Improve ActivityPub representations (#3844)

* Improve webfinger templates and make tests more flexible

* Clean up AS2 representation of actor

* Refactor outbox

* Create activities representation

* Add representations of followers/following collections, do not redirect /users/:username route if format is empty

* Remove unused translations

* ActivityPub endpoint for single statuses, add ActivityPub::TagManager for better
URL/URI generation

* Add ActivityPub::TagManager#to

* Represent all attachments as Document instead of Image/Video specifically
(Because for remote ones we may not know for sure)

Add mentions and hashtags representation to AP notes

* Add AP-resolvable hashtag URIs

* Use ActiveModelSerializers for ActivityPub

* Clean up unused translations

* Separate route for object and activity

* Adjust cc/to matrices

* Add to/cc to activities, ensure announce activity embeds target status and
not the wrapper status, add "id" to all collections

1 files changed, 21 insertions, 1 deletions

diff --git a/app/controllers/tags_controller.rb b/app/controllers/tags_controller.rb
index 53149edf0..8bcce9e13 100644
--- a/app/controllers/tags_controller.rb
+++ b/app/controllers/tags_controller.rb
@@ -5,7 +5,27 @@ class TagsController < ApplicationController
 
   def show
     @tag      = Tag.find_by!(name: params[:id].downcase)
-    @statuses = @tag.nil? ? [] : Status.as_tag_timeline(@tag, current_account, params[:local]).paginate_by_max_id(20, params[:max_id])
+    @statuses = Status.as_tag_timeline(@tag, current_account, params[:local]).paginate_by_max_id(20, params[:max_id])
     @statuses = cache_collection(@statuses, Status)
+
+    respond_to do |format|
+      format.html
+
+      format.json do
+        render json: collection_presenter, serializer: ActivityPub::CollectionSerializer, adapter: ActivityPub::Adapter
+      end
+    end
+  end
+
+  private
+
+  def collection_presenter
+    ActivityPub::CollectionPresenter.new(
+      id: tag_url(@tag),
+      type: :ordered,
+      current: tag_url(@tag),
+      size: @tag.statuses.count,
+      items: @statuses.map { |s| ActivityPub::TagManager.instance.uri_for(s) }
+    )
   end
 end