Gio.Socket

Subclasses:

None

Methods

Inherited:

GObject.Object (37), Gio.DatagramBased (5), Gio.Initable (2)

Structs:

GObject.ObjectClass (5)

class	new (family, type, protocol)
class	new_from_fd (fd)
	accept (cancellable)
	bind (address, allow_reuse)
	check_connect_result ()
	close ()
	condition_check (condition)
	condition_timed_wait (condition, timeout_us, cancellable)
	condition_wait (condition, cancellable)
	connect (address, cancellable)
	connection_factory_create_connection ()
	get_available_bytes ()
	get_blocking ()
	get_broadcast ()
	get_credentials ()
	get_family ()
	get_fd ()
	get_keepalive ()
	get_listen_backlog ()
	get_local_address ()
	get_multicast_loopback ()
	get_multicast_ttl ()
	get_option (level, optname)
	get_protocol ()
	get_remote_address ()
	get_socket_type ()
	get_timeout ()
	get_ttl ()
	is_closed ()
	is_connected ()
	join_multicast_group (group, source_specific, iface)
	join_multicast_group_ssm (group, source_specific, iface)
	leave_multicast_group (group, source_specific, iface)
	leave_multicast_group_ssm (group, source_specific, iface)
	listen ()
	receive (cancellable)
	receive_from (cancellable)
	receive_message (vectors, flags, cancellable)
	receive_messages (messages, flags, cancellable)
	receive_with_blocking (blocking, cancellable)
	send (buffer, cancellable)
	send_message (address, vectors, messages, flags, cancellable)
	send_message_with_timeout (address, vectors, messages, flags, timeout_us, cancellable)
	send_messages (messages, flags, cancellable)
	send_to (address, buffer, cancellable)
	send_with_blocking (buffer, blocking, cancellable)
	set_blocking (blocking)
	set_broadcast (broadcast)
	set_keepalive (keepalive)
	set_listen_backlog (backlog)
	set_multicast_loopback (loopback)
	set_multicast_ttl (ttl)
	set_option (level, optname, value)
	set_timeout (timeout)
	set_ttl (ttl)
	shutdown (shutdown_read, shutdown_write)
	speaks_ipv4 ()

Virtual Methods

Inherited:

GObject.Object (7), Gio.DatagramBased (5), Gio.Initable (1)

Properties

Name	Type	Flags	Short Description
blocking	bool	r/w	Whether or not I/O on this socket is blocking
broadcast	bool	r/w	Whether to allow sending to broadcast addresses
family	Gio.SocketFamily	r/w/co	The sockets address family
fd	int	r/w/co	The sockets file descriptor
keepalive	bool	r/w	Keep connection alive by sending periodic pings
listen-backlog	int	r/w	Outstanding connections in the listen queue
local-address	Gio.SocketAddress	r	The local address the socket is bound to
multicast-loopback	bool	r/w	Whether outgoing multicast packets loop back to the local host
multicast-ttl	int	r/w	Time-to-live of outgoing multicast packets
protocol	Gio.SocketProtocol	r/w/co	The id of the protocol to use, or -1 for unknown
remote-address	Gio.SocketAddress	r	The remote address the socket is connected to
timeout	int	r/w	The timeout in seconds on socket I/O
ttl	int	r/w	Time-to-live of outgoing unicast packets
type	Gio.SocketType	r/w/co	The sockets type

Signals

Inherited:

GObject.Object (1)

Fields

Inherited:

GObject.Object (1)

Name	Type	Access	Description
parent_instance	GObject.Object	r

Class Details

class Gio.Socket(**kwargs)

Bases:

GObject.Object, Gio.DatagramBased, Gio.Initable

Abstract:

No

Structure:

Gio.SocketClass

A Gio.Socket is a low-level networking primitive. It is a more or less direct mapping of the BSD socket API in a portable GObject.Object based API. It supports both the UNIX socket implementations and winsock2 on Windows.

Gio.Socket is the platform independent base upon which the higher level network primitives are based. Applications are not typically meant to use it directly, but rather through classes like Gio.SocketClient, Gio.SocketService and Gio.SocketConnection. However there may be cases where direct use of Gio.Socket is useful.

Gio.Socket implements the Gio.Initable interface, so if it is manually constructed by e.g. g_object_new() you must call Gio.Initable.init() and check the results before using the object. This is done automatically in Gio.Socket.new() and Gio.Socket.new_from_fd(), so these functions can return None.

Sockets operate in two general modes, blocking or non-blocking. When in blocking mode all operations (which don’t take an explicit blocking parameter) block until the requested operation is finished or there is an error. In non-blocking mode all calls that would block return immediately with a Gio.IOErrorEnum.WOULD_BLOCK error. To know when a call would successfully run you can call Gio.Socket.condition_check(), or Gio.Socket.condition_wait(). You can also use g_socket_create_source() and attach it to a GLib.MainContext to get callbacks when I/O is possible. Note that all sockets are always set to non blocking mode in the system, and blocking mode is emulated in Gio.Socket.

When working in non-blocking mode applications should always be able to handle getting a Gio.IOErrorEnum.WOULD_BLOCK error even when some other function said that I/O was possible. This can easily happen in case of a race condition in the application, but it can also happen for other reasons. For instance, on Windows a socket is always seen as writable until a write returns Gio.IOErrorEnum.WOULD_BLOCK.

Gio.Sockets can be either connection oriented or datagram based. For connection oriented types you must first establish a connection by either connecting to an address or accepting a connection from another address. For connectionless socket types the target/source address is specified or received in each I/O operation.

All socket file descriptors are set to be close-on-exec.

Note that creating a Gio.Socket causes the signal %SIGPIPE to be ignored for the remainder of the program. If you are writing a command-line utility that uses Gio.Socket, you may need to take into account the fact that your program will not automatically be killed if it tries to write to %stdout after it has been closed.

Like most other APIs in GLib, Gio.Socket is not inherently thread safe. To use a Gio.Socket concurrently from multiple threads, you must implement your own locking.

New in version 2.22.

classmethod new(family, type, protocol)

Parameters:

• family (Gio.SocketFamily) – the socket family to use, e.g. Gio.SocketFamily.IPV4.

• type (Gio.SocketType) – the socket type to use.

• protocol (Gio.SocketProtocol) – the id of the protocol to use, or 0 for default.

Raises:

GLib.Error

Returns:

a Gio.Socket or None on error. Free the returned object with GObject.Object.unref().

Return type:

Gio.Socket

Creates a new Gio.Socket with the defined family, type and protocol. If protocol is 0 (Gio.SocketProtocol.DEFAULT) the default protocol type for the family and type is used.

The protocol is a family and type specific int that specifies what kind of protocol to use. Gio.SocketProtocol lists several common ones. Many families only support one protocol, and use 0 for this, others support several and using 0 means to use the default protocol for the family and type.

The protocol id is passed directly to the operating system, so you can use protocols not listed in Gio.SocketProtocol if you know the protocol number used for it.

New in version 2.22.

classmethod new_from_fd(fd)

Parameters:

fd (int) – a native socket file descriptor.

Raises:

GLib.Error

Returns:

a Gio.Socket or None on error. Free the returned object with GObject.Object.unref().

Return type:

Gio.Socket

Creates a new Gio.Socket from a native file descriptor or winsock SOCKET handle.

This reads all the settings from the file descriptor so that all properties should work. Note that the file descriptor will be set to non-blocking mode, independent on the blocking mode of the Gio.Socket.

On success, the returned Gio.Socket takes ownership of fd. On failure, the caller must close fd themselves.

Since GLib 2.46, it is no longer a fatal error to call this on a non-socket descriptor. Instead, a GLib.Error will be set with code Gio.IOErrorEnum.FAILED

New in version 2.22.

accept(cancellable)

Parameters:

cancellable (Gio.Cancellable or None) – a Gio.Cancellable or None

Raises:

GLib.Error

Returns:

a new Gio.Socket, or None on error. Free the returned object with GObject.Object.unref().

Return type:

Gio.Socket

Accept incoming connections on a connection-based socket. This removes the first outstanding connection request from the listening socket and creates a Gio.Socket object for it.

The self must be bound to a local address with Gio.Socket.bind() and must be listening for incoming connections (Gio.Socket.listen()).

If there are no outstanding connections then the operation will block or return Gio.IOErrorEnum.WOULD_BLOCK if non-blocking I/O is enabled. To be notified of an incoming connection, wait for the GLib.IOCondition.IN condition.

New in version 2.22.

bind(address, allow_reuse)

Parameters:

• address (Gio.SocketAddress) – a Gio.SocketAddress specifying the local address.

• allow_reuse (bool) – whether to allow reusing this address

Raises:

GLib.Error

Returns:

True on success, False on error.

Return type:

bool

When a socket is created it is attached to an address family, but it doesn’t have an address in this family. Gio.Socket.bind() assigns the address (sometimes called name) of the socket.

It is generally required to bind to a local address before you can receive connections. (See Gio.Socket.listen() and Gio.Socket.accept() ). In certain situations, you may also want to bind a socket that will be used to initiate connections, though this is not normally required.

If self is a TCP socket, then allow_reuse controls the setting of the SO_REUSEADDR socket option; normally it should be True for server sockets (sockets that you will eventually call Gio.Socket.accept() on), and False for client sockets. (Failing to set this flag on a server socket may cause Gio.Socket.bind() to return Gio.IOErrorEnum.ADDRESS_IN_USE if the server program is stopped and then immediately restarted.)

If self is a UDP socket, then allow_reuse determines whether or not other UDP sockets can be bound to the same address at the same time. In particular, you can have several UDP sockets bound to the same address, and they will all receive all of the multicast and broadcast packets sent to that address. (The behavior of unicast UDP packets to an address with multiple listeners is not defined.)

New in version 2.22.

check_connect_result()

Raises:

GLib.Error

Returns:

True if no error, False otherwise, setting error to the error

Return type:

bool

Checks and resets the pending connect error for the socket. This is used to check for errors when Gio.Socket.connect() is used in non-blocking mode.

New in version 2.22.

close()

Raises:

GLib.Error

Returns:

True on success, False on error

Return type:

bool

Closes the socket, shutting down any active connection.

Closing a socket does not wait for all outstanding I/O operations to finish, so the caller should not rely on them to be guaranteed to complete even if the close returns with no error.

Once the socket is closed, all other operations will return Gio.IOErrorEnum.CLOSED. Closing a socket multiple times will not return an error.

Sockets will be automatically closed when the last reference is dropped, but you might want to call this function to make sure resources are released as early as possible.

Beware that due to the way that TCP works, it is possible for recently-sent data to be lost if either you close a socket while the GLib.IOCondition.IN condition is set, or else if the remote connection tries to send something to you after you close the socket but before it has finished reading all of the data you sent. There is no easy generic way to avoid this problem; the easiest fix is to design the network protocol such that the client will never send data “out of turn”. Another solution is for the server to half-close the connection by calling Gio.Socket.shutdown() with only the shutdown_write flag set, and then wait for the client to notice this and close its side of the connection, after which the server can safely call Gio.Socket.close(). (This is what Gio.TcpConnection does if you call Gio.TcpConnection.set_graceful_disconnect(). But of course, this only works if the client will close its connection after the server does.)

New in version 2.22.

condition_check(condition)

Parameters:

condition (GLib.IOCondition) – a GLib.IOCondition mask to check

Returns:

the GIOCondition mask of the current state

Return type:

GLib.IOCondition

Checks on the readiness of self to perform operations. The operations specified in condition are checked for and masked against the currently-satisfied conditions on self. The result is returned.

Note that on Windows, it is possible for an operation to return Gio.IOErrorEnum.WOULD_BLOCK even immediately after Gio.Socket.condition_check() has claimed that the socket is ready for writing. Rather than calling Gio.Socket.condition_check() and then writing to the socket if it succeeds, it is generally better to simply try writing to the socket right away, and try again later if the initial attempt returns Gio.IOErrorEnum.WOULD_BLOCK.

It is meaningless to specify GLib.IOCondition.ERR or GLib.IOCondition.HUP in condition; these conditions will always be set in the output if they are true.

This call never blocks.

New in version 2.22.

condition_timed_wait(condition, timeout_us, cancellable)

Parameters:

• condition (GLib.IOCondition) – a GLib.IOCondition mask to wait for

• timeout_us (int) – the maximum time (in microseconds) to wait, or -1

• cancellable (Gio.Cancellable or None) – a Gio.Cancellable, or None

Raises:

GLib.Error

Returns:

True if the condition was met, False otherwise

Return type:

bool

Waits for up to timeout_us microseconds for condition to become true on self. If the condition is met, True is returned.

If cancellable is cancelled before the condition is met, or if timeout_us (or the socket’s Gio.Socket :timeout) is reached before the condition is met, then False is returned and error, if non-None, is set to the appropriate value (Gio.IOErrorEnum.CANCELLED or Gio.IOErrorEnum.TIMED_OUT).

If you don’t want a timeout, use Gio.Socket.condition_wait(). (Alternatively, you can pass -1 for timeout_us.)

Note that although timeout_us is in microseconds for consistency with other GLib APIs, this function actually only has millisecond resolution, and the behavior is undefined if timeout_us is not an exact number of milliseconds.

New in version 2.32.

condition_wait(condition, cancellable)

Parameters:

• condition (GLib.IOCondition) – a GLib.IOCondition mask to wait for

• cancellable (Gio.Cancellable or None) – a Gio.Cancellable, or None

Raises:

GLib.Error

Returns:

True if the condition was met, False otherwise

Return type:

bool

Waits for condition to become true on self. When the condition is met, True is returned.

If cancellable is cancelled before the condition is met, or if the socket has a timeout set and it is reached before the condition is met, then False is returned and error, if non-None, is set to the appropriate value (Gio.IOErrorEnum.CANCELLED or Gio.IOErrorEnum.TIMED_OUT).

See also Gio.Socket.condition_timed_wait().

New in version 2.22.

connect(address, cancellable)

Parameters:

• address (Gio.SocketAddress) – a Gio.SocketAddress specifying the remote address.

• cancellable (Gio.Cancellable or None) – a Gio.Cancellable or None

Raises:

GLib.Error

Returns:

True if connected, False on error.

Return type:

bool

Connect the socket to the specified remote address.

For connection oriented socket this generally means we attempt to make a connection to the address. For a connection-less socket it sets the default address for Gio.Socket.send() and discards all incoming datagrams from other sources.

Generally connection oriented sockets can only connect once, but connection-less sockets can connect multiple times to change the default address.

If the connect call needs to do network I/O it will block, unless non-blocking I/O is enabled. Then Gio.IOErrorEnum.PENDING is returned and the user can be notified of the connection finishing by waiting for the GLib.IOCondition.OUT condition. The result of the connection must then be checked with Gio.Socket.check_connect_result().

New in version 2.22.

connection_factory_create_connection()

Returns:

a Gio.SocketConnection

Return type:

Gio.SocketConnection

Creates a Gio.SocketConnection subclass of the right type for self.

New in version 2.22.

get_available_bytes()

Returns:

the number of bytes that can be read from the socket without blocking or truncating, or -1 on error.

Return type:

int

Get the amount of data pending in the OS input buffer, without blocking.

If self is a UDP or SCTP socket, this will return the size of just the next packet, even if additional packets are buffered after that one.

Note that on Windows, this function is rather inefficient in the UDP case, and so if you know any plausible upper bound on the size of the incoming packet, it is better to just do a Gio.Socket.receive() with a buffer of that size, rather than calling Gio.Socket.get_available_bytes() first and then doing a receive of exactly the right size.

New in version 2.32.

get_blocking()

Returns:

True if blocking I/O is used, False otherwise.

Return type:

bool

Gets the blocking mode of the socket. For details on blocking I/O, see Gio.Socket.set_blocking().

New in version 2.22.

get_broadcast()

Returns:

the broadcast setting on self

Return type:

bool

Gets the broadcast setting on self; if True, it is possible to send packets to broadcast addresses.

New in version 2.32.

get_credentials()

Raises:

GLib.Error

Returns:

None if error is set, otherwise a Gio.Credentials object that must be freed with GObject.Object.unref().

Return type:

Gio.Credentials

Returns the credentials of the foreign process connected to this socket, if any (e.g. it is only supported for Gio.SocketFamily.UNIX sockets).

If this operation isn’t supported on the OS, the method fails with the Gio.IOErrorEnum.NOT_SUPPORTED error. On Linux this is implemented by reading the %SO_PEERCRED option on the underlying socket.

This method can be expected to be available on the following platforms:

• Linux since GLib 2.26

• OpenBSD since GLib 2.30

• Solaris, Illumos and OpenSolaris since GLib 2.40

• NetBSD since GLib 2.42

• macOS, tvOS, iOS since GLib 2.66

Other ways to obtain credentials from a foreign peer includes the Gio.UnixCredentialsMessage type and Gio.UnixConnection.send_credentials() / Gio.UnixConnection.receive_credentials() functions.

New in version 2.26.

get_family()

Returns:

a Gio.SocketFamily

Return type:

Gio.SocketFamily

Gets the socket family of the socket.

New in version 2.22.

get_fd()

Returns:

the file descriptor of the socket.

Return type:

int

Returns the underlying OS socket object. On unix this is a socket file descriptor, and on Windows this is a Winsock2 SOCKET handle. This may be useful for doing platform specific or otherwise unusual operations on the socket.

New in version 2.22.

get_keepalive()

Returns:

True if keepalive is active, False otherwise.

Return type:

bool

Gets the keepalive mode of the socket. For details on this, see Gio.Socket.set_keepalive().

New in version 2.22.

get_listen_backlog()

Returns:

the maximum number of pending connections.

Return type:

int

Gets the listen backlog setting of the socket. For details on this, see Gio.Socket.set_listen_backlog().

New in version 2.22.

get_local_address()

Raises:

GLib.Error

Returns:

a Gio.SocketAddress or None on error. Free the returned object with GObject.Object.unref().

Return type:

Gio.SocketAddress

Try to get the local address of a bound socket. This is only useful if the socket has been bound to a local address, either explicitly or implicitly when connecting.

New in version 2.22.

get_multicast_loopback()

Returns:

the multicast loopback setting on self

Return type:

bool

Gets the multicast loopback setting on self; if True (the default), outgoing multicast packets will be looped back to multicast listeners on the same host.

New in version 2.32.

get_multicast_ttl()

Returns:

the multicast time-to-live setting on self

Return type:

int

Gets the multicast time-to-live setting on self; see Gio.Socket.set_multicast_ttl() for more details.

New in version 2.32.

get_option(level, optname)

Parameters:

• level (int) – the “API level” of the option (eg, SOL_SOCKET)

• optname (int) – the “name” of the option (eg, SO_BROADCAST)

Raises:

GLib.Error

Returns:

success or failure. On failure, error will be set, and the system error value (errno or WSAGetLastError()) will still be set to the result of the getsockopt() call.

value:

return location for the option value

Return type:

(bool, value: int)

Gets the value of an integer-valued option on self, as with getsockopt(). (If you need to fetch a non-integer-valued option, you will need to call getsockopt() directly.)

The ‘<gio/gnetworking.h> [gio-gnetworking.h]’ header pulls in system headers that will define most of the standard/portable socket options. For unusual socket protocols or platform-dependent options, you may need to include additional headers.

Note that even for socket options that are a single byte in size, value is still a pointer to a int variable, not a #guchar; Gio.Socket.get_option() will handle the conversion internally.

New in version 2.36.

get_protocol()

Returns:

a protocol id, or -1 if unknown

Return type:

Gio.SocketProtocol

Gets the socket protocol id the socket was created with. In case the protocol is unknown, -1 is returned.

New in version 2.22.

get_remote_address()

Raises:

GLib.Error

Returns:

a Gio.SocketAddress or None on error. Free the returned object with GObject.Object.unref().

Return type:

Gio.SocketAddress

Try to get the remote address of a connected socket. This is only useful for connection oriented sockets that have been connected.

New in version 2.22.

get_socket_type()

Returns:

a Gio.SocketType

Return type:

Gio.SocketType

Gets the socket type of the socket.

New in version 2.22.

get_timeout()

Returns:

the timeout in seconds

Return type:

int

Gets the timeout setting of the socket. For details on this, see Gio.Socket.set_timeout().

New in version 2.26.

get_ttl()

Returns:

the time-to-live setting on self

Return type:

int

Gets the unicast time-to-live setting on self; see Gio.Socket.set_ttl() for more details.

New in version 2.32.

is_closed()

Returns:

True if socket is closed, False otherwise

Return type:

bool

Checks whether a socket is closed.

New in version 2.22.

is_connected()

Returns:

True if socket is connected, False otherwise.

Return type:

bool

Check whether the socket is connected. This is only useful for connection-oriented sockets.

If using Gio.Socket.shutdown(), this function will return True until the socket has been shut down for reading and writing. If you do a non-blocking connect, this function will not return True until after you call Gio.Socket.check_connect_result().

New in version 2.22.

join_multicast_group(group, source_specific, iface)

Parameters:

• group (Gio.InetAddress) – a Gio.InetAddress specifying the group address to join.

• source_specific (bool) – True if source-specific multicast should be used

• iface (str or None) – Name of the interface to use, or None

Raises:

GLib.Error

Returns:

True on success, False on error.

Return type:

bool

Registers self to receive multicast messages sent to group. self must be a Gio.SocketType.DATAGRAM socket, and must have been bound to an appropriate interface and port with Gio.Socket.bind().

If iface is None, the system will automatically pick an interface to bind to based on group.

If source_specific is True, source-specific multicast as defined in RFC 4604 is used. Note that on older platforms this may fail with a Gio.IOErrorEnum.NOT_SUPPORTED error.

To bind to a given source-specific multicast address, use Gio.Socket.join_multicast_group_ssm() instead.

New in version 2.32.

join_multicast_group_ssm(group, source_specific, iface)

Parameters:

• group (Gio.InetAddress) – a Gio.InetAddress specifying the group address to join.

• source_specific (Gio.InetAddress or None) – a Gio.InetAddress specifying the source-specific multicast address or None to ignore.

• iface (str or None) – Name of the interface to use, or None

Raises:

GLib.Error

Returns:

True on success, False on error.

Return type:

bool

Registers self to receive multicast messages sent to group. self must be a Gio.SocketType.DATAGRAM socket, and must have been bound to an appropriate interface and port with Gio.Socket.bind().

If iface is None, the system will automatically pick an interface to bind to based on group.

If source_specific is not None, use source-specific multicast as defined in RFC 4604. Note that on older platforms this may fail with a Gio.IOErrorEnum.NOT_SUPPORTED error.

Note that this function can be called multiple times for the same group with different source_specific in order to receive multicast packets from more than one source.

New in version 2.56.

leave_multicast_group(group, source_specific, iface)

Parameters:

• group (Gio.InetAddress) – a Gio.InetAddress specifying the group address to leave.

• source_specific (bool) – True if source-specific multicast was used

• iface (str or None) – Interface used

Raises:

GLib.Error

Returns:

True on success, False on error.

Return type:

bool

Removes self from the multicast group defined by group, iface, and source_specific (which must all have the same values they had when you joined the group).

self remains bound to its address and port, and can still receive unicast messages after calling this.

To unbind to a given source-specific multicast address, use Gio.Socket.leave_multicast_group_ssm() instead.

New in version 2.32.

leave_multicast_group_ssm(group, source_specific, iface)

Parameters:

• group (Gio.InetAddress) – a Gio.InetAddress specifying the group address to leave.

• source_specific (Gio.InetAddress or None) – a Gio.InetAddress specifying the source-specific multicast address or None to ignore.

• iface (str or None) – Name of the interface to use, or None

Raises:

GLib.Error

Returns:

True on success, False on error.

Return type:

bool

Removes self from the multicast group defined by group, iface, and source_specific (which must all have the same values they had when you joined the group).

self remains bound to its address and port, and can still receive unicast messages after calling this.

New in version 2.56.

listen()

Raises:

GLib.Error

Returns:

True on success, False on error.

Return type:

bool

Marks the socket as a server socket, i.e. a socket that is used to accept incoming requests using Gio.Socket.accept().

Before calling this the socket must be bound to a local address using Gio.Socket.bind().

To set the maximum amount of outstanding clients, use Gio.Socket.set_listen_backlog().

New in version 2.22.

receive(cancellable)

Parameters:

cancellable (Gio.Cancellable or None) – a Gio.Cancellable or None

Raises:

GLib.Error

Returns:

Number of bytes read, or 0 if the connection was closed by the peer, or -1 on error

buffer:

a buffer to read data into (which should be at least size bytes long).

Return type:

(int, buffer: bytes)

Receive data (up to size bytes) from a socket. This is mainly used by connection-oriented sockets; it is identical to Gio.Socket.receive_from() with address set to None.

For Gio.SocketType.DATAGRAM and Gio.SocketType.SEQPACKET sockets, Gio.Socket.receive() will always read either 0 or 1 complete messages from the socket. If the received message is too large to fit in buffer, then the data beyond size bytes will be discarded, without any explicit indication that this has occurred.

For Gio.SocketType.STREAM sockets, Gio.Socket.receive() can return any number of bytes, up to size. If more than size bytes have been received, the additional data will be returned in future calls to Gio.Socket.receive().

If the socket is in blocking mode the call will block until there is some data to receive, the connection is closed, or there is an error. If there is no data available and the socket is in non-blocking mode, a Gio.IOErrorEnum.WOULD_BLOCK error will be returned. To be notified when data is available, wait for the GLib.IOCondition.IN condition.

On error -1 is returned and error is set accordingly.

New in version 2.22.

receive_from(cancellable)

Parameters:

cancellable (Gio.Cancellable or None) – a Gio.Cancellable or None

Raises:

GLib.Error

Returns:

Number of bytes read, or 0 if the connection was closed by the peer, or -1 on error

address:

a pointer to a Gio.SocketAddress pointer, or None

buffer:

a buffer to read data into (which should be at least size bytes long).

Return type:

(int, address: Gio.SocketAddress, buffer: bytes)

Receive data (up to size bytes) from a socket.

If address is non-None then address will be set equal to the source address of the received packet. address is owned by the caller.

See Gio.Socket.receive() for additional information.

New in version 2.22.

receive_message(vectors, flags, cancellable)

Parameters:

• vectors ([Gio.InputVector]) – an array of Gio.InputVector structs

• flags (int) – a pointer to an int containing Gio.SocketMsgFlags flags, which may additionally contain other platform specific flags

• cancellable (Gio.Cancellable or None) – a Gio.Cancellable or None

Raises:

GLib.Error

Returns:

Number of bytes read, or 0 if the connection was closed by the peer, or -1 on error

address:

a pointer to a Gio.SocketAddress pointer, or None

messages:

a pointer which may be filled with an array of Gio.SocketControlMessages, or None

flags:

a pointer to an int containing Gio.SocketMsgFlags flags, which may additionally contain other platform specific flags

Return type:

(int, address: Gio.SocketAddress, messages: [Gio.SocketControlMessage], flags: int)

Receive data from a socket. For receiving multiple messages, see Gio.Socket.receive_messages(); for easier use, see Gio.Socket.receive() and Gio.Socket.receive_from().

If address is non-None then address will be set equal to the source address of the received packet. address is owned by the caller.

vector must point to an array of Gio.InputVector structs and num_vectors must be the length of this array. These structs describe the buffers that received data will be scattered into. If num_vectors is -1, then vectors is assumed to be terminated by a Gio.InputVector with a None buffer pointer.

As a special case, if num_vectors is 0 (in which case, vectors may of course be None), then a single byte is received and discarded. This is to facilitate the common practice of sending a single ‘\0’ byte for the purposes of transferring ancillary data.

messages, if non-None, will be set to point to a newly-allocated array of Gio.SocketControlMessage instances or None if no such messages was received. These correspond to the control messages received from the kernel, one Gio.SocketControlMessage per message from the kernel. This array is None-terminated and must be freed by the caller using GLib.free() after calling GObject.Object.unref() on each element. If messages is None, any control messages received will be discarded.

num_messages, if non-None, will be set to the number of control messages received.

If both messages and num_messages are non-None, then num_messages gives the number of Gio.SocketControlMessage instances in messages (ie: not including the None terminator).

flags is an in/out parameter. The commonly available arguments for this are available in the Gio.SocketMsgFlags enum, but the values there are the same as the system values, and the flags are passed in as-is, so you can pass in system-specific flags too (and Gio.Socket.receive_message() may pass system-specific flags out). Flags passed in to the parameter affect the receive operation; flags returned out of it are relevant to the specific returned message.

As with Gio.Socket.receive(), data may be discarded if self is Gio.SocketType.DATAGRAM or Gio.SocketType.SEQPACKET and you do not provide enough buffer space to read a complete message. You can pass Gio.SocketMsgFlags.PEEK in flags to peek at the current message without removing it from the receive queue, but there is no portable way to find out the length of the message other than by reading it into a sufficiently-large buffer.

If the socket is in blocking mode the call will block until there is some data to receive, the connection is closed, or there is an error. If there is no data available and the socket is in non-blocking mode, a Gio.IOErrorEnum.WOULD_BLOCK error will be returned. To be notified when data is available, wait for the GLib.IOCondition.IN condition.

On error -1 is returned and error is set accordingly.

New in version 2.22.

receive_messages(messages, flags, cancellable)

Parameters:

• messages ([Gio.InputMessage]) – an array of Gio.InputMessage structs

• flags (int) – an int containing Gio.SocketMsgFlags flags for the overall operation, which may additionally contain other platform specific flags

• cancellable (Gio.Cancellable or None) – a Gio.Cancellable or None

Raises:

GLib.Error

Returns:

number of messages received, or -1 on error. Note that the number of messages received may be smaller than num_messages if in non-blocking mode, if the peer closed the connection, or if num_messages was larger than UIO_MAXIOV (1024), in which case the caller may re-try to receive the remaining messages.

Return type:

int

Receive multiple data messages from self in one go. This is the most complicated and fully-featured version of this call. For easier use, see Gio.Socket.receive(), Gio.Socket.receive_from(), and Gio.Socket.receive_message().

messages must point to an array of Gio.InputMessage structs and num_messages must be the length of this array. Each Gio.InputMessage contains a pointer to an array of Gio.InputVector structs describing the buffers that the data received in each message will be written to. Using multiple Gio.InputVectors is more memory-efficient than manually copying data out of a single buffer to multiple sources, and more system-call-efficient than making multiple calls to Gio.Socket.receive(), such as in scenarios where a lot of data packets need to be received (e.g. high-bandwidth video streaming over RTP/UDP).

flags modify how all messages are received. The commonly available arguments for this are available in the Gio.SocketMsgFlags enum, but the values there are the same as the system values, and the flags are passed in as-is, so you can pass in system-specific flags too. These flags affect the overall receive operation. Flags affecting individual messages are returned in Gio.InputMessage.flags.

The other members of Gio.InputMessage are treated as described in its documentation.

If Gio.Socket :blocking is True the call will block until num_messages have been received, or the end of the stream is reached.

If Gio.Socket :blocking is False the call will return up to num_messages without blocking, or Gio.IOErrorEnum.WOULD_BLOCK if no messages are queued in the operating system to be received.

In blocking mode, if Gio.Socket :timeout is positive and is reached before any messages are received, Gio.IOErrorEnum.TIMED_OUT is returned, otherwise up to num_messages are returned. (Note: This is effectively the behaviour of MSG_WAITFORONE with recvmmsg().)

To be notified when messages are available, wait for the GLib.IOCondition.IN condition. Note though that you may still receive Gio.IOErrorEnum.WOULD_BLOCK from Gio.Socket.receive_messages() even if you were previously notified of a GLib.IOCondition.IN condition.

If the remote peer closes the connection, any messages queued in the operating system will be returned, and subsequent calls to Gio.Socket.receive_messages() will return 0 (with no error set).

On error -1 is returned and error is set accordingly. An error will only be returned if zero messages could be received; otherwise the number of messages successfully received before the error will be returned.

New in version 2.48.

receive_with_blocking(blocking, cancellable)

Parameters:

• blocking (bool) – whether to do blocking or non-blocking I/O

• cancellable (Gio.Cancellable or None) – a Gio.Cancellable or None

Raises:

GLib.Error

Returns:

Number of bytes read, or 0 if the connection was closed by the peer, or -1 on error

buffer:

a buffer to read data into (which should be at least size bytes long).

Return type:

(int, buffer: bytes)

This behaves exactly the same as Gio.Socket.receive(), except that the choice of blocking or non-blocking behavior is determined by the blocking argument rather than by self's properties.

New in version 2.26.

send(buffer, cancellable)

Parameters:

• buffer (bytes) – the buffer containing the data to send.

• cancellable (Gio.Cancellable or None) – a Gio.Cancellable or None

Raises:

GLib.Error

Returns:

Number of bytes written (which may be less than size), or -1 on error

Return type:

int

Tries to send size bytes from buffer on the socket. This is mainly used by connection-oriented sockets; it is identical to Gio.Socket.send_to() with address set to None.

If the socket is in blocking mode the call will block until there is space for the data in the socket queue. If there is no space available and the socket is in non-blocking mode a Gio.IOErrorEnum.WOULD_BLOCK error will be returned. To be notified when space is available, wait for the GLib.IOCondition.OUT condition. Note though that you may still receive Gio.IOErrorEnum.WOULD_BLOCK from Gio.Socket.send() even if you were previously notified of a GLib.IOCondition.OUT condition. (On Windows in particular, this is very common due to the way the underlying APIs work.)

On error -1 is returned and error is set accordingly.

New in version 2.22.

send_message(address, vectors, messages, flags, cancellable)

Parameters:

• address (Gio.SocketAddress or None) – a Gio.SocketAddress, or None

• vectors ([Gio.OutputVector]) – an array of Gio.OutputVector structs

• messages ([Gio.SocketControlMessage] or None) – a pointer to an array of Gio.SocketControlMessages, or None.

• flags (int) – an int containing Gio.SocketMsgFlags flags, which may additionally contain other platform specific flags

• cancellable (Gio.Cancellable or None) – a Gio.Cancellable or None

Raises:

GLib.Error

Returns:

Number of bytes written (which may be less than size), or -1 on error

Return type:

int

Send data to address on self. For sending multiple messages see Gio.Socket.send_messages(); for easier use, see Gio.Socket.send() and Gio.Socket.send_to().

If address is None then the message is sent to the default receiver (set by Gio.Socket.connect()).

vectors must point to an array of Gio.OutputVector structs and num_vectors must be the length of this array. (If num_vectors is -1, then vectors is assumed to be terminated by a Gio.OutputVector with a None buffer pointer.) The Gio.OutputVector structs describe the buffers that the sent data will be gathered from. Using multiple Gio.OutputVectors is more memory-efficient than manually copying data from multiple sources into a single buffer, and more network-efficient than making multiple calls to Gio.Socket.send().

messages, if non-None, is taken to point to an array of num_messages Gio.SocketControlMessage instances. These correspond to the control messages to be sent on the socket. If num_messages is -1 then messages is treated as a None-terminated array.

flags modify how the message is sent. The commonly available arguments for this are available in the Gio.SocketMsgFlags enum, but the values there are the same as the system values, and the flags are passed in as-is, so you can pass in system-specific flags too.

If the socket is in blocking mode the call will block until there is space for the data in the socket queue. If there is no space available and the socket is in non-blocking mode a Gio.IOErrorEnum.WOULD_BLOCK error will be returned. To be notified when space is available, wait for the GLib.IOCondition.OUT condition. Note though that you may still receive Gio.IOErrorEnum.WOULD_BLOCK from Gio.Socket.send() even if you were previously notified of a GLib.IOCondition.OUT condition. (On Windows in particular, this is very common due to the way the underlying APIs work.)

The sum of the sizes of each Gio.OutputVector in vectors must not be greater than GObject.G_MAXSSIZE. If the message can be larger than this, then it is mandatory to use the Gio.Socket.send_message_with_timeout() function.

On error -1 is returned and error is set accordingly.

New in version 2.22.

send_message_with_timeout(address, vectors, messages, flags, timeout_us, cancellable)

Parameters:

• address (Gio.SocketAddress or None) – a Gio.SocketAddress, or None

• vectors ([Gio.OutputVector]) – an array of Gio.OutputVector structs

• messages ([Gio.SocketControlMessage] or None) – a pointer to an array of Gio.SocketControlMessages, or None.

• flags (int) – an int containing Gio.SocketMsgFlags flags, which may additionally contain other platform specific flags

• timeout_us (int) – the maximum time (in microseconds) to wait, or -1

• cancellable (Gio.Cancellable or None) – a Gio.Cancellable or None

Raises:

GLib.Error

Returns:

Gio.PollableReturn.OK if all data was successfully written, Gio.PollableReturn.WOULD_BLOCK if the socket is currently not writable, or Gio.PollableReturn.FAILED if an error happened and error is set.

bytes_written:

location to store the number of bytes that were written to the socket

Return type:

(Gio.PollableReturn, bytes_written: int)

This behaves exactly the same as Gio.Socket.send_message(), except that the choice of timeout behavior is determined by the timeout_us argument rather than by self's properties.

On error Gio.PollableReturn.FAILED is returned and error is set accordingly, or if the socket is currently not writable Gio.PollableReturn.WOULD_BLOCK is returned. bytes_written will contain 0 in both cases.

New in version 2.60.

send_messages(messages, flags, cancellable)

Parameters:

• messages ([Gio.OutputMessage]) – an array of Gio.OutputMessage structs

• flags (int) – an int containing Gio.SocketMsgFlags flags, which may additionally contain other platform specific flags

• cancellable (Gio.Cancellable or None) – a Gio.Cancellable or None

Raises:

GLib.Error

Returns:

number of messages sent, or -1 on error. Note that the number of messages sent may be smaller than num_messages if the socket is non-blocking or if num_messages was larger than UIO_MAXIOV (1024), in which case the caller may re-try to send the remaining messages.

Return type:

int

Send multiple data messages from self in one go. This is the most complicated and fully-featured version of this call. For easier use, see Gio.Socket.send(), Gio.Socket.send_to(), and Gio.Socket.send_message().

messages must point to an array of Gio.OutputMessage structs and num_messages must be the length of this array. Each Gio.OutputMessage contains an address to send the data to, and a pointer to an array of Gio.OutputVector structs to describe the buffers that the data to be sent for each message will be gathered from. Using multiple Gio.OutputVectors is more memory-efficient than manually copying data from multiple sources into a single buffer, and more network-efficient than making multiple calls to Gio.Socket.send(). Sending multiple messages in one go avoids the overhead of making a lot of syscalls in scenarios where a lot of data packets need to be sent (e.g. high-bandwidth video streaming over RTP/UDP), or where the same data needs to be sent to multiple recipients.

flags modify how the message is sent. The commonly available arguments for this are available in the Gio.SocketMsgFlags enum, but the values there are the same as the system values, and the flags are passed in as-is, so you can pass in system-specific flags too.

If the socket is in blocking mode the call will block until there is space for all the data in the socket queue. If there is no space available and the socket is in non-blocking mode a Gio.IOErrorEnum.WOULD_BLOCK error will be returned if no data was written at all, otherwise the number of messages sent will be returned. To be notified when space is available, wait for the GLib.IOCondition.OUT condition. Note though that you may still receive Gio.IOErrorEnum.WOULD_BLOCK from Gio.Socket.send() even if you were previously notified of a GLib.IOCondition.OUT condition. (On Windows in particular, this is very common due to the way the underlying APIs work.)

On error -1 is returned and error is set accordingly. An error will only be returned if zero messages could be sent; otherwise the number of messages successfully sent before the error will be returned.

New in version 2.44.

send_to(address, buffer, cancellable)

Parameters:

• address (Gio.SocketAddress or None) – a Gio.SocketAddress, or None

• buffer (bytes) – the buffer containing the data to send.

• cancellable (Gio.Cancellable or None) – a Gio.Cancellable or None

Raises:

GLib.Error

Returns:

Number of bytes written (which may be less than size), or -1 on error

Return type:

int

Tries to send size bytes from buffer to address. If address is None then the message is sent to the default receiver (set by Gio.Socket.connect()).

See Gio.Socket.send() for additional information.

New in version 2.22.

send_with_blocking(buffer, blocking, cancellable)

Parameters:

• buffer (bytes) – the buffer containing the data to send.

• blocking (bool) – whether to do blocking or non-blocking I/O

• cancellable (Gio.Cancellable or None) – a Gio.Cancellable or None

Raises:

GLib.Error

Returns:

Number of bytes written (which may be less than size), or -1 on error

Return type:

int

This behaves exactly the same as Gio.Socket.send(), except that the choice of blocking or non-blocking behavior is determined by the blocking argument rather than by self's properties.

New in version 2.26.

set_blocking(blocking)

Parameters:

blocking (bool) – Whether to use blocking I/O or not.

Sets the blocking mode of the socket. In blocking mode all operations (which don’t take an explicit blocking parameter) block until they succeed or there is an error. In non-blocking mode all functions return results immediately or with a Gio.IOErrorEnum.WOULD_BLOCK error.

All sockets are created in blocking mode. However, note that the platform level socket is always non-blocking, and blocking mode is a Gio.Socket level feature.

New in version 2.22.

set_broadcast(broadcast)

Parameters:

broadcast (bool) – whether self should allow sending to broadcast addresses

Sets whether self should allow sending to broadcast addresses. This is False by default.

New in version 2.32.

set_keepalive(keepalive)

Parameters:

keepalive (bool) – Value for the keepalive flag

Sets or unsets the %SO_KEEPALIVE flag on the underlying socket. When this flag is set on a socket, the system will attempt to verify that the remote socket endpoint is still present if a sufficiently long period of time passes with no data being exchanged. If the system is unable to verify the presence of the remote endpoint, it will automatically close the connection.

This option is only functional on certain kinds of sockets. (Notably, Gio.SocketProtocol.TCP sockets.)

The exact time between pings is system- and protocol-dependent, but will normally be at least two hours. Most commonly, you would set this flag on a server socket if you want to allow clients to remain idle for long periods of time, but also want to ensure that connections are eventually garbage-collected if clients crash or become unreachable.

New in version 2.22.

set_listen_backlog(backlog)

Parameters:

backlog (int) – the maximum number of pending connections.

Sets the maximum number of outstanding connections allowed when listening on this socket. If more clients than this are connecting to the socket and the application is not handling them on time then the new connections will be refused.

Note that this must be called before Gio.Socket.listen() and has no effect if called after that.

New in version 2.22.

set_multicast_loopback(loopback)

Parameters:

loopback (bool) – whether self should receive messages sent to its multicast groups from the local host

Sets whether outgoing multicast packets will be received by sockets listening on that multicast address on the same host. This is True by default.

New in version 2.32.

set_multicast_ttl(ttl)

Parameters:

ttl (int) – the time-to-live value for all multicast datagrams on self

Sets the time-to-live for outgoing multicast datagrams on self. By default, this is 1, meaning that multicast packets will not leave the local network.

New in version 2.32.

set_option(level, optname, value)

Parameters:

• level (int) – the “API level” of the option (eg, SOL_SOCKET)

• optname (int) – the “name” of the option (eg, SO_BROADCAST)

• value (int) – the value to set the option to

Raises:

GLib.Error

Returns:

success or failure. On failure, error will be set, and the system error value (errno or WSAGetLastError()) will still be set to the result of the setsockopt() call.

Return type:

bool

Sets the value of an integer-valued option on self, as with setsockopt(). (If you need to set a non-integer-valued option, you will need to call setsockopt() directly.)

The ‘<gio/gnetworking.h> [gio-gnetworking.h]’ header pulls in system headers that will define most of the standard/portable socket options. For unusual socket protocols or platform-dependent options, you may need to include additional headers.

New in version 2.36.

set_timeout(timeout)

Parameters:

timeout (int) – the timeout for self, in seconds, or 0 for none

Sets the time in seconds after which I/O operations on self will time out if they have not yet completed.

On a blocking socket, this means that any blocking Gio.Socket operation will time out after timeout seconds of inactivity, returning Gio.IOErrorEnum.TIMED_OUT.

On a non-blocking socket, calls to Gio.Socket.condition_wait() will also fail with Gio.IOErrorEnum.TIMED_OUT after the given time. Sources created with g_socket_create_source() will trigger after timeout seconds of inactivity, with the requested condition set, at which point calling Gio.Socket.receive(), Gio.Socket.send(), Gio.Socket.check_connect_result(), etc, will fail with Gio.IOErrorEnum.TIMED_OUT.

If timeout is 0 (the default), operations will never time out on their own.

Note that if an I/O operation is interrupted by a signal, this may cause the timeout to be reset.

New in version 2.26.

set_ttl(ttl)

Parameters:

ttl (int) – the time-to-live value for all unicast packets on self

Sets the time-to-live for outgoing unicast packets on self. By default the platform-specific default value is used.

New in version 2.32.

shutdown(shutdown_read, shutdown_write)

Parameters:

• shutdown_read (bool) – whether to shut down the read side

• shutdown_write (bool) – whether to shut down the write side

Raises:

GLib.Error

Returns:

True on success, False on error

Return type:

bool

Shut down part or all of a full-duplex connection.

If shutdown_read is True then the receiving side of the connection is shut down, and further reading is disallowed.

If shutdown_write is True then the sending side of the connection is shut down, and further writing is disallowed.

It is allowed for both shutdown_read and shutdown_write to be True.

One example where it is useful to shut down only one side of a connection is graceful disconnect for TCP connections where you close the sending side, then wait for the other side to close the connection, thus ensuring that the other side saw all sent data.

New in version 2.22.

speaks_ipv4()

Returns:

True if this socket can be used with IPv4.

Return type:

bool

Checks if a socket is capable of speaking IPv4.

IPv4 sockets are capable of speaking IPv4. On some operating systems and under some combinations of circumstances IPv6 sockets are also capable of speaking IPv4. See RFC 3493 section 3.7 for more information.

No other types of sockets are currently considered as being capable of speaking IPv4.

New in version 2.22.

Property Details

Gio.Socket.props.blocking

Name:

blocking

Type:

bool

Default Value:

True

Flags:

READABLE, WRITABLE

Whether or not I/O on this socket is blocking

Gio.Socket.props.broadcast

Name:

broadcast

Type:

bool

Default Value:

False

Flags:

READABLE, WRITABLE

Whether the socket should allow sending to broadcast addresses.

New in version 2.32.

Gio.Socket.props.family

Name:

family

Type:

Gio.SocketFamily

Default Value:

Gio.SocketFamily.INVALID

Flags:

READABLE, WRITABLE, CONSTRUCT_ONLY

The sockets address family

Gio.Socket.props.fd

Name:

fd

Type:

int

Default Value:

-1

Flags:

READABLE, WRITABLE, CONSTRUCT_ONLY

The sockets file descriptor

Gio.Socket.props.keepalive

Name:

keepalive

Type:

bool

Default Value:

False

Flags:

READABLE, WRITABLE

Keep connection alive by sending periodic pings

Gio.Socket.props.listen_backlog

Name:

listen-backlog

Type:

int

Default Value:

10

Flags:

READABLE, WRITABLE

Outstanding connections in the listen queue

Gio.Socket.props.local_address

Name:

local-address

Type:

Gio.SocketAddress

Default Value:

None

Flags:

READABLE

The local address the socket is bound to

Gio.Socket.props.multicast_loopback

Name:

multicast-loopback

Type:

bool

Default Value:

True

Flags:

READABLE, WRITABLE

Whether outgoing multicast packets loop back to the local host.

New in version 2.32.

Gio.Socket.props.multicast_ttl

Name:

multicast-ttl

Type:

int

Default Value:

1

Flags:

READABLE, WRITABLE

Time-to-live out outgoing multicast packets

New in version 2.32.

Gio.Socket.props.protocol

Name:

protocol

Type:

Gio.SocketProtocol

Default Value:

Gio.SocketProtocol.UNKNOWN

Flags:

READABLE, WRITABLE, CONSTRUCT_ONLY

The id of the protocol to use, or -1 for unknown

Gio.Socket.props.remote_address

Name:

remote-address

Type:

Gio.SocketAddress

Default Value:

None

Flags:

READABLE

The remote address the socket is connected to

Gio.Socket.props.timeout

Name:

timeout

Type:

int

Default Value:

0

Flags:

READABLE, WRITABLE

The timeout in seconds on socket I/O

New in version 2.26.

Gio.Socket.props.ttl

Name:

ttl

Type:

int

Default Value:

0

Flags:

READABLE, WRITABLE

Time-to-live for outgoing unicast packets

New in version 2.32.

Gio.Socket.props.type

Name:

type

Type:

Gio.SocketType

Default Value:

Gio.SocketType.STREAM

Flags:

READABLE, WRITABLE, CONSTRUCT_ONLY

The sockets type