Perl Sockets question

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

HI all.
Firstly, I am not normally a Perl developer...I tinker with it when I need a specific solution....so forgive m if the below is obvious smile

What I have is a Perl script daemon that looks at a file using Tail and then outputs the data via a serial port. This works perfectly fine. BUT, I wanted to ramp it up a bit and instead of outputting the data via serial, I want to send it via TCP.
I googled around, and found some pretty simple code, but I get unexpected results.
Basically, I dont get any data output until I stop the daemon...which I only stumbled upon when testing.
Here is part of my code:-

my $sock = new IO::Socket::INET (
PeerAddr => '192.168.1.2',
PeerPort => '8000',
Proto => 'tcp'
);
while (defined(my $line=$file->read)) {

           print TTY "$line"; #out serial
           print $sock "$line"; #out tcp

}
close($sock);
[download]

As you can see, not exactly complex.
I tried moving the "my $sock" init of the socjet to just above the "print $sock" line, then closeing the socket, but this didnt really work. I tried $sock->send(); but this didnt make any difference.

I am sure someone will spot the problem beable to tell.

Thanks, Jeremy

Edit: g0n - code tags & formatting

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Re: Perl Sockets question by moritz (Cardinal) on Feb 08, 2008 at 23:01 UTC
then closeing the socket, but this didnt really work What do you mean by "didn't really work"? If you open the socket before each line, and close it after the line, each connection will only transport one line. Is that the desired behaviour? Edit: what you probably need is autoflushing the `$sock`. IO::Socket says As of VERSION 1.18 all IO::Socket objects have autoflush turned on by default. This was not the case with earlier releases. So which version of IO::Socket are you using? (And please but `<code>...</code>` tags around your example code.)	[reply] [d/l] [select]
Re^2: Perl Sockets question by jimbo (Initiate) on Feb 08, 2008 at 23:16 UTC
sorry about the bit :-) I am not 100% sure about what version I am using. I am using perl version 5.8.8 if thats any help. how can I tell what version f IO::Socket I am using? If I DO put the open and close around the `print socket$ $line` it just outputs empty strings which is what I was meaning byt "didnt really work" Thanks, jeremy	[reply] [d/l] [select]
Re^3: Perl Sockets question by redgreen (Priest) on Feb 09, 2008 at 03:41 UTC
`perl -MIO::Socket -e 'print "$IO::Socket::VERSION\n"'` [download]	[reply] [d/l]
Re^4: Perl Sockets question by jimbo (Initiate) on Feb 09, 2008 at 04:28 UTC
Re^5: Perl Sockets question by moritz (Cardinal) on Feb 09, 2008 at 08:58 UTC
Some notes below your chosen depth have not been shown here
Re: Perl Sockets question by zentara (Cardinal) on Feb 09, 2008 at 16:42 UTC
Try adding a newline after the socket print, that forces it to send(flush). Otherwise, it will tend to accumulate the sent data in a buffer for efficiency. Search groups.google.com for "perl socket flush" for other methods. The newline is the simplest, but there are modules which turn on auto-flushing. `print $sock $line,"\n"; #out tcp print $sock "$line\n"; #out tcp` [download] I'm not really a human, but I play one on earth. Cogito ergo sum a bum	[reply] [d/l]