'Detect, check and parse proxy protocol.
:raises: ForbiddenProxyRequest, InvalidProxyLine.
:return: True for proxy protocol line else False'

def proxy_protocol(self, line):

    if (not self.cfg.proxy_protocol):
        return False
    if (self.req_number != 1):
        return False
    if (not line.startswith('PROXY')):
        return False
    self.proxy_protocol_access_check()
    self.parse_proxy_protocol(line)
    return True
