Re^2: Is it possible to create a socket client and server that can send information back and forth using IO::Socket?

[p4R4d0x]

Maybe I'm just going about sending data back in the wrong way? I'm unsure of how to get the handle to send from the 'server' to the 'client'. Here's the socket portion of what I have so far:

'Server'

my $clientSocket = new IO::Socket::INET( 
        PeerAddr => $ipSend, 
        PeerPort => $sendPort, 
        Proto => 'tcp',
    );
$clientSocket or die "Could not create socket:$!\n"; 
print $clientSocket "HELLO 1.0";  
sleep(3); 
close $clientSocket;

'Client'

my $servSocket = IO::Socket::INET->new( 
        #LocalHost => 'localhost', 
        LocalPort => $listenPort, #7890
        Proto => 'tcp', 
        Listen => 2, 
        Reuse => 1
);
$servSocket or die "Could not create socket:$!\n"; 
my($tempSocket, $clientAddr, $buffer); 
while (($tempSocket, $clientAddr) = $servSocket->accept()) { 
    my ($clientPort, $clientIP) = sockaddr_in($clientAddr); 
    my $clientIPNum = inet_ntoa($clientIP); 
    my $clientHost = gethostbyaddr($clientIP, AF_INET); 
        while (defined ($buffer = <$tempSocket>)) { 
        print $buffer;
        if ($buffer =~ m/^HELLO (\d+.\d+)/) {
             my $version = $1;
             if ($version == "1.0") {
                 #This doesn't work
                      #Want to send "HELLO 1.0" back through the socke
+t
                      #Is the $tempSocket handle just wrong, or
                      #can I not use print to do this?
                      print $tempSocket "HELLO 1.0";
             }
        }
        last;
    }
}

[ikegami]

Assuming you meant to send a newline after the HELLO,

Side that initiates the handshake:

print $sock "HELLO 1.0";
chomp( my $greet = <$sock> );
die if $greet ne 'HELLO 1.0';
...continue...

Side that responds to the handshake:

chomp( my $greet = <$sock> );
die if $greet ne 'HELLO 1.0';
print $sock "HELLO 1.0";
...continue...

Without the newline, you'll need touse something other than <>. It won't return until a newline is received (by default).

[weismat]

Two obvious problems:
- Your client does not flush the buffer - thus nothing is sent, either call directly or check the autoflush property.
- Your server can handle only client and needs to flush as well.

[ikegami]

No, all sockets are being flushed. IO::Socket turns on autoflushing on the underlying handle.

[NetWallah]

Not sure if this is the cause of your problems, but there are some coding issues you should fix:

        if ($buffer =~ m/^HELLO (\d+.\d+)/) {
             my $version = $1;
             if ($version == "1.0") {

should be:

        if (my ($version) = $buffer =~ m/^HELLO (\d+\.\d+)/) { ## Esca
+pe the "."
             if ($version eq "1.0") {        # Do a "text" compare, no
+t numeric