scratchpad
joeface
<p>
First journey into two new worlds of Perl. Client/Server using IO::Socket, and Perl Tk because I got bored of using the CLI client on Windows...
</p>
<p>
The server runs on a linux box, and the client runs on an adjacent windows box
</p>
<p>
The client accepts a URL, and sends it off to the server, which receives it (along with a built-in "fetch" command), and uses wget to fetch whatever's at that location.
</p>
<p>
Silly use, yes, but it had to do more than Hello World. God only knows what kinds of ideas this is going to give me. Opened up and began illuminating a few dark, scary rooms that I was previously locked out of.
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<p>
Evolved out of just sending back the string it was originally given, then sending back a reversed string. That code is still in there, but the Tk client only sends the "fetch" command.
</p>
<p>
Server:
<code>
#!/usr/bin/perl -w
use strict;
use IO::Socket;
use Getopt::Long;
use File::Basename;
my $scriptname = basename($0);
my $scriptdir = dirname($0);
## Standard options
my $silent;
my $verbose;
GetOptions(
"s" => \$silent,
"v" => \$verbose,
);
my $localhost = '192.168.0.100';
my $port = 55555;
my $save_loc = '/var/tmp/client-server-gets';
my $server = new IO::Socket::INET (
LocalHost => $localhost,
LocalPort => $port,
Proto => 'tcp',
Listen => 1,
Reuse => 1,
);
$server or die "Can't create server: $!\n";
printinfo("$scriptname listening on port $port");
while(my $HANDLER = $server->accept()) {
$HANDLER or die "server->accept: $!\n";
my $peeraddr = $HANDLER->peeraddr;
my $peerhost = $HANDLER->peerhost;
my $hostinfo = gethostbyaddr($peeraddr, AF_INET);
printinfo("Accepted connection from $peerhost");
my $in = <$HANDLER>;
chomp($in);
if ($in) {
printinfo("Client said \"$in\"");
my ($cmd,) = split(/\s+/, $in);
$in =~ s/.*?\s+//;
if ($cmd eq 'repeat') {
print $HANDLER localtime() . ": you said \"$in\"\n";
printinfo("Sent \"$in\" to client");
} elsif ($cmd eq 'reverse') {
$in = reverse($in);
print $HANDLER localtime() . ": you said \"$in\"\n";
printinfo("Sent \"$in\" to client");
} elsif ($cmd eq 'fetch') {
my $file = basename($in);
if ($verbose) {
system("wget -N -P $save_loc $in");
} else {
system("wget -N -P $save_loc -q $in");
}
my $rc = $? >> 8;
if ($rc == 0) {
printinfo("Fetch of item \"$in\" successful");
print $HANDLER "Requested item saved as $save_loc/$file\n";
} else {
printinfo("Fetch of item \"$in\" failed");
print $HANDLER "Sorry, your request failed\n";
}
} else {
print $HANDLER "Sorry, there was no known command attached to your msg\n";
}
}
}
sub printinfo {
unless($silent) {
print localtime() . ": @_\n";
}
}
__END__
</code>
</p>
<p>
Client:
<code>
#!/usr/bin/perl -w
use Tk;
use strict;
use IO::Socket;
use File::Basename;
my $server = '192.168.0.100';
my $port = 55555;
my $mw = MainWindow->new;
$mw->Label(
-text => "\nURL to desired file"
)->pack;
my $url = $mw->Entry(
-width => 100
)->pack;
$mw->Label(-text => " ")->pack; ######################## SPACER
my $button = $mw->Button(
-text => 'Fetch',
-command => sub{do_fetch($url)},
-padx => 10,
)->pack;
#$button->bind('<Enter>', sub{do_fetch($url)});
$mw->Label(-text => " ")->pack; ######################## SPACER
my $ent_msg;
my $ent = $mw->Entry(-width => 100,
-state => "readonly",
-textvariable => \$ent_msg)->pack();
MainLoop;
sub print_status {
my $msg_txt = join(" ", @_);
$ent_msg = $msg_txt;
$ent->update();
}
################## CLIENT PORTION
sub do_fetch {
print_status("Submitted request to $server");
my $url = shift;
my $url_val = $url->get;
my $scriptname = basename($0);
my $command = 'fetch';
my $msg = $url_val;
unless($msg) {
print "Usage: $scriptname <msg>\n";
exit;
}
chomp($msg);
my $client = new IO::Socket::INET (
PeerAddr => $server,
PeerPort => $port,
Proto => "tcp",
)
or die "Can't connect to $server:$port : $!\n";
print $client $command . " " . $msg . "\n";
my $response = <$client>;
if ($response) {
chomp($response);
print_status("$response");
}
}
__END__
</code>
</p>