Beefy Boxes and Bandwidth Generously Provided by pair Networks
We don't bite newbies here... much
 
PerlMonks  

Re: asynchronous socket communication with perl tk

by kcott (Abbot)
on Sep 25, 2013 at 13:18 UTC ( #1055682=note: print w/ replies, xml ) Need Help??


in reply to asynchronous socket communication with perl tk

G'day simonz,

You took that code from this thread (which has exactly the same name): asynchronous socket comunication with perl tk

In that thread, the request was for: "... an example of asynchronous socket communication happening through a perl tk application. A very simple and primitive one."

When I wrote that code last month, I included links to related documentation. If you follow those links, particularly the ones to sections of perlipc, you'll find examples of more complex socket I/O (including multiple clients).

-- Ken


Comment on Re: asynchronous socket communication with perl tk
Re^2: asynchronous socket communication with perl tk
by simonz (Acolyte) on Sep 26, 2013 at 14:23 UTC

    Hi, I have made the following modifications in the server code for asynchronous communication, but the server gui hangs as I start the client.

    use strict; use warnings; use Tk; use IO::Socket; use IO::Select; my $status = ''; my $mw = MainWindow->new; $mw->geometry("200x200"); my $buttonFrame = $mw->Frame()->pack(-side => 'bottom'); $buttonFrame->Button(-text => 'Start', -command => sub { init_server(\$mw, \$status) } )->pack(-side => 'left'); my $displayFrame = $mw->Frame()->pack(-side => 'top'); $displayFrame->Label(-text => 'Status:')->pack(-side => 'left'); $displayFrame->Label(-textvariable => \$status)->pack(-side => 'left') +; my $server; MainLoop; sub init_server { my ($mw_ref, $status_ref) = @_; $server = IO::Socket::INET::->new( Proto => 'tcp', LocalPort => 55555, Listen => 1, Reuse => 1 ) or die "Server can't start: $!"; =cut my $client = $server->accept(); $client->autoflush; $$mw_ref->fileevent($client, 'readable', sub { if (defined(my $read = <$client>)) { chomp $read; $$status_ref = $read; } }); =cut #my $client = $server->accept(); $$mw_ref->fileevent($server, 'readable', sub { my $readable_handles = new IO::Select(); $readable_handles->add($server); my $buf; while (1) { #Infinite loop # select() blocks until a socket is ready to be read or written my ($new_readable) = IO::Select->select($readable_handles, undef, undef, 0); print "Inside while \n"; # If it comes here, there is at least one handle # to read from or write to. For the moment, worry only about # the read side. foreach my $sock (@$new_readable) { print "Inside foreach $sock \n"; if ($sock == $server) { my $new_sock = $sock->accept(); # Add it to the list, and go back to select because the # new socket may not be readable yet. $readable_handles->add($new_sock); } else { # It is an ordinary client socket, ready for reading. $buf = <$sock>; if ($buf) { # .... Do stuff with $buf $$status_ref = $buf; } else { # Client closed socket. We do the same here, and remov +e # it from the readable_handles list $readable_handles->remove($sock); close($sock); } } } } } ); }
Re^2: asynchronous socket communication with perl tk
by simonz (Acolyte) on Sep 27, 2013 at 08:56 UTC

    Hi
    I even modified the server code to make it working, i removed the gui portion. Now when i am starting the server and then starting the client from another terminal , it works. However, the first time when I start client.pl, it prints msg1, then stops. Again when i start client.pl , it prints msg1 amd msg2. Similarly third time msg1, msg2,msg3 .

    My question is

    1. why not all the five messages msg1..msg5 are getting printed in one go when i start client.pl

    The client code remains as it is as posted before
    Can someone please explain me the flow of the code.

    my $server; $server = IO::Socket::INET::->new( Proto => 'tcp', LocalPort => 55555, Listen => 1, Reuse => 1 ) or die "Server can't start: $!"; my $readable_handles = new IO::Select(); my $buf; while (my $client = $server->accept) { #Infinite loop # select() blocks until a socket is ready to be read or written my ($new_readable) = IO::Select->select($readable_handles, undef, undef, 0); # print "Inside while \n"; # If it comes here, there is at least one handle # to read from or write to. For the moment, worry only about # the read side. $readable_handles->add($client); foreach my $sock (@$new_readable) { if ($sock == $server) { my $new_sock = $sock->accept(); # Add it to the list, and go back to select because the # new socket may not be readable yet. $readable_handles->add($new_sock); } else { # It is an ordinary client socket, ready for reading. $buf = <$sock>; if ($buf) { # .... Do stuff with $buf #$$status_ref = $buf; print $buf ; } else { # Client closed socket. We do the same here, and remov +e # it from the readable_handles list $readable_handles->remove($sock); #close($sock); } } } }

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://1055682]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others surveying the Monastery: (6)
As of 2014-07-13 06:20 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    When choosing user names for websites, I prefer to use:








    Results (247 votes), past polls