def _perform_subrequest(self, orig_env, attributes, fp, keys):
        """
        Performs the subrequest and returns the response.

        :param orig_env: The WSGI environment dict; will only be used
                         to form a new env for the subrequest.
        :param attributes: dict of the attributes of the form so far.
        :param fp: The file-like object containing the request body.
        :param keys: The account keys to validate the signature with.
        :returns: (status_line, headers_list, message)
        """
        if not keys:
            raise FormUnauthorized('invalid signature')
        try:
            max_file_size = int(attributes.get('max_file_size') or 0)
        except ValueError:
            raise FormInvalid('max_file_size not an integer')
        subenv = make_pre_authed_env(orig_env, 'PUT', agent=None,
                                     swift_source='FP')
        if 'QUERY_STRING' in subenv:
            del subenv['QUERY_STRING']
        subenv['HTTP_TRANSFER_ENCODING'] = 'chunked'
        subenv['wsgi.input'] = _CappedFileLikeObject(fp, max_file_size)
        if not subenv['PATH_INFO'].endswith('/') and \
                subenv['PATH_INFO'].count('/') < 4:
            subenv['PATH_INFO'] += '/'
        subenv['PATH_INFO'] += attributes['filename'] or 'filename'
        if 'x_delete_at' in attributes:
            try:
                subenv['HTTP_X_DELETE_AT'] = int(attributes['x_delete_at'])
            except ValueError:
                raise FormInvalid('x_delete_at not an integer: '
                                  'Unix timestamp required.')
        if 'x_delete_after' in attributes:
            try:
                subenv['HTTP_X_DELETE_AFTER'] = int(
                    attributes['x_delete_after'])
            except ValueError:
                raise FormInvalid('x_delete_after not an integer: '
                                  'Number of seconds required.')
        if 'content-type' in attributes:
            subenv['CONTENT_TYPE'] = \
                attributes['content-type'] or 'application/octet-stream'
        elif 'CONTENT_TYPE' in subenv:
            del subenv['CONTENT_TYPE']
        try:
            if int(attributes.get('expires') or 0) < time():
                raise FormUnauthorized('form expired')
        except ValueError:
            raise FormInvalid('expired not an integer')
        hmac_body = '%s\n%s\n%s\n%s\n%s' % (
            orig_env['PATH_INFO'],
            attributes.get('redirect') or '',
            attributes.get('max_file_size') or '0',
            attributes.get('max_file_count') or '0',
            attributes.get('expires') or '0')

        has_valid_sig = False
        for key in keys:
            sig = hmac.new(key, hmac_body, sha1).hexdigest()
            if streq_const_time(sig, (attributes.get('signature') or
                                      'invalid')):
                has_valid_sig = True
        if not has_valid_sig:
            raise FormUnauthorized('invalid signature')

        substatus = [None]
        subheaders = [None]

        wsgi_input = subenv['wsgi.input']

        def _start_response(status, headers, exc_info=None):
            if wsgi_input.file_size_exceeded:
                raise EOFError("max_file_size exceeded")

            substatus[0] = status
            subheaders[0] = headers

        i = iter(self.app(subenv, _start_response))
        try:
            next(i)
        except StopIteration:
            pass
        return substatus[0], subheaders[0], ''
dataset/ETHPy150Open openstack/swift/swift/common/middleware/formpost.py/FormPost._perform_subrequest/original