Add support for AP C2S uploadMedia

Closes: https://git.pleroma.social/pleroma/pleroma/issues/1171

lib/pleroma/web/activity_pub/activity_pub_controller.ex

@@ -443,4 +443,31 @@ defmodule Pleroma.Web.ActivityPub.ActivityPubController do
 
     {new_user, for_user}
   end
+
+  # TODO: Add support for "object" field
+  @doc """
+  Endpoint based on <https://www.w3.org/wiki/SocialCG/ActivityPub/MediaUpload>
+
+  Parameters:
+  - (required) `file`: data of the media
+  - (optionnal) `description`: description of the media, intended for accessibility
+
+  Response:
+  - HTTP Code: 201 Created
+  - HTTP Body: ActivityPub object to be inserted into another's `attachment` field
+  """
+  def upload_media(%{assigns: %{user: user}} = conn, %{"file" => file} = data) do
+    with {:ok, object} <-
+           ActivityPub.upload(
+             file,
+             actor: User.ap_id(user),
+             description: Map.get(data, "description")
+           ) do
+      Logger.debug(inspect(object))
+
+      conn
+      |> put_status(:created)
+      |> json(object.data)
+    end
+  end
 end

lib/pleroma/web/activity_pub/views/user_view.ex

@@ -25,7 +25,8 @@ defmodule Pleroma.Web.ActivityPub.UserView do
       "oauthAuthorizationEndpoint" => Helpers.o_auth_url(Endpoint, :authorize),
       "oauthRegistrationEndpoint" => Helpers.mastodon_api_url(Endpoint, :create_app),
       "oauthTokenEndpoint" => Helpers.o_auth_url(Endpoint, :token_exchange),
-      "sharedInbox" => Helpers.activity_pub_url(Endpoint, :inbox)
+      "sharedInbox" => Helpers.activity_pub_url(Endpoint, :inbox),
+      "uploadMedia" => Helpers.activity_pub_url(Endpoint, :upload_media)
     }
   end
 

lib/pleroma/web/router.ex

@@ -572,6 +572,7 @@ defmodule Pleroma.Web.Router do
     scope [] do
       pipe_through(:oauth_write)
       post("/users/:nickname/outbox", ActivityPubController, :update_outbox)
+      post("/api/ap/uploadMedia", ActivityPubController, :upload_media)
     end
 
     scope [] do