           details: "When a user is added or removed in a group."

spec/initializers/web_hook_events_spec.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+RSpec.describe "Webhook event handlers" do
+  fab!(:user_badge) { Fabricate(:user_badge) }
+  fab!(:web_hook) { Fabricate(:user_badge_web_hook) }
+  fab!(:user) { Fabricate(:user) }
+  fab!(:badge) { Fabricate(:badge) }
+  fab!(:post) { Fabricate(:post) }
+
+  describe "user_badge events" do
+    it "enqueues user_badge_granted webhook event" do
+      expect do
+        BadgeGranter.grant(badge, user, granted_by: Discourse.system_user, post_id: post.id)
+      end.to change { Jobs::EmitWebHookEvent.jobs.size }.by(1)
+
+      job_args = Jobs::EmitWebHookEvent.jobs.last["args"].first
+      expect(job_args["id"]).to eq(user.user_badges.last.id)
+      expect(job_args["event_name"]).to eq("user_badge_granted")
+    end
+
+    it "enqueues user_badge_revoked webhook event" do
+      expect { BadgeGranter.revoke(user_badge) }.to change { Jobs::EmitWebHookEvent.jobs.size }.by(
+        1,
+      )
+
+      job_args = Jobs::EmitWebHookEvent.jobs.last["args"].first
+      expect(job_args["id"]).to eq(user_badge.id)
+      expect(job_args["event_name"]).to eq("user_badge_revoked")
+    end
+  end
+end

spec/models/user_badge_spec.rb

@@ -31,6 +31,22 @@ RSpec.describe UserBadge do
     end
   end
 
+  describe "#destroy" do
+    it "triggers the 'user_badge_revoked' DiscourseEvent" do
+      user_badge =
+        UserBadge.create(
+          badge: badge,
+          user: user,
+          granted_at: Time.zone.now,
+          granted_by: Discourse.system_user,
+        )
+
+      event = DiscourseEvent.track(:user_badge_revoked) { user_badge.destroy! }
+
+      expect(event).to be_present
+    end
+  end
+
   describe "featured rank" do
     fab!(:user) { Fabricate(:user) }
     fab!(:user_badge_tl1) do