in reply to Variable Variables

I just want to point out, since multiple people have suggested using foreach ($query->param()) { $$_ = $query->param($_) } that the CGI module provides a method for importing names: $query->import_names('Q'); imports all the parameters into the Q namespace. CGI warns against importing into the main package, for good reason: it's a huge security flaw! Someone could replace the value of any scalar variable in your code just by faking the form data.

Also note that using the above 'roll-your-own' approach to importing fails for multi-valued parameters, assigning them to scalars instead of to arrays. Using CGI's built-in method handles multi-valued parameters correctly.

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Re: Re: Variable Variables
by Anonymous Monk on Dec 06, 2000 at 02:10 UTC
    Using CGI's built-in method handles multi-valued parameters correctly.

    Actually I tried it ($cg->import_names('Q')) and it still loses values on muti-valued params. - Bob Niederman
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      I just tried it too. It turns out that import_names() does this in an interesting fashion; it imports all parameters as both scalars and arrays. 
      #!/usr/local/bin/perl
 
use CGI;
 
my $query = new CGI ( { single => 'one',
                        multi  => ['two', 'three'],
                      }
                    );
 
$query->import_names('Q');
 
1;

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      Now, using the debugger to examine the results: 
      Loading DB routines from perl5db.pl version 1.0402
Emacs support available.
 
Enter h or `h h' for help.
 
main::(tmp.cgi:5):      my $query = new CGI ( { single => 'one',
main::(tmp.cgi:6):                              multi  => ['two', 'thr
+ee'],
  DB<1> n
main::(tmp.cgi:10):     $query->import_names('Q');
  DB<1> n
main::(tmp.cgi:12):     1;
  DB<1> V Q
$single = 'one'
@single = (
   0  'one'
)
$multi = 'two'
@multi = (
   0  'two'
   1  'three'
)
  DB<2>

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