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

20 files changed, 12 insertions, 164 deletions

diff --git a/config/initializers/inflections.rb b/config/initializers/inflections.rb
index a7b1ef690..26275d092 100644
--- a/config/initializers/inflections.rb
+++ b/config/initializers/inflections.rb
@@ -14,4 +14,6 @@ ActiveSupport::Inflector.inflections(:en) do |inflect|
   inflect.acronym 'StatsD'
   inflect.acronym 'OEmbed'
   inflect.acronym 'ActivityPub'
+  inflect.acronym 'PubSubHubbub'
+  inflect.acronym 'ActivityStreams'
 end
diff --git a/config/initializers/mime_types.rb b/config/initializers/mime_types.rb
index b1b73c846..30e91ad63 100644
--- a/config/initializers/mime_types.rb
+++ b/config/initializers/mime_types.rb
@@ -1,5 +1,4 @@
 # Be sure to restart your server when you modify this file.
 
-Mime::Type.register "application/json",           :json, %w( text/x-json application/jsonrequest application/jrd+json )
-Mime::Type.register "text/xml",                   :xml,  %w( application/xml application/atom+xml application/xrd+xml )
-Mime::Type.register "application/activity+json",  :activitystreams2
+Mime::Type.register 'application/json', :json, %w(text/x-json application/jsonrequest application/jrd+json application/activity+json)
+Mime::Type.register 'text/xml',         :xml,  %w(application/xml application/atom+xml application/xrd+xml)
diff --git a/config/locales/ca.yml b/config/locales/ca.yml
index f63aee3e6..0ba893a12 100644
--- a/config/locales/ca.yml
+++ b/config/locales/ca.yml
@@ -30,15 +30,6 @@ ca:
     remote_follow: Seguir
     reserved_username: El nom d'usuari està reservat
     unfollow: Deixar de seguir
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} shared an activity."
-      create:
-        name: "%{account_name} created a note."
-    outbox:
-      name: "%{account_name}'s Outbox"
-      summary: A collection of activities from user %{account_name}.
   admin:
     accounts:
       are_you_sure: Estàs segur?
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 79efddfad..be1f15e25 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -44,15 +44,6 @@ en:
     remote_follow: Remote follow
     reserved_username: The username is reserved
     unfollow: Unfollow
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} shared an activity."
-      create:
-        name: "%{account_name} created a note."
-    outbox:
-      name: "%{account_name}'s Outbox"
-      summary: A collection of activities from user %{account_name}.
   admin:
     accounts:
       are_you_sure: Are you sure?
diff --git a/config/locales/fa.yml b/config/locales/fa.yml
index ade76d670..218d859bb 100644
--- a/config/locales/fa.yml
+++ b/config/locales/fa.yml
@@ -29,15 +29,6 @@ fa:
     posts: نوشته
     remote_follow: پیگیری غیرمستقیم
     unfollow: پایان پیگیری
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} فعالیتی آغاز کرد."
-      create:
-        name: "%{account_name} یادداشتی نوشت."
-    outbox:
-      name: صندوق خروجی %{account_name}
-      summary: مجموعه‌ای از فعالیت‌های کاربر %{account_name}.
   admin:
     accounts:
       are_you_sure: آیا مطمئن هستید؟
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index cba217651..65e681b20 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -30,15 +30,6 @@ fr:
     remote_follow: Suivre à distance
     reserved_username: Ce nom d’utilisateur⋅ice est réservé
     unfollow: Ne plus suivre
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} a partagé une activité."
-      create:
-        name: "%{account_name} a créé une note."
-    outbox:
-      name: Boîte d’envoi de %{account_name}
-      summary: Liste d’activités de %{account_name}
   admin:
     accounts:
       are_you_sure: Êtes-vous certain⋅e ?
diff --git a/config/locales/he.yml b/config/locales/he.yml
index 21f8f1dc4..251b6914e 100644
--- a/config/locales/he.yml
+++ b/config/locales/he.yml
@@ -29,15 +29,6 @@ he:
     posts: הודעות
     remote_follow: מעקב מרחוק
     unfollow: הפסקת מעקב
-  activitypub:
-    activity:
-      announce:
-        name: הודעה שותפה על ידי %{account_name}.
-      create:
-        name: הודעה חדשה מאת %{account_name}.
-    outbox:
-      name: תיבת הדוא"ל היוצא של %{account_name}
-      summary: אוסף הפעילויות של %{account_name}.
   admin:
     accounts:
       are_you_sure: בטוח?
diff --git a/config/locales/id.yml b/config/locales/id.yml
index e3fe96331..7bda52c78 100644
--- a/config/locales/id.yml
+++ b/config/locales/id.yml
@@ -29,15 +29,6 @@ id:
     posts: Postingan
     remote_follow: Mengikuti
     unfollow: Berhenti mengikuti
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} membagikan aktivitas."
-      create:
-        name: "%{account_name} membuat catatan."
-    outbox:
-      name: "%{account_name} Outbox"
-      summary: Koleksi aktivitas dari pengguna %{account_name}.
   admin:
     accounts:
       are_you_sure: Anda yakin?
diff --git a/config/locales/ja.yml b/config/locales/ja.yml
index 37d82a205..fda87526d 100644
--- a/config/locales/ja.yml
+++ b/config/locales/ja.yml
@@ -30,15 +30,6 @@ ja:
     remote_follow: リモートフォロー
     reserved_username: このユーザー名は予約されています。
     unfollow: フォロー解除
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} さんがアクティビティをシェアしました"
-      create:
-        name: "%{account_name} さんがノートを作成しました"
-    outbox:
-      name: "%{account_name} さんの送信トレイ"
-      summary: "%{account_name} さんからのアクティビティコレクション"
   admin:
     accounts:
       are_you_sure: 本当に実行しますか?
diff --git a/config/locales/ko.yml b/config/locales/ko.yml
index bafc19993..c7c310cfe 100644
--- a/config/locales/ko.yml
+++ b/config/locales/ko.yml
@@ -30,15 +30,6 @@ ko:
     remote_follow: 리모트 팔로우
     reserved_username: 이 아이디는 예약되어 있습니다.
     unfollow: 팔로우 해제
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} 님이 액티비티를 공유했습니다"
-      create:
-        name: "%{account_name} 님이 노트를 작성했습니다"
-    outbox:
-      name: "%{account_name} 님의 송신함"
-      summary: "%{account_name} 님의 액티비티 모음"
   admin:
     accounts:
       are_you_sure: 정말로 실행하시겠습니까?
diff --git a/config/locales/no.yml b/config/locales/no.yml
index 004e1ff80..cf94524d2 100644
--- a/config/locales/no.yml
+++ b/config/locales/no.yml
@@ -29,15 +29,6 @@
     posts: Poster
     remote_follow: Følg fra andre instanser
     unfollow: Avfølg
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} delte en aktivitet."
-      create:
-        name: "%{account_name} laget en aktivitet."
-    outbox:
-      name: "%{account_name} sin utboks"
-      summary: En samling aktiviteter fra brukeren %{account_name}.
   admin:
     accounts:
       are_you_sure: Er du sikker?
diff --git a/config/locales/oc.yml b/config/locales/oc.yml
index 91a6ca791..2eb85be58 100644
--- a/config/locales/oc.yml
+++ b/config/locales/oc.yml
@@ -29,15 +29,6 @@ oc:
     posts: Estatuts
     remote_follow: Sègre a distància
     unfollow: Quitar de sègre
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} a partejat una activitat."
-      create:
-        name: "%{account_name} a creat una nòta."
-    outbox:
-      name: "%{account_name}'s Outbox"
-      summary: A collection of activities from user %{account_name}.
   admin:
     accounts:
       are_you_sure: Sètz segur ?
diff --git a/config/locales/pl.yml b/config/locales/pl.yml
index 9ee6c0540..6f2831670 100644
--- a/config/locales/pl.yml
+++ b/config/locales/pl.yml
@@ -44,15 +44,6 @@ pl:
     remote_follow: Zdalne śledzenie
     reserved_username: Ta nazwa użytkownika jest zarezerwowana.
     unfollow: Przestań śledzić
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} udostępnił(a) aktywność."
-      create:
-        name: "%{account_name} utworzył(a) wpis."
-    outbox:
-      name: Skrzynka %{account_name}
-      summary: Zbiór aktywności użytkownika %{account_name}.
   admin:
     accounts:
       are_you_sure: Jesteś tego pewien?
diff --git a/config/locales/pt-BR.yml b/config/locales/pt-BR.yml
index 355c20d05..5ba763ae4 100644
--- a/config/locales/pt-BR.yml
+++ b/config/locales/pt-BR.yml
@@ -29,15 +29,6 @@ pt-BR:
     posts: Posts
     remote_follow: Acesso remoto
     unfollow: Unfollow
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} compartilhou uma atividade."
-      create:
-        name: "%{account_name} criou uma nota."
-    outbox:
-      name: "%{account_name}'s Outbox"
-      summary: Uma coleção de atividades do usuário %{account_name}.
   admin:
     accounts:
       are_you_sure: Você tem certeza?
diff --git a/config/locales/pt.yml b/config/locales/pt.yml
index 40be8a6c5..346fcdda8 100644
--- a/config/locales/pt.yml
+++ b/config/locales/pt.yml
@@ -29,15 +29,6 @@ pt:
     posts: Posts
     remote_follow: Seguir remotamente
     unfollow: Deixar de seguir
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} anunciou uma atividade."
-      create:
-        name: "%{account_name} criou uma nota."
-    outbox:
-      name: "%{account_name}'s Outbox"
-      summary: Uma coleção de atividades do usuário %{account_name}.
   admin:
     accounts:
       are_you_sure: Tens a certeza?
diff --git a/config/locales/th.yml b/config/locales/th.yml
index 263babdd0..17eb96110 100644
--- a/config/locales/th.yml
+++ b/config/locales/th.yml
@@ -29,15 +29,6 @@ th:
     posts: โพสต์
     remote_follow: Remote follow
     unfollow: เลิกติดตาม
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} แชร์กิจกรรม."
-      create:
-        name: "%{account_name} สร้างโน๊ต."
-    outbox:
-      name: "%{account_name}'s Outbox"
-      summary: รวมกิจกรรมของผู้ใช้ %{account_name}.
   admin:
     accounts:
       are_you_sure: แน่ใจนะ?
diff --git a/config/locales/tr.yml b/config/locales/tr.yml
index e7864cc57..bb83991cd 100644
--- a/config/locales/tr.yml
+++ b/config/locales/tr.yml
@@ -29,15 +29,6 @@ tr:
     posts: Gönderiler
     remote_follow: Uzaktan takip et
     unfollow: Takibi bırak
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} bir aktivite paylaştı."
-      create:
-        name: "%{account_name} bir not oluşturdu."
-    outbox:
-      name: "%{account_name}'in Gönderdikleri"
-      summary: "%{account_name}'den gelen aktiviteler."
   admin:
     accounts:
       are_you_sure: Emin misiniz?
diff --git a/config/locales/zh-CN.yml b/config/locales/zh-CN.yml
index 650d4bd15..0526ec1ba 100644
--- a/config/locales/zh-CN.yml
+++ b/config/locales/zh-CN.yml
@@ -29,15 +29,6 @@ zh-CN:
     posts: 嘟文
     remote_follow: 跨站关注
     unfollow: 取消关注
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} 分享了一个活动。"
-      create:
-        name: "%{account_name} 创建了一个记事。"
-    outbox:
-      name: "%{account_name} 的集合"
-      summary: "%{account_name} 的活动集合"
   admin:
     accounts:
       are_you_sure: 你确定吗？
diff --git a/config/locales/zh-HK.yml b/config/locales/zh-HK.yml
index d2db78be1..06f9ab63d 100644
--- a/config/locales/zh-HK.yml
+++ b/config/locales/zh-HK.yml
@@ -29,15 +29,6 @@ zh-HK:
     posts: 文章
     remote_follow: 跨站關注
     unfollow: 取消關注
-  activitypub:
-    activity:
-      announce:
-        name: "%{account_name} 分享了一項活動。"
-      create:
-        name: "%{account_name} 新增了一篇筆記。"
-    outbox:
-      name: "%{account_name} 的活動"
-      summary: "%{account_name} 分享的活動列表。"
   admin:
     accounts:
       are_you_sure: 你確定嗎？
diff --git a/config/routes.rb b/config/routes.rb
index 9171d02d4..dda3534eb 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -26,7 +26,7 @@ Rails.application.routes.draw do
     confirmations:      'auth/confirmations',
   }
 
-  get '/users/:username', to: redirect('/@%{username}'), constraints: { format: :html }
+  get '/users/:username', to: redirect('/@%{username}'), constraints: lambda { |req| req.format.nil? }
 
   resources :accounts, path: 'users', only: [:show], param: :username do
     resources :stream_entries, path: 'updates', only: [:show] do
@@ -38,10 +38,17 @@ Rails.application.routes.draw do
     get :remote_follow,  to: 'remote_follow#new'
     post :remote_follow, to: 'remote_follow#create'
 
+    resources :statuses, only: [:show] do
+      member do
+        get :activity
+      end
+    end
+
     resources :followers, only: [:index], controller: :follower_accounts
     resources :following, only: [:index], controller: :following_accounts
     resource :follow, only: [:create], controller: :account_follow
     resource :unfollow, only: [:create], controller: :account_unfollow
+    resource :outbox, only: [:show], module: :activitypub
   end
 
   get '/@:username', to: 'accounts#show', as: :short_account
@@ -119,13 +126,6 @@ Rails.application.routes.draw do
     # OEmbed
     get '/oembed', to: 'oembed#show', as: :oembed
 
-    # ActivityPub
-    namespace :activitypub do
-      get '/users/:id/outbox', to: 'outbox#show', as: :outbox
-      get '/statuses/:id', to: 'activities#show_status', as: :status
-      resources :notes, only: [:show]
-    end
-
     # JSON / REST API
     namespace :v1 do
       resources :statuses, only: [:create, :show, :destroy] do