cpython/Lib/socket.py

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# Wrapper module for _socket, providing some additional facilities
# implemented in Python.
"""\
This module provides socket operations and some related functions.
On Unix, it supports IP (Internet Protocol) and Unix domain sockets.
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On other systems, it only supports IP. Functions specific for a
socket are available as methods of the socket object.
Functions:
socket() -- create a new socket object
socketpair() -- create a pair of new socket objects [*]
fromfd() -- create a socket object from an open file descriptor [*]
gethostname() -- return the current hostname
gethostbyname() -- map a hostname to its IP number
gethostbyaddr() -- map an IP number or hostname to DNS info
getservbyname() -- map a service name and a protocol name to a port number
getprotobyname() -- mape a protocol name (e.g. 'tcp') to a number
ntohs(), ntohl() -- convert 16, 32 bit int from network to host byte order
htons(), htonl() -- convert 16, 32 bit int from host to network byte order
inet_aton() -- convert IP addr string (123.45.67.89) to 32-bit packed format
inet_ntoa() -- convert 32-bit packed format IP to string (123.45.67.89)
ssl() -- secure socket layer support (only available if configured)
socket.getdefaulttimeout() -- get the default timeout value
socket.setdefaulttimeout() -- set the default timeout value
create_connection() -- connects to an address, with an optional timeout
[*] not available on all platforms!
Special objects:
SocketType -- type object for socket objects
error -- exception raised for I/O errors
has_ipv6 -- boolean value indicating if IPv6 is supported
Integer constants:
AF_INET, AF_UNIX -- socket domains (first argument to socket() call)
SOCK_STREAM, SOCK_DGRAM, SOCK_RAW -- socket types (second argument)
Many other constants may be defined; these may be used in calls to
the setsockopt() and getsockopt() methods.
"""
import _socket
from _socket import *
_have_ssl = False
try:
import _ssl
from _ssl import *
_have_ssl = True
except ImportError:
pass
import os, sys
try:
from errno import EBADF
except ImportError:
EBADF = 9
__all__ = ["getfqdn"]
__all__.extend(os._get_exports_list(_socket))
if _have_ssl:
__all__.extend(os._get_exports_list(_ssl))
_realsocket = socket
if _have_ssl:
def ssl(sock, keyfile=None, certfile=None):
import ssl as realssl
return realssl.sslwrap_simple(sock, keyfile, certfile)
__all__.append("ssl")
# WSA error codes
if sys.platform.lower().startswith("win"):
errorTab = {}
errorTab[10004] = "The operation was interrupted."
errorTab[10009] = "A bad file handle was passed."
errorTab[10013] = "Permission denied."
errorTab[10014] = "A fault occurred on the network??" # WSAEFAULT
errorTab[10022] = "An invalid operation was attempted."
errorTab[10035] = "The socket operation would block"
errorTab[10036] = "A blocking operation is already in progress."
errorTab[10048] = "The network address is in use."
errorTab[10054] = "The connection has been reset."
errorTab[10058] = "The network has been shut down."
errorTab[10060] = "The operation timed out."
errorTab[10061] = "Connection refused."
errorTab[10063] = "The name is too long."
errorTab[10064] = "The host is down."
errorTab[10065] = "The host is unreachable."
__all__.append("errorTab")
def getfqdn(name=''):
"""Get fully qualified domain name from name.
An empty argument is interpreted as meaning the local host.
First the hostname returned by gethostbyaddr() is checked, then
possibly existing aliases. In case no FQDN is available, hostname
from gethostname() is returned.
"""
name = name.strip()
if not name or name == '0.0.0.0':
name = gethostname()
try:
hostname, aliases, ipaddrs = gethostbyaddr(name)
except error:
pass
else:
aliases.insert(0, hostname)
for name in aliases:
if '.' in name:
break
else:
name = hostname
return name
_socketmethods = (
'bind', 'connect', 'connect_ex', 'fileno', 'listen',
'getpeername', 'getsockname', 'getsockopt', 'setsockopt',
'sendall', 'setblocking',
'settimeout', 'gettimeout', 'shutdown')
if sys.platform == "riscos":
_socketmethods = _socketmethods + ('sleeptaskw',)
# All the method names that must be delegated to either the real socket
# object or the _closedsocket object.
_delegate_methods = ("recv", "recvfrom", "recv_into", "recvfrom_into",
"send", "sendto")
class _closedsocket(object):
__slots__ = []
def _dummy(*args):
raise error(EBADF, 'Bad file descriptor')
# All _delegate_methods must also be initialized here.
send = recv = recv_into = sendto = recvfrom = recvfrom_into = _dummy
__getattr__ = _dummy
# Wrapper around platform socket objects. This implements
# a platform-independent dup() functionality. The
# implementation currently relies on reference counting
# to close the underlying socket object.
class _socketobject(object):
__doc__ = _realsocket.__doc__
__slots__ = ["_sock", "__weakref__"] + list(_delegate_methods)
def __init__(self, family=AF_INET, type=SOCK_STREAM, proto=0, _sock=None):
if _sock is None:
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_sock = _realsocket(family, type, proto)
self._sock = _sock
for method in _delegate_methods:
setattr(self, method, getattr(_sock, method))
def close(self):
self._sock = _closedsocket()
dummy = self._sock._dummy
for method in _delegate_methods:
setattr(self, method, dummy)
close.__doc__ = _realsocket.close.__doc__
def accept(self):
sock, addr = self._sock.accept()
return _socketobject(_sock=sock), addr
accept.__doc__ = _realsocket.accept.__doc__
def dup(self):
"""dup() -> socket object
Return a new socket object connected to the same system resource."""
return _socketobject(_sock=self._sock)
def makefile(self, mode='r', bufsize=-1):
"""makefile([mode[, bufsize]]) -> file object
Return a regular file object corresponding to the socket. The mode
and bufsize arguments are as for the built-in open() function."""
return _fileobject(self._sock, mode, bufsize)
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family = property(lambda self: self._sock.family, doc="the socket family")
type = property(lambda self: self._sock.type, doc="the socket type")
proto = property(lambda self: self._sock.proto, doc="the socket protocol")
_s = ("def %s(self, *args): return self._sock.%s(*args)\n\n"
"%s.__doc__ = _realsocket.%s.__doc__\n")
for _m in _socketmethods:
exec _s % (_m, _m, _m, _m)
del _m, _s
socket = SocketType = _socketobject
class _fileobject(object):
"""Faux file object attached to a socket object."""
default_bufsize = 8192
name = "<socket>"
__slots__ = ["mode", "bufsize", "softspace",
# "closed" is a property, see below
"_sock", "_rbufsize", "_wbufsize", "_rbuf", "_wbuf",
"_close"]
def __init__(self, sock, mode='rb', bufsize=-1, close=False):
self._sock = sock
self.mode = mode # Not actually used in this version
if bufsize < 0:
bufsize = self.default_bufsize
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self.bufsize = bufsize
self.softspace = False
if bufsize == 0:
self._rbufsize = 1
elif bufsize == 1:
self._rbufsize = self.default_bufsize
else:
self._rbufsize = bufsize
self._wbufsize = bufsize
self._rbuf = "" # A string
self._wbuf = [] # A list of strings
self._close = close
def _getclosed(self):
return self._sock is None
closed = property(_getclosed, doc="True if the file is closed")
def close(self):
try:
if self._sock:
self.flush()
finally:
if self._close:
self._sock.close()
self._sock = None
def __del__(self):
try:
self.close()
except:
# close() may fail if __init__ didn't complete
pass
def flush(self):
if self._wbuf:
buffer = "".join(self._wbuf)
self._wbuf = []
self._sock.sendall(buffer)
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def fileno(self):
return self._sock.fileno()
def write(self, data):
data = str(data) # XXX Should really reject non-string non-buffers
if not data:
return
self._wbuf.append(data)
if (self._wbufsize == 0 or
self._wbufsize == 1 and '\n' in data or
self._get_wbuf_len() >= self._wbufsize):
self.flush()
def writelines(self, list):
# XXX We could do better here for very long lists
# XXX Should really reject non-string non-buffers
self._wbuf.extend(filter(None, map(str, list)))
if (self._wbufsize <= 1 or
self._get_wbuf_len() >= self._wbufsize):
self.flush()
def _get_wbuf_len(self):
buf_len = 0
for x in self._wbuf:
buf_len += len(x)
return buf_len
def read(self, size=-1):
data = self._rbuf
if size < 0:
# Read until EOF
buffers = []
if data:
buffers.append(data)
self._rbuf = ""
if self._rbufsize <= 1:
recv_size = self.default_bufsize
else:
recv_size = self._rbufsize
while True:
data = self._sock.recv(recv_size)
if not data:
break
buffers.append(data)
return "".join(buffers)
else:
# Read until size bytes or EOF seen, whichever comes first
buf_len = len(data)
if buf_len >= size:
self._rbuf = data[size:]
return data[:size]
buffers = []
if data:
buffers.append(data)
self._rbuf = ""
while True:
left = size - buf_len
recv_size = max(self._rbufsize, left)
data = self._sock.recv(recv_size)
if not data:
break
buffers.append(data)
n = len(data)
if n >= left:
self._rbuf = data[left:]
buffers[-1] = data[:left]
break
buf_len += n
return "".join(buffers)
def readline(self, size=-1):
data = self._rbuf
if size < 0:
# Read until \n or EOF, whichever comes first
if self._rbufsize <= 1:
# Speed up unbuffered case
assert data == ""
buffers = []
recv = self._sock.recv
while data != "\n":
data = recv(1)
if not data:
break
buffers.append(data)
return "".join(buffers)
nl = data.find('\n')
if nl >= 0:
nl += 1
self._rbuf = data[nl:]
return data[:nl]
buffers = []
if data:
buffers.append(data)
self._rbuf = ""
while True:
data = self._sock.recv(self._rbufsize)
if not data:
break
buffers.append(data)
nl = data.find('\n')
if nl >= 0:
nl += 1
self._rbuf = data[nl:]
buffers[-1] = data[:nl]
break
return "".join(buffers)
else:
# Read until size bytes or \n or EOF seen, whichever comes first
nl = data.find('\n', 0, size)
if nl >= 0:
nl += 1
self._rbuf = data[nl:]
return data[:nl]
buf_len = len(data)
if buf_len >= size:
self._rbuf = data[size:]
return data[:size]
buffers = []
if data:
buffers.append(data)
self._rbuf = ""
while True:
data = self._sock.recv(self._rbufsize)
if not data:
break
buffers.append(data)
left = size - buf_len
nl = data.find('\n', 0, left)
if nl >= 0:
nl += 1
self._rbuf = data[nl:]
buffers[-1] = data[:nl]
break
n = len(data)
if n >= left:
self._rbuf = data[left:]
buffers[-1] = data[:left]
break
buf_len += n
return "".join(buffers)
def readlines(self, sizehint=0):
total = 0
list = []
while True:
line = self.readline()
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if not line:
break
list.append(line)
total += len(line)
if sizehint and total >= sizehint:
break
return list
# Iterator protocols
def __iter__(self):
return self
def next(self):
line = self.readline()
if not line:
raise StopIteration
return line
def create_connection(address, timeout=None):
"""Connect to address (host, port) with an optional timeout.
Provides access to socketobject timeout for higher-level
protocols. Passing a timeout will set the timeout on the
socket instance (if not present, or passed as None, the
default global timeout setting will be used).
"""
msg = "getaddrinfo returns an empty list"
host, port = address
for res in getaddrinfo(host, port, 0, SOCK_STREAM):
af, socktype, proto, canonname, sa = res
sock = None
try:
sock = socket(af, socktype, proto)
if timeout is not None:
sock.settimeout(timeout)
sock.connect(sa)
return sock
except error, msg:
if sock is not None:
sock.close()
raise error, msg