CGI::Cookie(3) User Contributed Perl Documentation CGI::Cookie(3)
NAME
CGI::Cookie - Interface to HTTP Cookies
SYNOPSIS
use CGI qw/:standard/;
use CGI::Cookie;
# Create new cookies and send them
$cookie1 = CGI::Cookie->new(-name=>'ID',-value=>123456);
$cookie2 = CGI::Cookie->new(-name=>'preferences',
-value=>{ font => Helvetica,
size => 12 }
);
print header(-cookie=>[$cookie1,$cookie2]);
# fetch existing cookies
%cookies = CGI::Cookie->fetch;
$id = $cookies{'ID'}->value;
# create cookies returned from an external source
%cookies = CGI::Cookie->parse($ENV{COOKIE});
DESCRIPTION
CGI::Cookie is an interface to HTTP/1.1 cookies, a mechanism that allows
Web servers to store persistent information on the browser's side of the
connection. Although CGI::Cookie is intended to be used in conjunction
with CGI.pm (and is in fact used by it internally), you can use this
module independently.
For full information on cookies see
https://tools.ietf.org/html/rfc6265
USING CGI::Cookie
CGI::Cookie is object oriented. Each cookie object has a name and a
value. The name is any scalar value. The value is any scalar or array
value (associative arrays are also allowed). Cookies also have several
optional attributes, including:
1. expiration date
The expiration date tells the browser how long to hang on to the
cookie. If the cookie specifies an expiration date in the future,
the browser will store the cookie information in a disk file and
return it to the server every time the user reconnects (until the
expiration date is reached). If the cookie species an expiration
date in the past, the browser will remove the cookie from the disk
file. If the expiration date is not specified, the cookie will
persist only until the user quits the browser.
2. domain
This is a partial or complete domain name for which the cookie is
valid. The browser will return the cookie to any host that matches
the partial domain name. For example, if you specify a domain name
of ".capricorn.com", then the browser will return the cookie to Web
servers running on any of the machines "www.capricorn.com",
"ftp.capricorn.com", "feckless.capricorn.com", etc. Domain names
must contain at least two periods to prevent attempts to match on top
level domains like ".edu". If no domain is specified, then the
browser will only return the cookie to servers on the host the cookie
originated from.
3. path
If you provide a cookie path attribute, the browser will check it
against your script's URL before returning the cookie. For example,
if you specify the path "/cgi-bin", then the cookie will be returned
to each of the scripts "/cgi-bin/tally.pl", "/cgi-bin/order.pl", and
"/cgi-bin/customer_service/complain.pl", but not to the script
"/cgi-private/site_admin.pl". By default, the path is set to "/", so
that all scripts at your site will receive the cookie.
4. secure flag
If the "secure" attribute is set, the cookie will only be sent to
your script if the CGI request is occurring on a secure channel, such
as SSL.
5. httponly flag
If the "httponly" attribute is set, the cookie will only be
accessible through HTTP Requests. This cookie will be inaccessible
via JavaScript (to prevent XSS attacks).
This feature is supported by nearly all modern browsers.
See these URLs for more information:
http://msdn.microsoft.com/en-us/library/ms533046.aspx
http://www.browserscope.org/?category=security&v=top
6. samesite flag
Allowed settings are "Strict", "Lax" and "None".
As of June 2016, support is limited to recent releases of Chrome and
Opera.
<https://tools.ietf.org/html/draft-west-first-party-cookies-07>
7. priority flag
Allowed settings are "Low", "Medium" and "High".
Support is limited to recent releases of Chrome.
Creating New Cookies
my $c = CGI::Cookie->new(-name => 'foo',
-value => 'bar',
-expires => '+3M',
'-max-age' => '+3M',
-domain => '.capricorn.com',
-path => '/cgi-bin/database',
-secure => 1,
-samesite=> "Lax",
-priority=> "High",
);
Create cookies from scratch with the new method. The -name and -value
parameters are required. The name must be a scalar value. The value can
be a scalar, an array reference, or a hash reference. (At some point in
the future cookies will support one of the Perl object serialization
protocols for full generality).
-expires accepts any of the relative or absolute date formats recognized
by CGI.pm, for example "+3M" for three months in the future. See
CGI.pm's documentation for details.
-max-age accepts the same data formats as -expires, but sets a relative
value instead of an absolute like -expires. This is intended to be more
secure since a clock could be changed to fake an absolute time. In
practice, as of 2011, "-max-age" still does not enjoy the widespread
support that "-expires" has. You can set both, and browsers that support
"-max-age" should ignore the "Expires" header. The drawback to this
approach is the bit of bandwidth for sending an extra header on each
cookie.
-domain points to a domain name or to a fully qualified host name. If
not specified, the cookie will be returned only to the Web server that
created it.
-path points to a partial URL on the current server. The cookie will be
returned to all URLs beginning with the specified path. If not
specified, it defaults to '/', which returns the cookie to all pages at
your site.
-secure if set to a true value instructs the browser to return the cookie
only when a cryptographic protocol is in use.
-httponly if set to a true value, the cookie will not be accessible via
JavaScript.
-samesite may be "Lax", "Strict", or "None" and is an evolving part of
the standards for cookies. Please refer to current documentation
regarding it.
For compatibility with Apache::Cookie, you may optionally pass in a
mod_perl request object as the first argument to "new()". It will simply
be ignored:
my $c = CGI::Cookie->new($r,
-name => 'foo',
-value => ['bar','baz']);
Sending the Cookie to the Browser
The simplest way to send a cookie to the browser is by calling the bake()
method:
$c->bake;
This will print the Set-Cookie HTTP header to STDOUT using CGI.pm. CGI.pm
will be loaded for this purpose if it is not already. Otherwise CGI.pm is
not required or used by this module.
Under mod_perl, pass in an Apache request object:
$c->bake($r);
If you want to set the cookie yourself, Within a CGI script you can send
a cookie to the browser by creating one or more Set-Cookie: fields in the
HTTP header. Here is a typical sequence:
my $c = CGI::Cookie->new(-name => 'foo',
-value => ['bar','baz'],
-expires => '+3M');
print "Set-Cookie: $c\n";
print "Content-Type: text/html\n\n";
To send more than one cookie, create several Set-Cookie: fields.
If you are using CGI.pm, you send cookies by providing a -cookie argument
to the header() method:
print header(-cookie=>$c);
Mod_perl users can set cookies using the request object's header_out()
method:
$r->err_headers_out->add('Set-Cookie' => $c);
Internally, Cookie overloads the "" operator to call its as_string()
method when incorporated into the HTTP header. as_string() turns the
Cookie's internal representation into an RFC-compliant text
representation. You may call as_string() yourself if you prefer:
print "Set-Cookie: ",$c->as_string,"\n";
Recovering Previous Cookies
%cookies = CGI::Cookie->fetch;
fetch returns an associative array consisting of all cookies returned by
the browser. The keys of the array are the cookie names. You can
iterate through the cookies this way:
%cookies = CGI::Cookie->fetch;
for (keys %cookies) {
do_something($cookies{$_});
}
In a scalar context, fetch() returns a hash reference, which may be more
efficient if you are manipulating multiple cookies.
CGI.pm uses the URL escaping methods to save and restore reserved
characters in its cookies. If you are trying to retrieve a cookie set by
a foreign server, this escaping method may trip you up. Use raw_fetch()
instead, which has the same semantics as fetch(), but performs no
unescaping.
You may also retrieve cookies that were stored in some external form
using the parse() class method:
$COOKIES = `cat /usr/tmp/Cookie_stash`;
%cookies = CGI::Cookie->parse($COOKIES);
If you are in a mod_perl environment, you can save some overhead by
passing the request object to fetch() like this:
CGI::Cookie->fetch($r);
If the value passed to parse() is undefined, an empty array will returned
in list context, and an empty hashref will be returned in scalar context.
Manipulating Cookies
Cookie objects have a series of accessor methods to get and set cookie
attributes. Each accessor has a similar syntax. Called without
arguments, the accessor returns the current value of the attribute.
Called with an argument, the accessor changes the attribute and returns
its new value.
name()
Get or set the cookie's name. Example:
$name = $c->name;
$new_name = $c->name('fred');
value()
Get or set the cookie's value. Example:
$value = $c->value;
@new_value = $c->value(['a','b','c','d']);
value() is context sensitive. In a list context it will return the
current value of the cookie as an array. In a scalar context it will
return the first value of a multivalued cookie.
domain()
Get or set the cookie's domain.
path()
Get or set the cookie's path.
expires()
Get or set the cookie's expiration time.
max_age()
Get or set the cookie's max_age value.
AUTHOR INFORMATION
The CGI.pm distribution is copyright 1995-2007, Lincoln D. Stein. It is
distributed under the Artistic License 2.0. It is currently maintained by
Lee Johnson with help from many contributors.
Address bug reports and comments to:
https://github.com/leejo/CGI.pm/issues
The original bug tracker can be found at:
https://rt.cpan.org/Public/Dist/Display.html?Queue=CGI.pm
When sending bug reports, please provide the version of CGI.pm, the
version of Perl, the name and version of your Web server, and the name
and version of the operating system you are using. If the problem is
even remotely browser dependent, please provide information about the
affected browsers as well.
BUGS
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SEE ALSO
CGI::Carp(3), CGI(3)
RFC 2109 <http://www.ietf.org/rfc/rfc2109.txt>, RFC 2695
<http://www.ietf.org/rfc/rfc2965.txt>
perl v5.34.1 2023-03-03 CGI::Cookie(3)
cgi 4.560.0 - Generated Tue Mar 7 05:16:16 CST 2023