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

Dear community, I'm programming a simple socket client who connect to a server and send data. The below code works perfect, but I'm searching a method to check connection prior to send data. This because I'm sending data continuosly using a loop, and if, for some reason, the connection goes down, the script hangs. So, is there a way to check if the connection is established and, if not, call again OpenSocket Sub inside the loop? 
#!/usr/bin/perl
use IO::Socket;
my $sock1;

sub OpenSocket{
$sock1 = new IO::Socket::INET(
                  PeerAddr => '192.168.10.7',
                  PeerPort => 8000,
                  Proto    => 'tcp');
$sock1 or die "no socket :$!";
}

################ START SCRIPT #################

OpenSocket();
$str="Something to send";
while (1) {
$sock1->send($str);
}
close($sock1);

[download]

Replies are listed 'Best First'.
Re: Check connection state prior to send data
by BrowserUk (Patriarch) on Sep 24, 2016 at 07:04 UTC

    Take a look at select, IO::Select, PerlIPC.

    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority". I knew I was on the right track :)
    In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
      Sorry, I don't wish to be controversial, but your reply sounds like: "check perlmonks for solution" :-)
[reply]

        You achieved your wish. That's not controversial.

        With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority". I knew I was on the right track :)
        In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
Re: Check connection state prior to send data
by Lucas Rey (Sexton) on Sep 26, 2016 at 06:02 UTC
    Dear community, thank you all to partecipate, I would like to share my (very simply) solution to my question. The following code works perfect and suit my needs.

    BTW, the concept behind solution is simple too:
    -- Open a socket
    -- Server is listining?
    ---- YES: OK Connect
    ---- NO: Enter in loop until Server will be ready
    -- Send data
    -- Is there any response from server?
    ---- YES: Continue sending loop
    ---- NO: (Empty Response): Call OpenSocket and wait untill Server will be ready again.
    #!/usr/bin/perl
use IO::Socket;
my $sock1;
sub OpenSocket{
  while ( !$sock1 ) {
    $sock1 = IO::Socket::INET->new (
             Proto            => "tcp",
             PeerAddr    => "192.168.10.7",
             PeerPort        => "8000",
             Timeout        => "1")
  }
}

################ START SCRIPT #################

OpenSocket();
sleep(1);
my $str="DATA TO SEND"
while(1) {
  $sock1->send($str);
  sleep(1);
  $sock1->recv($channel1, 128);

  if ( !$channel1 ) {
    $sock1->shutdown(2);
    $sock1="";
    print "DISCONNECTED... I'M RECONNECTING AND RESEND PREVIOUS PACKET
+\n";
    OpenSocket();
    sleep(1);
    $sock1->send($str);
 }
}
close($sock1);

    [download]
[reply]
[d/l]

      What do you think this code does? $sock1  = shift; Ie. Where are you shifting the value you are assigning to $sock1 from?

      With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority". I knew I was on the right track :)
      In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]
[select]
        Thank you, that was a typo left there from previous tests. I modified my post with the right code. That one works perfect also with one or more parameters.
[reply]

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