Class SSLTransport

src/urllib3/util/ssltransport.py:22–271

The SSLTransport wraps an existing socket and establishes an SSL connection. Contrary to Python's implementation of SSLSocket, it allows you to chain multiple TLS connections together. It's particularly useful if you need to implement TLS within TLS. The class supports most of

class SSLTransport:
    """
    The SSLTransport wraps an existing socket and establishes an SSL connection.

    Contrary to Python's implementation of SSLSocket, it allows you to chain
    multiple TLS connections together. It's particularly useful if you need to
    implement TLS within TLS.

    The class supports most of the socket API operations.
    """

    @staticmethod
    def _validate_ssl_context_for_tls_in_tls(ssl_context: ssl.SSLContext) -> None:
        """
        Raises a ProxySchemeUnsupported if the provided ssl_context can't be used
        for TLS in TLS.

        The only requirement is that the ssl_context provides the 'wrap_bio'
        methods.
        """

        if not hasattr(ssl_context, "wrap_bio"):
            raise ProxySchemeUnsupported(
                "TLS in TLS requires SSLContext.wrap_bio() which isn't "
                "available on non-native SSLContext"
            )

    def __init__(
        self,
        socket: socket.socket,
        ssl_context: ssl.SSLContext,
        server_hostname: str | None = None,
        suppress_ragged_eofs: bool = True,
    ) -> None:
        """
        Create an SSLTransport around socket using the provided ssl_context.
        """
        self.incoming = ssl.MemoryBIO()
        self.outgoing = ssl.MemoryBIO()

        self.suppress_ragged_eofs = suppress_ragged_eofs
        self.socket = socket

        self.sslobj = ssl_context.wrap_bio(
            self.incoming, self.outgoing, server_hostname=server_hostname
        )

        # Perform initial handshake.
        self._ssl_io_loop(self.sslobj.do_handshake)

    def __enter__(self) -> Self:
        return self

    def __exit__(self, *_: typing.Any) -> None:
        self.close()

    def fileno(self) -> int:
        return self.socket.fileno()