Add plug to generate Matrix error

lib/matrix_server_web/controllers/account_controller.ex

@@ -1,7 +1,8 @@
 defmodule MatrixServerWeb.AccountController do
   use MatrixServerWeb, :controller
 
-  import MatrixServer, only: [get_mxid: 1]
+  import MatrixServer
+  import MatrixServerWeb.Plug.Error
 
   alias MatrixServer.Account
   alias Plug.Conn
@@ -9,21 +10,15 @@ defmodule MatrixServerWeb.AccountController do
   def available(conn, params) do
     localpart = Map.get(params, "username", "")
 
-    {status, data} =
-      case Account.available?(localpart) do
-        :ok ->
-          {200, %{available: true}}
+    case Account.available?(localpart) do
+      :ok ->
+        conn
+        |> put_status(200)
+        |> json(%{available: true})
 
-        {:error, :user_in_use} ->
-          {400, %{errcode: "M_USER_IN_USE", error: "Desired user ID is already taken."}}
-
-        {:error, :invalid_username} ->
-          {400, %{errocode: "M_INVALID_USERNAME", error: "Desired user ID is invalid."}}
-      end
-
-    conn
-    |> put_status(status)
-    |> json(data)
+      {:error, error} ->
+        put_error(conn, error)
+    end
   end
 
   def whoami(%Conn{assigns: %{account: %Account{localpart: localpart}}} = conn, _params) do

lib/matrix_server_web/controllers/auth_controller.ex

@@ -2,6 +2,7 @@ defmodule MatrixServerWeb.AuthController do
   use MatrixServerWeb, :controller
 
   import MatrixServer
+  import MatrixServerWeb.Plug.Error
 
   alias MatrixServer.{Repo, Account}
   alias Ecto.Changeset
@@ -38,7 +39,7 @@ defmodule MatrixServerWeb.AuthController do
           {200, data}
 
         {:error, error} ->
-          generate_error(error)
+          put_error(conn, error)
       end
 
     conn
@@ -48,11 +49,7 @@ defmodule MatrixServerWeb.AuthController do
 
   def register(conn, %{"auth" => _}) do
     # Other login types are unsupported for now.
-    data = %{errcode: "M_FORBIDDEN", error: "Login type not supported"}
-
-    conn
-    |> put_status(400)
-    |> json(data)
+    put_error(conn, :forbidden)
   end
 
   def register(conn, _params) do
@@ -80,9 +77,9 @@ defmodule MatrixServerWeb.AuthController do
   end
 
   defp get_register_error(%Changeset{errors: [error | _]}), do: get_register_error(error)
-  defp get_register_error({:localpart, {_, [{:constraint, :unique} | _]}}), do: "M_USER_IN_USE"
-  defp get_register_error({:localpart, {_, [{:validation, _} | _]}}), do: "M_INVALID_USERNAME"
-  defp get_register_error(_), do: "M_BAD_JSON"
+  defp get_register_error({:localpart, {_, [{:constraint, :unique} | _]}}), do: :user_in_use
+  defp get_register_error({:localpart, {_, [{:validation, _} | _]}}), do: :invalid_username
+  defp get_register_error(_), do: :bad_json
 
   defp register_schema do
     types = %{