How to disable multi-operation queries

[xxia-brex]

How can we disable multi-operation queries like "[{"operationName":"xxx1","variables":{},"query":"query xxx1 {}"},
{"operationName":"xxx2","variables":{},"query":"query xxx2 {}"},
{"operationName":"xxx3","variables":{},"query":"query xxx3 {*********}"},,
...repeat 1000x..."

for security reason, we prefer to only allow a single operation per http request

[benwilson512]

I think the right path here is a relatively simple batching: false option we enable on the plug.

Per our conversation on slack, a temporary work around could be to add the following plug ahead of your Absinthe.Plugs:

defmodule MyAppWeb.PreventBatchGraphQL do
  @behaviour Plug
  def init(opts), do: opts
  def call(conn, _opts) do
    case conn.body_params do
      %{"_json" => _} -> unprocessable(conn)
      %{"operations" => _} -> unprocessable(conn)
      _ -> conn
    end
  end
  defp unprocessable(conn) do
    conn
    |> Plug.Conn.send_resp(422, "batching not permitted")
    |> Plug.Conn.halt()
  end
end