Encode custom emojis as resolveable objects in ActivityPub (#5243)

* Encode custom emojis as resolveable objects in ActivityPub

* Improve code style

app/serializers/activitypub/actor_serializer.rb

@@ -10,20 +10,6 @@ class ActivityPub::ActorSerializer < ActiveModel::Serializer
 
   has_one :public_key, serializer: ActivityPub::PublicKeySerializer
 
-  class ImageSerializer < ActiveModel::Serializer
-    include RoutingHelper
-
-    attributes :type, :url
-
-    def type
-      'Image'
-    end
-
-    def url
-      full_asset_url(object.url(:original))
-    end
-  end
-
   class EndpointsSerializer < ActiveModel::Serializer
     include RoutingHelper
 
@@ -36,8 +22,8 @@ class ActivityPub::ActorSerializer < ActiveModel::Serializer
 
   has_one :endpoints, serializer: EndpointsSerializer
 
-  has_one :icon,  serializer: ImageSerializer, if: :avatar_exists?
-  has_one :image, serializer: ImageSerializer, if: :header_exists?
+  has_one :icon,  serializer: ActivityPub::ImageSerializer, if: :avatar_exists?
+  has_one :image, serializer: ActivityPub::ImageSerializer, if: :header_exists?
 
   def id
     account_url(object)

app/serializers/activitypub/emoji_serializer.rb

@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+class ActivityPub::EmojiSerializer < ActiveModel::Serializer
+  include RoutingHelper
+
+  attributes :id, :type, :name, :updated
+
+  has_one :icon, serializer: ActivityPub::ImageSerializer
+
+  def id
+    ActivityPub::TagManager.instance.uri_for(object)
+  end
+
+  def type
+    'Emoji'
+  end
+
+  def icon
+    object.image
+  end
+
+  def updated
+    object.updated_at.iso8601
+  end
+
+  def name
+    ":#{object.shortcode}:"
+  end
+end

app/serializers/activitypub/image_serializer.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+class ActivityPub::ImageSerializer < ActiveModel::Serializer
+  include RoutingHelper
+
+  attributes :type, :media_type, :url
+
+  def type
+    'Image'
+  end
+
+  def url
+    full_asset_url(object.url(:original))
+  end
+
+  def media_type
+    object.content_type
+  end
+end

app/serializers/activitypub/note_serializer.rb

@@ -142,21 +142,6 @@ class ActivityPub::NoteSerializer < ActiveModel::Serializer
     end
   end
 
-  class CustomEmojiSerializer < ActiveModel::Serializer
-    include RoutingHelper
-
-    attributes :type, :href, :name
-
-    def type
-      'Emoji'
-    end
-
-    def href
-      full_asset_url(object.image.url)
-    end
-
-    def name
-      ":#{object.shortcode}:"
-    end
+  class CustomEmojiSerializer < ActivityPub::EmojiSerializer
   end
 end