CGI::Cookie
CGI::Cookie(3) User Contributed Perl Documentation CGI::Cookie(3)
NAME
CGI::Cookie - Interface to Netscape Cookies
SYNOPSIS
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});
DESCRIPTION
CGI::Cookie is an interface to Netscape (HTTP/1.1) cookies, an innova-
tion 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 inter-
nally), 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.
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.capri-
corn.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 speci-
fied, 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.
4. httponly flag
If the "httponly" attribute is set, the cookie will only be acces-
sible through HTTP Requests. This cookie will be inaccessible via
JavaScript (to prevent XSS attacks).
But, currently this feature only used and recognised by MS Inter-
net Explorer 6 Service Pack 1 and later.
See this URL for more information:
<http://msdn.microsoft.com/workshop/author/dhtml/httponly_cook-
ies.asp>
Creating New Cookies
my $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 seri-
alization protocols for full generality).
-expires accepts any of the relative or absolute date formats recog-
nized by CGI.pm, for example "+3M" for three months in the future.
See CGI.pm’s documentation for details.
-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.
For compatibility with Apache::Cookie, you may optionally pass in a
mod_perl request object as the first argument to "new()". It will sim-
ply be ignored:
my $c = new CGI::Cookie($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;
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 = new CGI::Cookie(-name => ’foo’,
-value => [’bar’,’baz’],
-expires => ’+3M’);
print "Set-Cookie: $c\n";
print "Content-Type: text/html\n\n";
To send more than one cookie, create several Set-Cookie: fields.
If you are using CGI.pm, you send cookies by providing a -cookie argu-
ment to the header() method:
print header(-cookie=>$c);
Mod_perl users can set cookies using the request object’s header_out()
method:
$r->headers_out->set(’Set-Cookie’ => $c);
Internally, Cookie overloads the "" operator to call its as_string()
method when incorporated into the HTTP header. as_string() turns the
Cookie’s internal representation into an RFC-compliant text represen-
tation. You may call as_string() yourself if you prefer:
print "Set-Cookie: ",$c->as_string,"\n";
Recovering Previous Cookies
%cookies = fetch CGI::Cookie;
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 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 per-
forms 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 argu-
ments, 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.
AUTHOR INFORMATION
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
BUGS
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SEE ALSO
CGI::Carp, CGI
perl v5.8.8 2008-03-28 CGI::Cookie(3)
