Gio.SocketClient¶

class — extends GObject.Object

GSocketClient is a lightweight high-level utility class for connecting to a network host using a connection oriented socket type.

You create a GSocketClient object, set any options you want, and then call a sync or async connect operation, which returns a SocketConnection subclass on success.

The type of the SocketConnection object returned depends on the type of the underlying socket that is in use. For instance, for a TCP/IP connection it will be a TcpConnection.

As GSocketClient is a lightweight object, you don't need to cache it. You can just create a new one any time you need one.

Constructors¶

new¶

@classmethod
def new(cls) -> SocketClient

Creates a new SocketClient with the default options.

Methods¶

add_application_proxy¶

def add_application_proxy(self, protocol: str) -> None

Enable proxy protocols to be handled by the application. When the indicated proxy protocol is returned by the ProxyResolver, SocketClient will consider this protocol as supported but will not try to find a Proxy instance to handle handshaking. The application must check for this case by calling SocketConnection.get_remote_address on the returned SocketConnection, and seeing if it's a ProxyAddress of the appropriate type, to determine whether or not it needs to handle the proxy handshaking itself.

This should be used for proxy protocols that are dialects of another protocol such as HTTP proxy. It also allows cohabitation of proxy protocols that are reused between protocols. A good example is HTTP. It can be used to proxy HTTP, FTP and Gopher and can also be use as generic socket proxy through the HTTP CONNECT method.

When the proxy is detected as being an application proxy, TLS handshake will be skipped. This is required to let the application do the proxy specific handshake.

Parameters:

protocol — The proxy protocol

connect¶

def connect(self, connectable: SocketConnectable, cancellable: Cancellable | None = ...) -> SocketConnection

Tries to resolve the connectable and make a network connection to it.

Upon a successful connection, a new SocketConnection is constructed and returned. The caller owns this new object and must drop their reference to it when finished with it.

The type of the SocketConnection object returned depends on the type of the underlying socket that is used. For instance, for a TCP/IP connection it will be a TcpConnection.

The socket created will be the same family as the address that the connectable resolves to, unless family is set with SocketClient.set_family or indirectly via SocketClient.set_local_address. The socket type defaults to SocketType.STREAM but can be set with SocketClient.set_socket_type.

If a local address is specified with SocketClient.set_local_address the socket will be bound to this address before connecting.

Parameters:

connectable — a SocketConnectable specifying the remote address.
cancellable — optional Cancellable object, None to ignore.

connect_async¶

def connect_async(self, connectable: SocketConnectable, cancellable: Cancellable | None = ..., callback: Callable[[SocketClient | None, AsyncResult], None] | None = ...) -> None

This is the asynchronous version of SocketClient.connect.

You may wish to prefer the asynchronous version even in synchronous command line programs because, since 2.60, it implements RFC 8305 "Happy Eyeballs" recommendations to work around long connection timeouts in networks where IPv6 is broken by performing an IPv4 connection simultaneously without waiting for IPv6 to time out, which is not supported by the synchronous call. (This is not an API guarantee, and may change in the future.)

When the operation is finished callback will be called. You can then call SocketClient.connect_finish to get the result of the operation.

Parameters:

connectable — a SocketConnectable specifying the remote address.
cancellable — a Cancellable, or None
callback — a GAsyncReadyCallback

connect_finish¶

def connect_finish(self, result: AsyncResult) -> SocketConnection

Finishes an async connect operation. See SocketClient.connect_async

Parameters:

result — a AsyncResult.

connect_to_host¶

def connect_to_host(self, host_and_port: str, default_port: int, cancellable: Cancellable | None = ...) -> SocketConnection

This is a helper function for SocketClient.connect.

Attempts to create a TCP connection to the named host.

host_and_port may be in any of a number of recognized formats; an IPv6 address, an IPv4 address, or a domain name (in which case a DNS lookup is performed). Quoting with [] is supported for all address types. A port override may be specified in the usual way with a colon. Ports may be given as decimal numbers or symbolic names (in which case an /etc/services lookup is performed).

If no port override is given in host_and_port then default_port will be used as the port number to connect to.

In general, host_and_port is expected to be provided by the user (allowing them to give the hostname, and a port override if necessary) and default_port is expected to be provided by the application.

In the case that an IP address is given, a single connection attempt is made. In the case that a name is given, multiple connection attempts may be made, in turn and according to the number of address records in DNS, until a connection succeeds.

Upon a successful connection, a new SocketConnection is constructed and returned. The caller owns this new object and must drop their reference to it when finished with it.

In the event of any failure (DNS error, service not found, no hosts connectable) None is returned and error (if non-None) is set accordingly.

Parameters:

host_and_port — the name and optionally port of the host to connect to
default_port — the default port to connect to
cancellable — a Cancellable, or None

connect_to_host_async¶

def connect_to_host_async(self, host_and_port: str, default_port: int, cancellable: Cancellable | None = ..., callback: Callable[[SocketClient | None, AsyncResult], None] | None = ...) -> None

This is the asynchronous version of SocketClient.connect_to_host.

When the operation is finished callback will be called. You can then call SocketClient.connect_to_host_finish to get the result of the operation.

Parameters:

host_and_port — the name and optionally the port of the host to connect to
default_port — the default port to connect to
cancellable — a Cancellable, or None
callback — a GAsyncReadyCallback

connect_to_host_finish¶

def connect_to_host_finish(self, result: AsyncResult) -> SocketConnection

Finishes an async connect operation. See SocketClient.connect_to_host_async

Parameters:

result — a AsyncResult.

connect_to_service¶

def connect_to_service(self, domain: str, service: str, cancellable: Cancellable | None = ...) -> SocketConnection

Attempts to create a TCP connection to a service.

This call looks up the SRV record for service at domain for the "tcp" protocol. It then attempts to connect, in turn, to each of the hosts providing the service until either a connection succeeds or there are no hosts remaining.

Upon a successful connection, a new SocketConnection is constructed and returned. The caller owns this new object and must drop their reference to it when finished with it.

In the event of any failure (DNS error, service not found, no hosts connectable) None is returned and error (if non-None) is set accordingly.

Parameters:

domain — a domain name
service — the name of the service to connect to
cancellable — a Cancellable, or None

connect_to_service_async¶

def connect_to_service_async(self, domain: str, service: str, cancellable: Cancellable | None = ..., callback: Callable[[SocketClient | None, AsyncResult], None] | None = ...) -> None

This is the asynchronous version of SocketClient.connect_to_service.

Parameters:

domain — a domain name
service — the name of the service to connect to
cancellable — a Cancellable, or None
callback — a GAsyncReadyCallback

connect_to_service_finish¶

def connect_to_service_finish(self, result: AsyncResult) -> SocketConnection

Finishes an async connect operation. See SocketClient.connect_to_service_async

Parameters:

result — a AsyncResult.

connect_to_uri¶

def connect_to_uri(self, uri: str, default_port: int, cancellable: Cancellable | None = ...) -> SocketConnection

This is a helper function for SocketClient.connect.

Attempts to create a TCP connection with a network URI.

uri may be any valid URI containing an "authority" (hostname/port) component. If a port is not specified in the URI, default_port will be used. TLS will be negotiated if SocketClient:tls is True. (SocketClient does not know to automatically assume TLS for certain URI schemes.)

Using this rather than SocketClient.connect or SocketClient.connect_to_host allows SocketClient to determine when to use application-specific proxy protocols.

Upon a successful connection, a new SocketConnection is constructed and returned. The caller owns this new object and must drop their reference to it when finished with it.

In the event of any failure (DNS error, service not found, no hosts connectable) None is returned and error (if non-None) is set accordingly.

Parameters:

uri — A network URI
default_port — the default port to connect to
cancellable — a Cancellable, or None

connect_to_uri_async¶

def connect_to_uri_async(self, uri: str, default_port: int, cancellable: Cancellable | None = ..., callback: Callable[[SocketClient | None, AsyncResult], None] | None = ...) -> None

This is the asynchronous version of SocketClient.connect_to_uri.

When the operation is finished callback will be called. You can then call SocketClient.connect_to_uri_finish to get the result of the operation.

Parameters:

uri — a network uri
default_port — the default port to connect to
cancellable — a Cancellable, or None
callback — a GAsyncReadyCallback

connect_to_uri_finish¶

def connect_to_uri_finish(self, result: AsyncResult) -> SocketConnection

Finishes an async connect operation. See SocketClient.connect_to_uri_async

Parameters:

result — a AsyncResult.

get_enable_proxy¶

def get_enable_proxy(self) -> bool

Gets the proxy enable state; see SocketClient.set_enable_proxy

get_family¶

def get_family(self) -> SocketFamily

Gets the socket family of the socket client.

See SocketClient.set_family for details.

get_local_address¶

def get_local_address(self) -> SocketAddress | None

Gets the local address of the socket client.

See SocketClient.set_local_address for details.

get_protocol¶

def get_protocol(self) -> SocketProtocol

Gets the protocol name type of the socket client.

See SocketClient.set_protocol for details.

get_proxy_resolver¶

def get_proxy_resolver(self) -> ProxyResolver

Gets the ProxyResolver being used by client. Normally, this will be the resolver returned by ProxyResolver.get_default, but you can override it with SocketClient.set_proxy_resolver.

get_socket_type¶

def get_socket_type(self) -> SocketType

Gets the socket type of the socket client.

See SocketClient.set_socket_type for details.

get_timeout¶

def get_timeout(self) -> int

Gets the I/O timeout time for sockets created by client.

See SocketClient.set_timeout for details.

get_tls¶

def get_tls(self) -> bool

Gets whether client creates TLS connections. See SocketClient.set_tls for details.

get_tls_validation_flags¶

def get_tls_validation_flags(self) -> TlsCertificateFlags

:::warning Deprecated since 2.72 This API is deprecated. :::

Gets the TLS validation flags used creating TLS connections via client.

This function does not work as originally designed and is impossible to use correctly. See SocketClient:tls-validation-flags for more information.

set_enable_proxy¶

def set_enable_proxy(self, enable: bool) -> None

Sets whether or not client attempts to make connections via a proxy server. When enabled (the default), SocketClient will use a ProxyResolver to determine if a proxy protocol such as SOCKS is needed, and automatically do the necessary proxy negotiation.

Parameters:

enable — whether to enable proxies

set_family¶

def set_family(self, family: SocketFamily | int) -> None

Sets the socket family of the socket client. If this is set to something other than SocketFamily.INVALID then the sockets created by this object will be of the specified family.

This might be useful for instance if you want to force the local connection to be an ipv4 socket, even though the address might be an ipv6 mapped to ipv4 address.

Parameters:

family — a SocketFamily

set_local_address¶

def set_local_address(self, address: SocketAddress | None = ...) -> None

Sets the local address of the socket client. The sockets created by this object will bound to the specified address (if not None) before connecting.

This is useful if you want to ensure that the local side of the connection is on a specific port, or on a specific interface.

Parameters:

address — a SocketAddress, or None

set_protocol¶

def set_protocol(self, protocol: SocketProtocol | int) -> None

Sets the protocol of the socket client. The sockets created by this object will use of the specified protocol.

If protocol is SocketProtocol.DEFAULT that means to use the default protocol for the socket family and type.

Parameters:

protocol — a SocketProtocol

set_proxy_resolver¶

def set_proxy_resolver(self, proxy_resolver: ProxyResolver | None = ...) -> None

Overrides the ProxyResolver used by client. You can call this if you want to use specific proxies, rather than using the system default proxy settings.

Note that whether or not the proxy resolver is actually used depends on the setting of SocketClient:enable-proxy, which is not changed by this function (but which is True by default)

Parameters:

proxy_resolver — a ProxyResolver, or None for the default.

set_socket_type¶

def set_socket_type(self, type: SocketType | int) -> None

Sets the socket type of the socket client. The sockets created by this object will be of the specified type.

It doesn't make sense to specify a type of SocketType.DATAGRAM, as GSocketClient is used for connection oriented services.

Parameters:

type — a SocketType

set_timeout¶

def set_timeout(self, timeout: int) -> None

Sets the I/O timeout for sockets created by client. timeout is a time in seconds, or 0 for no timeout (the default).

The timeout value affects the initial connection attempt as well, so setting this may cause calls to SocketClient.connect, etc, to fail with IOErrorEnum.TIMED_OUT.

Parameters:

timeout — the timeout

set_tls¶

def set_tls(self, tls: bool) -> None

Sets whether client creates TLS (aka SSL) connections. If tls is True, client will wrap its connections in a TlsClientConnection and perform a TLS handshake when connecting.

Note that since SocketClient must return a SocketConnection, but TlsClientConnection is not a SocketConnection, this actually wraps the resulting TlsClientConnection in a TcpWrapperConnection when returning it. You can use TcpWrapperConnection.get_base_io_stream on the return value to extract the TlsClientConnection.

If you need to modify the behavior of the TLS handshake (eg, by setting a client-side certificate to use, or connecting to the TlsConnection::accept-certificate signal), you can connect to client's SocketClient::event signal and wait for it to be emitted with SocketClientEvent.TLS_HANDSHAKING, which will give you a chance to see the TlsClientConnection before the handshake starts.

Parameters:

tls — whether to use TLS

set_tls_validation_flags¶

def set_tls_validation_flags(self, flags: TlsCertificateFlags | int) -> None

:::warning Deprecated since 2.72 This API is deprecated. :::

Sets the TLS validation flags used when creating TLS connections via client. The default value is TlsCertificateFlags.VALIDATE_ALL.

This function does not work as originally designed and is impossible to use correctly. See SocketClient:tls-validation-flags for more information.

Parameters:

flags — the validation flags

Virtual methods¶

do_event¶

def do_event(self, event: SocketClientEvent | int, connectable: SocketConnectable, connection: IOStream) -> None

Properties¶

enable_proxy¶

enable_proxy: bool  # read/write

Enable proxy support.

family¶

family: SocketFamily | int  # read/write

The address family to use for socket construction.

local_address¶

local_address: SocketAddress  # read/write

The local address constructed sockets will be bound to.

protocol¶

protocol: SocketProtocol | int  # read/write

The protocol to use for socket construction, or 0 for default.

proxy_resolver¶

proxy_resolver: ProxyResolver  # read/write

The proxy resolver to use

timeout¶

timeout: int  # read/write

The I/O timeout for sockets, in seconds, or 0 for none.

tls¶

tls: bool  # read/write

Whether to create TLS connections.

tls_validation_flags¶

tls_validation_flags: TlsCertificateFlags | int  # read/write

:::warning Deprecated since 2.72 This API is deprecated. :::

The TLS validation flags used when creating TLS connections. The default value is TlsCertificateFlags.VALIDATE_ALL.

GLib guarantees that if certificate verification fails, at least one flag will be set, but it does not guarantee that all possible flags will be set. Accordingly, you may not safely decide to ignore any particular type of error. For example, it would be incorrect to mask TlsCertificateFlags.EXPIRED if you want to allow expired certificates, because this could potentially be the only error flag set even if other problems exist with the certificate. Therefore, there is no safe way to use this property. This is not a horrible problem, though, because you should not be attempting to ignore validation errors anyway. If you really must ignore TLS certificate errors, connect to the SocketClient::event signal, wait for it to be emitted with SocketClientEvent.TLS_HANDSHAKING, and use that to connect to TlsConnection::accept-certificate.

type¶

type: SocketType | int  # read/write

The type to use for socket construction.

Signals¶

event¶

def on_event(self, event: SocketClientEvent, connectable: SocketConnectable, connection: IOStream | None) -> None: ...

Emitted when client's activity on connectable changes state. Among other things, this can be used to provide progress information about a network connection in the UI. The meanings of the different event values are as follows:

SocketClientEvent.RESOLVING: client is about to look up connectable in DNS. connection will be None.
SocketClientEvent.RESOLVED: client has successfully resolved connectable in DNS. connection will be None.
SocketClientEvent.CONNECTING: client is about to make a connection to a remote host; either a proxy server or the destination server itself. connection is the SocketConnection, which is not yet connected. Since GLib 2.40, you can access the remote address via SocketConnection.get_remote_address.
SocketClientEvent.CONNECTED: client has successfully connected to a remote host. connection is the connected SocketConnection.
SocketClientEvent.PROXY_NEGOTIATING: client is about to negotiate with a proxy to get it to connect to connectable. connection is the SocketConnection to the proxy server.
SocketClientEvent.PROXY_NEGOTIATED: client has negotiated a connection to connectable through a proxy server. connection is the stream returned from Proxy.connect, which may or may not be a SocketConnection.
SocketClientEvent.TLS_HANDSHAKING: client is about to begin a TLS handshake. connection is a TlsClientConnection.
SocketClientEvent.TLS_HANDSHAKED: client has successfully completed the TLS handshake. connection is a TlsClientConnection.
SocketClientEvent.COMPLETE: client has either successfully connected to connectable (in which case connection is the SocketConnection that it will be returning to the caller) or has failed (in which case connection is None and the client is about to return an error).

Each event except SocketClientEvent.COMPLETE may be emitted multiple times (or not at all) for a given connectable (in particular, if client ends up attempting to connect to more than one address). However, if client emits the SocketClient::event signal at all for a given connectable, then it will always emit it with SocketClientEvent.COMPLETE when it is done.

Note that there may be additional SocketClientEvent values in the future; unrecognized event values should be ignored.