kertis
asked on
connections left open with IO:select
Hi there!
I have problems with connections left open by my little server.
If you run it on your system and start a browser requesting http://127.0.0.1:1234 everything is all right.
But when you do multiple requests (just hold the enter key) you have some open connections, but the old ones are not handled by my server anymore, because you can't read on these connections (the browser has closed the connection already).
Do you have an idea (without forking), how I can get rid of these dead connections? I hope, there's an easy and fast running solution.
#!/usr/bin/perl
use IO::Select;
use IO::Socket;
$lsn = new IO::Socket::INET(Proto => 'tcp', Listen => 1, LocalPort => 1234);
$sel = new IO::Select( $lsn );
$|=1;
$i=1;
$msg="HTTP/1.0 200 OK\nContent-type: text/html\n\n<html></html>
while ($i<5000)
{$msg.="<b>test</b> <i>testasdfjklsa j ajskdl</i>\n"; # some test output
$i++;
}
while(@ready = $sel->can_read) {
foreach $fh (@ready) {
if($fh == $lsn) {
# Create a new socket
$new = $lsn->accept;
$sel->add($new);
print "opening on fileno ".$new->fileno."!\n";
}
else {
# Process socket
# only a dummy receive and send
print " receiving on fileno ".$fh->fileno."!\n";
$fh->recv($test,1000);
print " processing for fileno ".$fh->fileno."!\n";
sleep 1; # processing the input may take a while
print " sending on fileno ".$fh->fileno."!\n";
$fh->send($msg);
# Maybe we have finished with the socket
print " closing on fileno ".$fh->fileno."!\n";
$sel->remove($fh);
$fh->close;
}
}
}
I have problems with connections left open by my little server.
If you run it on your system and start a browser requesting http://127.0.0.1:1234 everything is all right.
But when you do multiple requests (just hold the enter key) you have some open connections, but the old ones are not handled by my server anymore, because you can't read on these connections (the browser has closed the connection already).
Do you have an idea (without forking), how I can get rid of these dead connections? I hope, there's an easy and fast running solution.
#!/usr/bin/perl
use IO::Select;
use IO::Socket;
$lsn = new IO::Socket::INET(Proto => 'tcp', Listen => 1, LocalPort => 1234);
$sel = new IO::Select( $lsn );
$|=1;
$i=1;
$msg="HTTP/1.0 200 OK\nContent-type: text/html\n\n<html></html>
while ($i<5000)
{$msg.="<b>test</b> <i>testasdfjklsa j ajskdl</i>\n"; # some test output
$i++;
}
while(@ready = $sel->can_read) {
foreach $fh (@ready) {
if($fh == $lsn) {
# Create a new socket
$new = $lsn->accept;
$sel->add($new);
print "opening on fileno ".$new->fileno."!\n";
}
else {
# Process socket
# only a dummy receive and send
print " receiving on fileno ".$fh->fileno."!\n";
$fh->recv($test,1000);
print " processing for fileno ".$fh->fileno."!\n";
sleep 1; # processing the input may take a while
print " sending on fileno ".$fh->fileno."!\n";
$fh->send($msg);
# Maybe we have finished with the socket
print " closing on fileno ".$fh->fileno."!\n";
$sel->remove($fh);
$fh->close;
}
}
}
ASKER
Adjusted points to 170
Have the 'old ones' been accepted by the server ? If so, what do mean by 'you can't read on these' ? Normally, the (next) read on these connections will return a 0-length message, indicating that the remote side of the connection has been closed down (by the browser, in this case).
If you mean that some of your browser connections never got accepted by the server, you need to increase the listen queue size (set to '1' in your server, this will almost certainly reject some connections requested by the browser when you hold down the enter key). Especially when implementing servers handling multiple connections without forking, the queue size should be set higher (try '5' or so).
If you mean that some of your browser connections never got accepted by the server, you need to increase the listen queue size (set to '1' in your server, this will almost certainly reject some connections requested by the browser when you hold down the enter key). Especially when implementing servers handling multiple connections without forking, the queue size should be set higher (try '5' or so).
ASKER
All connections have been accepted by the server. But the problem is, that after opening connections ($fh == $lsn) not every connection still is a connection included in $sel->can_read, because having been closed by the browser. So these opened connections will never get into the "else" part (not new and readable).
I need a way to sort out and get rid of these dead connections by the server. 200 Points now for the best answer!
I need a way to sort out and get rid of these dead connections by the server. 200 Points now for the best answer!
What do you have against forking?
ASKER CERTIFIED SOLUTION
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Do you really get different fileno's on your connections ? If so, try to call the 'has_error' to see if these fd's are flagged in error. You will have to rearrange the while loop a bit. Make it loop forever and call $sel->has_error(0) first, than $sel->can_read. Check for fd's set after the has_error call and remove those from the list. (the 0 argument to has_error will poll and return instantly even if no fd is marked in error.
ASKER
Thanx for your answer, thoellri - and sorry for not grading earlier, I've been moving during the last weeks.
I've bought the Perl Cookbook, too - it really IS great.
But I sometimes get a strange error:
Bad arg length for Socket::unpack_sockaddr_in
be 16 at /usr/lib/perl5/i586-linux/
Has anybody of you seen this error msg before and knows a way to avoid it? I'm trying to test when the error occurs. You can post your answer to my new question: Bad arg length for Socket::unpack_sockaddr_in
I've bought the Perl Cookbook, too - it really IS great.
But I sometimes get a strange error:
Bad arg length for Socket::unpack_sockaddr_in
be 16 at /usr/lib/perl5/i586-linux/
Has anybody of you seen this error msg before and knows a way to avoid it? I'm trying to test when the error occurs. You can post your answer to my new question: Bad arg length for Socket::unpack_sockaddr_in
ASKER