Add ActivityPub inbox (#4216)

* Add ActivityPub inbox

* Handle ActivityPub deletes

* Handle ActivityPub creates

* Handle ActivityPub announces

* Stubs for handling all activities that need to be handled

* Add ActivityPub actor resolving

* Handle conversation URI passing in ActivityPub

* Handle content language in ActivityPub

* Send accept header when fetching actor, handle JSON parse errors

* Test for ActivityPub::FetchRemoteAccountService

* Handle public key and icon/image when embedded/as array/as resolvable URI

* Implement ActivityPub::FetchRemoteStatusService

* Add stubs for more interactions

* Undo activities implemented

* Handle out of order activities

* Hook up ActivityPub to ResolveRemoteAccountService, handle
Update Account activities

* Add fragment IDs to all transient activity serializers

* Add tests and fixes

* Add stubs for missing tests

* Add more tests

* Add more tests

spec/lib/activitypub/activity/create_spec.rb

@@ -0,0 +1,221 @@
+require 'rails_helper'
+
+RSpec.describe ActivityPub::Activity::Create do
+  let(:sender) { Fabricate(:account, followers_url: 'http://example.com/followers') }
+
+  let(:json) do
+    {
+      '@context': 'https://www.w3.org/ns/activitystreams',
+      id: 'foo',
+      type: 'Create',
+      actor: ActivityPub::TagManager.instance.uri_for(sender),
+      object: object_json,
+    }.with_indifferent_access
+  end
+
+  subject { described_class.new(json, sender) }
+
+  before do
+    stub_request(:get, 'http://example.com/attachment.png').to_return(request_fixture('avatar.txt'))
+  end
+
+  describe '#perform' do
+    before do
+      subject.perform
+    end
+
+    context 'standalone' do
+      let(:object_json) do
+        {
+          id: 'bar',
+          type: 'Note',
+          content: 'Lorem ipsum',
+        }
+      end
+
+      it 'creates status' do
+        status = sender.statuses.first
+
+        expect(status).to_not be_nil
+        expect(status.text).to eq 'Lorem ipsum'
+      end
+
+      it 'missing to/cc defaults to direct privacy' do
+        status = sender.statuses.first
+
+        expect(status).to_not be_nil
+        expect(status.visibility).to eq 'direct'
+      end
+    end
+
+    context 'public' do
+      let(:object_json) do
+        {
+          id: 'bar',
+          type: 'Note',
+          content: 'Lorem ipsum',
+          to: 'https://www.w3.org/ns/activitystreams#Public',
+        }
+      end
+
+      it 'creates status' do
+        status = sender.statuses.first
+
+        expect(status).to_not be_nil
+        expect(status.visibility).to eq 'public'
+      end
+    end
+
+    context 'unlisted' do
+      let(:object_json) do
+        {
+          id: 'bar',
+          type: 'Note',
+          content: 'Lorem ipsum',
+          cc: 'https://www.w3.org/ns/activitystreams#Public',
+        }
+      end
+
+      it 'creates status' do
+        status = sender.statuses.first
+
+        expect(status).to_not be_nil
+        expect(status.visibility).to eq 'unlisted'
+      end
+    end
+
+    context 'private' do
+      let(:object_json) do
+        {
+          id: 'bar',
+          type: 'Note',
+          content: 'Lorem ipsum',
+          to: 'http://example.com/followers',
+        }
+      end
+
+      it 'creates status' do
+        status = sender.statuses.first
+
+        expect(status).to_not be_nil
+        expect(status.visibility).to eq 'private'
+      end
+    end
+
+    context 'direct' do
+      let(:recipient) { Fabricate(:account) }
+
+      let(:object_json) do
+        {
+          id: 'bar',
+          type: 'Note',
+          content: 'Lorem ipsum',
+          to: ActivityPub::TagManager.instance.uri_for(recipient),
+        }
+      end
+
+      it 'creates status' do
+        status = sender.statuses.first
+
+        expect(status).to_not be_nil
+        expect(status.visibility).to eq 'direct'
+      end
+    end
+
+    context 'as a reply' do
+      let(:original_status) { Fabricate(:status) }
+
+      let(:object_json) do
+        {
+          id: 'bar',
+          type: 'Note',
+          content: 'Lorem ipsum',
+          inReplyTo: ActivityPub::TagManager.instance.uri_for(original_status),
+        }
+      end
+
+      it 'creates status' do
+        status = sender.statuses.first
+
+        expect(status).to_not be_nil
+        expect(status.thread).to eq original_status
+        expect(status.reply?).to be true
+        expect(status.in_reply_to_account).to eq original_status.account
+        expect(status.conversation).to eq original_status.conversation
+      end
+    end
+
+    context 'with mentions' do
+      let(:recipient) { Fabricate(:account) }
+
+      let(:object_json) do
+        {
+          id: 'bar',
+          type: 'Note',
+          content: 'Lorem ipsum',
+          tag: [
+            {
+              type: 'Mention',
+              href: ActivityPub::TagManager.instance.uri_for(recipient),
+            },
+          ],
+        }
+      end
+
+      it 'creates status' do
+        status = sender.statuses.first
+
+        expect(status).to_not be_nil
+        expect(status.mentions.map(&:account)).to include(recipient)
+      end
+    end
+
+    context 'with media attachments' do
+      let(:object_json) do
+        {
+          id: 'bar',
+          type: 'Note',
+          content: 'Lorem ipsum',
+          attachment: [
+            {
+              type: 'Document',
+              mime_type: 'image/png',
+              url: 'http://example.com/attachment.png',
+            },
+          ],
+        }
+      end
+
+      it 'creates status' do
+        status = sender.statuses.first
+
+        expect(status).to_not be_nil
+        expect(status.media_attachments.map(&:remote_url)).to include('http://example.com/attachment.png')
+      end
+    end
+
+    context 'with hashtags' do
+      let(:object_json) do
+        {
+          id: 'bar',
+          type: 'Note',
+          content: 'Lorem ipsum',
+          tag: [
+            {
+              type: 'Hashtag',
+              href: 'http://example.com/blah',
+              name: '#test',
+            },
+          ],
+        }
+      end
+
+      it 'creates status' do
+        status = sender.statuses.first
+
+        expect(status).to_not be_nil
+        expect(status.tags.map(&:name)).to include('test')
+      end
+    end
+  end
+end