DEV: Improve performance on actor lookup (#266)

Two fixes here:
- eager load the associated model when looking up an actor by ap_key
- add a unique index on ap_key

Should improve performance on `post "actor/:key/inbox"` requests

Author: pmusaraj

app/controllers/discourse_activity_pub/a_p/actors_controller.rb

@@ -19,7 +19,7 @@ def show
   protected
 
   def ensure_actor_exists
-    unless @actor = DiscourseActivityPubActor.find_by(ap_key: params[:key])
+    unless @actor = DiscourseActivityPubActor.includes(:model).find_by(ap_key: params[:key])
       render_activity_pub_error("not_found", 404)
     end
   end

app/models/discourse_activity_pub_actor.rb

@@ -390,33 +390,34 @@ def local_username_uniqueness
 # Table name: discourse_activity_pub_actors
 #
 #  id                 :bigint           not null, primary key
-#  ap_id              :string           not null
+#  ap_former_type     :string
 #  ap_key             :string
 #  ap_type            :string           not null
-#  domain             :string
-#  local              :boolean
 #  available          :boolean          default(TRUE)
+#  default_visibility :string
+#  deleted_at         :datetime
+#  domain             :string
+#  enabled            :boolean
+#  icon_url           :string
 #  inbox              :string
-#  outbox             :string
-#  username           :string
-#  name               :string
-#  model_id           :integer
+#  local              :boolean
 #  model_type         :string
+#  name               :string
+#  outbox             :string
+#  post_object_type   :string
 #  private_key        :text
 #  public_key         :text
+#  publication_type   :string
+#  shared_inbox       :string
+#  username           :string
 #  created_at         :datetime         not null
 #  updated_at         :datetime         not null
-#  icon_url           :string
-#  shared_inbox       :string
-#  enabled            :boolean
-#  default_visibility :string
-#  publication_type   :string
-#  post_object_type   :string
-#  deleted_at         :datetime
-#  ap_former_type     :string
+#  ap_id              :string           not null
+#  model_id           :integer
 #
 # Indexes
 #
-#  index_discourse_activity_pub_actors_on_ap_id  (ap_id) UNIQUE
-#  unique_activity_pub_actor_models              (model_type,model_id) UNIQUE
+#  index_discourse_activity_pub_actors_on_ap_id   (ap_id) UNIQUE
+#  index_discourse_activity_pub_actors_on_ap_key  (ap_key) UNIQUE
+#  unique_activity_pub_actor_models               (model_type,model_id) UNIQUE
 #

app/models/discourse_activity_pub_authorization.rb

@@ -13,12 +13,12 @@ class DiscourseActivityPubAuthorization < ActiveRecord::Base
 # Table name: discourse_activity_pub_authorizations
 #
 #  id         :bigint           not null, primary key
-#  user_id    :integer          not null
-#  actor_id   :bigint
-#  client_id  :bigint
 #  token      :string(1000)
 #  created_at :datetime         not null
 #  updated_at :datetime         not null
+#  actor_id   :bigint
+#  client_id  :bigint
+#  user_id    :integer          not null
 #
 # Indexes
 #

app/models/discourse_activity_pub_client.rb

@@ -92,8 +92,8 @@ def verify_credentials
 #
 #  id          :bigint           not null, primary key
 #  auth_type   :integer          not null
-#  domain      :string(1000)     not null
 #  credentials :json             not null
+#  domain      :string(1000)     not null
 #  created_at  :datetime         not null
 #  updated_at  :datetime         not null
 #

db/migrate/20251203000001_add_index_to_discourse_activity_pub_actors_ap_key.rb

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+class AddIndexToDiscourseActivityPubActorsApKey < ActiveRecord::Migration[7.2]
+  def change
+    add_index :discourse_activity_pub_actors, :ap_key, unique: true
+  end
+end