Add ActivityPub secure mode (#11269)

* Add HTTP signature requirement for served ActivityPub resources

* Change `SECURE_MODE` to `AUTHORIZED_FETCH`

* Add 'Signature' to 'Vary' header and improve code style

* Improve code style by adding `public_fetch_mode?` method

1 files changed, 5 insertions, 4 deletions

diff --git a/app/controllers/statuses_controller.rb b/app/controllers/statuses_controller.rb
index 13ce5c691..22e7519f9 100644
--- a/app/controllers/statuses_controller.rb
+++ b/app/controllers/statuses_controller.rb
@@ -8,11 +8,12 @@ class StatusesController < ApplicationController
 
   layout 'public'
 
+  before_action :require_signature!, only: :show, if: -> { request.format == :json && authorized_fetch_mode? }
   before_action :set_status
   before_action :set_instance_presenter
   before_action :set_link_headers
-  before_action :redirect_to_original, only: [:show]
-  before_action :set_referrer_policy_header, only: [:show]
+  before_action :redirect_to_original, only: :show
+  before_action :set_referrer_policy_header, only: :show
   before_action :set_cache_headers
   before_action :set_body_classes
   before_action :set_autoplay, only: :embed
@@ -30,14 +31,14 @@ class StatusesController < ApplicationController
       end
 
       format.json do
-        expires_in 3.minutes, public: @status.distributable?
+        expires_in 3.minutes, public: @status.distributable? && public_fetch_mode?
         render json: @status, content_type: 'application/activity+json', serializer: ActivityPub::NoteSerializer, adapter: ActivityPub::Adapter
       end
     end
   end
 
   def activity
-    expires_in 3.minutes, public: @status.distributable?
+    expires_in 3.minutes, public: @status.distributable? && public_fetch_mode?
     render json: @status, content_type: 'application/activity+json', serializer: ActivityPub::ActivitySerializer, adapter: ActivityPub::Adapter
   end