@callback handle_invalid_update(Plug.Conn.t(), Ecto.Changeset.t()) :: Plug.Conn.t()

Returns a Plug.Conn in response to errors during update.

Default implementation sets the status to :unprocessable_entity and renders the error messages provided.

@callback handle_update(
  Plug.Conn.t(),
  ExTeal.Resource.record(),
  ExTeal.Resource.attributes()
) ::
  Plug.Conn.t() | ExTeal.Resource.record() | nil

Returns an unpersisted changeset or persisted model representing the newly updated model.

Receives the conn, the model as found by record/2, and the attributes argument from the permitted_attributes function.

Default implementation returns the results of calling Model.changeset(model, attrs).

handle_update/3 can return an %Ecto.Changeset, an Ecto.Schema struct, a list of errors ({:error, [email: "is not valid"]} or a conn with any response/body.

Example custom implementation:

def handle_update(conn, post, attributes) do
  current_user_id = conn.assigns[:current_user].id
  case post.author_id do
    ^current_user_id -> {:error, author_id: "you can only edit your own posts"}
    _                -> Post.changeset(post, attributes, :update)
  end
end

@callback render_update(Plug.Conn.t(), ExTeal.Resource.record()) :: Plug.Conn.t()

Returns a Plug.Conn in response to successful update.

Default implementation renders the view.