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{{Short description|Perl module for web applications}}
{{primary sources|date=September 2011}}
{{primary sources|date=September 2011}}
{{one source |date=April 2024}}
{{Infobox Software
{{Infobox software
| name = CGI.pm
| name = CGI.pm
| logo =
| logo =
| screenshot =
| screenshot =
| caption =
| caption =
| author = [[Lincoln Stein]]
| author = [[Lincoln Stein]]
| developer =
| developer = Lee Johnson
| released =
| released =
| latest release version = 3.49
| latest release version = 4.21
| latest release date = 2010-02-05
| latest release date = 2015-06-22
| latest preview version =
| latest preview version =
| latest preview date =
| latest preview date =
Line 15: Line 17:
| platform = [[Perl]]
| platform = [[Perl]]
| language =
| language =
| status =
| genre = [[Perl module]] for [[Common Gateway Interface|CGI]]
| genre = [[Perl module]] for [[Common Gateway Interface|CGI]]
| license =
| license =
| website = http://search.cpan.org/dist/CGI/
| website = {{URL|https://metacpan.org/release/CGI}}
}}
}}
'''CGI.pm''' is a large and widely used [[Perl module]] for [[Computer programming|programming]] [[Common Gateway Interface]] (CGI) [[WWW|web]] applications, providing a consistent [[Application programming interface|API]] for receiving user input and producing [[HTML]] or [[XHTML]] output.


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


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


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


use strict;
use strict;
use warnings;
use warnings;

use CGI;
use CGI;


my $cgi = CGI->new();
my $cgi = CGI->new;


⚫
print $cgi->header('text/html');
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;


print << "EndOfHTML";
⚫
if ( $cgi->param('name') ) {
<!DOCTYPE html>
⚫
print 'Your name is ', $cgi->param('name'), $cgi->br;
<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 ( $cgi->param('age') ) {
if ( my $age = $cgi->param('age') ) {
print 'You are ', $cgi->param('age'), ' years old.';
print "You are $age years old.";
}
}


print $cgi->end_html;
print '</body></html>';
</syntaxhighlight>
</source>


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 <tt>$cgi-></tt>.
This would print a very simple webform, asking for your name and age, and after having been submitted, redisplaying the form with the name and age displayed below it. This sample makes use of CGI.pm's object-oriented abilities; it can also be done by calling functions directly, without the {{mono|$cgi->}}, however the necessary functions must be imported into the namespace of the script that requires access to those functions:


⚫
<syntaxhighlight lang="perl">
⚫
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.
#!perl


Here is another script that produces the same output using CGI.pm's [[Procedural programming|procedural]] interface:

⚫
<source lang="perl">
#!/usr/bin/perl
use strict;
use strict;
use warnings;
use warnings;
use CGI ':standard';
use CGI qw/ :standard /;


print header,
print header('text/html');
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;


# ... HTML output same as above example
⚫
print 'Your name is ', param('name'), br if param 'name';
⚫
print 'You are ', param('age'), ' years old.' if param 'age';


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

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==
==See also==
*[[Mod perl|mod_perl]]
*[[mod_perl]]


==External links==
==References==
{{Reflist}}
*[http://stein.cshl.org/WWW/software/CGI/ Official homepage]
⚫
*[http://search.cpan.org/dist/CGI.pm/ CGI.pm] &ndash; at the [[CPAN]]


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

⚫
{{unix-stub}}


[[Category:Perl modules]]
[[Category:Perl modules]]


⚫
{{unix-stub}}

Latest revision as of 02:53, 17 October 2024

CGI.pm
Original author(s)Lincoln Stein
Developer(s)Lee Johnson
Stable release
4.21 / 2015-06-22
PlatformPerl
TypePerl module for CGI
Websitemetacpan.org/release/CGI

CGI.pm is a large and once widely used Perl module for programming Common Gateway Interface (CGI) web applications, providing a consistent 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.[1] CGI.pm was a core Perl module but has been removed as of v5.22 of Perl.[1] The module was written by Lincoln Stein and is now maintained by Lee Johnson.

Examples

[edit]

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

#!/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>';

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->, however the necessary functions must be imported into the namespace of the script that requires access to those functions: 

#!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>';

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

See also

[edit]

References

[edit]
  1. ^ a b "CGI - Handle Common Gateway Interface requests and responses - metacpan.org". metacpan.org.
[edit]
The Wikibook Perl Programming has a page on the topic of: CGI


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