[ python-Bugs-777588 ] asyncore is broken for windows if connection is refused

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Bugs item #777588, was opened at 2003-07-25 18:43
Message generated for change (Comment added) made by klimkin
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=105470&aid=777588&group_id=5470

Category: Python Library
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Garth Bushell (garth42)
Assigned to: Nobody/Anonymous (nobody)
Summary: asyncore is broken for windows if connection is refused

Initial Comment:
asyncore.poll is broken on windows. If a connection is
refused happens it will hang for ever and never raise
an exception.

The Select statment never checks the exfds. This is
needed as this is where windows reports failed
connections. The documentation in the microsoft
platform SDK mentions this. 

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winsock/winsock/select_2.asp

The suggested fix is shown below althought this is
untested. The correct error number is recived from
getsockopt(SOL_SOCKET,SO_ERROR) 

def poll(timeout=0.0, map=None):
     if map is None:
         map = socket_map
     if map:
         r = []; w = []; e = []
         for fd, obj in map.items():
             if obj.readable():
                 r.append(fd)
             if obj.writable():
                 w.append(fd)

             if sys.platform == 'win32':
                 if not obj.connected:
                     e.append(fd)
         if [] == r == w == e:
             time.sleep(timeout)
         else:
             try:
                 r, w, e = select.select(r, w, e, timeout)
             except select.error, err:
                 if err[0] != EINTR:
                     raise
                 else:
                     return

         if sys.platform == 'win32':
             for fd in e:
                 obj = map.get(fd)
                 if obj is None:
                     continue
                 errno =
fs.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR)
                 raise
socket.error,(errno,socketerrorTab[error])

         for fd in r:
             obj = map.get(fd)
             if obj is None:
                 continue
             read(obj)

         for fd in w:
             obj = map.get(fd)
             if obj is None:
                 continue
             write(obj)


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Comment By: Alexey Klimkin (klimkin)
Date: 2004-03-04 11:23

Message:
Logged In: YES 
user_id=410460

Patch #909005 fixes the problem.

----------------------------------------------------------------------

Comment By: John J Smith (johnjsmith)
Date: 2003-07-29 16:49

Message:
Logged In: YES 
user_id=830565

I was bitten by the same problem.  My workaround (in a
Tkinter application) is given below.

Would it make sense to modify poll() to simply add the union
of r and w to e, and call handle_error() for any fd in e?

Workaround:

        try:
            self.connect(send_addr)
        except socket.error:
            self.handle_error()
        if sys.platform == 'win32':
            # Win98 select() doesn't seem to report errors for a
            # non-blocking connect().
            self.__connected = 0
            self.__frame.after(2000, self.__win_connect_poll)

...

    if sys.platform == 'win32':
        def __win_connect_poll (self):
            if self.__connected:
                return
            e = self.socket.getsockopt(socket.SOL_SOCKET,
                                       socket.SO_ERROR)
            if e in (0, errno.EINPROGRESS, 
errno.WSAEINPROGRESS):
                self.__frame.after(2000, self.__win_connect_poll)
            else:
                try:
                    str = socket.errorTab[e]
                except KeyError:
                    str = os.strerror(e)
                try:
                    raise socket.error(e, str)
                except socket.error:
                    self.handle_error()


----------------------------------------------------------------------

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