'Main hook into the WSGI paste.deploy filter/app pipeline.
:param env: The WSGI environment dict.
:param start_response: The WSGI start_response hook.
:returns: Response as per WSGI.'

def __call__(self, env, start_response):

    if (env['REQUEST_METHOD'] == 'POST'):
        try:
            (content_type, attrs) = parse_content_disposition((env.get('CONTENT_TYPE') or ''))
            if ((content_type == 'multipart/form-data') and ('boundary' in attrs)):
                http_user_agent = ('%s    FormPost' % env.get('HTTP_USER_AGENT', ''))
                env['HTTP_USER_AGENT'] = http_user_agent.strip()
                (status, headers, body) = self._translate_form(env, attrs['boundary'])
                start_response(status, headers)
                return [body]
        except MimeInvalid:
            body = 'FormPost:    invalid    starting    boundary'
            start_response('400    Bad    Request', (('Content-Type', 'text/plain'), ('Content-Length', str(len(body)))))
            return [body]
        except (FormInvalid, EOFError) as err:
            body = ('FormPost:    %s' % err)
            start_response('400    Bad    Request', (('Content-Type', 'text/plain'), ('Content-Length', str(len(body)))))
            return [body]
        except FormUnauthorized as err:
            message = ('FormPost:    %s' % str(err).title())
            return HTTPUnauthorized(body=message)(env, start_response)
    return self.app(env, start_response)
