werkzeug.BaseRequest.max_form_memory_size

BaseRequest.max_form_memory_size = None

the maximum form field size. This is forwarded to the form data parsing function (parse_form_data()). When set and the form or files attribute is accessed and the data in memory for post data is longer than the specified value a RequestEntityTooLarge exception is raised.

Have a look at dealing-with-request-data for more details.

New in version 0.5.