Can you tell me why?

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

I want to make a chat script based on SOCKET.It listen() to a port and when a user come it accept() it and builds a NEW_SOCKET contacting with the user(print the web page). The parent process fork() a child process that will print to the NEW_SOCKETand use pipe() talk to the child. The child section looks like: ############

$connect=0;
$readpipe="READ$connect";
$writepipe="WRITE$connect";
pipe($readpipe,$writepipe);
$writepipe->autoflush();
my $pid;
if (!($pid=fork))
{
   close $writepipe;
   $readpipe->autoflush;
   select(NEW_SOCKET);
   while(1)                          {
   my $words;
   my $rbits='';
   vec($rbits,fileno($readpipe),1)=1;
   select($rbits,undef,undef,undef);   
   $words=<$readpipe>;
   print "<br>$words";     }
   close NEW_SOCKET;
   exit;
}
$connect++;
close $readpipe;
$writepipe->autoflush();
$pipes{$pid}=$writepipe;
[download]

############### First it worked well lasting for 3 or 4 minutes.But suddenly it was out of control.I think "select($rbits,undef,undef,undef);" statement lose his effect and he didn't like to wait for the filehandle become ready any more.The child print innumerable "
" to user's browser Madly and Continually! Now I am stranded.Can you give me a lesson?Thank you.

Comment on Can you tell me why? Download Code

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Re: Can you tell me why? by chromatic (Archbishop) on Feb 23, 2000 at 21:27 UTC
In my experience, accept() returns a valid filehandle -- you can print directly to it without having to use a pipe. I would look into the HTTP::Daemon module from libwww-perl. It takes care of most of the dirty low-level work. See also Randal Schwartz's Web Techniques columns, particularly 23 and 24. He builds a fork()ing mini web server there. If you're determined to keep your existing code, I would look at your while loop. There seems to be no way to exit it, and perhaps the socket is timing out.	[reply]

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Re: Can you tell me why?
by chromatic (Archbishop) on Feb 23, 2000 at 21:27 UTC

See also Randal Schwartz's Web Techniques columns, particularly 23 and 24. He builds a fork()ing mini web server there.

If you're determined to keep your existing code, I would look at your while loop. There seems to be no way to exit it, and perhaps the socket is timing out.

[reply]