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Troubles with Complex Data Structures

by madhatter (Sexton)
on Jan 23, 2001 at 02:54 UTC ( #53608=perlquestion: print w/replies, xml ) Need Help??

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

I'm trying to get information from port 43030 and forward its contents to other IP:Ports. My problem is that the loop runs twice, but uses the first "forward to" IP and port both times.

I can receive data fine, and it forwards information (be it twice to the same IP/port, but my socket code _does_ work)

$CFG{listen_port} = 43030; %data = ( '' => [ ["","43035"], ["","43040"], ], ); $socket = IO::Socket::INET->new(LocalPort => $CFG{listen_port}, Type = +> SOCK_DGRAM, Proto => 'udp') || die "ERROR: can't open socket\n"; while ($socket->recv($in, 1024) ) { $ip = inet_ntoa($socket->peeraddr); # print "Info from $ip"; foreach(@{$data{$ip}}){ my $tip = ${$_}[0]; $sock = IO::Socket::INET->new(Proto => 'udp', PeerPort => +$data{$ip}[$tip][1], PeerAddr => $data{$ip}[$tip][0]); $sock->send($in) or die "send: $!"; print "Sent to $data{$ip}[$tip][0]:$data{$ip}[$tip][1]\n"; } print $in; }

I don't usually mess with complex data structures because of problems like this. Once I get this worked out though, and I can loop through different layers, I think they'll come in handy.

Any help on how to get it to loop properly would be greatly appreciated. Note: I'm using extra variables to try to make things easier. ($tip = temporary IP) I realize the code sucks. I haven't cleaned it up yet.

Thanks for any help you could offer,

Replies are listed 'Best First'.
Re: Troubles with Complex Data Structures
by chipmunk (Parson) on Jan 23, 2001 at 03:10 UTC
    $tip will hold an IP address, but you're using it as an array index.

    Here's how I might write the foreach loop:

    foreach my $ip_port (@{$data{$ip}}) { # $ip_port = [""," +43035"]; $sock = IO::Socket::INET->new(Proto => 'udp', PeerAddr => $ip_port->[0], PeerPort => $ip_port->[1] ); $sock->send($in) or die "send: $!"; print "Sent to $ip_port->[0]:$ip_port->[1]\n"; }
    The trick here is that, once you have a reference to a sublevel of the data structure -- in this case $ip_port, which points to one of the inner arrays -- you can work directly from that reference.

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