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Display output from server for every command sent by client via Socket

Posted on 2010-09-02
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Last Modified: 2013-11-05
There are 4 commands that my client needs to send to server using socket named TCP_SOCK in sequence and my client needs to display the output from server for every command sent to it. How can I achieve this goal? Every command is ended by semi-column ";" to ask server to execute it.
I use "print scalar <TCP_SOCK>;" but the client cannot display all the text from the sever, it misses some texts. When I try to use:

while ($line = <>)
{
      print $line;
}

only the first command is executed, not continue with the other commands.
select TCP_SOCK; $| = 1; select STDOUT;
my @command;
$command[0] = qq/Do the first one;/;
$command[1] = qq/Do the second one;/;
$command[2] = qq/Do the third one;/;
$command[3] = qq/Do the fourth one;/;
print TCP_SOCK $command[0];
print TCP_SOCK $command[1];
print TCP_SOCK $command[2];
print TCP_SOCK $command[3];
close TCP_SOCK;

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Question by:tballah
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6 Comments
 
LVL 3

Expert Comment

by:gremwell
ID: 33589754
Try the attached code.

#!/usr/bin/perl -w

use strict;
use IO::Socket::INET;

sub transaction($$) {
	my $socket = shift;
	my $command = shift;

	$socket->print($command . ";");
	my $res = <$socket>;
	chomp $res;

	return $res;
}

# ----

my $socket = new IO::Socket::INET(PeerAddr => "localhost:10000") || die;
$socket->autoflush(1);

# ----

my $res1 = transaction($socket, qq/Do the first one/);
printf "res1: >%s<\n", $res1;

# ----

my $res2 = transaction($socket, qq/Do the second one/);
printf "res2: >%s<\n", $res2;

# ----
$socket->close();

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Author Comment

by:tballah
ID: 33590085
The response from the server contains many lines and I follow the solution from the sample code you provide to me, I can see only the first line from the output, there are many other lines missing. I can see all the lines when I use while loop but it blocks me from executing other commands.
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Expert Comment

by:gremwell
ID: 33590114
If the response is multiline, how do you know which line is the last line of the response?
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Author Comment

by:tballah
ID: 33590378
The response for the first command looks like:

+++    SGSN                2010-09-02 22:10:27
O&M    #852
%%LGI:OP="ballah",PWD="*****",SER="MML Backup";%%
RETCODE = 0  Execution succeeded


---    END

The last line is "---    END". From the sample of your code provided I can see only the first line "+++    SGSN                2010-09-02 22:10:27". If I do loop with while I can see all the lines responded from the server but it could not exit loop and it loops forever and I cannot execute other commands. Please see my code.
select TCP_SOCK; $| = 1; select STDOUT;
my @sgsn_command;
$sgsn_command[0] = qq/LGI:OP="$user_name",PWD="$password",SER="MML Backup";/;
$sgsn_command[1] = qq/SAVE CFG:;/;
$sgsn_command[2] = qq/SET FTPENABLE:;/;
$sgsn_command[3] = qq/LGO:;/;
exec_mml($sgsn_command[0]);
exec_mml($sgsn_command[1]);
exec_mml($sgsn_command[2]);
exec_mml($sgsn_command[3]);
close TCP_SOCK;
}

sub exec_mml
{
  print TCP_SOCK shift;
  while (<TCP_SOCK>)
  {
    print;
  }
}

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Accepted Solution

by:
gremwell earned 500 total points
ID: 33590438
Then you should add a stop condition to your loop, such as
     last if /^---    END$/;
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LVL 1

Author Closing Comment

by:tballah
ID: 33590644
sub exec_mml
{
  print TCP_SOCK shift;
  while ()
  {
    print;
    last if /END/;
  }
}
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