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

1 files changed, 11 insertions, 0 deletions

diff --git a/app/serializers/rest/status_serializer.rb b/app/serializers/rest/status_serializer.rb
index 298a3bb40..d8efa8e60 100644
--- a/app/serializers/rest/status_serializer.rb
+++ b/app/serializers/rest/status_serializer.rb
@@ -17,6 +17,7 @@ class REST::StatusSerializer < ActiveModel::Serializer
   has_many :media_attachments, serializer: REST::MediaAttachmentSerializer
   has_many :mentions
   has_many :tags
+  has_many :emojis
 
   def current_user?
     !current_user.nil?
@@ -106,4 +107,14 @@ class REST::StatusSerializer < ActiveModel::Serializer
       tag_url(object)
     end
   end
+
+  class CustomEmojiSerializer < ActiveModel::Serializer
+    include RoutingHelper
+
+    attributes :shortcode, :url
+
+    def url
+      full_asset_url(object.image.url)
+    end
+  end
 end