Passing Variable with redirect in cgi/perl - perl

Question

I have two cgi script. Login.cgi and welcome.cgi
I want to pass variable between these two pages
Here are the two pages i have
#!C:/Perl/bin/perl.exe -w
#login.cgi
use strict;
use warnings;
use CGI::Pretty qw(:all);
my $cgi = new CGI;
my $username = $cgi->param('username');
my $password = $cgi->param('password');
if ( ( $cgi->param('username') eq 'demo' ) && ( $cgi->param('password') eq 'demo' ) ) {
print $cgi->redirect("welcome.cgi");
}
else {
print header();
print start_html( -title => "Login" );
if ( $cgi->param('username') or $cgi->param('password') ) {
print center( font( { -color => 'red' }, "Invalid input" ) );
}
print generate_form();
print end_html();
}
sub generate_form {
return start_form,
h1("Please Login"),
p( "username", textfield('username') ),
p( "password", textfield('password') ), p(submit),
end_form;
}
Another page welcome.cgi
#!C:/Perl/bin/perl.exe -w
#welcome.cgi
use warnings;
use CGI::Pretty qw(:all);
use strict;
my $cgi=new CGI;
my $username;
print header();
print start_html("Welcome"),h1("Hello, $username");
print end_html();
How do I get the username variable passed to welcome.cgi?

Answer 1

use CGI::Session.
For a tutorial on all the different ways to pass information between scripts and why this implementation is a good choice, read CGI::Session::Tutorial
Implemented in your login script:
#login.cgi
use strict;
use warnings;
use CGI::Pretty qw(:all);
use CGI::Session;
my $cgi = new CGI;
my $session = CGI::Session->new($cgi) or die CGI->Session->errstr;
my $username = $cgi->param('username') // '';
my $password = $cgi->param('password') // '';
if ( $username eq 'demo' && $password eq 'demo' ) {
$session->param(username => $username);
print $cgi->redirect("welcome.cgi");
exit;
}
print $session->header();
print start_html( -title => "Login" );
if ( $username or $cgi->param('password') ) {
print center( font( { -color => 'red' }, "Invalid input" ) );
}
print start_form,
h1("Please Login"),
p( "username", textfield('username') ),
p( "password", textfield('password') ), p(submit),
end_form,
end_html();
And in your welcome script:
#welcome.cgi
use strict;
use warnings;
use CGI::Pretty qw(:all);
use CGI::Session;
my $cgi = new CGI;
my $session = CGI::Session->new($cgi) or die CGI->Session->errstr;
my $username = $session->param('username');
print header();
print start_html("Welcome"),h1("Hello, $username");
print end_html();

Answer 2

You can either pass it directly (by encoding it in a query string and adding that to the URL you are redirecting to) or you can store it in a cookie or a session and then retrieve it in the other script.

Answer 3

I would have to slightly disagree with Mr.Miller here. CGI::Session is at present outdated in many regards especially due to:
The method to set cookies is outdated, and does not adhere to the RFC6265
The Cookie ID algorithm is not secure enough, the author has moved on to other projects.
And thus should not be used unless for educational purposes.
With regards to the original question, you can look at this simple tutorial
http://practicalperl5.blogspot.in/2014/07/perl-login-script.html