Re: [Pyobjc-dev] Question about Python sockets and NSFileDescriptors

[Bob I. <bo...@re...>]

On Feb 19, 2004, at 8:33 PM, Bob Ippolito wrote:

>
> On Feb 19, 2004, at 8:04 PM, Jim Clause wrote:
>
>> Hello,
>> 	I've narrowed my problem down a bit more.  I'm wrapping a python  
>> socket in an NSFileDescriptor and then registering to receive  
>> ConnectionAccepted notifications.  When I run my code listed below I  
>> just get an infinite number of notifications.  Can anyone see any  
>> errors in my code or explain why I might be getting some many  
>> connection notices?
>
> Take a look at the notification's userInfo(), those are not connection  
> notifications, they are EBADF errors..  Why they keep coming is beyond  
> me, but that's what's happening.

Ok on further inspection here's what's happening:

- You are creating a Python socket.  When this python socket gets  
garbage collected, it automatically closes (hence the initial  
ECONNABORTED error).  You need to make sure this Python socket does not  
get garbage collected by keeping a reference to it somewhere.
- You are telling the NSFileHandle to listen to a connection over and  
over again.  You should only do that once (hence the continuing EBADF  
errors).

Here is a working example, slightly modified to run nibless and it has  
a waker so ^C can work:

import socket
import signal

from Foundation import *
from AppKit import *
from PyObjCTools import AppHelper

class TestServer(NSObject):
     def applicationDidFinishLaunching_(self, aNotification):
         sock = self._sock = socket.socket(socket.AF_INET,  
socket.SOCK_STREAM)
         sock.bind((socket.gethostname(), 0))
         sock.listen(5)
         print 'Listening on:', sock.getsockname()

         # Wrap the socket in an NSFileHandle using fileno() to get the
         # file descriptor for the socket object
         listeningSocket =  
NSFileHandle.alloc().initWithFileDescriptor_(sock.fileno())

         # Register that we want to be informed of connection  
notifications
          
NSNotificationCenter.defaultCenter().addObserver_selector_name_object_(s 
elf, "handleConnectionNotification:",  
NSFileHandleConnectionAcceptedNotification, listeningSocket)
         listeningSocket.acceptConnectionInBackgroundAndNotify()

     def handleConnectionNotification_(self, aNotification):
         print "Got Connection", aNotification.userInfo()

class Waker(NSObject):
     def init(self):
         self = super(Waker, self).init()
         self._shouldQuit = False
         self._timer =  
NSTimer.scheduledTimerWithTimeInterval_target_selector_userInfo_repeats_ 
(0.5, self, self.wakeUp_, None, True)
         signal.signal(signal.SIGINT, self.setQuit)

     def wakeUp_(self, userInfo):
         if self._shouldQuit:
             NSApplication.sharedApplication().terminate_(None)
             self._shouldQuit = False

     def setQuit(self, aSignal, aStackFrame):
         self._shouldQuit = True

if __name__ == "__main__":
     server = TestServer.alloc().init()
     app = NSApplication.sharedApplication()
     app.setDelegate_(server)
     # make ^C kill the process in a reasonable amount of time
     waker = Waker.alloc().init()
     # start
     app.run()