CGI.pm

CGI.pm

Original author(s)	Lincoln Stein
Stable release	3.49 / 2010-02-05
Platform	Perl
Type	Perl module for CGI
Website	http://stein.cshl.org/WWW/software/CGI/

CGI.pm is a large and widely used Perl module for programming Common Gateway Interface (CGI) web applications, providing a consistent API for receiving user input and producing HTML or XHTML output.

The module was written Lincoln Stein and is now maintained by Mark Stosberg.

A Sample CGI Page

Here is a simple CGI page, written in Perl using CGI.pm (in object oriented style):

#!/usr/bin/perl
 
use strict;
use warnings;
use CGI;
 
my $cgi = CGI->new();
 
print 
    $cgi->header('text/html'),
    $cgi->start_html('A Simple CGI Page'),
    $cgi->h1('A Simple CGI Page'),
    $cgi->start_form,
    'Name: ',
    $cgi->textfield('name'), $cgi->br,
    'Age: ',
    $cgi->textfield('age'), $cgi->p,
    $cgi->submit('Submit!'),
    $cgi->end_form, $cgi->p,
    $cgi->hr;
 
if ( $cgi->param('name') ) {
    print 'Your name is ', $cgi->param('name'), $cgi->br;
}
 
if ( $cgi->param('age') ) {
    print 'You are ', $cgi->param('age'), ' years old.';
}
 
print $cgi->end_html;

This would print a very simple webform, asking for your name and age, and after having been submitted, redisplaying the form with the name and age displayed below it. This sample makes use of CGI.pm's object-oriented abilities; it can also be done by calling functions directly, without the $cgi->.

Note: in many examples $q, short for query, is used to store a CGI object. As the above example illustrates, this might be very misleading.

Here is another script that produces the same output using CGI.pm's procedural interface:

#!/usr/bin/perl
use strict;
use warnings;
use CGI ':standard';
 
print header,
    start_html('A Simple CGI Page'),
    h1('A Simple CGI Page'),
    start_form,
    'Name: ',
    textfield('name'), br,
    'Age: ',
    textfield('age'), p,
    submit('Submit!'),
    end_form, p,
    hr;
 
print 'Your name is ', param('name'), br if param 'name';
print 'You are ', param('age'), ' years old.' if param 'age';
 
print end_html;

See also

• mod_perl

External links

• Official homepage
• CGI.pm – at the CPAN