Creating New Cookies¶

        my $c = CGI::Cookie->new(-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.

-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.

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->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 = 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 contact, 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.