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

Hi,

I have been reading up on lexical and package variables but this branch is just out of my reach.

I am submitting a basic form to a cgi - the problem is the perl cgi is outdated and i dont know how to translate the code into lexical. The refernced $key values keep throwing a undefined global at $Form data so i threw a few 'my's at it. now the erorrs are syntax at "$FORM_DATA{" around lines 60. Where might I go from here? 

#! /usr/bin/perl -Tw

use strict;
use warnings;
use CGI::Carp qw(fatalsToBrowser), qw(warningsToBrowser);

my ($webmaster, $user);
our($FORM_DATA, $change_text);

$webmaster = "http\:\/\/www.mysite.com\/";

&parseform(*change_text);

print "Content-type: text/plain\r\n\r\n";

#  $user = $change_text{'user'};

print "\$user:\n$user\n\n";


exit(0);

sub parseform
{
   local (*FORM_DATA) = @_;
    my ( $reqmet, $qst, $keyval, $key, $val, $keyvalpears);

   $reqmet = $ENV{'REQUEST_METHOD'};
    
     if ($reqmet eq "GET") {
     
        print "This type of request is not accepted please update via 
+the authenticated edit form at $webmaster";
     }
     elsif($reqmet eq "POST"){
       
        read (STDIN, $qst, $ENV{'CONTENT_LENGTH'});
     } else { 

          &reterr (500, "Server Error",
                         "Server uses unsupported method");
     }

print "\$qst:\n$qst\n\n"; 

   @keyvalpears = split (/&/, $qst);

print "\@keyvalpears:\n@keyvalpears\n\n";

  foreach $keyval (@keyvalpears) {

     ($key, $val) = split (/=/, $keyval);
     
      $val =~ tr/+/ /;
      $val =~ s/%([\dA-Fa-f][\dA-Fa-f])/pack ("C", hex ($1))/eg;


# if defined no need to use anymore re my?

       if(defined($FORM_DATA{$key})) {
        
             $FORM_DATA{$key} = join ("\0", $FORM_DATA{$key}, $val);
       }else{
             $FORM_DATA{$key} = $val;
       }
      print "\$FORM_DATA val :\n$FORM_DATA{$val}\n\n";
   }

}




sub reterr
{
    my ($status, $keyword, $message) = @_;
    print "Content-type: text/html", "\r\n\r\n";
    print "Status: ", $status, " ", $keyword, "\n\n";
    print <<End_of_Error;
<HTML>
<HEAD>
    <TITLE>CGI Program - Unexpected Error</TITLE>
</HEAD>
<BODY>
<H1>$keyword</H1>
<HR>$message<HR>
Please contact $webmaster for more information.
</BODY>
</HTML>
End_of_Error
    exit(1);
}

[download]

Replies are listed 'Best First'.
Re: globbed variable in parse cgi form - beyond me
by ikegami (Patriarch) on Jun 27, 2011 at 00:05 UTC
    Don't recreate CGI!
[reply]

      thanks ikegami,

      it was not my intention to recreate cgi - i was just following the instructions as it were.

      Basically I need to be doing something along these lines then(see code), although the input element names are being returned where the values are not. yet... 

      #! /usr/bin/perl -w

use strict;
use warnings;
use CGI;
use CGI::Carp qw(fatalsToBrowser), qw(warningsToBrowser);


my ($webmaster, $user, $name, @names, $value, @values, $query);

$query = CGI->new;

$webmaster = "http\:\/\/www.mysite.com\/";

 @names= $query->param;
 
 foreach $name(@names){ 
          
          $value = $query->param('$name');
           
          push(@values, $value);
 }

 

print "Content-type: text/plain\r\n\r\n";

print "names @names \n\n";
print "values: @values \n\n";


exit(0);

      [download]
[reply]
[d/l]

        '$name' creates the 5 character string "$","n","a","m","e". Double-quoted strings interpolate, but no need for that either. Use ->param($name)

        May I also recommend that you don't declare your variables until you need them? No need to make their scope larger than needed. 

        #! /usr/bin/perl -w

use strict;
use warnings;
use CGI;
use CGI::Carp qw( fatalsToBrowser warningsToBrowser );

my $query = CGI->new;

my $webmaster = "http://www.mysite.com/";

my @names = $query->param;
my @values;
foreach my $name (@names) { 
    my $value = $query->param($name);
    push(@values, $value);
}

print "Content-Type: text/plain\r\n\r\n";

print "names @names\n\n";
print "values: @values\n\n";

        [download]
[reply]
[d/l]
[select]
Re: globbed variable in parse cgi form - beyond me
by Anonymous Monk on Jun 27, 2011 at 01:11 UTC
[reply]

      How does mentioning Catalyst help somebody who is struggling with their first CGI program, and has problems with when variables interpolate and when not? Catalyst may or may not be a fantastic framework, but it is at least a few steps away for somebody just starting to learn Perl.

[reply]

        How does mentioning Catalyst help somebody who is struggling with their first CGI program

        FWIW, when I posted this "SEE ALSO" section, it was only apparent the OP did not know CGI, not apparent the OP was just starting to learn perl

        Mentioning Catalyst, including offering a walkthrough, demonstrates how Catalyst makes life easier

[reply]

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