而且在使用Misultin的时候对参数的处理应该怎么做？目前的做法感觉很臃肿，我该如何处理参数的异常？

handle('GET', ["datalock", "checkall"], Req) ->
    Args = Req:parse_qs(),
    case {Req:get_variable("keys", Args), Req:get_variable("user", Args), Req:get_variable("callback", Args)} of
        {undefined, _, _} ->
            Req:ok([{"Content-Type", "text/plain"}], "error param.");
        {_, undefined, _} ->
            Req:ok([{"Content-Type", "text/plain"}], "error param.");
        {_, _, undefined} ->
                Req:ok([{"Content-Type", "text/plain"}], "error param.");
        {Keys, User, Callback} ->
            case checkIds(Keys, User) of
                {ok, Result} -> 
                    Req:ok([{"Content-Type", "application/json;charset=utf-8"}], Callback++"("++Result++")")
            end
    end;