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21.3. Accessing Cookie Values

21.3.1. Problem

You want to examine values client sent you in a cookie.

21.3.2. Solution

Use the CPAN module Apache::Cookie to populate a hash of cookie objects derived from the header sent by the client.

use Apache::Cookie; $ac = Apache::Cookie->new($r); %all_cookies = $ac->parse( );

Now each element of that hash is an object representing a single cookie:

$one_cookie = $all_cookies{COOKIE_NAME};

Interrogate the object to learn about that cookie's values:

$one_cookie->value( ) $one_cookie->name( ) $one_cookie->domain( ) $one_cookie->path( ) $one_cookie->expires( ) $one_cookie->secure( )

21.3.3. Discussion

To test whether a cookie was sent by the browser, use exists on the hash element:

unless (exists $all_cookies{chocolate}) { $r->header_out(Location => "http://www.site.com/login"); return REDIRECT; }

Don't simply test for truth:

unless ($all_cookies{chocolate}) { # BAD

Valid cookie values include the empty string and 0, both false to Perl. See the Introduction to Chapter 1 for more.

The CGI::Cookie module is a pure Perl substitute for Apache::Cookie. Its strategy for getting a hash of cookies is slightly different from that of Apache::Cookies:

use CGI::Cookie; %all_cookies = CGI::Cookie->fetch;

This hash of cookies works the same as the one by Apache::Cookie.

21.3.4. See Also

Writing Apache Modules with Perl and C; Recipe 20.14; Recipe 3.7 in mod_perl Developer's Cookbook; the Apache.pm manpage; documentation for the CGI::Cookie and Apache::Cookie modules from CPAN

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