GET variables overwriting POST variables

mjgp2 has asked for the wisdom of the Perl Monks concerning the following question:

I am using Apache 1.3 + mod_perl with perl 5.6.1. Requesting the page test.pl?urlRedirect=TEST which contains this:

use CGI;
$query = CGI->new();

my $urlG = $query->url_param("urlRedirect");
my $urlP = $query->param("urlRedirect");

print $query->header,
        $query->start_html('A Simple Example');

print("CGI version: ".(CGI->VERSION)."<BR>");
print("Url redirect: form=>$urlP, url=>$urlG<BR>");
[download]

produces this:

CGI version: 3.09
Url redirect: form=>TEST, url=>TEST

There is NO posted form data though! Help!

Comment on GET variables overwriting POST variables Download Code

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Re: GET variables overwriting POST variables by Aristotle (Chancellor) on Nov 16, 2005 at 13:07 UTC
When you make `POST` request, `CGI::param()` uses the `POST` parameters and ignores the URL. When you make a `GET` request – as you did – (or `HEAD`, etc), it uses the URL parameters. Most of the time, this is just fine and is what you want. This means that if you do need to know where `CGI::param()` got its values from, you can check `CGI::request_method()` to find out. Makeshifts last the longest.	[reply]
Re: GET variables overwriting POST variables by derby (Abbot) on Nov 16, 2005 at 13:57 UTC
In order to make param processing DWIM, CGI stores GET and/or POST params into the same internal variable. Here's the relevant bits from CGI: # If method is GET or HEAD, fetch the query from # the environment. if ($meth=~/^(GET\|HEAD)$/) { if ($MOD_PERL) { $query_string = $self->r->args; } else { $query_string = $ENV{'QUERY_STRING'} if defined $ENV{'QUERY_STRING'}; $query_string \|\|= $ENV{'REDIRECT_QUERY_STRING'} if defined $ENV{'REDIRECT_QUERY_STRING'}; } last METHOD; } if ($meth eq 'POST') { $self->read_from_client(\$query_string,$content_length,0) if $content_length > 0; # Some people want to have their cake and eat it too! # Uncomment this line to have the contents of the query # string # APPENDED to the POST data. # $query_string .= (length($query_string) ? '&' : '') . # $ENV{'QUERY_STRING'} if defined $ENV{'QUERY_STRING'}; last METHOD; } [download] I've always loved that cake comment in CGI -derby	[reply] [d/l]