Socket#
Added in version 2.22.
Superclasses: Object
Implemented Interfaces: DatagramBased
, Initable
A GSocket
is a low-level networking primitive. It is a more or less
direct mapping of the BSD socket API in a portable GObject based API.
It supports both the UNIX socket implementations and winsock2 on Windows.
GSocket
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 SocketClient
,
SocketService
and SocketConnection
. However there may
be cases where direct use of GSocket
is useful.
GSocket
implements the Initable
interface, so if it is manually
constructed by e.g. new
you must call
init
and check the results before using the object.
This is done automatically in new
and
new_from_fd
, so these functions can return NULL
.
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 G_IO_ERROR_WOULD_BLOCK
error.
To know when a call would successfully run you can call
condition_check
, or condition_wait
.
You can also use create_source
and attach it to a
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 GSocket
.
When working in non-blocking mode applications should always be able to
handle getting a G_IO_ERROR_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 G_IO_ERROR_WOULD_BLOCK
.
GSocket
’s 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 GSocket
causes the signal SIGPIPE
to be
ignored for the remainder of the program. If you are writing a
command-line utility that uses GSocket
, 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, GSocket
is not inherently thread safe. To use
a GSocket
concurrently from multiple threads, you must implement your own
locking.
Nagle’s algorithm#
Since GLib 2.80, GSocket
will automatically set the TCP_NODELAY
option on
all G_SOCKET_TYPE_STREAM
sockets. This disables
Nagle’s algorithm <https://en.wikipedia.org/wiki/Nagle``%27s_algorithm`
>`_ as it
typically does more harm than good on modern networks.
If your application needs Nagle’s algorithm enabled, call
set_option
after constructing a GSocket
to enable it:
socket = g_socket_new (…, G_SOCKET_TYPE_STREAM, …);
if (socket != NULL)
{
g_socket_set_option (socket, IPPROTO_TCP, TCP_NODELAY, FALSE, &local_error);
// handle error if needed
}
Constructors#
- class Socket
- classmethod new(family: SocketFamily, type: SocketType, protocol: SocketProtocol) Socket #
Creates a new
Socket
with the defined family, type and protocol. Ifprotocol
is 0 (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.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
SocketProtocol
if you know the protocol number used for it.Added in version 2.22.
- Parameters:
family – the socket family to use, e.g.
IPV4
.type – the socket type to use.
protocol – the id of the protocol to use, or 0 for default.
- classmethod new_from_fd(fd: int) Socket #
Creates a new
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
Socket
.On success, the returned
Socket
takes ownership offd
. On failure, the caller must closefd
themselves.Since GLib 2.46, it is no longer a fatal error to call this on a non-socket descriptor. Instead, a GError will be set with code
FAILED
Added in version 2.22.
- Parameters:
fd – a native socket file descriptor.
Methods#
- class Socket
- accept(cancellable: Cancellable | None = None) Socket #
Accept incoming connections on a connection-based socket. This removes the first outstanding connection request from the listening socket and creates a
Socket
object for it.The
socket
must be bound to a local address withbind()
and must be listening for incoming connections (listen()
).If there are no outstanding connections then the operation will block or return
WOULD_BLOCK
if non-blocking I/O is enabled. To be notified of an incoming connection, wait for the%G_IO_IN
condition.Added in version 2.22.
- Parameters:
cancellable – a
%GCancellable
orNone
- bind(address: SocketAddress, allow_reuse: bool) bool #
When a socket is created it is attached to an address family, but it doesn’t have an address in this family.
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
listen()
andaccept()
). 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
socket
is a TCP socket, thenallow_reuse
controls the setting of theSO_REUSEADDR
socket option; normally it should beTrue
for server sockets (sockets that you will eventually callaccept()
on), andFalse
for client sockets. (Failing to set this flag on a server socket may causebind()
to returnADDRESS_IN_USE
if the server program is stopped and then immediately restarted.)If
socket
is a UDP socket, thenallow_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.)Added in version 2.22.
- Parameters:
address – a
SocketAddress
specifying the local address.allow_reuse – whether to allow reusing this address
- check_connect_result() bool #
Checks and resets the pending connect error for the socket. This is used to check for errors when
connect()
is used in non-blocking mode.Added in version 2.22.
- close() 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
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
%G_IO_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 callingshutdown()
with only theshutdown_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 callclose()
. (This is whatTcpConnection
does if you callset_graceful_disconnect()
. But of course, this only works if the client will close its connection after the server does.)Added in version 2.22.
- condition_check(condition: IOCondition) IOCondition #
Checks on the readiness of
socket
to perform operations. The operations specified incondition
are checked for and masked against the currently-satisfied conditions onsocket
. The result is returned.Note that on Windows, it is possible for an operation to return
WOULD_BLOCK
even immediately aftercondition_check()
has claimed that the socket is ready for writing. Rather than callingcondition_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 returnsWOULD_BLOCK
.It is meaningless to specify
%G_IO_ERR
or%G_IO_HUP
in condition; these conditions will always be set in the output if they are true.This call never blocks.
Added in version 2.22.
- Parameters:
condition – a
IOCondition
mask to check
- condition_timed_wait(condition: IOCondition, timeout_us: int, cancellable: Cancellable | None = None) bool #
Waits for up to
timeout_us
microseconds forcondition
to become true onsocket
. If the condition is met,True
is returned.If
cancellable
is cancelled before the condition is met, or iftimeout_us
(or the socket’sSocket
:timeout) is reached before the condition is met, thenFalse
is returned anderror
, if non-None
, is set to the appropriate value (CANCELLED
orTIMED_OUT
).If you don’t want a timeout, use
condition_wait()
. (Alternatively, you can pass -1 fortimeout_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 iftimeout_us
is not an exact number of milliseconds.Added in version 2.32.
- Parameters:
condition – a
IOCondition
mask to wait fortimeout_us – the maximum time (in microseconds) to wait, or -1
cancellable – a
Cancellable
, orNone
- condition_wait(condition: IOCondition, cancellable: Cancellable | None = None) bool #
Waits for
condition
to become true onsocket
. 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, thenFalse
is returned anderror
, if non-None
, is set to the appropriate value (CANCELLED
orTIMED_OUT
).See also
condition_timed_wait()
.Added in version 2.22.
- Parameters:
condition – a
IOCondition
mask to wait forcancellable – a
Cancellable
, orNone
- connect(address: SocketAddress, cancellable: Cancellable | None = None) 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 forsend()
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
PENDING
is returned and the user can be notified of the connection finishing by waiting for the G_IO_OUT condition. The result of the connection must then be checked withcheck_connect_result()
.Added in version 2.22.
- Parameters:
address – a
SocketAddress
specifying the remote address.cancellable – a
%GCancellable
orNone
- connection_factory_create_connection() SocketConnection #
Creates a
SocketConnection
subclass of the right type forsocket
.Added in version 2.22.
- get_available_bytes() int #
Get the amount of data pending in the OS input buffer, without blocking.
If
socket
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
receive()
with a buffer of that size, rather than callingget_available_bytes()
first and then doing a receive of exactly the right size.Added in version 2.32.
- get_blocking() bool #
Gets the blocking mode of the socket. For details on blocking I/O, see
set_blocking()
.Added in version 2.22.
- get_broadcast() bool #
Gets the broadcast setting on
socket
; ifTrue
, it is possible to send packets to broadcast addresses.Added in version 2.32.
- get_credentials() Credentials #
Returns the credentials of the foreign process connected to this socket, if any (e.g. it is only supported for
UNIX
sockets).If this operation isn’t supported on the OS, the method fails with the
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
UnixCredentialsMessage
type andsend_credentials()
/receive_credentials()
functions.Added in version 2.26.
- get_family() SocketFamily #
Gets the socket family of the socket.
Added in version 2.22.
- get_fd() 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.
Added in version 2.22.
- get_keepalive() bool #
Gets the keepalive mode of the socket. For details on this, see
set_keepalive()
.Added in version 2.22.
- get_listen_backlog() int #
Gets the listen backlog setting of the socket. For details on this, see
set_listen_backlog()
.Added in version 2.22.
- get_local_address() 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.
Added in version 2.22.
- get_multicast_loopback() bool #
Gets the multicast loopback setting on
socket
; ifTrue
(the default), outgoing multicast packets will be looped back to multicast listeners on the same host.Added in version 2.32.
- get_multicast_ttl() int #
Gets the multicast time-to-live setting on
socket
; seeset_multicast_ttl()
for more details.Added in version 2.32.
- get_option(level: int, optname: int) tuple[bool, int] #
Gets the value of an integer-valued option on
socket
, as with getsockopt(). (If you need to fetch a non-integer-valued option, you will need to call getsockopt() directly.)The
`<gio/gnetworking.h>
<networking.html>`_ 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 aint
variable, not aguint8
;get_option()
will handle the conversion internally.Added in version 2.36.
- Parameters:
level – the “API level” of the option (eg,
SOL_SOCKET
)optname – the “name” of the option (eg,
SO_BROADCAST
)
- get_protocol() SocketProtocol #
Gets the socket protocol id the socket was created with. In case the protocol is unknown, -1 is returned.
Added in version 2.22.
- get_remote_address() SocketAddress #
Try to get the remote address of a connected socket. This is only useful for connection oriented sockets that have been connected.
Added in version 2.22.
- get_socket_type() SocketType #
Gets the socket type of the socket.
Added in version 2.22.
- get_timeout() int #
Gets the timeout setting of the socket. For details on this, see
set_timeout()
.Added in version 2.26.
- get_ttl() int #
Gets the unicast time-to-live setting on
socket
; seeset_ttl()
for more details.Added in version 2.32.
- is_connected() bool #
Check whether the socket is connected. This is only useful for connection-oriented sockets.
If using
shutdown()
, this function will returnTrue
until the socket has been shut down for reading and writing. If you do a non-blocking connect, this function will not returnTrue
until after you callcheck_connect_result()
.Added in version 2.22.
- join_multicast_group(group: InetAddress, source_specific: bool, iface: str | None = None) bool #
Registers
socket
to receive multicast messages sent togroup
.socket
must be aDATAGRAM
socket, and must have been bound to an appropriate interface and port withbind()
.If
iface
isNone
, the system will automatically pick an interface to bind to based ongroup
.If
source_specific
isTrue
, source-specific multicast as defined in RFC 4604 is used. Note that on older platforms this may fail with aNOT_SUPPORTED
error.To bind to a given source-specific multicast address, use
join_multicast_group_ssm()
instead.Added in version 2.32.
- Parameters:
group – a
InetAddress
specifying the group address to join.source_specific –
True
if source-specific multicast should be usediface – Name of the interface to use, or
None
- join_multicast_group_ssm(group: InetAddress, source_specific: InetAddress | None = None, iface: str | None = None) bool #
Registers
socket
to receive multicast messages sent togroup
.socket
must be aDATAGRAM
socket, and must have been bound to an appropriate interface and port withbind()
.If
iface
isNone
, the system will automatically pick an interface to bind to based ongroup
.If
source_specific
is notNone
, use source-specific multicast as defined in RFC 4604. Note that on older platforms this may fail with aNOT_SUPPORTED
error.Note that this function can be called multiple times for the same
group
with differentsource_specific
in order to receive multicast packets from more than one source.Added in version 2.56.
- Parameters:
group – a
InetAddress
specifying the group address to join.source_specific – a
InetAddress
specifying the source-specific multicast address orNone
to ignore.iface – Name of the interface to use, or
None
- leave_multicast_group(group: InetAddress, source_specific: bool, iface: str | None = None) bool #
Removes
socket
from the multicast group defined bygroup
,iface
, andsource_specific
(which must all have the same values they had when you joined the group).socket
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
leave_multicast_group_ssm()
instead.Added in version 2.32.
- Parameters:
group – a
InetAddress
specifying the group address to leave.source_specific –
True
if source-specific multicast was usediface – Interface used
- leave_multicast_group_ssm(group: InetAddress, source_specific: InetAddress | None = None, iface: str | None = None) bool #
Removes
socket
from the multicast group defined bygroup
,iface
, andsource_specific
(which must all have the same values they had when you joined the group).socket
remains bound to its address and port, and can still receive unicast messages after calling this.Added in version 2.56.
- Parameters:
group – a
InetAddress
specifying the group address to leave.source_specific – a
InetAddress
specifying the source-specific multicast address orNone
to ignore.iface – Name of the interface to use, or
None
- listen() bool #
Marks the socket as a server socket, i.e. a socket that is used to accept incoming requests using
accept()
.Before calling this the socket must be bound to a local address using
bind()
.To set the maximum amount of outstanding clients, use
set_listen_backlog()
.Added in version 2.22.
- receive(cancellable: Cancellable | None = None) tuple[int, bytes] #
Receive data (up to
size
bytes) from a socket. This is mainly used by connection-oriented sockets; it is identical toreceive_from()
withaddress
set toNone
.For
DATAGRAM
andSEQPACKET
sockets,receive()
will always read either 0 or 1 complete messages from the socket. If the received message is too large to fit inbuffer
, then the data beyondsize
bytes will be discarded, without any explicit indication that this has occurred.For
STREAM
sockets,receive()
can return any number of bytes, up tosize
. If more thansize
bytes have been received, the additional data will be returned in future calls toreceive()
.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
WOULD_BLOCK
error will be returned. To be notified when data is available, wait for the%G_IO_IN
condition.On error -1 is returned and
error
is set accordingly.Added in version 2.22.
- Parameters:
cancellable – a
%GCancellable
orNone
- receive_bytes(size: int, timeout_us: int, cancellable: Cancellable | None = None) Bytes #
Receives data (up to
size
bytes) from a socket.This function is a variant of
receive
which returns aBytes
rather than a plain buffer.Pass
-1
totimeout_us
to block indefinitely until data is received (or the connection is closed, or there is an error). Pass0
to use the default timeout fromtimeout
, or pass a positive number to wait for that many microseconds for data before returningG_IO_ERROR_TIMED_OUT
.Added in version 2.80.
- Parameters:
size – the number of bytes you want to read from the socket
timeout_us – the timeout to wait for, in microseconds, or
-1
to block indefinitelycancellable – a
%GCancellable
, orNULL
- receive_bytes_from(size: int, timeout_us: int, cancellable: Cancellable | None = None) tuple[Bytes, SocketAddress] #
Receive data (up to
size
bytes) from a socket.This function is a variant of
receive_from
which returns aBytes
rather than a plain buffer.If
address
is non-None
thenaddress
will be set equal to the source address of the received packet.The
address
is owned by the caller.Pass
-1
totimeout_us
to block indefinitely until data is received (or the connection is closed, or there is an error). Pass0
to use the default timeout fromtimeout
, or pass a positive number to wait for that many microseconds for data before returningG_IO_ERROR_TIMED_OUT
.Added in version 2.80.
- Parameters:
size – the number of bytes you want to read from the socket
timeout_us – the timeout to wait for, in microseconds, or
-1
to block indefinitelycancellable – a
Cancellable
, orNULL
- receive_from(cancellable: Cancellable | None = None) tuple[int, SocketAddress, bytes] #
Receive data (up to
size
bytes) from a socket.If
address
is non-None
thenaddress
will be set equal to the source address of the received packet.address
is owned by the caller.See
receive()
for additional information.Added in version 2.22.
- Parameters:
cancellable – a
%GCancellable
orNone
- receive_message(vectors: Sequence[InputVector], cancellable: Cancellable | None = None) tuple[int, SocketAddress, list[SocketControlMessage], int] #
Receive data from a socket. For receiving multiple messages, see
receive_messages()
; for easier use, seereceive()
andreceive_from()
.If
address
is non-None
thenaddress
will be set equal to the source address of the received packet.address
is owned by the caller.vector
must point to an array ofInputVector
structs andnum_vectors
must be the length of this array. These structs describe the buffers that received data will be scattered into. Ifnum_vectors
is -1, thenvectors
is assumed to be terminated by aInputVector
with aNone
buffer pointer.As a special case, if
num_vectors
is 0 (in which case,vectors
may of course beNone
), 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 ofSocketControlMessage
instances orNone
if no such messages was received. These correspond to the control messages received from the kernel, oneSocketControlMessage
per message from the kernel. This array isNone
-terminated and must be freed by the caller usingfree()
after callingunref()
on each element. Ifmessages
isNone
, 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
andnum_messages
are non-None
, thennum_messages
gives the number ofSocketControlMessage
instances inmessages
(ie: not including theNone
terminator).flags
is an in/out parameter. The commonly available arguments for this are available in theGSocketMsgFlags
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 (andreceive_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
receive()
, data may be discarded ifsocket
isDATAGRAM
orSEQPACKET
and you do not provide enough buffer space to read a complete message. You can passPEEK
inflags
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
WOULD_BLOCK
error will be returned. To be notified when data is available, wait for the%G_IO_IN
condition.On error -1 is returned and
error
is set accordingly.Added in version 2.22.
- Parameters:
vectors – an array of
InputVector
structscancellable – a
%GCancellable
orNone
- receive_messages(messages: Sequence[InputMessage], flags: int, cancellable: Cancellable | None = None) int #
Receive multiple data messages from
socket
in one go. This is the most complicated and fully-featured version of this call. For easier use, seereceive()
,receive_from()
, andreceive_message()
.messages
must point to an array ofInputMessage
structs andnum_messages
must be the length of this array. EachInputMessage
contains a pointer to an array ofInputVector
structs describing the buffers that the data received in each message will be written to. Using multipleInputVector
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 toreceive()
, 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 theGSocketMsgFlags
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 inInputMessage
.flags.The other members of
InputMessage
are treated as described in its documentation.If
Socket
:blocking isTrue
the call will block untilnum_messages
have been received, or the end of the stream is reached.If
Socket
:blocking isFalse
the call will return up tonum_messages
without blocking, orWOULD_BLOCK
if no messages are queued in the operating system to be received.In blocking mode, if
Socket
:timeout is positive and is reached before any messages are received,TIMED_OUT
is returned, otherwise up tonum_messages
are returned. (Note: This is effectively the behaviour ofMSG_WAITFORONE
with recvmmsg().)To be notified when messages are available, wait for the
%G_IO_IN
condition. Note though that you may still receiveWOULD_BLOCK
fromreceive_messages()
even if you were previously notified of a%G_IO_IN
condition.If the remote peer closes the connection, any messages queued in the operating system will be returned, and subsequent calls to
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.Added in version 2.48.
- Parameters:
messages – an array of
InputMessage
structsflags – an int containing
GSocketMsgFlags
flags for the overall operation, which may additionally contain other platform specific flagscancellable – a
%GCancellable
orNone
- receive_with_blocking(blocking: bool, cancellable: Cancellable | None = None) tuple[int, bytes] #
This behaves exactly the same as
receive()
, except that the choice of blocking or non-blocking behavior is determined by theblocking
argument rather than bysocket
’s properties.Added in version 2.26.
- Parameters:
blocking – whether to do blocking or non-blocking I/O
cancellable – a
%GCancellable
orNone
- send(buffer: Sequence[int], cancellable: Cancellable | None = None) int #
Tries to send
size
bytes frombuffer
on the socket. This is mainly used by connection-oriented sockets; it is identical tosend_to()
withaddress
set toNone
.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
WOULD_BLOCK
error will be returned. To be notified when space is available, wait for the%G_IO_OUT
condition. Note though that you may still receiveWOULD_BLOCK
fromsend()
even if you were previously notified of a%G_IO_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.Added in version 2.22.
- Parameters:
buffer – the buffer containing the data to send.
cancellable – a
%GCancellable
orNone
- send_message(address: SocketAddress | None, vectors: Sequence[OutputVector], messages: Sequence[SocketControlMessage] | None, flags: int, cancellable: Cancellable | None = None) int #
Send data to
address
onsocket
. For sending multiple messages seesend_messages()
; for easier use, seesend()
andsend_to()
.If
address
isNone
then the message is sent to the default receiver (set byconnect()
).vectors
must point to an array ofOutputVector
structs andnum_vectors
must be the length of this array. (Ifnum_vectors
is -1, thenvectors
is assumed to be terminated by aOutputVector
with aNone
buffer pointer.) TheOutputVector
structs describe the buffers that the sent data will be gathered from. Using multipleOutputVector
is more memory-efficient than manually copying data from multiple sources into a single buffer, and more network-efficient than making multiple calls tosend()
.messages
, if non-None
, is taken to point to an array ofnum_messages
SocketControlMessage
instances. These correspond to the control messages to be sent on the socket. Ifnum_messages
is -1 thenmessages
is treated as aNone
-terminated array.flags
modify how the message is sent. The commonly available arguments for this are available in theGSocketMsgFlags
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
WOULD_BLOCK
error will be returned. To be notified when space is available, wait for the%G_IO_OUT
condition. Note though that you may still receiveWOULD_BLOCK
fromsend()
even if you were previously notified of a%G_IO_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
OutputVector
in vectors must not be greater than%G_MAXSSIZE
. If the message can be larger than this, then it is mandatory to use thesend_message_with_timeout()
function.On error -1 is returned and
error
is set accordingly.Added in version 2.22.
- Parameters:
address – a
SocketAddress
, orNone
vectors – an array of
OutputVector
structsmessages – a pointer to an array of
SocketControlMessage
, orNone
.flags –
an int containing
GSocketMsgFlags
flags, which may additionally contain other platform specific flagscancellable – a
%GCancellable
orNone
- send_message_with_timeout(address: SocketAddress | None, vectors: Sequence[OutputVector], messages: Sequence[SocketControlMessage] | None, flags: int, timeout_us: int, cancellable: Cancellable | None = None) tuple[PollableReturn, int] #
This behaves exactly the same as
send_message()
, except that the choice of timeout behavior is determined by thetimeout_us
argument rather than bysocket
’s properties.On error
FAILED
is returned anderror
is set accordingly, or if the socket is currently not writableWOULD_BLOCK
is returned.bytes_written
will contain 0 in both cases.Added in version 2.60.
- Parameters:
address – a
SocketAddress
, orNone
vectors – an array of
OutputVector
structsmessages – a pointer to an array of
SocketControlMessage
, orNone
.flags –
an int containing
GSocketMsgFlags
flags, which may additionally contain other platform specific flagstimeout_us – the maximum time (in microseconds) to wait, or -1
cancellable – a
%GCancellable
orNone
- send_messages(messages: Sequence[OutputMessage], flags: int, cancellable: Cancellable | None = None) int #
Send multiple data messages from
socket
in one go. This is the most complicated and fully-featured version of this call. For easier use, seesend()
,send_to()
, andsend_message()
.messages
must point to an array ofOutputMessage
structs andnum_messages
must be the length of this array. EachOutputMessage
contains an address to send the data to, and a pointer to an array ofOutputVector
structs to describe the buffers that the data to be sent for each message will be gathered from. Using multipleOutputVector
is more memory-efficient than manually copying data from multiple sources into a single buffer, and more network-efficient than making multiple calls tosend()
. 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 theGSocketMsgFlags
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
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%G_IO_OUT
condition. Note though that you may still receiveWOULD_BLOCK
fromsend()
even if you were previously notified of a%G_IO_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.Added in version 2.44.
- Parameters:
messages – an array of
OutputMessage
structsflags –
an int containing
GSocketMsgFlags
flags, which may additionally contain other platform specific flagscancellable – a
%GCancellable
orNone
- send_to(address: SocketAddress | None, buffer: Sequence[int], cancellable: Cancellable | None = None) int #
Tries to send
size
bytes frombuffer
toaddress
. Ifaddress
isNone
then the message is sent to the default receiver (set byconnect()
).See
send()
for additional information.Added in version 2.22.
- Parameters:
address – a
SocketAddress
, orNone
buffer – the buffer containing the data to send.
cancellable – a
%GCancellable
orNone
- send_with_blocking(buffer: Sequence[int], blocking: bool, cancellable: Cancellable | None = None) int #
This behaves exactly the same as
send()
, except that the choice of blocking or non-blocking behavior is determined by theblocking
argument rather than bysocket
’s properties.Added in version 2.26.
- Parameters:
buffer – the buffer containing the data to send.
blocking – whether to do blocking or non-blocking I/O
cancellable – a
%GCancellable
orNone
- set_blocking(blocking: bool) None #
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
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 GSocket level feature.
Added in version 2.22.
- Parameters:
blocking – Whether to use blocking I/O or not.
- set_broadcast(broadcast: bool) None #
Sets whether
socket
should allow sending to broadcast addresses. This isFalse
by default.Added in version 2.32.
- Parameters:
broadcast – whether
socket
should allow sending to broadcast addresses
- set_keepalive(keepalive: bool) None #
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,
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.
Added in version 2.22.
- Parameters:
keepalive – Value for the keepalive flag
- set_listen_backlog(backlog: int) None #
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
listen()
and has no effect if called after that.Added in version 2.22.
- Parameters:
backlog – the maximum number of pending connections.
- set_multicast_loopback(loopback: bool) None #
Sets whether outgoing multicast packets will be received by sockets listening on that multicast address on the same host. This is
True
by default.Added in version 2.32.
- Parameters:
loopback – whether
socket
should receive messages sent to its multicast groups from the local host
- set_multicast_ttl(ttl: int) None #
Sets the time-to-live for outgoing multicast datagrams on
socket
. By default, this is 1, meaning that multicast packets will not leave the local network.Added in version 2.32.
- Parameters:
ttl – the time-to-live value for all multicast datagrams on
socket
- set_option(level: int, optname: int, value: int) bool #
Sets the value of an integer-valued option on
socket
, as with setsockopt(). (If you need to set a non-integer-valued option, you will need to call setsockopt() directly.)The
`<gio/gnetworking.h>
<networking.html>`_ 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.Added in version 2.36.
- Parameters:
level – the “API level” of the option (eg,
SOL_SOCKET
)optname – the “name” of the option (eg,
SO_BROADCAST
)value – the value to set the option to
- set_timeout(timeout: int) None #
Sets the time in seconds after which I/O operations on
socket
will time out if they have not yet completed.On a blocking socket, this means that any blocking
Socket
operation will time out aftertimeout
seconds of inactivity, returningTIMED_OUT
.On a non-blocking socket, calls to
condition_wait()
will also fail withTIMED_OUT
after the given time. Sources created withcreate_source()
will trigger aftertimeout
seconds of inactivity, with the requested condition set, at which point callingreceive()
,send()
,check_connect_result()
, etc, will fail withTIMED_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.
Added in version 2.26.
- Parameters:
timeout – the timeout for
socket
, in seconds, or 0 for none
- set_ttl(ttl: int) None #
Sets the time-to-live for outgoing unicast packets on
socket
. By default the platform-specific default value is used.Added in version 2.32.
- Parameters:
ttl – the time-to-live value for all unicast packets on
socket
- shutdown(shutdown_read: bool, shutdown_write: bool) bool #
Shut down part or all of a full-duplex connection.
If
shutdown_read
isTrue
then the receiving side of the connection is shut down, and further reading is disallowed.If
shutdown_write
isTrue
then the sending side of the connection is shut down, and further writing is disallowed.It is allowed for both
shutdown_read
andshutdown_write
to beTrue
.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.
Added in version 2.22.
- Parameters:
shutdown_read – whether to shut down the read side
shutdown_write – whether to shut down the write side
- speaks_ipv4() 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.
Added in version 2.22.
Properties#
- class Socket
-
- props.family: SocketFamily#
The type of the None singleton.
Added in version 2.22.
- props.local_address: SocketAddress#
The type of the None singleton.
Added in version 2.22.
- props.protocol: SocketProtocol#
The type of the None singleton.
Added in version 2.22.
- props.remote_address: SocketAddress#
The type of the None singleton.
Added in version 2.22.
- props.type: SocketType#
The type of the None singleton.
Added in version 2.22.