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

5 files changed, 19 insertions, 320 deletions

diff --git a/spec/controllers/accounts_controller_spec.rb b/spec/controllers/accounts_controller_spec.rb
index 447e2dd53..d61c8c9bd 100644
--- a/spec/controllers/accounts_controller_spec.rb
+++ b/spec/controllers/accounts_controller_spec.rb
@@ -38,7 +38,7 @@ RSpec.describe AccountsController, type: :controller do
 
     context 'activitystreams2' do
       before do
-        get :show, params: { username: alice.username }, format: 'activitystreams2'
+        get :show, params: { username: alice.username }, format: 'json'
       end
 
       it 'assigns @account' do
diff --git a/spec/controllers/api/activitypub/activities_controller_spec.rb b/spec/controllers/api/activitypub/activities_controller_spec.rb
deleted file mode 100644
index 07df28ac2..000000000
--- a/spec/controllers/api/activitypub/activities_controller_spec.rb
+++ /dev/null
@@ -1,69 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe Api::ActivityPub::ActivitiesController, type: :controller do
-  render_views
-
-  let(:user)  { Fabricate(:user, account: Fabricate(:account, username: 'alice')) }
-
-  describe 'GET #show' do
-    describe 'normal status' do
-      public_status = nil
-
-      before do
-        public_status = Fabricate(:status, account: user.account, text: 'Hello world', visibility: :public)
-
-        @request.env['HTTP_ACCEPT'] = 'application/activity+json'
-        get :show_status, params: { id: public_status.id }
-      end
-
-      it 'returns http success' do
-        expect(response).to have_http_status(:success)
-      end
-
-      it 'sets Content-Type header to AS2' do
-        expect(response.header['Content-Type']).to include 'application/activity+json'
-      end
-
-      it 'returns http success' do
-        json_data = JSON.parse(response.body)
-        expect(json_data).to include('@context' => 'https://www.w3.org/ns/activitystreams')
-        expect(json_data).to include('type' => 'Create')
-        expect(json_data).to include('id' => @request.url)
-        expect(json_data).to include('type' => 'Create')
-        expect(json_data).to include('object' => api_activitypub_note_url(public_status))
-        expect(json_data).to include('url' => TagManager.instance.url_for(public_status))
-      end
-    end
-
-    describe 'reblog' do
-      original = nil
-      reblog = nil
-
-      before do
-        original = Fabricate(:status, account: user.account, text: 'Hello world', visibility: :public)
-        reblog = Fabricate(:status, account: user.account, reblog_of_id: original.id, visibility: :public)
-
-        @request.env['HTTP_ACCEPT'] = 'application/activity+json'
-        get :show_status, params: { id: reblog.id }
-      end
-
-      it 'returns http success' do
-        expect(response).to have_http_status(:success)
-      end
-
-      it 'sets Content-Type header to AS2' do
-        expect(response.header['Content-Type']).to include 'application/activity+json'
-      end
-
-      it 'returns http success' do
-        json_data = JSON.parse(response.body)
-        expect(json_data).to include('@context' => 'https://www.w3.org/ns/activitystreams')
-        expect(json_data).to include('type' => 'Announce')
-        expect(json_data).to include('id' => @request.url)
-        expect(json_data).to include('type' => 'Announce')
-        expect(json_data).to include('object' => api_activitypub_status_url(original))
-        expect(json_data).to include('url' => TagManager.instance.url_for(reblog))
-      end
-    end
-  end
-end
diff --git a/spec/controllers/api/activitypub/notes_controller_spec.rb b/spec/controllers/api/activitypub/notes_controller_spec.rb
deleted file mode 100644
index a0f05dc65..000000000
--- a/spec/controllers/api/activitypub/notes_controller_spec.rb
+++ /dev/null
@@ -1,73 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe Api::ActivityPub::NotesController, type: :controller do
-  render_views
-
-  let(:user_alice)  { Fabricate(:user, account: Fabricate(:account, username: 'alice')) }
-  let(:user_bob)  { Fabricate(:user, account: Fabricate(:account, username: 'bob')) }
-
-  describe 'GET #show' do
-    describe 'normal status' do
-      public_status = nil
-
-      before do
-        public_status = Fabricate(:status, account: user_alice.account, text: 'Hello world', visibility: :public)
-
-        @request.env['HTTP_ACCEPT'] = 'application/activity+json'
-        get :show, params: { id: public_status.id }
-      end
-
-      it 'returns http success' do
-        expect(response).to have_http_status(:success)
-      end
-
-      it 'sets Content-Type header to AS2' do
-        expect(response.header['Content-Type']).to include 'application/activity+json'
-      end
-
-      it 'returns http success' do
-        json_data = JSON.parse(response.body)
-        expect(json_data).to include('@context' => 'https://www.w3.org/ns/activitystreams')
-        expect(json_data).to include('type' => 'Note')
-        expect(json_data).to include('id' => @request.url)
-        expect(json_data).to include('name' => 'Hello world')
-        expect(json_data).to include('content' => 'Hello world')
-        expect(json_data).to include('published')
-        expect(json_data).to include('url' => TagManager.instance.url_for(public_status))
-      end
-    end
-
-    describe 'reply' do
-      original = nil
-      reply = nil
-
-      before do
-        original = Fabricate(:status, account: user_alice.account, text: 'Hello world', visibility: :public)
-        reply = Fabricate(:status, account: user_bob.account, text: 'Hello world', in_reply_to_id: original.id, visibility: :public)
-
-        @request.env['HTTP_ACCEPT'] = 'application/activity+json'
-        get :show, params: { id: reply.id }
-      end
-
-      it 'returns http success' do
-        expect(response).to have_http_status(:success)
-      end
-
-      it 'sets Content-Type header to AS2' do
-        expect(response.header['Content-Type']).to include 'application/activity+json'
-      end
-
-      it 'returns http success' do
-        json_data = JSON.parse(response.body)
-        expect(json_data).to include('@context' => 'https://www.w3.org/ns/activitystreams')
-        expect(json_data).to include('type' => 'Note')
-        expect(json_data).to include('id' => @request.url)
-        expect(json_data).to include('name' => 'Hello world')
-        expect(json_data).to include('content' => 'Hello world')
-        expect(json_data).to include('published')
-        expect(json_data).to include('url' => TagManager.instance.url_for(reply))
-        expect(json_data).to include('inReplyTo' => api_activitypub_note_url(original))
-      end
-    end
-  end
-end
diff --git a/spec/controllers/api/activitypub/outbox_controller_spec.rb b/spec/controllers/api/activitypub/outbox_controller_spec.rb
deleted file mode 100644
index 049cf451d..000000000
--- a/spec/controllers/api/activitypub/outbox_controller_spec.rb
+++ /dev/null
@@ -1,156 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe Api::ActivityPub::OutboxController, type: :controller do
-  render_views
-
-  let(:user)  { Fabricate(:user, account: Fabricate(:account, username: 'alice')) }
-
-  describe 'GET #show' do
-    before do
-      @request.headers['ACCEPT'] = 'application/activity+json'
-    end
-
-    describe 'collection with small number of statuses' do
-      public_status = nil
-
-      before do
-        public_status = Fabricate(:status, account: user.account, text: 'Hello world', visibility: :public)
-        Fabricate(:status, account: user.account, text: 'Hello world', visibility: :private)
-        Fabricate(:status, account: user.account, text: 'Hello world', visibility: :unlisted)
-        Fabricate(:status, account: user.account, text: 'Hello world', visibility: :direct)
-
-        get :show, params: { id: user.account.id }
-      end
-
-      it 'returns http success' do
-        expect(response).to have_http_status(:success)
-      end
-
-      it 'sets Content-Type header to AS2' do
-        expect(response.header['Content-Type']).to include 'application/activity+json'
-      end
-
-      it 'returns AS2 JSON body' do
-        json_data = JSON.parse(response.body)
-        expect(json_data).to include('@context' => 'https://www.w3.org/ns/activitystreams')
-        expect(json_data).to include('id' => @request.url)
-        expect(json_data).to include('type' => 'OrderedCollection')
-        expect(json_data).to include('totalItems' => 1)
-        expect(json_data).to include('current')
-        expect(json_data).to include('first')
-        expect(json_data).to include('last')
-      end
-    end
-
-    describe 'collection with large number of statuses' do
-      before do
-        30.times do
-          Fabricate(:status, account: user.account, text: 'Hello world', visibility: :public)
-        end
-
-        Fabricate(:status, account: user.account, text: 'Hello world', visibility: :private)
-        Fabricate(:status, account: user.account, text: 'Hello world', visibility: :unlisted)
-        Fabricate(:status, account: user.account, text: 'Hello world', visibility: :direct)
-
-        get :show, params: { id: user.account.id }
-      end
-
-      it 'returns http success' do
-        expect(response).to have_http_status(:success)
-      end
-
-      it 'sets Content-Type header to AS2' do
-        expect(response.header['Content-Type']).to include 'application/activity+json'
-      end
-
-      it 'returns AS2 JSON body' do
-        json_data = JSON.parse(response.body)
-        expect(json_data).to include('@context' => 'https://www.w3.org/ns/activitystreams')
-        expect(json_data).to include('id' => @request.url)
-        expect(json_data).to include('type' => 'OrderedCollection')
-        expect(json_data).to include('totalItems' => 30)
-        expect(json_data).to include('current')
-        expect(json_data).to include('first')
-        expect(json_data).to include('last')
-      end
-    end
-
-    describe 'page with small number of statuses' do
-      statuses = []
-
-      before do
-        5.times do
-          statuses << Fabricate(:status, account: user.account, text: 'Hello world', visibility: :public)
-        end
-
-        Fabricate(:status, account: user.account, text: 'Hello world', visibility: :private)
-        Fabricate(:status, account: user.account, text: 'Hello world', visibility: :unlisted)
-        Fabricate(:status, account: user.account, text: 'Hello world', visibility: :direct)
-
-        get :show, params: { id: user.account.id, max_id: statuses.last.id + 1 }
-      end
-
-      it 'returns http success' do
-        expect(response).to have_http_status(:success)
-      end
-
-      it 'sets Content-Type header to AS2' do
-        expect(response.header['Content-Type']).to include 'application/activity+json'
-      end
-
-      it 'returns AS2 JSON body' do
-        json_data = JSON.parse(response.body)
-        expect(json_data).to include('@context' => 'https://www.w3.org/ns/activitystreams')
-        expect(json_data).to include('id' => @request.url)
-        expect(json_data).to include('type' => 'OrderedCollectionPage')
-        expect(json_data).to include('partOf')
-        expect(json_data).to include('items')
-        expect(json_data['items'].length).to eq(5)
-        expect(json_data).to include('prev')
-        expect(json_data).to include('next')
-        expect(json_data).to include('current')
-        expect(json_data).to include('first')
-        expect(json_data).to include('last')
-      end
-    end
-
-    describe 'page with large number of statuses' do
-      statuses = []
-
-      before do
-        30.times do
-          statuses << Fabricate(:status, account: user.account, text: 'Hello world', visibility: :public)
-        end
-
-        Fabricate(:status, account: user.account, text: 'Hello world', visibility: :private)
-        Fabricate(:status, account: user.account, text: 'Hello world', visibility: :unlisted)
-        Fabricate(:status, account: user.account, text: 'Hello world', visibility: :direct)
-
-        get :show, params: { id: user.account.id, max_id: statuses.last.id + 1 }
-      end
-
-      it 'returns http success' do
-        expect(response).to have_http_status(:success)
-      end
-
-      it 'sets Content-Type header to AS2' do
-        expect(response.header['Content-Type']).to include 'application/activity+json'
-      end
-
-      it 'returns AS2 JSON body' do
-        json_data = JSON.parse(response.body)
-        expect(json_data).to include('@context' => 'https://www.w3.org/ns/activitystreams')
-        expect(json_data).to include('id' => @request.url)
-        expect(json_data).to include('type' => 'OrderedCollectionPage')
-        expect(json_data).to include('partOf')
-        expect(json_data).to include('items')
-        expect(json_data['items'].length).to eq(20)
-        expect(json_data).to include('prev')
-        expect(json_data).to include('next')
-        expect(json_data).to include('current')
-        expect(json_data).to include('first')
-        expect(json_data).to include('last')
-      end
-    end
-  end
-end
diff --git a/spec/controllers/well_known/webfinger_controller_spec.rb b/spec/controllers/well_known/webfinger_controller_spec.rb
index 3699efb56..466f87c45 100644
--- a/spec/controllers/well_known/webfinger_controller_spec.rb
+++ b/spec/controllers/well_known/webfinger_controller_spec.rb
@@ -9,7 +9,7 @@ describe WellKnown::WebfingerController, type: :controller do
     end
 
     before do
-      alice.private_key = <<PEM
+      alice.private_key = <<-PEM
 -----BEGIN RSA PRIVATE KEY-----
 MIICXQIBAAKBgQDHgPoPJlrfMZrVcuF39UbVssa8r4ObLP3dYl9Y17Mgp5K4mSYD
 R/Y2ag58tSi6ar2zM3Ze3QYsNfTq0NqN1g89eAu0MbSjWqpOsgntRPJiFuj3hai2
@@ -27,7 +27,7 @@ FTX8IvYBNTbpEttc1VCf/0ccnNpfb0CrFNSPWxRj7t7D
 -----END RSA PRIVATE KEY-----
 PEM
 
-      alice.public_key = <<PEM
+      alice.public_key = <<-PEM
 -----BEGIN PUBLIC KEY-----
 MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDHgPoPJlrfMZrVcuF39UbVssa8
 r4ObLP3dYl9Y17Mgp5K4mSYDR/Y2ag58tSi6ar2zM3Ze3QYsNfTq0NqN1g89eAu0
@@ -48,29 +48,23 @@ PEM
     it 'returns JSON when account can be found' do
       get :show, params: { resource: alice.to_webfinger_s }, format: :json
 
+      json = body_as_json
+
       expect(response).to have_http_status(:success)
       expect(response.content_type).to eq 'application/jrd+json'
-      expect(response.body).to eq "{\"subject\":\"acct:alice@cb6e6126.ngrok.io\",\"aliases\":[\"https://cb6e6126.ngrok.io/@alice\",\"https://cb6e6126.ngrok.io/users/alice\"],\"links\":[{\"rel\":\"http://webfinger.net/rel/profile-page\",\"type\":\"text/html\",\"href\":\"https://cb6e6126.ngrok.io/@alice\"},{\"rel\":\"http://schemas.google.com/g/2010#updates-from\",\"type\":\"application/atom+xml\",\"href\":\"https://cb6e6126.ngrok.io/users/alice.atom\"},{\"rel\":\"self\",\"type\":\"application/activity+json\",\"href\":\"https://cb6e6126.ngrok.io/@alice\"},{\"rel\":\"salmon\",\"href\":\"#{api_salmon_url(alice.id)}\"},{\"rel\":\"magic-public-key\",\"href\":\"data:application/magic-public-key,RSA.x4D6DyZa3zGa1XLhd_VG1bLGvK-Dmyz93WJfWNezIKeSuJkmA0f2NmoOfLUoumq9szN2Xt0GLDX06tDajdYPPXgLtDG0o1qqTrIJ7UTyYhbo94Wotl9iJvEwa5IjP1Mn00YJ_KvFrzKCm15PC7up6r-NtHsqoYS8X1KAqcbnptU=.AQAB\"},{\"rel\":\"http://ostatus.org/schema/1.0/subscribe\",\"template\":\"https://cb6e6126.ngrok.io/authorize_follow?acct={uri}\"}]}"
+      expect(json[:subject]).to eq 'acct:alice@cb6e6126.ngrok.io'
+      expect(json[:aliases]).to include('https://cb6e6126.ngrok.io/@alice', 'https://cb6e6126.ngrok.io/users/alice')
     end
 
     it 'returns JSON when account can be found' do
       get :show, params: { resource: alice.to_webfinger_s }, format: :xml
 
+      xml = Nokogiri::XML(response.body)
+
       expect(response).to have_http_status(:success)
       expect(response.content_type).to eq 'application/xrd+xml'
-      expect(response.body).to eq <<"XML"
-<?xml version="1.0"?>
-<XRD xmlns="http://docs.oasis-open.org/ns/xri/xrd-1.0">
-  <Subject>acct:alice@cb6e6126.ngrok.io</Subject>
-  <Alias>https://cb6e6126.ngrok.io/@alice</Alias>
-  <Alias>https://cb6e6126.ngrok.io/users/alice</Alias>
-  <Link rel="http://webfinger.net/rel/profile-page" type="text/html" href="https://cb6e6126.ngrok.io/@alice"/>
-  <Link rel="http://schemas.google.com/g/2010#updates-from" type="application/atom+xml" href="https://cb6e6126.ngrok.io/users/alice.atom"/>
-  <Link rel="salmon" href="#{api_salmon_url(alice.id)}"/>
-  <Link rel="magic-public-key" href="data:application/magic-public-key,RSA.x4D6DyZa3zGa1XLhd_VG1bLGvK-Dmyz93WJfWNezIKeSuJkmA0f2NmoOfLUoumq9szN2Xt0GLDX06tDajdYPPXgLtDG0o1qqTrIJ7UTyYhbo94Wotl9iJvEwa5IjP1Mn00YJ_KvFrzKCm15PC7up6r-NtHsqoYS8X1KAqcbnptU=.AQAB"/>
-  <Link rel="http://ostatus.org/schema/1.0/subscribe" template="https://cb6e6126.ngrok.io/authorize_follow?acct={uri}"/>
-</XRD>
-XML
+      expect(xml.at_xpath('//xmlns:Subject').content).to eq 'acct:alice@cb6e6126.ngrok.io'
+      expect(xml.xpath('//xmlns:Alias').map(&:content)).to include('https://cb6e6126.ngrok.io/@alice', 'https://cb6e6126.ngrok.io/users/alice')
     end
 
     it 'returns http not found when account cannot be found' do
@@ -80,19 +74,22 @@ XML
     end
 
     it 'returns JSON when account can be found with alternate domains' do
-      Rails.configuration.x.alternate_domains = ["foo.org"]
-      username, domain = alice.to_webfinger_s.split("@")
+      Rails.configuration.x.alternate_domains = ['foo.org']
+      username, = alice.to_webfinger_s.split('@')
 
       get :show, params: { resource: "#{username}@foo.org" }, format: :json
 
+      json = body_as_json
+
       expect(response).to have_http_status(:success)
       expect(response.content_type).to eq 'application/jrd+json'
-      expect(response.body).to eq "{\"subject\":\"acct:alice@cb6e6126.ngrok.io\",\"aliases\":[\"https://cb6e6126.ngrok.io/@alice\",\"https://cb6e6126.ngrok.io/users/alice\"],\"links\":[{\"rel\":\"http://webfinger.net/rel/profile-page\",\"type\":\"text/html\",\"href\":\"https://cb6e6126.ngrok.io/@alice\"},{\"rel\":\"http://schemas.google.com/g/2010#updates-from\",\"type\":\"application/atom+xml\",\"href\":\"https://cb6e6126.ngrok.io/users/alice.atom\"},{\"rel\":\"self\",\"type\":\"application/activity+json\",\"href\":\"https://cb6e6126.ngrok.io/@alice\"},{\"rel\":\"salmon\",\"href\":\"#{api_salmon_url(alice.id)}\"},{\"rel\":\"magic-public-key\",\"href\":\"data:application/magic-public-key,RSA.x4D6DyZa3zGa1XLhd_VG1bLGvK-Dmyz93WJfWNezIKeSuJkmA0f2NmoOfLUoumq9szN2Xt0GLDX06tDajdYPPXgLtDG0o1qqTrIJ7UTyYhbo94Wotl9iJvEwa5IjP1Mn00YJ_KvFrzKCm15PC7up6r-NtHsqoYS8X1KAqcbnptU=.AQAB\"},{\"rel\":\"http://ostatus.org/schema/1.0/subscribe\",\"template\":\"https://cb6e6126.ngrok.io/authorize_follow?acct={uri}\"}]}"
+      expect(json[:subject]).to eq 'acct:alice@cb6e6126.ngrok.io'
+      expect(json[:aliases]).to include('https://cb6e6126.ngrok.io/@alice', 'https://cb6e6126.ngrok.io/users/alice')
     end
 
     it 'returns http not found when account can not be found with alternate domains' do
-      Rails.configuration.x.alternate_domains = ["foo.org"]
-      username, domain = alice.to_webfinger_s.split("@")
+      Rails.configuration.x.alternate_domains = ['foo.org']
+      username, = alice.to_webfinger_s.split('@')
 
       get :show, params: { resource: "#{username}@bar.org" }, format: :json