Cara menggunakan python socket recv example

This module provides access to the BSD socket interface. It is available on all modern Unix systems, Windows, MacOS, and probably additional platforms.

Note

Some behavior may be platform dependent, since calls are made to the operating system socket APIs.

: not Emscripten, not WASI.

This module does not work or is not available on WebAssembly platforms

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
6 and
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
7. See for more information.

The Python interface is a straightforward transliteration of the Unix system call and library interface for sockets to Python’s object-oriented style: the

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
8 function returns a socket object whose methods implement the various socket system calls. Parameter types are somewhat higher-level than in the C interface: as with
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
9 and
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
0 operations on Python files, buffer allocation on receive operations is automatic, and buffer length is implicit on send operations.

See also

Module

Classes that simplify writing network servers.

Module

A TLS/SSL wrapper for socket objects.

Socket families

Depending on the system and the build options, various socket families are supported by this module.

The address format required by a particular socket object is automatically selected based on the address family specified when the socket object was created. Socket addresses are represented as follows:

  • The address of an socket bound to a file system node is represented as a string, using the file system encoding and the

    >>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
    [(socket.AF_INET6, socket.SOCK_STREAM,
     6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
     (socket.AF_INET, socket.SOCK_STREAM,
     6, '', ('93.184.216.34', 80))]
    
    4 error handler (see PEP 383). An address in Linux’s abstract namespace is returned as a with an initial null byte; note that sockets in this namespace can communicate with normal file system sockets, so programs intended to run on Linux may need to deal with both types of address. A string or bytes-like object can be used for either type of address when passing it as an argument.

    Changed in version 3.3: Previously, socket paths were assumed to use UTF-8 encoding.

    Changed in version 3.5: Writable is now accepted.

  • A pair

    >>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
    [(socket.AF_INET6, socket.SOCK_STREAM,
     6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
     (socket.AF_INET, socket.SOCK_STREAM,
     6, '', ('93.184.216.34', 80))]
    
    6 is used for the address family, where host is a string representing either a hostname in internet domain notation like
    >>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
    [(socket.AF_INET6, socket.SOCK_STREAM,
     6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
     (socket.AF_INET, socket.SOCK_STREAM,
     6, '', ('93.184.216.34', 80))]
    
    8 or an IPv4 address like
    >>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
    [(socket.AF_INET6, socket.SOCK_STREAM,
     6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
     (socket.AF_INET, socket.SOCK_STREAM,
     6, '', ('93.184.216.34', 80))]
    
    9, and port is an integer.

    • For IPv4 addresses, two special forms are accepted instead of a host address:

      import socket, array
      
      def recv_fds(sock, msglen, maxfds):
          fds = array.array("i")   # Array of ints
          msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
          for cmsg_level, cmsg_type, cmsg_data in ancdata:
              if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
                  # Append data, ignoring any truncated integers at the end.
                  fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
          return msg, list(fds)
      
      0 represents
      import socket, array
      
      def recv_fds(sock, msglen, maxfds):
          fds = array.array("i")   # Array of ints
          msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
          for cmsg_level, cmsg_type, cmsg_data in ancdata:
              if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
                  # Append data, ignoring any truncated integers at the end.
                  fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
          return msg, list(fds)
      
      1, which is used to bind to all interfaces, and the string
      import socket, array
      
      def recv_fds(sock, msglen, maxfds):
          fds = array.array("i")   # Array of ints
          msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
          for cmsg_level, cmsg_type, cmsg_data in ancdata:
              if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
                  # Append data, ignoring any truncated integers at the end.
                  fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
          return msg, list(fds)
      
      2 represents
      import socket, array
      
      def recv_fds(sock, msglen, maxfds):
          fds = array.array("i")   # Array of ints
          msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
          for cmsg_level, cmsg_type, cmsg_data in ancdata:
              if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
                  # Append data, ignoring any truncated integers at the end.
                  fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
          return msg, list(fds)
      
      3. This behavior is not compatible with IPv6, therefore, you may want to avoid these if you intend to support IPv6 with your Python programs.

  • For address family, a four-tuple

    import socket, array
    
    def recv_fds(sock, msglen, maxfds):
        fds = array.array("i")   # Array of ints
        msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
        for cmsg_level, cmsg_type, cmsg_data in ancdata:
            if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
                # Append data, ignoring any truncated integers at the end.
                fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
        return msg, list(fds)
    
    5 is used, where flowinfo and scope_id represent the
    import socket, array
    
    def recv_fds(sock, msglen, maxfds):
        fds = array.array("i")   # Array of ints
        msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
        for cmsg_level, cmsg_type, cmsg_data in ancdata:
            if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
                # Append data, ignoring any truncated integers at the end.
                fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
        return msg, list(fds)
    
    6 and
    import socket, array
    
    def recv_fds(sock, msglen, maxfds):
        fds = array.array("i")   # Array of ints
        msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
        for cmsg_level, cmsg_type, cmsg_data in ancdata:
            if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
                # Append data, ignoring any truncated integers at the end.
                fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
        return msg, list(fds)
    
    7 members in
    import socket, array
    
    def recv_fds(sock, msglen, maxfds):
        fds = array.array("i")   # Array of ints
        msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
        for cmsg_level, cmsg_type, cmsg_data in ancdata:
            if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
                # Append data, ignoring any truncated integers at the end.
                fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
        return msg, list(fds)
    
    8 in C. For module methods, flowinfo and scope_id can be omitted just for backward compatibility. Note, however, omission of scope_id can cause problems in manipulating scoped IPv6 addresses.

    Changed in version 3.7: For multicast addresses (with scope_id meaningful) address may not contain

    >>> import socket
    >>> s1, s2 = socket.socketpair()
    >>> b1 = bytearray(b'----')
    >>> b2 = bytearray(b'0123456789')
    >>> b3 = bytearray(b'--------------')
    >>> s1.send(b'Mary had a little lamb')
    22
    >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
    (22, [], 0, None)
    >>> [b1, b2, b3]
    [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
    
    0 (or
    >>> import socket
    >>> s1, s2 = socket.socketpair()
    >>> b1 = bytearray(b'----')
    >>> b2 = bytearray(b'0123456789')
    >>> b3 = bytearray(b'--------------')
    >>> s1.send(b'Mary had a little lamb')
    22
    >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
    (22, [], 0, None)
    >>> [b1, b2, b3]
    [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
    
    1) part. This information is superfluous and may be safely omitted (recommended).

  • >>> import socket
    >>> s1, s2 = socket.socketpair()
    >>> b1 = bytearray(b'----')
    >>> b2 = bytearray(b'0123456789')
    >>> b3 = bytearray(b'--------------')
    >>> s1.send(b'Mary had a little lamb')
    22
    >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
    (22, [], 0, None)
    >>> [b1, b2, b3]
    [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
    
    2 sockets are represented as pairs
    >>> import socket
    >>> s1, s2 = socket.socketpair()
    >>> b1 = bytearray(b'----')
    >>> b2 = bytearray(b'0123456789')
    >>> b3 = bytearray(b'--------------')
    >>> s1.send(b'Mary had a little lamb')
    22
    >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
    (22, [], 0, None)
    >>> [b1, b2, b3]
    [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
    
    3.

  • Linux-only support for TIPC is available using the

    >>> import socket
    >>> s1, s2 = socket.socketpair()
    >>> b1 = bytearray(b'----')
    >>> b2 = bytearray(b'0123456789')
    >>> b3 = bytearray(b'--------------')
    >>> s1.send(b'Mary had a little lamb')
    22
    >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
    (22, [], 0, None)
    >>> [b1, b2, b3]
    [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
    
    4 address family. TIPC is an open, non-IP based networked protocol designed for use in clustered computer environments. Addresses are represented by a tuple, and the fields depend on the address type. The general tuple form is
    >>> import socket
    >>> s1, s2 = socket.socketpair()
    >>> b1 = bytearray(b'----')
    >>> b2 = bytearray(b'0123456789')
    >>> b3 = bytearray(b'--------------')
    >>> s1.send(b'Mary had a little lamb')
    22
    >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
    (22, [], 0, None)
    >>> [b1, b2, b3]
    [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
    
    5, where:

    • addr_type is one of

      >>> import socket
      >>> s1, s2 = socket.socketpair()
      >>> b1 = bytearray(b'----')
      >>> b2 = bytearray(b'0123456789')
      >>> b3 = bytearray(b'--------------')
      >>> s1.send(b'Mary had a little lamb')
      22
      >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
      (22, [], 0, None)
      >>> [b1, b2, b3]
      [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
      
      6,
      >>> import socket
      >>> s1, s2 = socket.socketpair()
      >>> b1 = bytearray(b'----')
      >>> b2 = bytearray(b'0123456789')
      >>> b3 = bytearray(b'--------------')
      >>> s1.send(b'Mary had a little lamb')
      22
      >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
      (22, [], 0, None)
      >>> [b1, b2, b3]
      [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
      
      7, or
      >>> import socket
      >>> s1, s2 = socket.socketpair()
      >>> b1 = bytearray(b'----')
      >>> b2 = bytearray(b'0123456789')
      >>> b3 = bytearray(b'--------------')
      >>> s1.send(b'Mary had a little lamb')
      22
      >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
      (22, [], 0, None)
      >>> [b1, b2, b3]
      [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
      
      8.

    • scope is one of

      >>> import socket
      >>> s1, s2 = socket.socketpair()
      >>> b1 = bytearray(b'----')
      >>> b2 = bytearray(b'0123456789')
      >>> b3 = bytearray(b'--------------')
      >>> s1.send(b'Mary had a little lamb')
      22
      >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
      (22, [], 0, None)
      >>> [b1, b2, b3]
      [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
      
      9,
      import socket, array
      
      def send_fds(sock, msg, fds):
          return sock.sendmsg([msg], [(socket.SOL_SOCKET, socket.SCM_RIGHTS, array.array("i", fds))])
      
      0, and
      import socket, array
      
      def send_fds(sock, msg, fds):
          return sock.sendmsg([msg], [(socket.SOL_SOCKET, socket.SCM_RIGHTS, array.array("i", fds))])
      
      1.

    • If addr_type is

      >>> import socket
      >>> s1, s2 = socket.socketpair()
      >>> b1 = bytearray(b'----')
      >>> b2 = bytearray(b'0123456789')
      >>> b3 = bytearray(b'--------------')
      >>> s1.send(b'Mary had a little lamb')
      22
      >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
      (22, [], 0, None)
      >>> [b1, b2, b3]
      [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
      
      7, then v1 is the server type, v2 is the port identifier, and v3 should be 0.

      If addr_type is

      >>> import socket
      >>> s1, s2 = socket.socketpair()
      >>> b1 = bytearray(b'----')
      >>> b2 = bytearray(b'0123456789')
      >>> b3 = bytearray(b'--------------')
      >>> s1.send(b'Mary had a little lamb')
      22
      >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
      (22, [], 0, None)
      >>> [b1, b2, b3]
      [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
      
      6, then v1 is the server type, v2 is the lower port number, and v3 is the upper port number.

      If addr_type is

      >>> import socket
      >>> s1, s2 = socket.socketpair()
      >>> b1 = bytearray(b'----')
      >>> b2 = bytearray(b'0123456789')
      >>> b3 = bytearray(b'--------------')
      >>> s1.send(b'Mary had a little lamb')
      22
      >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
      (22, [], 0, None)
      >>> [b1, b2, b3]
      [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
      
      8, then v1 is the node, v2 is the reference, and v3 should be set to 0.

  • A tuple

    import socket, array
    
    def send_fds(sock, msg, fds):
        return sock.sendmsg([msg], [(socket.SOL_SOCKET, socket.SCM_RIGHTS, array.array("i", fds))])
    
    5 is used for the address family, where interface is a string representing a network interface name like
    import socket, array
    
    def send_fds(sock, msg, fds):
        return sock.sendmsg([msg], [(socket.SOL_SOCKET, socket.SCM_RIGHTS, array.array("i", fds))])
    
    7. The network interface name
    import socket, array
    
    def recv_fds(sock, msglen, maxfds):
        fds = array.array("i")   # Array of ints
        msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
        for cmsg_level, cmsg_type, cmsg_data in ancdata:
            if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
                # Append data, ignoring any truncated integers at the end.
                fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
        return msg, list(fds)
    
    0 can be used to receive packets from all network interfaces of this family.

    • protocol require a tuple

      # Echo server program
      import socket
      
      HOST = ''                 # Symbolic name meaning all available interfaces
      PORT = 50007              # Arbitrary non-privileged port
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.bind((HOST, PORT))
          s.listen(1)
          conn, addr = s.accept()
          with conn:
              print('Connected by', addr)
              while True:
                  data = conn.recv(1024)
                  if not data: break
                  conn.sendall(data)
      
      0 where both additional parameters are unsigned long integer that represent a CAN identifier (standard or extended).

    • protocol require a tuple

      # Echo server program
      import socket
      
      HOST = ''                 # Symbolic name meaning all available interfaces
      PORT = 50007              # Arbitrary non-privileged port
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.bind((HOST, PORT))
          s.listen(1)
          conn, addr = s.accept()
          with conn:
              print('Connected by', addr)
              while True:
                  data = conn.recv(1024)
                  if not data: break
                  conn.sendall(data)
      
      2 where additional parameters are 64-bit unsigned integer representing the ECU name, a 32-bit unsigned integer representing the Parameter Group Number (PGN), and an 8-bit integer representing the address.

  • A string or a tuple

    # Echo server program
    import socket
    
    HOST = ''                 # Symbolic name meaning all available interfaces
    PORT = 50007              # Arbitrary non-privileged port
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.bind((HOST, PORT))
        s.listen(1)
        conn, addr = s.accept()
        with conn:
            print('Connected by', addr)
            while True:
                data = conn.recv(1024)
                if not data: break
                conn.sendall(data)
    
    3 is used for the
    # Echo server program
    import socket
    
    HOST = ''                 # Symbolic name meaning all available interfaces
    PORT = 50007              # Arbitrary non-privileged port
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.bind((HOST, PORT))
        s.listen(1)
        conn, addr = s.accept()
        with conn:
            print('Connected by', addr)
            while True:
                data = conn.recv(1024)
                if not data: break
                conn.sendall(data)
    
    4 protocol of the
    # Echo server program
    import socket
    
    HOST = ''                 # Symbolic name meaning all available interfaces
    PORT = 50007              # Arbitrary non-privileged port
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.bind((HOST, PORT))
        s.listen(1)
        conn, addr = s.accept()
        with conn:
            print('Connected by', addr)
            while True:
                data = conn.recv(1024)
                if not data: break
                conn.sendall(data)
    
    5 family. The string is the name of a kernel control using a dynamically assigned ID. The tuple can be used if ID and unit number of the kernel control are known or if a registered ID is used.

    New in version 3.3.

  • # Echo server program
    import socket
    
    HOST = ''                 # Symbolic name meaning all available interfaces
    PORT = 50007              # Arbitrary non-privileged port
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.bind((HOST, PORT))
        s.listen(1)
        conn, addr = s.accept()
        with conn:
            print('Connected by', addr)
            while True:
                data = conn.recv(1024)
                if not data: break
                conn.sendall(data)
    
    6 supports the following protocols and address formats:

    • # Echo server program
      import socket
      
      HOST = ''                 # Symbolic name meaning all available interfaces
      PORT = 50007              # Arbitrary non-privileged port
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.bind((HOST, PORT))
          s.listen(1)
          conn, addr = s.accept()
          with conn:
              print('Connected by', addr)
              while True:
                  data = conn.recv(1024)
                  if not data: break
                  conn.sendall(data)
      
      7 accepts
      # Echo server program
      import socket
      
      HOST = ''                 # Symbolic name meaning all available interfaces
      PORT = 50007              # Arbitrary non-privileged port
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.bind((HOST, PORT))
          s.listen(1)
          conn, addr = s.accept()
          with conn:
              print('Connected by', addr)
              while True:
                  data = conn.recv(1024)
                  if not data: break
                  conn.sendall(data)
      
      8 where
      # Echo server program
      import socket
      
      HOST = ''                 # Symbolic name meaning all available interfaces
      PORT = 50007              # Arbitrary non-privileged port
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.bind((HOST, PORT))
          s.listen(1)
          conn, addr = s.accept()
          with conn:
              print('Connected by', addr)
              while True:
                  data = conn.recv(1024)
                  if not data: break
                  conn.sendall(data)
      
      9 is the Bluetooth address as a string and
      # Echo client program
      import socket
      
      HOST = 'daring.cwi.nl'    # The remote host
      PORT = 50007              # The same port as used by the server
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.connect((HOST, PORT))
          s.sendall(b'Hello, world')
          data = s.recv(1024)
      print('Received', repr(data))
      
      0 is an integer.

    • # Echo client program
      import socket
      
      HOST = 'daring.cwi.nl'    # The remote host
      PORT = 50007              # The same port as used by the server
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.connect((HOST, PORT))
          s.sendall(b'Hello, world')
          data = s.recv(1024)
      print('Received', repr(data))
      
      1 accepts
      # Echo client program
      import socket
      
      HOST = 'daring.cwi.nl'    # The remote host
      PORT = 50007              # The same port as used by the server
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.connect((HOST, PORT))
          s.sendall(b'Hello, world')
          data = s.recv(1024)
      print('Received', repr(data))
      
      2 where
      # Echo server program
      import socket
      
      HOST = ''                 # Symbolic name meaning all available interfaces
      PORT = 50007              # Arbitrary non-privileged port
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.bind((HOST, PORT))
          s.listen(1)
          conn, addr = s.accept()
          with conn:
              print('Connected by', addr)
              while True:
                  data = conn.recv(1024)
                  if not data: break
                  conn.sendall(data)
      
      9 is the Bluetooth address as a string and
      # Echo client program
      import socket
      
      HOST = 'daring.cwi.nl'    # The remote host
      PORT = 50007              # The same port as used by the server
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.connect((HOST, PORT))
          s.sendall(b'Hello, world')
          data = s.recv(1024)
      print('Received', repr(data))
      
      4 is an integer.

    • # Echo client program
      import socket
      
      HOST = 'daring.cwi.nl'    # The remote host
      PORT = 50007              # The same port as used by the server
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.connect((HOST, PORT))
          s.sendall(b'Hello, world')
          data = s.recv(1024)
      print('Received', repr(data))
      
      5 accepts
      # Echo client program
      import socket
      
      HOST = 'daring.cwi.nl'    # The remote host
      PORT = 50007              # The same port as used by the server
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.connect((HOST, PORT))
          s.sendall(b'Hello, world')
          data = s.recv(1024)
      print('Received', repr(data))
      
      6 where
      # Echo client program
      import socket
      
      HOST = 'daring.cwi.nl'    # The remote host
      PORT = 50007              # The same port as used by the server
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.connect((HOST, PORT))
          s.sendall(b'Hello, world')
          data = s.recv(1024)
      print('Received', repr(data))
      
      7 is either an integer or a string with the Bluetooth address of the interface. (This depends on your OS; NetBSD and DragonFlyBSD expect a Bluetooth address while everything else expects an integer.)

      Changed in version 3.2: NetBSD and DragonFlyBSD support added.

    • # Echo client program
      import socket
      
      HOST = 'daring.cwi.nl'    # The remote host
      PORT = 50007              # The same port as used by the server
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.connect((HOST, PORT))
          s.sendall(b'Hello, world')
          data = s.recv(1024)
      print('Received', repr(data))
      
      8 accepts
      # Echo server program
      import socket
      
      HOST = ''                 # Symbolic name meaning all available interfaces
      PORT = 50007              # Arbitrary non-privileged port
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.bind((HOST, PORT))
          s.listen(1)
          conn, addr = s.accept()
          with conn:
              print('Connected by', addr)
              while True:
                  data = conn.recv(1024)
                  if not data: break
                  conn.sendall(data)
      
      9 where
      # Echo server program
      import socket
      
      HOST = ''                 # Symbolic name meaning all available interfaces
      PORT = 50007              # Arbitrary non-privileged port
      with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
          s.bind((HOST, PORT))
          s.listen(1)
          conn, addr = s.accept()
          with conn:
              print('Connected by', addr)
              while True:
                  data = conn.recv(1024)
                  if not data: break
                  conn.sendall(data)
      
      9 is a object containing the Bluetooth address in a string format. (ex.
      # Echo server program
      import socket
      import sys
      
      HOST = None               # Symbolic name meaning all available interfaces
      PORT = 50007              # Arbitrary non-privileged port
      s = None
      for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC,
                                    socket.SOCK_STREAM, 0, socket.AI_PASSIVE):
          af, socktype, proto, canonname, sa = res
          try:
              s = socket.socket(af, socktype, proto)
          except OSError as msg:
              s = None
              continue
          try:
              s.bind(sa)
              s.listen(1)
          except OSError as msg:
              s.close()
              s = None
              continue
          break
      if s is None:
          print('could not open socket')
          sys.exit(1)
      conn, addr = s.accept()
      with conn:
          print('Connected by', addr)
          while True:
              data = conn.recv(1024)
              if not data: break
              conn.send(data)
      
      2) This protocol is not supported under FreeBSD.

  • is a Linux-only socket based interface to Kernel cryptography. An algorithm socket is configured with a tuple of two to four elements

    # Echo server program
    import socket
    import sys
    
    HOST = None               # Symbolic name meaning all available interfaces
    PORT = 50007              # Arbitrary non-privileged port
    s = None
    for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC,
                                  socket.SOCK_STREAM, 0, socket.AI_PASSIVE):
        af, socktype, proto, canonname, sa = res
        try:
            s = socket.socket(af, socktype, proto)
        except OSError as msg:
            s = None
            continue
        try:
            s.bind(sa)
            s.listen(1)
        except OSError as msg:
            s.close()
            s = None
            continue
        break
    if s is None:
        print('could not open socket')
        sys.exit(1)
    conn, addr = s.accept()
    with conn:
        print('Connected by', addr)
        while True:
            data = conn.recv(1024)
            if not data: break
            conn.send(data)
    
    4, where:

    • type is the algorithm type as string, e.g.

      # Echo server program
      import socket
      import sys
      
      HOST = None               # Symbolic name meaning all available interfaces
      PORT = 50007              # Arbitrary non-privileged port
      s = None
      for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC,
                                    socket.SOCK_STREAM, 0, socket.AI_PASSIVE):
          af, socktype, proto, canonname, sa = res
          try:
              s = socket.socket(af, socktype, proto)
          except OSError as msg:
              s = None
              continue
          try:
              s.bind(sa)
              s.listen(1)
          except OSError as msg:
              s.close()
              s = None
              continue
          break
      if s is None:
          print('could not open socket')
          sys.exit(1)
      conn, addr = s.accept()
      with conn:
          print('Connected by', addr)
          while True:
              data = conn.recv(1024)
              if not data: break
              conn.send(data)
      
      5,
      # Echo server program
      import socket
      import sys
      
      HOST = None               # Symbolic name meaning all available interfaces
      PORT = 50007              # Arbitrary non-privileged port
      s = None
      for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC,
                                    socket.SOCK_STREAM, 0, socket.AI_PASSIVE):
          af, socktype, proto, canonname, sa = res
          try:
              s = socket.socket(af, socktype, proto)
          except OSError as msg:
              s = None
              continue
          try:
              s.bind(sa)
              s.listen(1)
          except OSError as msg:
              s.close()
              s = None
              continue
          break
      if s is None:
          print('could not open socket')
          sys.exit(1)
      conn, addr = s.accept()
      with conn:
          print('Connected by', addr)
          while True:
              data = conn.recv(1024)
              if not data: break
              conn.send(data)
      
      6,
      # Echo server program
      import socket
      import sys
      
      HOST = None               # Symbolic name meaning all available interfaces
      PORT = 50007              # Arbitrary non-privileged port
      s = None
      for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC,
                                    socket.SOCK_STREAM, 0, socket.AI_PASSIVE):
          af, socktype, proto, canonname, sa = res
          try:
              s = socket.socket(af, socktype, proto)
          except OSError as msg:
              s = None
              continue
          try:
              s.bind(sa)
              s.listen(1)
          except OSError as msg:
              s.close()
              s = None
              continue
          break
      if s is None:
          print('could not open socket')
          sys.exit(1)
      conn, addr = s.accept()
      with conn:
          print('Connected by', addr)
          while True:
              data = conn.recv(1024)
              if not data: break
              conn.send(data)
      
      7 or
      # Echo server program
      import socket
      import sys
      
      HOST = None               # Symbolic name meaning all available interfaces
      PORT = 50007              # Arbitrary non-privileged port
      s = None
      for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC,
                                    socket.SOCK_STREAM, 0, socket.AI_PASSIVE):
          af, socktype, proto, canonname, sa = res
          try:
              s = socket.socket(af, socktype, proto)
          except OSError as msg:
              s = None
              continue
          try:
              s.bind(sa)
              s.listen(1)
          except OSError as msg:
              s.close()
              s = None
              continue
          break
      if s is None:
          print('could not open socket')
          sys.exit(1)
      conn, addr = s.accept()
      with conn:
          print('Connected by', addr)
          while True:
              data = conn.recv(1024)
              if not data: break
              conn.send(data)
      
      8.

    • name is the algorithm name and operation mode as string, e.g.

      # Echo server program
      import socket
      import sys
      
      HOST = None               # Symbolic name meaning all available interfaces
      PORT = 50007              # Arbitrary non-privileged port
      s = None
      for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC,
                                    socket.SOCK_STREAM, 0, socket.AI_PASSIVE):
          af, socktype, proto, canonname, sa = res
          try:
              s = socket.socket(af, socktype, proto)
          except OSError as msg:
              s = None
              continue
          try:
              s.bind(sa)
              s.listen(1)
          except OSError as msg:
              s.close()
              s = None
              continue
          break
      if s is None:
          print('could not open socket')
          sys.exit(1)
      conn, addr = s.accept()
      with conn:
          print('Connected by', addr)
          while True:
              data = conn.recv(1024)
              if not data: break
              conn.send(data)
      
      9,
      # Echo client program
      import socket
      import sys
      
      HOST = 'daring.cwi.nl'    # The remote host
      PORT = 50007              # The same port as used by the server
      s = None
      for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC, socket.SOCK_STREAM):
          af, socktype, proto, canonname, sa = res
          try:
              s = socket.socket(af, socktype, proto)
          except OSError as msg:
              s = None
              continue
          try:
              s.connect(sa)
          except OSError as msg:
              s.close()
              s = None
              continue
          break
      if s is None:
          print('could not open socket')
          sys.exit(1)
      with s:
          s.sendall(b'Hello, world')
          data = s.recv(1024)
      print('Received', repr(data))
      
      0,
      # Echo client program
      import socket
      import sys
      
      HOST = 'daring.cwi.nl'    # The remote host
      PORT = 50007              # The same port as used by the server
      s = None
      for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC, socket.SOCK_STREAM):
          af, socktype, proto, canonname, sa = res
          try:
              s = socket.socket(af, socktype, proto)
          except OSError as msg:
              s = None
              continue
          try:
              s.connect(sa)
          except OSError as msg:
              s.close()
              s = None
              continue
          break
      if s is None:
          print('could not open socket')
          sys.exit(1)
      with s:
          s.sendall(b'Hello, world')
          data = s.recv(1024)
      print('Received', repr(data))
      
      1 or
      # Echo client program
      import socket
      import sys
      
      HOST = 'daring.cwi.nl'    # The remote host
      PORT = 50007              # The same port as used by the server
      s = None
      for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC, socket.SOCK_STREAM):
          af, socktype, proto, canonname, sa = res
          try:
              s = socket.socket(af, socktype, proto)
          except OSError as msg:
              s = None
              continue
          try:
              s.connect(sa)
          except OSError as msg:
              s.close()
              s = None
              continue
          break
      if s is None:
          print('could not open socket')
          sys.exit(1)
      with s:
          s.sendall(b'Hello, world')
          data = s.recv(1024)
      print('Received', repr(data))
      
      2.

    • feat and mask are unsigned 32bit integers.

    : Linux >= 2.6.38.

    Some algorithm types require more recent Kernels.

    New in version 3.6.

  • allows communication between virtual machines and their hosts. The sockets are represented as a

    # Echo client program
    import socket
    import sys
    
    HOST = 'daring.cwi.nl'    # The remote host
    PORT = 50007              # The same port as used by the server
    s = None
    for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC, socket.SOCK_STREAM):
        af, socktype, proto, canonname, sa = res
        try:
            s = socket.socket(af, socktype, proto)
        except OSError as msg:
            s = None
            continue
        try:
            s.connect(sa)
        except OSError as msg:
            s.close()
            s = None
            continue
        break
    if s is None:
        print('could not open socket')
        sys.exit(1)
    with s:
        s.sendall(b'Hello, world')
        data = s.recv(1024)
    print('Received', repr(data))
    
    4 tuple where the context ID or CID and port are integers.

    : Linux >= 3.9

    See vsock(7)

    New in version 3.7.

  • is a low-level interface directly to network devices. The packets are represented by the tuple

    # Echo client program
    import socket
    import sys
    
    HOST = 'daring.cwi.nl'    # The remote host
    PORT = 50007              # The same port as used by the server
    s = None
    for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC, socket.SOCK_STREAM):
        af, socktype, proto, canonname, sa = res
        try:
            s = socket.socket(af, socktype, proto)
        except OSError as msg:
            s = None
            continue
        try:
            s.connect(sa)
        except OSError as msg:
            s.close()
            s = None
            continue
        break
    if s is None:
        print('could not open socket')
        sys.exit(1)
    with s:
        s.sendall(b'Hello, world')
        data = s.recv(1024)
    print('Received', repr(data))
    
    6 where:

    • ifname - String specifying the device name.

    • proto - An in network-byte-order integer specifying the Ethernet protocol number.

    • pkttype - Optional integer specifying the packet type:

      • # Echo client program
        import socket
        import sys
        
        HOST = 'daring.cwi.nl'    # The remote host
        PORT = 50007              # The same port as used by the server
        s = None
        for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC, socket.SOCK_STREAM):
            af, socktype, proto, canonname, sa = res
            try:
                s = socket.socket(af, socktype, proto)
            except OSError as msg:
                s = None
                continue
            try:
                s.connect(sa)
            except OSError as msg:
                s.close()
                s = None
                continue
            break
        if s is None:
            print('could not open socket')
            sys.exit(1)
        with s:
            s.sendall(b'Hello, world')
            data = s.recv(1024)
        print('Received', repr(data))
        
        7 (the default) - Packet addressed to the local host.

      • # Echo client program
        import socket
        import sys
        
        HOST = 'daring.cwi.nl'    # The remote host
        PORT = 50007              # The same port as used by the server
        s = None
        for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC, socket.SOCK_STREAM):
            af, socktype, proto, canonname, sa = res
            try:
                s = socket.socket(af, socktype, proto)
            except OSError as msg:
                s = None
                continue
            try:
                s.connect(sa)
            except OSError as msg:
                s.close()
                s = None
                continue
            break
        if s is None:
            print('could not open socket')
            sys.exit(1)
        with s:
            s.sendall(b'Hello, world')
            data = s.recv(1024)
        print('Received', repr(data))
        
        8 - Physical-layer broadcast packet.

      • # Echo client program
        import socket
        import sys
        
        HOST = 'daring.cwi.nl'    # The remote host
        PORT = 50007              # The same port as used by the server
        s = None
        for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC, socket.SOCK_STREAM):
            af, socktype, proto, canonname, sa = res
            try:
                s = socket.socket(af, socktype, proto)
            except OSError as msg:
                s = None
                continue
            try:
                s.connect(sa)
            except OSError as msg:
                s.close()
                s = None
                continue
            break
        if s is None:
            print('could not open socket')
            sys.exit(1)
        with s:
            s.sendall(b'Hello, world')
            data = s.recv(1024)
        print('Received', repr(data))
        
        9 - Packet sent to a physical-layer multicast address.

      • import socket
        
        addr = ("", 8080)  # all interfaces, port 8080
        if socket.has_dualstack_ipv6():
            s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
        else:
            s = socket.create_server(addr)
        
        00 - Packet to some other host that has been caught by a device driver in promiscuous mode.

      • import socket
        
        addr = ("", 8080)  # all interfaces, port 8080
        if socket.has_dualstack_ipv6():
            s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
        else:
            s = socket.create_server(addr)
        
        01 - Packet originating from the local host that is looped back to a packet socket.

    • hatype - Optional integer specifying the ARP hardware address type.

    • addr - Optional bytes-like object specifying the hardware physical address, whose interpretation depends on the device.

    : Linux >= 2.2.

  • is a Linux-only socket based interface for communicating with services running on co-processors in Qualcomm platforms. The address family is represented as a

    import socket
    
    addr = ("", 8080)  # all interfaces, port 8080
    if socket.has_dualstack_ipv6():
        s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
    else:
        s = socket.create_server(addr)
    
    03 tuple where the node and port are non-negative integers.

    : Linux >= 4.7.

    New in version 3.8.

  • import socket
    
    addr = ("", 8080)  # all interfaces, port 8080
    if socket.has_dualstack_ipv6():
        s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
    else:
        s = socket.create_server(addr)
    
    04 is a variant of UDP which allows you to specify what portion of a packet is covered with the checksum. It adds two socket options that you can change.
    import socket
    
    addr = ("", 8080)  # all interfaces, port 8080
    if socket.has_dualstack_ipv6():
        s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
    else:
        s = socket.create_server(addr)
    
    05 will change what portion of outgoing packets are covered by the checksum and
    import socket
    
    addr = ("", 8080)  # all interfaces, port 8080
    if socket.has_dualstack_ipv6():
        s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
    else:
        s = socket.create_server(addr)
    
    06 will filter out packets which cover too little of their data. In both cases
    import socket
    
    addr = ("", 8080)  # all interfaces, port 8080
    if socket.has_dualstack_ipv6():
        s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
    else:
        s = socket.create_server(addr)
    
    07 should be in
    import socket
    
    addr = ("", 8080)  # all interfaces, port 8080
    if socket.has_dualstack_ipv6():
        s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
    else:
        s = socket.create_server(addr)
    
    08.

    Such a socket should be constructed with

    import socket
    
    addr = ("", 8080)  # all interfaces, port 8080
    if socket.has_dualstack_ipv6():
        s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
    else:
        s = socket.create_server(addr)
    
    09 for IPv4 or
    import socket
    
    addr = ("", 8080)  # all interfaces, port 8080
    if socket.has_dualstack_ipv6():
        s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
    else:
        s = socket.create_server(addr)
    
    10 for IPv6.

    : Linux >= 2.6.20, FreeBSD >= 10.1

    New in version 3.9.

If you use a hostname in the host portion of IPv4/v6 socket address, the program may show a nondeterministic behavior, as Python uses the first address returned from the DNS resolution. The socket address will be resolved differently into an actual IPv4/v6 address, depending on the results from DNS resolution and/or the host configuration. For deterministic behavior use a numeric address in host portion.

All errors raise exceptions. The normal exceptions for invalid argument types and out-of-memory conditions can be raised. Errors related to socket or address semantics raise or one of its subclasses.

Non-blocking mode is supported through . A generalization of this based on timeouts is supported through .

Module contents

The module exports the following elements.

Exceptions

exception socket.error

A deprecated alias of .

Changed in version 3.3: Following PEP 3151, this class was made an alias of .

exception socket.herror

A subclass of , this exception is raised for address-related errors, i.e. for functions that use h_errno in the POSIX C API, including and . The accompanying value is a pair

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
20 representing an error returned by a library call. h_errno is a numeric value, while string represents the description of h_errno, as returned by the
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
21 C function.

Changed in version 3.3: This class was made a subclass of .

exception socket.gaierror

A subclass of , this exception is raised for address-related errors by and . The accompanying value is a pair

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
26 representing an error returned by a library call. string represents the description of error, as returned by the
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
27 C function. The numeric error value will match one of the
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
28 constants defined in this module.

Changed in version 3.3: This class was made a subclass of .

exception socket.timeout

A deprecated alias of .

A subclass of , this exception is raised when a timeout occurs on a socket which has had timeouts enabled via a prior call to (or implicitly through ). The accompanying value is a string whose value is currently always “timed out”.

Changed in version 3.3: This class was made a subclass of .

Changed in version 3.10: This class was made an alias of .

Constants

The AF_* and SOCK_* constants are now

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
36 and
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
37 collections.

New in version 3.4.

socket.AF_UNIXsocket.AF_INETsocket.AF_INET6

These constants represent the address (and protocol) families, used for the first argument to

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
8. If the constant is not defined then this protocol is unsupported. More constants may be available depending on the system.

socket.SOCK_STREAMsocket.SOCK_DGRAMsocket.SOCK_RAWsocket.SOCK_RDMsocket.SOCK_SEQPACKET

These constants represent the socket types, used for the second argument to

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
8. More constants may be available depending on the system. (Only and appear to be generally useful.)

socket.SOCK_CLOEXECsocket.SOCK_NONBLOCK

These two constants, if defined, can be combined with the socket types and allow you to set some flags atomically (thus avoiding possible race conditions and the need for separate calls).

See also

Secure File Descriptor Handling for a more thorough explanation.

: Linux >= 2.6.27.

New in version 3.2.

SO_*socket.SOMAXCONNMSG_*SOL_*SCM_*IPPROTO_*IPPORT_*INADDR_*IP_*IPV6_*EAI_*AI_*NI_*TCP_*

Many constants of these forms, documented in the Unix documentation on sockets and/or the IP protocol, are also defined in the socket module. They are generally used in arguments to the

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
44 and
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
45 methods of socket objects. In most cases, only those symbols that are defined in the Unix header files are defined; for a few symbols, default values are provided.

Changed in version 3.6:

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
46,
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
47,
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
48,
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
49,
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
50,
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
51 were added.

Changed in version 3.6.5: On Windows,

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
52,
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
53 appear if run-time Windows supports.

Changed in version 3.7:

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
54 was added.

On Windows,

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
55,
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
56 appear if run-time Windows supports.

Changed in version 3.10:

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
57 was added. Added
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
58. On MacOS this constant can be used in the same way that
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
55 is used on Linux.

Changed in version 3.11: Added

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
60. On MacOS this constant can be used in the same way that
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
61 is used on Linux and BSD.

socket.AF_CANsocket.PF_CANSOL_CAN_*CAN_*

Many constants of these forms, documented in the Linux documentation, are also defined in the socket module.

: Linux >= 2.6.25, NetBSD >= 8.

New in version 3.3.

Changed in version 3.11: NetBSD support was added.

socket.CAN_BCMCAN_BCM_*

CAN_BCM, in the CAN protocol family, is the broadcast manager (BCM) protocol. Broadcast manager constants, documented in the Linux documentation, are also defined in the socket module.

: Linux >= 2.6.25.

Note

The

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
62 flag is only available on Linux >= 4.8.

New in version 3.4.

socket.CAN_RAW_FD_FRAMES

Enables CAN FD support in a CAN_RAW socket. This is disabled by default. This allows your application to send both CAN and CAN FD frames; however, you must accept both CAN and CAN FD frames when reading from the socket.

This constant is documented in the Linux documentation.

: Linux >= 3.6.

New in version 3.5.

socket.CAN_RAW_JOIN_FILTERS

Joins the applied CAN filters such that only CAN frames that match all given CAN filters are passed to user space.

This constant is documented in the Linux documentation.

: Linux >= 4.1.

New in version 3.9.

socket.CAN_ISOTP

CAN_ISOTP, in the CAN protocol family, is the ISO-TP (ISO 15765-2) protocol. ISO-TP constants, documented in the Linux documentation.

: Linux >= 2.6.25.

New in version 3.7.

socket.CAN_J1939

CAN_J1939, in the CAN protocol family, is the SAE J1939 protocol. J1939 constants, documented in the Linux documentation.

: Linux >= 5.4.

New in version 3.9.

socket.AF_PACKETsocket.PF_PACKETPACKET_*

Many constants of these forms, documented in the Linux documentation, are also defined in the socket module.

: Linux >= 2.2.

socket.AF_RDSsocket.PF_RDSsocket.SOL_RDSRDS_*

Many constants of these forms, documented in the Linux documentation, are also defined in the socket module.

: Linux >= 2.6.30.

New in version 3.3.

socket.SIO_RCVALLsocket.SIO_KEEPALIVE_VALSsocket.SIO_LOOPBACK_FAST_PATHRCVALL_*

Constants for Windows’ WSAIoctl(). The constants are used as arguments to the method of socket objects.

Changed in version 3.6:

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
64 was added.

TIPC_*

TIPC related constants, matching the ones exported by the C socket API. See the TIPC documentation for more information.

socket.AF_ALGsocket.SOL_ALGALG_*

Constants for Linux Kernel cryptography.

: Linux >= 2.6.38.

New in version 3.6.

socket.AF_VSOCKsocket.IOCTL_VM_SOCKETS_GET_LOCAL_CIDVMADDR*SO_VM*

Constants for Linux host/guest communication.

: Linux >= 4.8.

New in version 3.7.

socket.AF_LINK

: BSD, macOS.

New in version 3.4.

socket.has_ipv6

This constant contains a boolean value which indicates if IPv6 is supported on this platform.

socket.BDADDR_ANYsocket.BDADDR_LOCAL

These are string constants containing Bluetooth addresses with special meanings. For example, can be used to indicate any address when specifying the binding socket with

# Echo client program
import socket

HOST = 'daring.cwi.nl'    # The remote host
PORT = 50007              # The same port as used by the server
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.connect((HOST, PORT))
    s.sendall(b'Hello, world')
    data = s.recv(1024)
print('Received', repr(data))
1.

socket.HCI_FILTERsocket.HCI_TIME_STAMPsocket.HCI_DATA_DIR

For use with

# Echo client program
import socket

HOST = 'daring.cwi.nl'    # The remote host
PORT = 50007              # The same port as used by the server
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.connect((HOST, PORT))
    s.sendall(b'Hello, world')
    data = s.recv(1024)
print('Received', repr(data))
5. is not available for NetBSD or DragonFlyBSD. and are not available for FreeBSD, NetBSD, or DragonFlyBSD.

socket.AF_QIPCRTR

Constant for Qualcomm’s IPC router protocol, used to communicate with service providing remote processors.

: Linux >= 4.7.

socket.SCM_CREDS2socket.LOCAL_CREDSsocket.LOCAL_CREDS_PERSISTENT

LOCAL_CREDS and LOCAL_CREDS_PERSISTENT can be used with SOCK_DGRAM, SOCK_STREAM sockets, equivalent to Linux/DragonFlyBSD SO_PASSCRED, while LOCAL_CREDS sends the credentials at first read, LOCAL_CREDS_PERSISTENT sends for each read, SCM_CREDS2 must be then used for the latter for the message type.

New in version 3.11.

: FreeBSD.

socket.SO_INCOMING_CPU

Constant to optimize CPU locality, to be used in conjunction with

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
71.

New in version 3.11.

: Linux >= 3.9

Functions

Creating sockets

The following functions all create .

class socket.socket(family=AF_INET, type=SOCK_STREAM, proto=0, fileno=None)

Create a new socket using the given address family, socket type and protocol number. The address family should be (the default), , , , , or . The socket type should be (the default), , or perhaps one of the other

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
81 constants. The protocol number is usually zero and may be omitted or in the case where the address family is the protocol should be one of
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
83, , or .

If fileno is specified, the values for family, type, and proto are auto-detected from the specified file descriptor. Auto-detection can be overruled by calling the function with explicit family, type, or proto arguments. This only affects how Python represents e.g. the return value of but not the actual OS resource. Unlike , fileno will return the same socket and not a duplicate. This may help close a detached socket using .

The newly created socket is .

Raises an

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
90 with arguments
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
91,
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
92,
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
93,
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
94.

Changed in version 3.3: The AF_CAN family was added. The AF_RDS family was added.

Changed in version 3.4: The CAN_BCM protocol was added.

Changed in version 3.4: The returned socket is now non-inheritable.

Changed in version 3.7: The CAN_ISOTP protocol was added.

Changed in version 3.7: When or bit flags are applied to type they are cleared, and will not reflect them. They are still passed to the underlying system

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
8 call. Therefore,

sock = socket.socket(
    socket.AF_INET,
    socket.SOCK_STREAM | socket.SOCK_NONBLOCK)

will still create a non-blocking socket on OSes that support

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
95, but
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
00 will be set to
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
01.

Changed in version 3.9: The CAN_J1939 protocol was added.

Changed in version 3.10: The IPPROTO_MPTCP protocol was added.

socket.socketpair([family[, type[, proto]]])

Build a pair of connected socket objects using the given address family, socket type, and protocol number. Address family, socket type, and protocol number are as for the

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
8 function above. The default family is if defined on the platform; otherwise, the default is .

The newly created sockets are .

Changed in version 3.2: The returned socket objects now support the whole socket API, rather than a subset.

Changed in version 3.4: The returned sockets are now non-inheritable.

Changed in version 3.5: Windows support added.

socket.create_connection(address, timeout=GLOBAL_DEFAULT, source_address=None, *, all_errors=False)

Connect to a TCP service listening on the internet address (a 2-tuple

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
6), and return the socket object. This is a higher-level function than : if host is a non-numeric hostname, it will try to resolve it for both and , and then try to connect to all possible addresses in turn until a connection succeeds. This makes it easy to write clients that are compatible to both IPv4 and IPv6.

Passing the optional timeout parameter will set the timeout on the socket instance before attempting to connect. If no timeout is supplied, the global default timeout setting returned by is used.

If supplied, source_address must be a 2-tuple

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
6 for the socket to bind to as its source address before connecting. If host or port are ‘’ or 0 respectively the OS default behavior will be used.

When a connection cannot be created, an exception is raised. By default, it is the exception from the last address in the list. If all_errors is

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
11, it is an containing the errors of all attempts.

Changed in version 3.2: source_address was added.

Changed in version 3.11: all_errors was added.

socket.create_server(address, *, family=AF_INET, backlog=None, reuse_port=False, dualstack_ipv6=False)

Convenience function which creates a TCP socket bound to address (a 2-tuple

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
6) and return the socket object.

family should be either or . backlog is the queue size passed to ; if not specified , a default reasonable value is chosen. reuse_port dictates whether to set the

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
71 socket option.

If dualstack_ipv6 is true and the platform supports it the socket will be able to accept both IPv4 and IPv6 connections, else it will raise . Most POSIX platforms and Windows are supposed to support this functionality. When this functionality is enabled the address returned by when an IPv4 connection occurs will be an IPv6 address represented as an IPv4-mapped IPv6 address. If dualstack_ipv6 is false it will explicitly disable this functionality on platforms that enable it by default (e.g. Linux). This parameter can be used in conjunction with :

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)

Note

On POSIX platforms the

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
21 socket option is set in order to immediately reuse previous sockets which were bound on the same address and remained in TIME_WAIT state.

New in version 3.8.

socket.has_dualstack_ipv6()

Return

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
11 if the platform supports creating a TCP socket which can handle both IPv4 and IPv6 connections.

New in version 3.8.

socket.fromfd(fd, family, type, proto=0)

Duplicate the file descriptor fd (an integer as returned by a file object’s

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
23 method) and build a socket object from the result. Address family, socket type and protocol number are as for the
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
8 function above. The file descriptor should refer to a socket, but this is not checked — subsequent operations on the object may fail if the file descriptor is invalid. This function is rarely needed, but can be used to get or set socket options on a socket passed to a program as standard input or output (such as a server started by the Unix inet daemon). The socket is assumed to be in blocking mode.

The newly created socket is .

Changed in version 3.4: The returned socket is now non-inheritable.

socket.fromshare(data)

Instantiate a socket from data obtained from the method. The socket is assumed to be in blocking mode.

: Windows.

New in version 3.3.

socket.SocketType

This is a Python type object that represents the socket object type. It is the same as

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
26.

Other functions

The module also offers various network-related services:

socket.close(fd)

Close a socket file descriptor. This is like , but for sockets. On some platforms (most noticeable Windows) does not work for socket file descriptors.

New in version 3.7.

socket.getaddrinfo(host, port, family=0, type=0, proto=0, flags=0)

Translate the host/port argument into a sequence of 5-tuples that contain all the necessary arguments for creating a socket connected to that service. host is a domain name, a string representation of an IPv4/v6 address or

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
30. port is a string service name such as
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
31, a numeric port number or
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
30. By passing
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
30 as the value of host and port, you can pass
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
34 to the underlying C API.

The family, type and proto arguments can be optionally specified in order to narrow the list of addresses returned. Passing zero as a value for each of these arguments selects the full range of results. The flags argument can be one or several of the

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
35 constants, and will influence how results are computed and returned. For example,
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
36 will disable domain name resolution and will raise an error if host is a domain name.

The function returns a list of 5-tuples with the following structure:

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
37

In these tuples, family, type, proto are all integers and are meant to be passed to the

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
8 function. canonname will be a string representing the canonical name of the host if
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
39 is part of the flags argument; else canonname will be empty. sockaddr is a tuple describing a socket address, whose format depends on the returned family (a
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
40 2-tuple for , a
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
42 4-tuple for ), and is meant to be passed to the method.

Raises an

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
45 with arguments
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
46,
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
47,
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
92,
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
93,
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
94.

The following example fetches address information for a hypothetical TCP connection to

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
51 on port 80 (results may differ on your system if IPv6 isn’t enabled):

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]

Changed in version 3.2: parameters can now be passed using keyword arguments.

Changed in version 3.7: for IPv6 multicast addresses, string representing an address will not contain

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
0 part.

socket.getfqdn([name])

Return a fully qualified domain name for name. If name is omitted or empty, it is interpreted as the local host. To find the fully qualified name, the hostname returned by is checked, followed by aliases for the host, if available. The first name which includes a period is selected. In case no fully qualified domain name is available and name was provided, it is returned unchanged. If name was empty or equal to

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
54, the hostname from is returned.

socket.gethostbyname(hostname)

Translate a host name to IPv4 address format. The IPv4 address is returned as a string, such as

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
9. If the host name is an IPv4 address itself it is returned unchanged. See for a more complete interface. does not support IPv6 name resolution, and should be used instead for IPv4/v6 dual stack support.

Raises an

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
60 with argument
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
61.

: not WASI.

socket.gethostbyname_ex(hostname)

Translate a host name to IPv4 address format, extended interface. Return a triple

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
62 where hostname is the host’s primary host name, aliaslist is a (possibly empty) list of alternative host names for the same address, and ipaddrlist is a list of IPv4 addresses for the same interface on the same host (often but not always a single address). does not support IPv6 name resolution, and should be used instead for IPv4/v6 dual stack support.

Raises an

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
60 with argument
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
61.

: not WASI.

socket.gethostname()

Return a string containing the hostname of the machine where the Python interpreter is currently executing.

Raises an

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
67 with no arguments.

Note: doesn’t always return the fully qualified domain name; use for that.

: not WASI.

socket.gethostbyaddr(ip_address)

Return a triple

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
62 where hostname is the primary host name responding to the given ip_address, aliaslist is a (possibly empty) list of alternative host names for the same address, and ipaddrlist is a list of IPv4/v6 addresses for the same interface on the same host (most likely containing only a single address). To find the fully qualified domain name, use the function . supports both IPv4 and IPv6.

Raises an

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
73 with argument
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
74.

: not WASI.

socket.getnameinfo(sockaddr, flags)

Translate a socket address sockaddr into a 2-tuple

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
6. Depending on the settings of flags, the result can contain a fully qualified domain name or numeric address representation in host. Similarly, port can contain a string port name or a numeric port number.

For IPv6 addresses,

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
0 is appended to the host part if sockaddr contains meaningful scope_id. Usually this happens for multicast addresses.

For more information about flags you can consult getnameinfo(3).

Raises an

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
77 with argument
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
78.

: not WASI.

socket.getprotobyname(protocolname)

Translate an internet protocol name (for example,

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
79) to a constant suitable for passing as the (optional) third argument to the
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
8 function. This is usually only needed for sockets opened in “raw” mode (); for the normal socket modes, the correct protocol is chosen automatically if the protocol is omitted or zero.

: not WASI.

socket.getservbyname(servicename[, protocolname])

Translate an internet service name and protocol name to a port number for that service. The optional protocol name, if given, should be

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
82 or
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
83, otherwise any protocol will match.

Raises an

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
84 with arguments
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
85,
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
86.

: not WASI.

socket.getservbyport(port[, protocolname])

Translate an internet port number and protocol name to a service name for that service. The optional protocol name, if given, should be

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
82 or
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
83, otherwise any protocol will match.

Raises an

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
89 with arguments
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
47,
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
86.

: not WASI.

socket.ntohl(x)

Convert 32-bit positive integers from network to host byte order. On machines where the host byte order is the same as network byte order, this is a no-op; otherwise, it performs a 4-byte swap operation.

socket.ntohs(x)

Convert 16-bit positive integers from network to host byte order. On machines where the host byte order is the same as network byte order, this is a no-op; otherwise, it performs a 2-byte swap operation.

Changed in version 3.10: Raises if x does not fit in a 16-bit unsigned integer.

socket.htonl(x)

Convert 32-bit positive integers from host to network byte order. On machines where the host byte order is the same as network byte order, this is a no-op; otherwise, it performs a 4-byte swap operation.

socket.htons(x)

Convert 16-bit positive integers from host to network byte order. On machines where the host byte order is the same as network byte order, this is a no-op; otherwise, it performs a 2-byte swap operation.

Changed in version 3.10: Raises if x does not fit in a 16-bit unsigned integer.

socket.inet_aton(ip_string)

Convert an IPv4 address from dotted-quad string format (for example, ‘123.45.67.89’) to 32-bit packed binary format, as a bytes object four characters in length. This is useful when conversing with a program that uses the standard C library and needs objects of type

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
94, which is the C type for the 32-bit packed binary this function returns.

also accepts strings with less than three dots; see the Unix manual page inet(3) for details.

If the IPv4 address string passed to this function is invalid, will be raised. Note that exactly what is valid depends on the underlying C implementation of

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
95.

does not support IPv6, and should be used instead for IPv4/v6 dual stack support.

socket.inet_ntoa(packed_ip)

Convert a 32-bit packed IPv4 address (a four bytes in length) to its standard dotted-quad string representation (for example, ‘123.45.67.89’). This is useful when conversing with a program that uses the standard C library and needs objects of type

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
94, which is the C type for the 32-bit packed binary data this function takes as an argument.

If the byte sequence passed to this function is not exactly 4 bytes in length, will be raised. does not support IPv6, and should be used instead for IPv4/v6 dual stack support.

Changed in version 3.5: Writable is now accepted.

socket.inet_pton(address_family, ip_string)

Convert an IP address from its family-specific string format to a packed, binary format. is useful when a library or network protocol calls for an object of type

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
94 (similar to ) or
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
07.

Supported values for address_family are currently and . If the IP address string ip_string is invalid, will be raised. Note that exactly what is valid depends on both the value of address_family and the underlying implementation of

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
99.

: Unix, Windows.

Changed in version 3.4: Windows support added

socket.inet_ntop(address_family, packed_ip)

Convert a packed IP address (a of some number of bytes) to its standard, family-specific string representation (for example,

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
12 or
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
13). is useful when a library or network protocol returns an object of type
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
94 (similar to ) or
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
07.

Supported values for address_family are currently and . If the bytes object packed_ip is not the correct length for the specified address family, will be raised. is raised for errors from the call to .

: Unix, Windows.

Changed in version 3.4: Windows support added

Changed in version 3.5: Writable is now accepted.

socket.CMSG_LEN(length)

Return the total length, without trailing padding, of an ancillary data item with associated data of the given length. This value can often be used as the buffer size for to receive a single item of ancillary data, but RFC 3542 requires portable applications to use and thus include space for padding, even when the item will be the last in the buffer. Raises if length is outside the permissible range of values.

: Unix, not Emscripten, not WASI.

Most Unix platforms.

New in version 3.3.

socket.CMSG_SPACE(length)

Return the buffer size needed for to receive an ancillary data item with associated data of the given length, along with any trailing padding. The buffer space needed to receive multiple items is the sum of the values for their associated data lengths. Raises if length is outside the permissible range of values.

Note that some systems might support ancillary data without providing this function. Also note that setting the buffer size using the results of this function may not precisely limit the amount of ancillary data that can be received, since additional data may be able to fit into the padding area.

: Unix, not Emscripten, not WASI.

most Unix platforms.

New in version 3.3.

socket.getdefaulttimeout()

Return the default timeout in seconds (float) for new socket objects. A value of

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
30 indicates that new socket objects have no timeout. When the socket module is first imported, the default is
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
30.

socket.setdefaulttimeout(timeout)

Set the default timeout in seconds (float) for new socket objects. When the socket module is first imported, the default is

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
30. See for possible values and their respective meanings.

socket.sethostname(name)

Set the machine’s hostname to name. This will raise an if you don’t have enough rights.

Raises an

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
34 with argument
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
35.

: Unix.

New in version 3.3.

socket.if_nameindex()

Return a list of network interface information (index int, name string) tuples. if the system call fails.

: Unix, Windows, not Emscripten, not WASI.

New in version 3.3.

Changed in version 3.8: Windows support was added.

Note

On Windows network interfaces have different names in different contexts (all names are examples):

  • UUID:

    import socket, array
    
    def recv_fds(sock, msglen, maxfds):
        fds = array.array("i")   # Array of ints
        msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
        for cmsg_level, cmsg_type, cmsg_data in ancdata:
            if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
                # Append data, ignoring any truncated integers at the end.
                fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
        return msg, list(fds)
    
    37

  • name:

    import socket, array
    
    def recv_fds(sock, msglen, maxfds):
        fds = array.array("i")   # Array of ints
        msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
        for cmsg_level, cmsg_type, cmsg_data in ancdata:
            if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
                # Append data, ignoring any truncated integers at the end.
                fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
        return msg, list(fds)
    
    38

  • friendly name:

    import socket, array
    
    def recv_fds(sock, msglen, maxfds):
        fds = array.array("i")   # Array of ints
        msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
        for cmsg_level, cmsg_type, cmsg_data in ancdata:
            if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
                # Append data, ignoring any truncated integers at the end.
                fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
        return msg, list(fds)
    
    39

  • description:

    import socket, array
    
    def recv_fds(sock, msglen, maxfds):
        fds = array.array("i")   # Array of ints
        msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
        for cmsg_level, cmsg_type, cmsg_data in ancdata:
            if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
                # Append data, ignoring any truncated integers at the end.
                fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
        return msg, list(fds)
    
    40

This function returns names of the second form from the list,

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
38 in this example case.

socket.if_nametoindex(if_name)

Return a network interface index number corresponding to an interface name. if no interface with the given name exists.

: Unix, Windows, not Emscripten, not WASI.

New in version 3.3.

Changed in version 3.8: Windows support was added.

See also

“Interface name” is a name as documented in .

socket.if_indextoname(if_index)

Return a network interface name corresponding to an interface index number. if no interface with the given index exists.

: Unix, Windows, not Emscripten, not WASI.

New in version 3.3.

Changed in version 3.8: Windows support was added.

See also

“Interface name” is a name as documented in .

socket.send_fds(sock, buffers, fds[, flags[, address]])

Send the list of file descriptors fds over an socket sock. The fds parameter is a sequence of file descriptors. Consult

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
47 for the documentation of these parameters.

: Unix, Windows, not Emscripten, not WASI.

Unix platforms supporting and

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
49 mechanism.

New in version 3.9.

socket.recv_fds(sock, bufsize, maxfds[, flags])

Receive up to maxfds file descriptors from an socket sock. Return

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
51. Consult
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
23 for the documentation of these parameters.

: Unix, Windows, not Emscripten, not WASI.

Unix platforms supporting and

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
49 mechanism.

New in version 3.9.

Note

Any truncated integers at the end of the list of file descriptors.

Socket Objects

Socket objects have the following methods. Except for , these correspond to Unix system calls applicable to sockets.

Changed in version 3.2: Support for the protocol was added. Exiting the context manager is equivalent to calling .

socket.accept()

Accept a connection. The socket must be bound to an address and listening for connections. The return value is a pair

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
57 where conn is a new socket object usable to send and receive data on the connection, and address is the address bound to the socket on the other end of the connection.

The newly created socket is .

Changed in version 3.4: The socket is now non-inheritable.

Changed in version 3.5: If the system call is interrupted and the signal handler does not raise an exception, the method now retries the system call instead of raising an exception (see PEP 475 for the rationale).

socket.bind(address)

Bind the socket to address. The socket must not already be bound. (The format of address depends on the address family — see above.)

Raises an

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
59 with arguments
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
91,
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
61.

: not WASI.

socket.close()

Mark the socket closed. The underlying system resource (e.g. a file descriptor) is also closed when all file objects from are closed. Once that happens, all future operations on the socket object will fail. The remote end will receive no more data (after queued data is flushed).

Sockets are automatically closed when they are garbage-collected, but it is recommended to them explicitly, or to use a statement around them.

Changed in version 3.6: is now raised if an error occurs when the underlying

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
56 call is made.

Note

releases the resource associated with a connection but does not necessarily close the connection immediately. If you want to close the connection in a timely fashion, call before .

socket.connect(address)

Connect to a remote socket at address. (The format of address depends on the address family — see above.)

If the connection is interrupted by a signal, the method waits until the connection completes, or raise a on timeout, if the signal handler doesn’t raise an exception and the socket is blocking or has a timeout. For non-blocking sockets, the method raises an exception if the connection is interrupted by a signal (or the exception raised by the signal handler).

Raises an

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
72 with arguments
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
91,
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
61.

Changed in version 3.5: The method now waits until the connection completes instead of raising an exception if the connection is interrupted by a signal, the signal handler doesn’t raise an exception and the socket is blocking or has a timeout (see the PEP 475 for the rationale).

: not WASI.

socket.connect_ex(address)

Like

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
76, but return an error indicator instead of raising an exception for errors returned by the C-level
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
77 call (other problems, such as “host not found,” can still raise exceptions). The error indicator is
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
78 if the operation succeeded, otherwise the value of the
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
79 variable. This is useful to support, for example, asynchronous connects.

Raises an

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
72 with arguments
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
91,
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
61.

: not WASI.

socket.detach()

Put the socket object into closed state without actually closing the underlying file descriptor. The file descriptor is returned, and can be reused for other purposes.

New in version 3.2.

socket.dup()

Duplicate the socket.

The newly created socket is .

Changed in version 3.4: The socket is now non-inheritable.

: not WASI.

socket.fileno()

Return the socket’s file descriptor (a small integer), or -1 on failure. This is useful with .

Under Windows the small integer returned by this method cannot be used where a file descriptor can be used (such as ). Unix does not have this limitation.

socket.get_inheritable()

Get the of the socket’s file descriptor or socket’s handle:

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
11 if the socket can be inherited in child processes,
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
86 if it cannot.

New in version 3.4.

socket.getpeername()

Return the remote address to which the socket is connected. This is useful to find out the port number of a remote IPv4/v6 socket, for instance. (The format of the address returned depends on the address family — see above.) On some systems this function is not supported.

socket.getsockname()

Return the socket’s own address. This is useful to find out the port number of an IPv4/v6 socket, for instance. (The format of the address returned depends on the address family — see above.)

socket.getsockopt(level, optname[, buflen])

Return the value of the given socket option (see the Unix man page getsockopt(2)). The needed symbolic constants (

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
87 etc.) are defined in this module. If buflen is absent, an integer option is assumed and its integer value is returned by the function. If buflen is present, it specifies the maximum length of the buffer used to receive the option in, and this buffer is returned as a bytes object. It is up to the caller to decode the contents of the buffer (see the optional built-in module for a way to decode C structures encoded as byte strings).

: not WASI.

socket.getblocking()

Return

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
11 if socket is in blocking mode,
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
86 if in non-blocking.

This is equivalent to checking

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
91.

New in version 3.7.

socket.gettimeout()

Return the timeout in seconds (float) associated with socket operations, or

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
30 if no timeout is set. This reflects the last call to or .

socket.ioctl(control, option)Platform

Windows

The method is a limited interface to the WSAIoctl system interface. Please refer to the Win32 documentation for more information.

On other platforms, the generic and functions may be used; they accept a socket object as their first argument.

Currently only the following control codes are supported:

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
98,
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
99, and
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
64.

Changed in version 3.6:

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
64 was added.

socket.listen([backlog])

Enable a server to accept connections. If backlog is specified, it must be at least 0 (if it is lower, it is set to 0); it specifies the number of unaccepted connections that the system will allow before refusing new connections. If not specified, a default reasonable value is chosen.

: not WASI.

Changed in version 3.5: The backlog parameter is now optional.

socket.makefile(mode='r', buffering=None, *, encoding=None, errors=None, newline=None)

Return a associated with the socket. The exact returned type depends on the arguments given to . These arguments are interpreted the same way as by the built-in function, except the only supported mode values are

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
04 (default),
>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
05 and
>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
06.

The socket must be in blocking mode; it can have a timeout, but the file object’s internal buffer may end up in an inconsistent state if a timeout occurs.

Closing the file object returned by won’t close the original socket unless all other file objects have been closed and has been called on the socket object.

Note

On Windows, the file-like object created by cannot be used where a file object with a file descriptor is expected, such as the stream arguments of .

socket.recv(bufsize[, flags])

Receive data from the socket. The return value is a bytes object representing the data received. The maximum amount of data to be received at once is specified by bufsize. See the Unix manual page recv(2) for the meaning of the optional argument flags; it defaults to zero.

Note

For best match with hardware and network realities, the value of bufsize should be a relatively small power of 2, for example, 4096.

Changed in version 3.5: If the system call is interrupted and the signal handler does not raise an exception, the method now retries the system call instead of raising an exception (see PEP 475 for the rationale).

socket.recvfrom(bufsize[, flags])

Receive data from the socket. The return value is a pair

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
12 where bytes is a bytes object representing the data received and address is the address of the socket sending the data. See the Unix manual page recv(2) for the meaning of the optional argument flags; it defaults to zero. (The format of address depends on the address family — see above.)

Changed in version 3.5: If the system call is interrupted and the signal handler does not raise an exception, the method now retries the system call instead of raising an exception (see PEP 475 for the rationale).

Changed in version 3.7: For multicast IPv6 address, first item of address does not contain

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
0 part anymore. In order to get full IPv6 address use .

socket.recvmsg(bufsize[, ancbufsize[, flags]])

Receive normal data (up to bufsize bytes) and ancillary data from the socket. The ancbufsize argument sets the size in bytes of the internal buffer used to receive the ancillary data; it defaults to 0, meaning that no ancillary data will be received. Appropriate buffer sizes for ancillary data can be calculated using or , and items which do not fit into the buffer might be truncated or discarded. The flags argument defaults to 0 and has the same meaning as for .

The return value is a 4-tuple:

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
19. The data item is a object holding the non-ancillary data received. The ancdata item is a list of zero or more tuples
>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
21 representing the ancillary data (control messages) received: cmsg_level and cmsg_type are integers specifying the protocol level and protocol-specific type respectively, and cmsg_data is a object holding the associated data. The msg_flags item is the bitwise OR of various flags indicating conditions on the received message; see your system documentation for details. If the receiving socket is unconnected, address is the address of the sending socket, if available; otherwise, its value is unspecified.

On some systems, and can be used to pass file descriptors between processes over an socket. When this facility is used (it is often restricted to sockets), will return, in its ancillary data, items of the form

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
28, where fds is a object representing the new file descriptors as a binary array of the native C int type. If raises an exception after the system call returns, it will first attempt to close any file descriptors received via this mechanism.

Some systems do not indicate the truncated length of ancillary data items which have been only partially received. If an item appears to extend beyond the end of the buffer, will issue a , and will return the part of it which is inside the buffer provided it has not been truncated before the start of its associated data.

On systems which support the

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
49 mechanism, the following function will receive up to maxfds file descriptors, returning the message data and a list containing the descriptors (while ignoring unexpected conditions such as unrelated control messages being received). See also .

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)

: Unix.

Most Unix platforms.

New in version 3.3.

Changed in version 3.5: If the system call is interrupted and the signal handler does not raise an exception, the method now retries the system call instead of raising an exception (see PEP 475 for the rationale).

socket.recvmsg_into(buffers[, ancbufsize[, flags]])

Receive normal data and ancillary data from the socket, behaving as would, but scatter the non-ancillary data into a series of buffers instead of returning a new bytes object. The buffers argument must be an iterable of objects that export writable buffers (e.g. objects); these will be filled with successive chunks of the non-ancillary data until it has all been written or there are no more buffers. The operating system may set a limit ( value

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
39) on the number of buffers that can be used. The ancbufsize and flags arguments have the same meaning as for .

The return value is a 4-tuple:

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
41, where nbytes is the total number of bytes of non-ancillary data written into the buffers, and ancdata, msg_flags and address are the same as for .

Example:

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]

: Unix.

Most Unix platforms.

New in version 3.3.

socket.recvfrom_into(buffer[, nbytes[, flags]])

Receive data from the socket, writing it into buffer instead of creating a new bytestring. The return value is a pair

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
43 where nbytes is the number of bytes received and address is the address of the socket sending the data. See the Unix manual page recv(2) for the meaning of the optional argument flags; it defaults to zero. (The format of address depends on the address family — see above.)

socket.recv_into(buffer[, nbytes[, flags]])

Receive up to nbytes bytes from the socket, storing the data into a buffer rather than creating a new bytestring. If nbytes is not specified (or 0), receive up to the size available in the given buffer. Returns the number of bytes received. See the Unix manual page recv(2) for the meaning of the optional argument flags; it defaults to zero.

socket.send(bytes[, flags])

Send data to the socket. The socket must be connected to a remote socket. The optional flags argument has the same meaning as for above. Returns the number of bytes sent. Applications are responsible for checking that all data has been sent; if only some of the data was transmitted, the application needs to attempt delivery of the remaining data. For further information on this topic, consult the .

Changed in version 3.5: If the system call is interrupted and the signal handler does not raise an exception, the method now retries the system call instead of raising an exception (see PEP 475 for the rationale).

socket.sendall(bytes[, flags])

Send data to the socket. The socket must be connected to a remote socket. The optional flags argument has the same meaning as for above. Unlike , this method continues to send data from bytes until either all data has been sent or an error occurs.

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
30 is returned on success. On error, an exception is raised, and there is no way to determine how much data, if any, was successfully sent.

Changed in version 3.5: The socket timeout is no more reset each time data is sent successfully. The socket timeout is now the maximum total duration to send all data.

Changed in version 3.5: If the system call is interrupted and the signal handler does not raise an exception, the method now retries the system call instead of raising an exception (see PEP 475 for the rationale).

socket.sendto(bytes, address)socket.sendto(bytes, flags, address)

Send data to the socket. The socket should not be connected to a remote socket, since the destination socket is specified by address. The optional flags argument has the same meaning as for above. Return the number of bytes sent. (The format of address depends on the address family — see above.)

Raises an

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
51 with arguments
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
91,
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
61.

Changed in version 3.5: If the system call is interrupted and the signal handler does not raise an exception, the method now retries the system call instead of raising an exception (see PEP 475 for the rationale).

socket.sendmsg(buffers[, ancdata[, flags[, address]]])

Send normal and ancillary data to the socket, gathering the non-ancillary data from a series of buffers and concatenating it into a single message. The buffers argument specifies the non-ancillary data as an iterable of (e.g. objects); the operating system may set a limit ( value

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
39) on the number of buffers that can be used. The ancdata argument specifies the ancillary data (control messages) as an iterable of zero or more tuples
>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
21, where cmsg_level and cmsg_type are integers specifying the protocol level and protocol-specific type respectively, and cmsg_data is a bytes-like object holding the associated data. Note that some systems (in particular, systems without ) might support sending only one control message per call. The flags argument defaults to 0 and has the same meaning as for . If address is supplied and not
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
30, it sets a destination address for the message. The return value is the number of bytes of non-ancillary data sent.

The following function sends the list of file descriptors fds over an socket, on systems which support the

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
49 mechanism. See also .

import socket, array

def send_fds(sock, msg, fds):
    return sock.sendmsg([msg], [(socket.SOL_SOCKET, socket.SCM_RIGHTS, array.array("i", fds))])

: Unix, not WASI.

Most Unix platforms.

Raises an

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
65 with arguments
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
91,
import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
61.

New in version 3.3.

Changed in version 3.5: If the system call is interrupted and the signal handler does not raise an exception, the method now retries the system call instead of raising an exception (see PEP 475 for the rationale).

socket.sendmsg_afalg([msg, ]*, op[, iv[, assoclen[, flags]]])

Specialized version of for socket. Set mode, IV, AEAD associated data length and flags for socket.

: Linux >= 2.6.38.

New in version 3.6.

socket.sendfile(file, offset=0, count=None)

Send a file until EOF is reached by using high-performance and return the total number of bytes which were sent. file must be a regular file object opened in binary mode. If is not available (e.g. Windows) or file is not a regular file will be used instead. offset tells from where to start reading the file. If specified, count is the total number of bytes to transmit as opposed to sending the file until EOF is reached. File position is updated on return or also in case of error in which case can be used to figure out the number of bytes which were sent. The socket must be of type. Non-blocking sockets are not supported.

New in version 3.5.

socket.set_inheritable(inheritable)

Set the of the socket’s file descriptor or socket’s handle.

New in version 3.4.

socket.setblocking(flag)

Set blocking or non-blocking mode of the socket: if flag is false, the socket is set to non-blocking, else to blocking mode.

This method is a shorthand for certain calls:

  • >>> import socket
    >>> s1, s2 = socket.socketpair()
    >>> b1 = bytearray(b'----')
    >>> b2 = bytearray(b'0123456789')
    >>> b3 = bytearray(b'--------------')
    >>> s1.send(b'Mary had a little lamb')
    22
    >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
    (22, [], 0, None)
    >>> [b1, b2, b3]
    [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
    
    78 is equivalent to
    >>> import socket
    >>> s1, s2 = socket.socketpair()
    >>> b1 = bytearray(b'----')
    >>> b2 = bytearray(b'0123456789')
    >>> b3 = bytearray(b'--------------')
    >>> s1.send(b'Mary had a little lamb')
    22
    >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
    (22, [], 0, None)
    >>> [b1, b2, b3]
    [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
    
    79

  • >>> import socket
    >>> s1, s2 = socket.socketpair()
    >>> b1 = bytearray(b'----')
    >>> b2 = bytearray(b'0123456789')
    >>> b3 = bytearray(b'--------------')
    >>> s1.send(b'Mary had a little lamb')
    22
    >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
    (22, [], 0, None)
    >>> [b1, b2, b3]
    [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
    
    80 is equivalent to
    >>> import socket
    >>> s1, s2 = socket.socketpair()
    >>> b1 = bytearray(b'----')
    >>> b2 = bytearray(b'0123456789')
    >>> b3 = bytearray(b'--------------')
    >>> s1.send(b'Mary had a little lamb')
    22
    >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
    (22, [], 0, None)
    >>> [b1, b2, b3]
    [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
    
    81

Changed in version 3.7: The method no longer applies flag on .

socket.settimeout(value)

Set a timeout on blocking socket operations. The value argument can be a nonnegative floating point number expressing seconds, or

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
30. If a non-zero value is given, subsequent socket operations will raise a exception if the timeout period value has elapsed before the operation has completed. If zero is given, the socket is put in non-blocking mode. If
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
30 is given, the socket is put in blocking mode.

For further information, please consult the .

Changed in version 3.7: The method no longer toggles flag on .

socket.setsockopt(level, optname, value: )socket.setsockopt(level, optname, value: buffer)socket.setsockopt(level, optname, None, optlen: int)

Set the value of the given socket option (see the Unix manual page setsockopt(2)). The needed symbolic constants are defined in the module (

import socket, array

def recv_fds(sock, msglen, maxfds):
    fds = array.array("i")   # Array of ints
    msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize))
    for cmsg_level, cmsg_type, cmsg_data in ancdata:
        if cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS:
            # Append data, ignoring any truncated integers at the end.
            fds.frombytes(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)])
    return msg, list(fds)
87 etc.). The value can be an integer,
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
30 or a representing a buffer. In the later case it is up to the caller to ensure that the bytestring contains the proper bits (see the optional built-in module for a way to encode C structures as bytestrings). When value is set to
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
30, optlen argument is required. It’s equivalent to call
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
44 C function with
>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
95 and
>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
96.

Changed in version 3.5: Writable is now accepted.

Changed in version 3.6: setsockopt(level, optname, None, optlen: int) form added.

: not WASI.

socket.shutdown(how)

Shut down one or both halves of the connection. If how is

>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
97, further receives are disallowed. If how is
>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
98, further sends are disallowed. If how is
>>> import socket
>>> s1, s2 = socket.socketpair()
>>> b1 = bytearray(b'----')
>>> b2 = bytearray(b'0123456789')
>>> b3 = bytearray(b'--------------')
>>> s1.send(b'Mary had a little lamb')
22
>>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3])
(22, [], 0, None)
>>> [b1, b2, b3]
[bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')]
99, further sends and receives are disallowed.

: not WASI.

socket.share(process_id)

Duplicate a socket and prepare it for sharing with a target process. The target process must be provided with process_id. The resulting bytes object can then be passed to the target process using some form of interprocess communication and the socket can be recreated there using . Once this method has been called, it is safe to close the socket since the operating system has already duplicated it for the target process.

: Windows.

New in version 3.3.

Note that there are no methods

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
9 or
>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
0; use and without flags argument instead.

Socket objects also have these (read-only) attributes that correspond to the values given to the constructor.

socket.family

The socket family.

socket.type

The socket type.

socket.proto

The socket protocol.

Notes on socket timeouts

A socket object can be in one of three modes: blocking, non-blocking, or timeout. Sockets are by default always created in blocking mode, but this can be changed by calling .

  • In blocking mode, operations block until complete or the system returns an error (such as connection timed out).

  • In non-blocking mode, operations fail (with an error that is unfortunately system-dependent) if they cannot be completed immediately: functions from the can be used to know when and whether a socket is available for reading or writing.

  • In timeout mode, operations fail if they cannot be completed within the timeout specified for the socket (they raise a exception) or if the system returns an error.

Note

At the operating system level, sockets in timeout mode are internally set in non-blocking mode. Also, the blocking and timeout modes are shared between file descriptors and socket objects that refer to the same network endpoint. This implementation detail can have visible consequences if e.g. you decide to use the of a socket.

Timeouts and the import socket, array def send_fds(sock, msg, fds): return sock.sendmsg([msg], [(socket.SOL_SOCKET, socket.SCM_RIGHTS, array.array("i", fds))]) 10 method

The operation is also subject to the timeout setting, and in general it is recommended to call before calling or pass a timeout parameter to . However, the system network stack may also return a connection timeout error of its own regardless of any Python socket timeout setting.

Timeouts and the import socket, array def send_fds(sock, msg, fds): return sock.sendmsg([msg], [(socket.SOL_SOCKET, socket.SCM_RIGHTS, array.array("i", fds))]) 15 method

If is not , sockets returned by the method inherit that timeout. Otherwise, the behaviour depends on settings of the listening socket:

  • if the listening socket is in blocking mode or in timeout mode, the socket returned by is in blocking mode;

  • if the listening socket is in non-blocking mode, whether the socket returned by is in blocking or non-blocking mode is operating system-dependent. If you want to ensure cross-platform behaviour, it is recommended you manually override this setting.

Example

Here are four minimal example programs using the TCP/IP protocol: a server that echoes all data that it receives back (servicing only one client), and a client using it. Note that a server must perform the sequence

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
8, , , (possibly repeating the to service more than one client), while a client only needs the sequence
import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
8, . Also note that the server does not / on the socket it is listening on but on the new socket returned by .

The first two examples support IPv4 only.

# Echo server program
import socket

HOST = ''                 # Symbolic name meaning all available interfaces
PORT = 50007              # Arbitrary non-privileged port
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.bind((HOST, PORT))
    s.listen(1)
    conn, addr = s.accept()
    with conn:
        print('Connected by', addr)
        while True:
            data = conn.recv(1024)
            if not data: break
            conn.sendall(data)

# Echo client program
import socket

HOST = 'daring.cwi.nl'    # The remote host
PORT = 50007              # The same port as used by the server
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    s.connect((HOST, PORT))
    s.sendall(b'Hello, world')
    data = s.recv(1024)
print('Received', repr(data))

The next two examples are identical to the above two, but support both IPv4 and IPv6. The server side will listen to the first address family available (it should listen to both instead). On most of IPv6-ready systems, IPv6 will take precedence and the server may not accept IPv4 traffic. The client side will try to connect to the all addresses returned as a result of the name resolution, and sends traffic to the first one connected successfully.

# Echo server program
import socket
import sys

HOST = None               # Symbolic name meaning all available interfaces
PORT = 50007              # Arbitrary non-privileged port
s = None
for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC,
                              socket.SOCK_STREAM, 0, socket.AI_PASSIVE):
    af, socktype, proto, canonname, sa = res
    try:
        s = socket.socket(af, socktype, proto)
    except OSError as msg:
        s = None
        continue
    try:
        s.bind(sa)
        s.listen(1)
    except OSError as msg:
        s.close()
        s = None
        continue
    break
if s is None:
    print('could not open socket')
    sys.exit(1)
conn, addr = s.accept()
with conn:
    print('Connected by', addr)
    while True:
        data = conn.recv(1024)
        if not data: break
        conn.send(data)

# Echo client program
import socket
import sys

HOST = 'daring.cwi.nl'    # The remote host
PORT = 50007              # The same port as used by the server
s = None
for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC, socket.SOCK_STREAM):
    af, socktype, proto, canonname, sa = res
    try:
        s = socket.socket(af, socktype, proto)
    except OSError as msg:
        s = None
        continue
    try:
        s.connect(sa)
    except OSError as msg:
        s.close()
        s = None
        continue
    break
if s is None:
    print('could not open socket')
    sys.exit(1)
with s:
    s.sendall(b'Hello, world')
    data = s.recv(1024)
print('Received', repr(data))

The next example shows how to write a very simple network sniffer with raw sockets on Windows. The example requires administrator privileges to modify the interface:

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
0

The next example shows how to use the socket interface to communicate to a CAN network using the raw socket protocol. To use CAN with the broadcast manager protocol instead, open a socket with:

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
1

After binding (

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
83) or connecting () the socket, you can use the , and the operations (and their counterparts) on the socket object as usual.

This last example might require special privileges:

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
2

Running an example several times with too small delay between executions, could lead to this error:

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
3

This is because the previous execution has left the socket in a

import socket, array

def send_fds(sock, msg, fds):
    return sock.sendmsg([msg], [(socket.SOL_SOCKET, socket.SCM_RIGHTS, array.array("i", fds))])
35 state, and can’t be immediately reused.

There is a flag to set, in order to prevent this,

import socket, array

def send_fds(sock, msg, fds):
    return sock.sendmsg([msg], [(socket.SOL_SOCKET, socket.SCM_RIGHTS, array.array("i", fds))])
37:

import socket

addr = ("", 8080)  # all interfaces, port 8080
if socket.has_dualstack_ipv6():
    s = socket.create_server(addr, family=socket.AF_INET6, dualstack_ipv6=True)
else:
    s = socket.create_server(addr)
4

the

>>> socket.getaddrinfo("example.org", 80, proto=socket.IPPROTO_TCP)
[(socket.AF_INET6, socket.SOCK_STREAM,
 6, '', ('2606:2800:220:1:248:1893:25c8:1946', 80, 0, 0)),
 (socket.AF_INET, socket.SOCK_STREAM,
 6, '', ('93.184.216.34', 80))]
21 flag tells the kernel to reuse a local socket in
import socket, array

def send_fds(sock, msg, fds):
    return sock.sendmsg([msg], [(socket.SOL_SOCKET, socket.SCM_RIGHTS, array.array("i", fds))])
35 state, without waiting for its natural timeout to expire.

See also

For an introduction to socket programming (in C), see the following papers:

  • An Introductory 4.3BSD Interprocess Communication Tutorial, by Stuart Sechrest

  • An Advanced 4.3BSD Interprocess Communication Tutorial, by Samuel J. Leffler et al,

both in the UNIX Programmer’s Manual, Supplementary Documents 1 (sections PS1:7 and PS1:8). The platform-specific reference material for the various socket-related system calls are also a valuable source of information on the details of socket semantics. For Unix, refer to the manual pages; for Windows, see the WinSock (or Winsock 2) specification. For IPv6-ready APIs, readers may want to refer to RFC 3493 titled Basic Socket Interface Extensions for IPv6.