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""" Sockets with timeouts.
Defines a "timeout_socket" class for connections that can potentially
cause the server to hang. It uses select, and is based on code originally
from Scott Cotton.
The following people have contributed to the development of this module:
Scott Cotton <scott@chronis.pobox.com>
Lloyd Zusman <ljz@asfast.com
Phil Mayes <pmayes@olivebr.com>
Piers Lauder <piers@cs.su.oz.au>
Here are examples using smtplib.py and poplib.py by inheriting:
class timeout_POP3(poplib.POP3):
def __init__(self, host, port = poplib.POP3_PORT):
self.host = host
self.port = port
self.sock = timeout_socket.timeout_socket()
self.sock.connect(self.host, self.port)
self.file = self.sock.makefile('rb') # same as poplib.POP3
self._debugging = 0
self.welcome = self._getresp()
class timeout_SMTP(smtplib.SMTP):
def connect(self, host='localhost', port = 0):
'''Connect to a host on a given port.
Override the std SMTP connect in order to use a timeout_socket.
'''
if not port:
i = string.find(host, ':')
if i >= 0:
host, port = host[:i], host[i+1:]
try: port = string.atoi(port)
except string.atoi_error:
raise socket.error, "nonnumeric port"
if not port: port = smtplib.SMTP_PORT
self.sock = timeout_socket.timeout_socket()
if self.debuglevel > 0: print 'connect:', (host, port)
self.sock.connect(host, port)
(code,msg)=self.getreply()
if self.debuglevel >0 : print "connect:", msg
return (code,msg)
This allows one to use poplib.py & smtplib.py unchanged.
"""
__version__ = "1.7"
__author__ = "Scott Cotton <scott@chronis.pobox.com>"
import socket
import errno
import select
import string
_TIMEOUT = 20.0
class Timeout(Exception):
pass
class timeout_socket:
""" Instantiate with:
timeout_socket(timeout=20, sock=None)
where `timeout' is the desired timeout in seconds (default 20),
and `sock' is a pre-existing socket (default: one is created).
"""
def __init__(self, timeout=_TIMEOUT, sock=None):
self.ndups = 0
self.timeout(timeout)
self.inbuf = ''
if sock is None:
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.s = sock
self.ndups = 1
self.s.setblocking(0)
# destructor notes: socket.socket will close when destroyed
def __getattr__(self, name):
return getattr(self.s, name) # Other socket methods
def accept(self):
timeout = self._timeout
s = self.s
try:
# Non-blocking mode
s.setblocking(1)
sa = s.accept()
s.setblocking(timeout != 0)
return sa
except socket.error,why:
if not timeout:
raise
s.setblocking(1)
# The exception arguments can be (string) or (int,string)
if len(why.args) == 1:
code = 0
else:
code,why = why
if code not in (errno.EAGAIN, errno.EWOULDBLOCK):
raise
# Ok, then wait...
r,w,e = select.select([s],[],[],timeout)
if r:
try:
sa = s.accept()
return sa
except socket.error,why:
# This can throw string or (int,string)
if len(why.args) == 1:
code = 0
else:
code,why = why
raise
msg = 'accept timed out after %s seconds' % self._timeout
raise Timeout(msg)
def connect(self, *addr):
timeout = self._timeout
s = self.s
try:
# Non-blocking mode
s.setblocking(0)
apply(s.connect, addr)
s.setblocking(timeout != 0)
return 1
except socket.error,why:
if not timeout:
raise
s.setblocking(1)
# The exception arguments can be (string) or (int,string)
if len(why.args) == 1:
code = 0
else:
code,why = why
if code not in (errno.EINPROGRESS, errno.EALREADY, errno.EWOULDBLOCK): # WSAEWOULDBLOCK
raise
# Ok, then wait...
r,w,e = select.select([],[s],[],timeout)
if w:
try:
apply(s.connect, addr)
return 1
except socket.error,why:
# This can throw string or (int,string)
if len(why.args) == 1:
code = 0
else:
code,why = why
if code == errno.EISCONN:
return 1
raise
msg = 'connect to %s timed out after %s seconds' % (host, self._timeout)
raise Timeout(msg)
def send(self, data, flags=0):
next = 0
t = self._timeout
total = len(data)
while 1:
r,w,e = select.select([],[self.s], [], t)
if w:
buf = data[next:next+8192]
sent = self.s.send(buf, flags)
next = next + sent
if next == total:
return
else:
raise Timeout('timeout while sending "%.20s...": %d sec' % (data, t))
def recv(self, amt, flags=0):
r,w,e = select.select([self.s], [], [], self._timeout)
if r:
recvd = self.s.recv(amt, flags)
return recvd
raise Timeout("timeout while receiving from %s: %d sec" % (`self.s.getpeername()`, self._timeout))
def makefile(self, flags="r", buffsize=-1):
# makefile needs parameters
# Just return ourself - watch out for multiple close(), and
# provide read and readline methods expected by makefile result below.
self.ndups = self.ndups+1 # nubmer or dupped descriptors
return self
def close(self):
#if self.s.fileno() >= 0:
self.ndups = self.ndups-1
#print self.ndups
if self.ndups == 0:
#print "closing", self.s
self.s.close()
# New (non-standard socket) methods to support `makefile'.
def read(self, amt):
""" This only returns when amt has been read or socket times out """
while len(self.inbuf) < amt:
self.inbuf = self.inbuf + self.recv(4096)
data = self.inbuf[:amt]
self.inbuf = self.inbuf[amt:]
return data
def readline(self):
""" readine for socket - buffers data """
# Much slower than built-in method!
while 1:
lf = string.find(self.inbuf, '\n')
if lf >= 0:
break
r = self.recv(4096)
if not r:
# connection broken
# without this readline would enter infinite loop
break
self.inbuf = self.inbuf + r
lf = lf + 1
data = self.inbuf[:lf]
self.inbuf = self.inbuf[lf:]
return data
# Other new methods
def recvpending(self, timeout=0):
""" returns 1/0 """
return [] != select.select([self.s], [], [], int(timeout) or self._timeout)[0]
def timeout(self, newtimo):
""" change socket timeout """
self._timeout = int(newtimo)
def flush(self):
# TCPServer needs this
pass
def write(self, data):
self.send(data)
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