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

I am very new to perl and I am trying to write some code that is portable accross OS's and part of the code is making socket calls to a remote server. However I need the sockets to timeout when the response takes too long. Even with the timeout value set when I create the socket, the script does not timeout and continues to wait until it recieves a response on the socket or the webserver kills the script because it is taking too long to execute. What am I doing wrong, and can I explicitly check to see if a timeout occured? The socket communciations are working apart from the timeout issue. I have extracted the sockets code that I am using. Any feedback is welcome. 
    use strict;
    use CGI;
    use IO::Socket;

    my $clientIP     = $params{'HostName'};
    my $clientPort   = $params{'Port'};
    my $client       = undef;
    my $timeOut      = 10;
    my $reqString    = $params{'RequestString'};
    my $resString    = "";

    $client = IO::Socket::INET->new
    (
        PeerAddr => $clientIP,
        PeerPort => $clientPort,
        Proto    => "tcp",
        Type     => SOCK_STREAM,
        Timeout  => $timeOut
    );

    # Send the request (appended with a newline character) to the sock
+et
    print $client $reqString."\n";

    # Retrieve the response from the socket buffer
    $resString = <$client>;

[download]

Replies are listed 'Best First'.
Re: Implementing Sockets Timeouts
by DigitalKitty (Parson) on Aug 02, 2002 at 02:39 UTC
    Hi Anonymous Monk,

    Internally, IO::Socket uses non-blocking i/o with regard to timeouts. I would specify an integer for the timeout period since I didn't see where it was passed in via a form. Something like this: 

    #!/usr/bin/perl -wT

use strict;
use CGI qw( :standard );
use IO::Socket;

my $client = IO::Socket::INET->new
    (
        PeerAddr => $clientIP,
        PeerPort => $clientPort,
        Proto    => "tcp",
        Type     => SOCK_STREAM,
        Timeout  => 10
    );
    
$client or die $@, "\n";


#Remainder of code...

    [download]

    If the connection occurs within the alloted time frame, the IO::Socket obj. is returned and saved in $client. If not, the error will be stored in $@ with the error message "IO::Socket::INET:Operation now in progress".
    Hope this helps,
    -Katie.
[reply]
[d/l]
      Hi Katie,

      Thanks for your help. Your suggestion on the error message contained in $@ solved my problem.

      Chris
[reply]

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