I didn't know where to begin, so I pretty much rewrote them X_X It was basically overly complex. If you wonder why I made a certain change, feel free to ask.

I did find it odd that "12" is hardcoded in the server (as opposed to being looked up by $process_name, or specified by the client), but "cs2" isn't.

server.pl

#!/usr/bin/perl

# die commands probably need to be replaced with something else.

use strict;
use warnings;

use IO::Socket;

my $EOL = "\015\012";

my $listen_sock = new IO::Socket::INET (
   LocalAddr => '127.0.0.1',  ###
   LocalPort => '8888',
   Proto     => 'tcp',
   Listen    => 1,
   Reuse     => 1,
) or die("Could not create socket: $!\n");

my $client_sock = $listen_sock->accept()
or die("Error accecpting connnection: $!\n");

{
   local $/ = $EOL;
   my $incoming;
   while (defined($incoming = <$client_sock>)) {
      chomp($incoming);

      die("Received nothing.\n") unless length $incoming;

      my $command;
      ($command, $incoming) = split /\s+/, $incoming, 2;

      if ($command eq "check") {
         my $process_name = $incoming;
         die("check: Bad process name.\n") unless $process_name =~ /^\
+w+$/;
#         my $num_processes = grep { /$process/ } `ps -ef`;
         my $num_processes = int(rand()*24);  ###
         print $client_sock ($num_processes >= 12 ? "up" : "down"), $E
+OL;
         next;
      }

      die("Bad command $command.\n");
   }
}

close($client_sock);
close($listen_sock);

[download]

client.pl

#!/usr/bin/perl

use strict;
use warnings;

use IO::Socket;

my $EOL = "\015\012";

my $mpts;

### Until I get cgi working.
open OUT, "> testpage.html"
or die("Unable to open output file: $!\n");
select(OUT);

if (0) ###
{
   local *HEADER;
   open HEADER, "< 1.html"
   or die("Unable to open header file: $!\n");
   print while (<HEADER>);
   close HEADER;
}

my $sock = new IO::Socket::INET(
#   PeerAddr => '53.230.116.97',
   PeerAddr => '127.0.0.1',  ###
   PeerPort => '8888',
   Proto    => 'tcp',
) or die("Error creating connnection: $!\n");

for (1..20) {
   my $command = "check cs2";
   print $sock $command, $EOL;

   local $/ = $EOL;
   my $reply = <$sock>;
   die("Lost connection to server.\n") unless defined $reply;
   chomp($reply);

   if ($reply eq "up") {
      print STDERR "up\n";
      print "<img src=\"./cs2up.gif\">\n";
      $mpts++;
   } elsif ($reply eq "down") {
      print STDERR "down\n";
      print "<img src=\"./cs2down.gif\">\n";
   } else {
      die("Bad reply $reply\n");
   }

   sleep(1);
}

close($sock);
close(OUT);

[download]

In reply to Re^6: two-way socket works once only? by ikegami
in thread two-way socket works once only? by wolfger

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.