poplib.py 文件源码

def stls(self, context=None):
        """Start a TLS session on the active connection as specified in RFC 2595.

                context - a ssl.SSLContext
        """
        if not HAVE_SSL:
            raise error_proto('-ERR TLS support missing')
        if self._tls_established:
            raise error_proto('-ERR TLS session already established')
        caps = self.capa()
        if not 'STLS' in caps:
            raise error_proto('-ERR STLS not supported by server')
        if context is None:
            context = ssl._create_stdlib_context()
        resp = self._shortcmd('STLS')
        server_hostname = self.host if ssl.HAS_SNI else None
        self.sock = context.wrap_socket(self.sock,
                                        server_hostname=server_hostname)
        self.file = self.sock.makefile('rb')
        self._tls_established = True
        return resp