Use conversation mapping objects to get / retrieve context from TwAPI.

lib/pleroma/object.ex

@@ -13,4 +13,8 @@ defmodule Pleroma.Object do
     Repo.one(from object in Object,
       where: fragment("? @> ?", object.data, ^%{id: ap_id}))
   end
+
+  def context_mapping(context) do
+    %Object{data: %{"id" => context}}
+  end
 end

lib/pleroma/web/twitter_api/representers/activity_representer.ex

@@ -1,9 +1,9 @@
 defmodule Pleroma.Web.TwitterAPI.Representers.ActivityRepresenter do
   use Pleroma.Web.TwitterAPI.Representers.BaseRepresenter
   alias Pleroma.Web.TwitterAPI.Representers.{UserRepresenter, ObjectRepresenter}
+  alias Pleroma.Web.TwitterAPI.TwitterAPI
   alias Pleroma.Activity
 
-
   defp user_by_ap_id(user_list, ap_id) do
     Enum.find(user_list, fn (%{ap_id: user_id}) -> ap_id == user_id end)
   end
@@ -82,6 +82,12 @@ defmodule Pleroma.Web.TwitterAPI.Representers.ActivityRepresenter do
     |> Enum.filter(&(&1))
     |> Enum.map(fn (user) -> UserRepresenter.to_map(user, opts) end)
 
+
+    conversation_id = with context when not is_nil(context) <- activity.data["context"] do
+      TwitterAPI.context_to_conversation_id(context)
+    else _e -> nil
+    end
+
     %{
       "id" => activity.id,
       "user" => UserRepresenter.to_map(user, opts),
@@ -92,7 +98,7 @@ defmodule Pleroma.Web.TwitterAPI.Representers.ActivityRepresenter do
       "is_post_verb" => true,
       "created_at" => created_at,
       "in_reply_to_status_id" => activity.data["object"]["inReplyToStatusId"],
-      "statusnet_conversation_id" => activity.data["object"]["statusnetConversationId"],
+      "statusnet_conversation_id" => conversation_id,
       "attachments" => (activity.data["object"]["attachment"] || []) |> ObjectRepresenter.enum_to_list(opts),
       "attentions" => attentions,
       "fave_num" => like_count,

lib/pleroma/web/twitter_api/twitter_api.ex

@@ -102,12 +102,7 @@ defmodule Pleroma.Web.TwitterAPI.TwitterAPI do
   end
 
   def fetch_conversation(user, id) do
-    query = from activity in Activity,
-      where: fragment("? @> ?", activity.data, ^%{ statusnetConversationId: id}),
-      limit: 1
-
-    with %Activity{} = activity <- Repo.one(query),
-         context <- activity.data["context"],
+    with context when is_binary(context) <- conversation_id_to_context(id),
          activities <- ActivityPub.fetch_activities_for_context(context),
          statuses <- activities |> activities_to_statuses(%{for: user})
     do
@@ -322,4 +317,22 @@ defmodule Pleroma.Web.TwitterAPI.TwitterAPI do
   defp make_date do
     DateTime.utc_now() |> DateTime.to_iso8601
   end
+
+  def context_to_conversation_id(context) do
+    with %Object{id: id} <- Object.get_by_ap_id(context) do
+      id
+    else _e ->
+      changeset = Object.context_mapping(context)
+      {:ok, %{id: id}} = Repo.insert(changeset)
+      id
+    end
+  end
+
+  def conversation_id_to_context(id) do
+    with %Object{data: %{"id" => context}} <- Repo.get(Object, id) do
+      context
+    else _e ->
+      {:error, "No such conversation"}
+    end
+  end
 end