[Tutor] python sockets

[Jon Engle]

Thank you for your help, this definitely gets me going in the right
direction!


On Wed, Jun 11, 2014 at 4:16 AM, Marc Tompkins <marc.tompkins at gmail.com>
wrote:

> On Tue, Jun 10, 2014 at 4:08 PM, Jon Engle <jon.engle at gmail.com> wrote:
> > Ok, so when I run the code it immediately terminates and never 'listens'
> to
> > the ports in the loop. I have verified by running netstat -an | grep
> 65530
> > and the startingPort is not binding.
>
> The problem is that all threads started by a program terminate when
> the program terminates - and you haven't told your program to stick
> around when it's done setting up.    So it's setting up and then
> immediately exiting - and by the time you run netstat a few seconds
> later you find nothing.  (Also, by leaving HOST = '', you're listening
> at address 0.0.0.0, so good luck catching any traffic...)
> Try something like this:
>
>
> #!/usr/bin/python         # This is server.py file
> from socket import *      #import the socket library
> import thread  #import the thread library
>
> def setup(PORT):
>     HOST = '127.0.0.1'    #we are the host
>     ADDR = (HOST,PORT)    #we need a tuple for the address
>     BUFSIZE = 4096    #reasonably sized buffer for data
>
>     serv = socket( AF_INET,SOCK_STREAM)
>
>     serv.bind((ADDR))    #the double parens are to create a tuple with
> one element
>     serv.listen(5)    #5 is the maximum number of queued connections we'll
> allow
>     print '\nlistening on port %i...' % PORT
>     conn,addr = serv.accept() #accept the connection
>     print '\n...port %i connected!'  % PORT
>     conn.send('TEST')
>     conn.close()
>
> def main():
>     startingPort=int(raw_input("\nPlease enter starting port: "))
>     for port in range (startingPort, 65535):
>         thread.start_new_thread(setup, (port,))
>     quitNow = ''
>     while quitNow not in ('Q', 'q'):
>         quitNow = raw_input('Enter Q to quit.')
>
> if __name__ == '__main__':
>     main()
>
>
> This will stick around until you enter 'Q', and if you run netstat in
> another window you'll see that it's LISTENING on all the ports you
> asked for.  (All of those print statements will show up in a
> surprising order!)
>
> I'm not running the other side of this experiment, so I haven't tested
> a successful connection... good luck.
>



-- 
Cheers,

   Jon S. Engle
   jon.engle at gmail.com
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