tornado.tcpclient — IOStream connection factory

A non-blocking TCP connection factory.

class tornado.tcpclient.TCPClient(resolver: Resolver | None = None)[source]

A non-blocking TCP connection factory.

Changed in version 5.0: The io_loop argument (deprecated since version 4.1) has been removed.

async connect(host: str, port: int, af: AddressFamily = AddressFamily.AF_UNSPEC, ssl_options: dict[str, Any] | SSLContext | None = None, max_buffer_size: int | None = None, source_ip: str | None = None, source_port: int | None = None, timeout: float | timedelta | None = None) → IOStream[source]

Connect to the given host and port.

Asynchronously returns an IOStream (or SSLIOStream if ssl_options is not None).

Using the source_ip kwarg, one can specify the source IP address to use when establishing the connection. In case the user needs to resolve and use a specific interface, it has to be handled outside of Tornado as this depends very much on the platform.

Raises TimeoutError if the input future does not complete before timeout, which may be specified in any form allowed by IOLoop.add_timeout (i.e. a datetime.timedelta or an absolute time relative to IOLoop.time)

The message of the TimeoutError indicates which phase of the connection timed out: resolving the hostname, establishing the TCP connection (listing the addresses being tried), or performing the TLS handshake.

Similarly, when the user requires a certain source port, it can be specified using the source_port arg.

Changed in version 4.5: Added the source_ip and source_port arguments.

Changed in version 5.0: Added the timeout argument.

Changed in version 6.6: Timeout errors now have messages describing which phase of the connection process timed out.