View source for CGI.pm

{{Short description|Perl module for web applications}}
{{primary sources|date=September 2011}}
{{one source |date=April 2024}}
{{Infobox software
| name = CGI.pm
| logo =
| screenshot = 
| caption = 
| author = [[Lincoln Stein]]
| developer = Lee Johnson
| released = 
| latest release version = 4.21
| latest release date = 2015-06-22
| latest preview version = 
| latest preview date = 
| operating system = 
| platform = [[Perl]]
| language = 
| genre = [[Perl module]] for [[Common Gateway Interface|CGI]]
| license = 
| website = {{URL|https://metacpan.org/release/CGI}}
}}

'''CGI.pm''' is a large and once widely used [[Perl module]] for [[Computer programming|programming]] [[Common Gateway Interface]] (CGI) [[WWW|web]] applications, providing a consistent [[Application programming interface|API]] for receiving and processing user input. There are also functions for producing [[HTML]] or [[XHTML]] output, but these are now unmaintained and are to be avoided.<ref name="auto">{{Cite web|url=https://metacpan.org/dist/CGI/view/lib/CGI.pod|title=CGI - Handle Common Gateway Interface requests and responses - metacpan.org|website=metacpan.org}}</ref> CGI.pm was a core Perl module but has been removed as of v5.22 of Perl.<ref name="auto"/> The module was written by [[Lincoln Stein]] and is now maintained by Lee Johnson.

== Examples ==
Here is a simple CGI page, written in Perl using CGI.pm (in [[Object-oriented programming|object-oriented]] style):

<syntaxhighlight lang="perl">
#!/usr/bin/env perl

use strict;
use warnings;

use CGI;

my $cgi = CGI->new;

print $cgi->header('text/html');

print << "EndOfHTML";
<!DOCTYPE html>
<html>
    <head>
        <title>A Simple CGI Page</title>
        <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
    </head>
    <body>
        <h1>A Simple CGI Page</h1>
        <form method="post" enctype="multipart/form-data">
            Name: <input type="text" name="name"  /><br />
            Age: <input type="text" name="age"  /><p>
            <input type="submit" name="Submit!" value="Submit!" />
        </form>
        <hr />
EndOfHTML

if ( my $name = $cgi->param('name') ) {
    print "Your name is $name.<br />";
}

if ( my $age = $cgi->param('age') ) {
    print "You are $age years old.";
}

print '</body></html>';
</syntaxhighlight>

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 {{mono|$cgi->}}, however the necessary functions must be imported into the namespace of the script that requires access to those functions:

<syntaxhighlight lang="perl">
#!perl

use strict;
use warnings;
use CGI qw/ :standard /;

print header('text/html');

# ... HTML output same as above example

if ( my $name = param('name') ) {
    print "Your name is $name.<br />";
}

if ( my $age = param('age') ) {
    print "You are $age years old.";
}

print '</body></html>';
</syntaxhighlight>

Note: in many examples {{var|$q}}, short for query, is used to store a CGI object.

==See also==
*[[mod_perl]]

==References==
{{Reflist}}

==External links==
{{Wikibooks|Perl Programming|CGI}}
*[https://metacpan.org/module/CGI CGI.pm] &ndash; at the [[CPAN]]

[[Category:Perl modules]]


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