FIX: Generate webhook payloads before destroy events (#6325)

app/models/category.rb

@@ -8,6 +8,7 @@ class Category < ActiveRecord::Base
   include HasCustomFields
   include CategoryHashtag
   include AnonCacheInvalidator
+  include HasDestroyedWebHook
 
   REQUIRE_TOPIC_APPROVAL = 'require_topic_approval'
   REQUIRE_REPLY_APPROVAL = 'require_reply_approval'

app/models/concerns/has_destroyed_web_hook.rb

@@ -0,0 +1,17 @@
+module HasDestroyedWebHook
+  extend ActiveSupport::Concern
+
+  included do
+    around_destroy :enqueue_destroyed_web_hook
+  end
+
+  def enqueue_destroyed_web_hook
+    type = self.class.name.underscore.to_sym
+    payload = WebHook.generate_payload(type, self)
+    yield
+    WebHook.enqueue_hooks(type, "#{type}_destroyed".to_sym,
+      id: id,
+      payload: payload
+    )
+  end
+end

app/models/group.rb

@@ -5,6 +5,7 @@ require_dependency 'enum'
 class Group < ActiveRecord::Base
   include HasCustomFields
   include AnonCacheInvalidator
+  include HasDestroyedWebHook
 
   cattr_accessor :preloaded_custom_field_names
   self.preloaded_custom_field_names = Set.new

app/models/tag.rb

@@ -1,5 +1,6 @@
 class Tag < ActiveRecord::Base
   include Searchable
+  include HasDestroyedWebHook
 
   validates :name, presence: true, uniqueness: true
 

app/models/user.rb

@@ -19,6 +19,7 @@ class User < ActiveRecord::Base
   include Roleable
   include HasCustomFields
   include SecondFactorManager
+  include HasDestroyedWebHook
 
   has_many :posts
   has_many :notifications, dependent: :destroy

app/models/web_hook.rb

@@ -41,24 +41,21 @@ class WebHook < ActiveRecord::Base
       .distinct
   end
 
-  def self.enqueue_hooks(type, opts = {})
+  def self.enqueue_hooks(type, event, opts = {})
     active_web_hooks(type).each do |web_hook|
       Jobs.enqueue(:emit_web_hook_event, opts.merge(
-        web_hook_id: web_hook.id, event_type: type.to_s
+        web_hook_id: web_hook.id, event_name: event.to_s, event_type: type.to_s
       ))
     end
   end
 
   def self.enqueue_object_hooks(type, object, event, serializer = nil)
     if active_web_hooks(type).exists?
-      serializer ||= "WebHook#{type.capitalize}Serializer".constantize
+      payload = WebHook.generate_payload(type, object, serializer)
 
-      WebHook.enqueue_hooks(type,
-        event_name: event.to_s,
-        payload: serializer.new(object,
-          scope: self.guardian,
-          root: false
-        ).to_json
+      WebHook.enqueue_hooks(type, event,
+        id: object.id,
+        payload: payload
       )
     end
   end
@@ -66,31 +63,38 @@ class WebHook < ActiveRecord::Base
   def self.enqueue_topic_hooks(event, topic)
     if active_web_hooks('topic').exists?
       topic_view = TopicView.new(topic.id, Discourse.system_user)
+      payload = WebHook.generate_payload(:topic, topic_view, WebHookTopicViewSerializer)
 
-      WebHook.enqueue_hooks(:topic,
+      WebHook.enqueue_hooks(:topic, event,
+        id: topic.id,
         category_id: topic&.category_id,
-        event_name: event.to_s,
-        payload: WebHookTopicViewSerializer.new(topic_view,
-          scope: self.guardian,
-          root: false
-        ).to_json
+        payload: payload
       )
     end
   end
 
   def self.enqueue_post_hooks(event, post)
     if active_web_hooks('post').exists?
-      WebHook.enqueue_hooks(:post,
+      payload = WebHook.generate_payload(:post, post)
+
+      WebHook.enqueue_hooks(:post, event,
+        id: post.id,
         category_id: post&.topic&.category_id,
-        event_name: event.to_s,
-        payload: WebHookPostSerializer.new(post,
-          scope: self.guardian,
-          root: false
-        ).to_json
+        payload: payload
       )
     end
   end
 
+  def self.generate_payload(type, object, serializer = nil)
+    serializer ||= TagSerializer if type == :tag
+    serializer ||= "WebHook#{type.capitalize}Serializer".constantize
+
+    serializer.new(object,
+      scope: self.guardian,
+      root: false
+    ).to_json
+  end
+
   private
 
   def self.guardian