CGI::Cookie(3p) Perl Programmers Reference Guide CGI::Cookie(3p)
CGI::Cookie - Interface to Netscape Cookies
use CGI qw/:standard/;
use CGI::Cookie;
# Create new cookies and send them
$cookie1 = new CGI::Cookie(-name=>'ID',-value=>123456);
$cookie2 = new CGI::Cookie(-name=>'preferences',
-value=>{ font => Helvetica,
size => 12 }
);
print header(-cookie=>[$cookie1,$cookie2]);
# fetch existing cookies
%cookies = fetch CGI::Cookie;
$id = $cookies{'ID'}->value;
# create cookies returned from an external source
%cookies = parse CGI::Cookie($ENV{COOKIE});
CGI::Cookie is an interface to Netscape (HTTP/1.1) cookies,
an innovation 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
http://www.ics.uci.edu/pub/ietf/http/rfc2109.txt
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.
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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 Netscape 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 con-
tain 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.
Creating New Cookies
$c = new CGI::Cookie(-name => 'foo',
-value => 'bar',
-expires => '+3M',
-domain => '.capricorn.com',
-path => '/cgi-bin/database',
-secure => 1
);
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 for-
mats recognized by CGI.pm, for example "+3M" for three
months in the future. See CGI.pm's documentation for
details.
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-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.
Sending the Cookie to the Browser
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 = new CGI::Cookie(-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->headers_out->set('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 = fetch CGI::Cookie;
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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 = fetch CGI::Cookie;
foreach (keys %cookies) {
do_something($cookies{$_});
}
In a scalar context, fetch() returns a hash reference, which
may be more efficient if you are manipulating multiple cook-
ies.
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:
$COOKIES = `cat /usr/tmp/Cookie_stash`;
%cookies = parse CGI::Cookie($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);
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 acces-
sor 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
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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.
Copyright 1997-1998, Lincoln D. Stein. All rights reserved.
This library is free software; you can redistribute it
and/or modify it under the same terms as Perl itself.
Address bug reports and comments to: lstein@cshl.org
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CGI::Carp, CGI
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