Custom emoji (#4988)

* Custom emoji

- In OStatus: `<link rel="emoji" name="coolcat" href="http://..." />`
- In ActivityPub: `{ type: "Emoji", name: ":coolcat:", href: "http://..." }`
- In REST API: Status object includes `emojis` array (`shortcode`, `url`)
- Domain blocks with reject media stop emojis
- Emoji file up to 50KB
- Web UI handles custom emojis
- Static pages render custom emojis as `<img />` tags

Side effects:

- Undo #4500 optimization, as I needed to modify it to restore
  shortcode handling in emojify()
- Formatter#plaintext should now make sure stripped out line-breaks
  and paragraphs are replaced with newlines

* Fix emoji at the start not being converted

3 files changed, 117 insertions, 2 deletions

diff --git a/spec/lib/activitypub/activity/create_spec.rb b/spec/lib/activitypub/activity/create_spec.rb
index fcb044ebc..1a9520f04 100644
--- a/spec/lib/activitypub/activity/create_spec.rb
+++ b/spec/lib/activitypub/activity/create_spec.rb
@@ -17,6 +17,7 @@ RSpec.describe ActivityPub::Activity::Create do
 
   before do
     stub_request(:get, 'http://example.com/attachment.png').to_return(request_fixture('avatar.txt'))
+    stub_request(:get, 'http://example.com/emoji.png').to_return(body: attachment_fixture('emojo.png'))
   end
 
   describe '#perform' do
@@ -217,5 +218,29 @@ RSpec.describe ActivityPub::Activity::Create do
         expect(status.tags.map(&:name)).to include('test')
       end
     end
+
+    context 'with emojis' do
+      let(:object_json) do
+        {
+          id: 'bar',
+          type: 'Note',
+          content: 'Lorem ipsum :tinking:',
+          tag: [
+            {
+              type: 'Emoji',
+              href: 'http://example.com/emoji.png',
+              name: 'tinking',
+            },
+          ],
+        }
+      end
+
+      it 'creates status' do
+        status = sender.statuses.first
+
+        expect(status).to_not be_nil
+        expect(status.emojis.map(&:shortcode)).to include('tinking')
+      end
+    end
   end
 end
diff --git a/spec/lib/formatter_spec.rb b/spec/lib/formatter_spec.rb
index b714b317a..71b6b78d2 100644
--- a/spec/lib/formatter_spec.rb
+++ b/spec/lib/formatter_spec.rb
@@ -223,6 +223,45 @@ RSpec.describe Formatter do
 
         include_examples 'encode and link URLs'
       end
+
+      context 'with custom_emojify option' do
+        let!(:emoji) { Fabricate(:custom_emoji) }
+        let(:status) { Fabricate(:status, account: local_account, text: text) }
+
+        subject { Formatter.instance.format(status, custom_emojify: true) }
+
+        context 'with emoji at the start' do
+          let(:text) { ':coolcat: Beep boop' }
+
+          it 'converts shortcode to image tag' do
+            is_expected.to match(/<p><img draggable="false" class="emojione" alt=":coolcat:"/)
+          end
+        end
+
+        context 'with emoji in the middle' do
+          let(:text) { 'Beep :coolcat: boop' }
+
+          it 'converts shortcode to image tag' do
+            is_expected.to match(/Beep <img draggable="false" class="emojione" alt=":coolcat:"/)
+          end
+        end
+
+        context 'with concatenated emoji' do
+          let(:text) { ':coolcat::coolcat:' }
+
+          it 'does not touch the shortcodes' do
+            is_expected.to match(/:coolcat::coolcat:/)
+          end
+        end
+
+        context 'with emoji at the end' do
+          let(:text) { 'Beep boop :coolcat:' }
+
+          it 'converts shortcode to image tag' do
+            is_expected.to match(/boop <img draggable="false" class="emojione" alt=":coolcat:"/)
+          end
+        end
+      end
     end
 
     context 'with remote status' do
@@ -231,6 +270,45 @@ RSpec.describe Formatter do
       it 'reformats' do
         is_expected.to eq 'Beep boop'
       end
+
+      context 'with custom_emojify option' do
+        let!(:emoji) { Fabricate(:custom_emoji, domain: remote_account.domain) }
+        let(:status) { Fabricate(:status, account: remote_account, text: text) }
+
+        subject { Formatter.instance.format(status, custom_emojify: true) }
+
+        context 'with emoji at the start' do
+          let(:text) { '<p>:coolcat: Beep boop<br />' }
+
+          it 'converts shortcode to image tag' do
+            is_expected.to match(/<p><img draggable="false" class="emojione" alt=":coolcat:"/)
+          end
+        end
+
+        context 'with emoji in the middle' do
+          let(:text) { '<p>Beep :coolcat: boop</p>' }
+
+          it 'converts shortcode to image tag' do
+            is_expected.to match(/Beep <img draggable="false" class="emojione" alt=":coolcat:"/)
+          end
+        end
+
+        context 'with concatenated emoji' do
+          let(:text) { '<p>:coolcat::coolcat:</p>' }
+
+          it 'does not touch the shortcodes' do
+            is_expected.to match(/<p>:coolcat::coolcat:<\/p>/)
+          end
+        end
+
+        context 'with emoji at the end' do
+          let(:text) { '<p>Beep boop<br />:coolcat:</p>' }
+
+          it 'converts shortcode to image tag' do
+            is_expected.to match(/<br><img draggable="false" class="emojione" alt=":coolcat:"/)
+          end
+        end
+      end
     end
   end
 
diff --git a/spec/lib/ostatus/atom_serializer_spec.rb b/spec/lib/ostatus/atom_serializer_spec.rb
index 0451eceeb..b2480a53b 100644
--- a/spec/lib/ostatus/atom_serializer_spec.rb
+++ b/spec/lib/ostatus/atom_serializer_spec.rb
@@ -97,11 +97,23 @@ RSpec.describe OStatus::AtomSerializer do
 
       mentioned = element.nodes.find do |node|
         node.name == 'link' &&
-        node[:rel] == 'mentioned' &&
-        node['ostatus:object-type'] == TagManager::TYPES[:person]
+          node[:rel] == 'mentioned' &&
+          node['ostatus:object-type'] == TagManager::TYPES[:person]
       end
+
       expect(mentioned[:href]).to eq 'https://cb6e6126.ngrok.io/users/username'
     end
+
+    it 'appends link elements for emojis' do
+      Fabricate(:custom_emoji)
+
+      status  = Fabricate(:status, text: ':coolcat:')
+      element = serialize(status)
+      emoji   = element.nodes.find { |node| node.name == 'link' && node[:rel] == 'emoji' }
+
+      expect(emoji[:name]).to eq 'coolcat'
+      expect(emoji[:href]).to_not be_blank
+    end
   end
 
   describe 'render' do