allow external emoji

config/emoji.txt

@@ -1,3 +1,4 @@
 firefox, /emoji/Firefox.gif, Gif,Fun
 blank, /emoji/blank.png, Fun
 dinosaur, /emoji/dino walking.gif, Gif
+external_emoji, https://example.com/emoji.png

lib/pleroma/emoji/formatter.ex

@@ -5,6 +5,7 @@
 defmodule Pleroma.Emoji.Formatter do
   alias Pleroma.Emoji
   alias Pleroma.HTML
+  alias Pleroma.Web
   alias Pleroma.Web.MediaProxy
 
   def emojify(text) do
@@ -43,7 +44,7 @@ def get_emoji_map(text) when is_binary(text) do
     Emoji.get_all()
     |> Enum.filter(fn {emoji, %Emoji{}} -> String.contains?(text, ":#{emoji}:") end)
     |> Enum.reduce(%{}, fn {name, %Emoji{file: file}}, acc ->
-      Map.put(acc, name, "#{Pleroma.Web.Endpoint.static_url()}#{file}")
+      Map.put(acc, name, to_string(URI.merge(Web.base_url(), file)))
     end)
   end
 

test/pleroma/web/common_api_test.exs

@@ -504,6 +504,19 @@ test "it adds emoji in the object" do
   end
 
   describe "posting" do
+    test "it adds an emoji on an external site" do
+      user = insert(:user)
+      {:ok, activity} = CommonAPI.post(user, %{status: "hey :external_emoji:"})
+
+      assert %{"external_emoji" => url} = Object.normalize(activity).data["emoji"]
+      assert url == "https://example.com/emoji.png"
+
+      {:ok, activity} = CommonAPI.post(user, %{status: "hey :blank:"})
+
+      assert %{"blank" => url} = Object.normalize(activity).data["emoji"]
+      assert url == "#{Pleroma.Web.base_url()}/emoji/blank.png"
+    end
+
     test "deactivated users can't post" do
       user = insert(:user, deactivated: true)
       assert {:error, _} = CommonAPI.post(user, %{status: "ye"})