Retrieve uploaded file in webapp2

    def get_uploaded_file(self, post_key_name):
        """
        Get an uploaded file by post key name.

        :param str post_key_name:
        :rtype: cgi.FieldStorage
        :return: cgi.FieldStorage or None
        """
        import cgi
        import logging

        field_storage = self.request.POST.get(post_key_name, None)
        if isinstance(field_storage, cgi.FieldStorage):
            file_data = field_storage.file.read()
            logging.error(field_storage)
            logging.error(field_storage.filename)
            logging.error(field_storage.type)

            return field_storage
        return None