I have an external program I am required to use to issue SQL statements to a database. The way the query works is that I issue a statement and when the result set changes, the program will dump back out to stdout. This keeps me from having to poll the database. I don't have direct access to the DB (that would be preferable) so I'm stuck with this.

The shell command looks like this:

MyDbQueryProgram "SELECT * FROM MY_TABLE;"

It runs fine from the command line, but I'm having a bear of a time getting it to work from POE. Any ideas on how to escape the string here? POE::Wheel::Run does a "sh -c" to run the command. Just running from the shell, this works:

sh -c 'MyDbQueryProgram "SELECT * FROM MY_TABLE;"'

Does anyone have any ideas? Thanks in advance for your help.

#!/usr/bin/perl

use warnings;
use strict;

use POE;
use POE::Wheel::Run;
use POE::Filter::Line;
use POE::Filter::Stream;

$| = 1;
my $outCT = 0;
my $program = "MyDbQueryProgram";
my @progargs = ("SELECT * FROM MY_TABLE;");
POE::Session->create(
 inline_states => {
  _start => \&startup,
  stdout => \&stdout,
  stdin => \&stdin,
  stderr => \&stderr,
 }
);
POE::Kernel->run();

sub startup {
 my $heap = $_[HEAP];
 
 my $wheel = POE::Wheel::Run->new(
  Program => $program,
  ProgramArgs => \@progargs,

  StdinEvent => 'stdin',
  StderrEvent => 'stderr',
  StdoutEvent => "stdout",     
  StdoutFilter => POE::Filter::Stream->new(),
 );


 print "Wheel ID is ".$wheel->ID."\n";
 print "Wheel's PID is ".$wheel->PID."\n";
 $heap->{program} = $wheel;
}


sub stdout {
 my ($heap, $input, $wheelID) = @_[HEAP, ARG0, ARG1];
 print "$input\n";
 $outCT++;
 print $outCT;
}

sub stderr {
 my ($op, $errnum, $errstr, $wheel_id) = @_[ARG0, ARG1, ARG2, ARG3];
 print "stderr\n";
 print "OP = $op\nERRNUM = $errnum\nERRSTR = $errstr\nID = $wheel_id\n
+";
}

sub stdin {
 print "stdin\n";
}
[download]

---

---

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! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

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:
	&		&
	<		&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.