CGI::Cookie(3) Perl Programmers Reference Guide CGI::Cookie(3)NAMECGI::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});
DESCRIPTIONCGI::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::CookieCGI::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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CGI::Cookie(3) Perl Programmers Reference Guide CGI::Cookie(3)
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
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, path
is set to "/", which causes the cookie to be sent to
any CGI script on your site.
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
formats recognized by CGI.pm, for example "+3M" for three
months in the future. See CGI.pm's documentation for
details.
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CGI::Cookie(3) Perl Programmers Reference Guide CGI::Cookie(3)-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: $c\n";
print "Content-Type: text/html\n\n";
To send more than one cookie, create several Set-Cookie:
fields. Alternatively, you may concatenate the cookies
together with "; " and send them in one field.
If you are using CGI.pm, you send cookies by providing a
-cookie argument to the header() method:
print header(-cookie=>$c);
Mod_perl users can set cookies using the request object's
header_out() method:
$r->header_out('Set-Cookie',$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: ",$c->as_string,"\n";
Recovering Previous Cookies
%cookies = fetch CGI::Cookie;
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CGI::Cookie(3) Perl Programmers Reference Guide CGI::Cookie(3)
fetch returns an associative array consisting of all
cookies returned by the browser. The keys of the array
are the cookie names. You can iterate through the cookies
this way:
%cookies = fetch CGI::Cookie;
foreach (keys %cookies) {
do_something($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 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);
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 an array 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.
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CGI::Cookie(3) Perl Programmers Reference Guide CGI::Cookie(3)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
the CGI::Carp manpage, the CGI manpage
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