noslenj123 has asked for the wisdom of the Perl Monks concerning the following question:

I am humbly aspiring to learn mod_perl by converting an existing, fairly complex, cgi application. Though I have been pretty successful getting most scripts to run under ModPerl::Registry, I'm getting remembered cgi.pm params. Which leads me to believe I have no clue on what gets shared. I have one module called Security.pm with no global vars. I call a function which creates $q=CGI->new;, checks authorization and displays a login page with a param('login_name') if they are not logged in yet. I have many different scripts with the following basic format: 
sub main {
   my $q = CGI->new;
   my $func = $q->param('func');
   if ($func eq 'somefunc') { &somefunc }
}

sub somefunc {
    my $q = CGI->new;
}

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My problem is that if I use param('login_name') in &somefunc it has a retained value from elsewhere, like the one entered in during login from the Security module. I tried '-override=>1' on that param and received an error that indicated I could not change the value of that param.

So are $q vars being somehow loaded up once in mod_perl and never cleared with each CGI->new?

I could certainly use some tips on understanding variable usage and sharing/not sharing under mod_perl. I am searching through 'practical mod_perl' as well.

I'd appreciate any pointers or direction on how to properly use modules like CGI.pm or how modules behave after they are loaded and compiled in mod_perl.

Your Humble Servant

Replies are listed 'Best First'.
Re: mod_perl and CGI variable lifetime puzzle
by perrin (Chancellor) on May 13, 2005 at 19:59 UTC
    You're creating a closure somewhere. You have code somewhere that looks like this: 
    my $q = CGI->new();

sub something {
    $q->param()....
}

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    You need to explicitly pass the CGI object to each sub that uses it.
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[d/l]
      Okay, I'll go back through all the scripts and instantiate one instance of CGI in the main sub, and then passed it to any subs being called. Also, if I had any lingering CGI.pm calls using the old function oriented calls rather than the object oriented calls, might that cause an issue?
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        The function syntax isn't a problem.
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Re: mod_perl and CGI variable lifetime puzzle
by Adrade (Pilgrim) on May 14, 2005 at 02:13 UTC
    Check out 17.3.2 of CGI Programming with Perl. There's a section there on mod_perl considerations that's quite concise and helpful. Converting from CGI to mod_perl can sometimes be painful, but once all the kinks have been ironed out, the benefit is really quite nice. As for CGI, I'm still stuck in the stone-ages - I use a variant of ReadParse from an old cgi-lib.pl for most of my stuff.. :-)
      -Adam
    P.S. Also be sure so check out the mod_perl docs, though I'm sure you prob already have :-)
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