CGI::Cookie(3pm)

1CGI::Cookie(3)        User Contributed Perl Documentation       CGI::Cookie(3)
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NAME

6       CGI::Cookie - Interface to HTTP Cookies
7

SYNOPSIS

9           use CGI qw/:standard/;
10           use CGI::Cookie;
11
12           # Create new cookies and send them
13           $cookie1 = CGI::Cookie->new(-name=>'ID',-value=>123456);
14           $cookie2 = CGI::Cookie->new(-name=>'preferences',
15                                      -value=>{ font => Helvetica,
16                                                size => 12 }
17                                      );
18           print header(-cookie=>[$cookie1,$cookie2]);
19
20           # fetch existing cookies
21           %cookies = CGI::Cookie->fetch;
22           $id = $cookies{'ID'}->value;
23
24           # create cookies returned from an external source
25           %cookies = CGI::Cookie->parse($ENV{COOKIE});
26

DESCRIPTION

28       CGI::Cookie is an interface to HTTP/1.1 cookies, a mechanism that
29       allows Web servers to store persistent information on the browser's
30       side of the connection.  Although CGI::Cookie is intended to be used in
31       conjunction with CGI.pm (and is in fact used by it internally), you can
32       use this module independently.
33
34       For full information on cookies see
35
36           https://tools.ietf.org/html/rfc6265
37

39       CGI::Cookie is object oriented.  Each cookie object has a name and a
40       value.  The name is any scalar value.  The value is any scalar or array
41       value (associative arrays are also allowed).  Cookies also have several
42       optional attributes, including:
43
44       1. expiration date
45           The expiration date tells the browser how long to hang on to the
46           cookie.  If the cookie specifies an expiration date in the future,
47           the browser will store the cookie information in a disk file and
48           return it to the server every time the user reconnects (until the
49           expiration date is reached).  If the cookie species an expiration
50           date in the past, the browser will remove the cookie from the disk
51           file.  If the expiration date is not specified, the cookie will
52           persist only until the user quits the browser.
53
54       2. domain
55           This is a partial or complete domain name for which the cookie is
56           valid.  The browser will return the cookie to any host that matches
57           the partial domain name.  For example, if you specify a domain name
58           of ".capricorn.com", then the browser will return the cookie to Web
59           servers running on any of the machines "www.capricorn.com",
60           "ftp.capricorn.com", "feckless.capricorn.com", etc.  Domain names
61           must contain at least two periods to prevent attempts to match on
62           top level domains like ".edu".  If no domain is specified, then the
63           browser will only return the cookie to servers on the host the
64           cookie originated from.
65
66       3. path
67           If you provide a cookie path attribute, the browser will check it
68           against your script's URL before returning the cookie.  For
69           example, if you specify the path "/cgi-bin", then the cookie will
70           be returned to each of the scripts "/cgi-bin/tally.pl",
71           "/cgi-bin/order.pl", and "/cgi-bin/customer_service/complain.pl",
72           but not to the script "/cgi-private/site_admin.pl".  By default,
73           the path is set to "/", so that all scripts at your site will
74           receive the cookie.
75
76       4. secure flag
77           If the "secure" attribute is set, the cookie will only be sent to
78           your script if the CGI request is occurring on a secure channel,
79           such as SSL.
80
81       5. httponly flag
82           If the "httponly" attribute is set, the cookie will only be
83           accessible through HTTP Requests. This cookie will be inaccessible
84           via JavaScript (to prevent XSS attacks).
85
86           This feature is supported by nearly all modern browsers.
87
88           See these URLs for more information:
89
90               http://msdn.microsoft.com/en-us/library/ms533046.aspx
91               http://www.browserscope.org/?category=security&v=top
92
93       6. samesite flag
94           Allowed settings are "Strict", "Lax" and "None".
95
96           As of June 2016, support is limited to recent releases of Chrome
97           and Opera.
98
99           <https://tools.ietf.org/html/draft-west-first-party-cookies-07>
100
101   Creating New Cookies
102               my $c = CGI::Cookie->new(-name    =>  'foo',
103                                    -value   =>  'bar',
104                                    -expires =>  '+3M',
105                                  '-max-age' =>  '+3M',
106                                    -domain  =>  '.capricorn.com',
107                                    -path    =>  '/cgi-bin/database',
108                                    -secure  =>  1,
109                                    -samesite=>  "Lax"
110                                   );
111
112       Create cookies from scratch with the new method.  The -name and -value
113       parameters are required.  The name must be a scalar value.  The value
114       can be a scalar, an array reference, or a hash reference.  (At some
115       point in the future cookies will support one of the Perl object
116       serialization protocols for full generality).
117
118       -expires accepts any of the relative or absolute date formats
119       recognized by CGI.pm, for example "+3M" for three months in the future.
120       See CGI.pm's documentation for details.
121
122       -max-age accepts the same data formats as -expires, but sets a relative
123       value instead of an absolute like -expires. This is intended to be more
124       secure since a clock could be changed to fake an absolute time. In
125       practice, as of 2011, "-max-age" still does not enjoy the widespread
126       support that "-expires" has. You can set both, and browsers that
127       support "-max-age" should ignore the "Expires" header. The drawback to
128       this approach is the bit of bandwidth for sending an extra header on
129       each cookie.
130
131       -domain points to a domain name or to a fully qualified host name.  If
132       not specified, the cookie will be returned only to the Web server that
133       created it.
134
135       -path points to a partial URL on the current server.  The cookie will
136       be returned to all URLs beginning with the specified path.  If not
137       specified, it defaults to '/', which returns the cookie to all pages at
138       your site.
139
140       -secure if set to a true value instructs the browser to return the
141       cookie only when a cryptographic protocol is in use.
142
143       -httponly if set to a true value, the cookie will not be accessible via
144       JavaScript.
145
146       -samesite may be "Lax", "Strict", or "None" and is an evolving part of
147       the standards for cookies. Please refer to current documentation
148       regarding it.
149
150       For compatibility with Apache::Cookie, you may optionally pass in a
151       mod_perl request object as the first argument to "new()". It will
152       simply be ignored:
153
154         my $c = CGI::Cookie->new($r,
155                                 -name    =>  'foo',
156                                 -value   =>  ['bar','baz']);
157
158   Sending the Cookie to the Browser
159       The simplest way to send a cookie to the browser is by calling the
160       bake() method:
161
162         $c->bake;
163
164       This will print the Set-Cookie HTTP header to STDOUT using CGI.pm.
165       CGI.pm will be loaded for this purpose if it is not already. Otherwise
166       CGI.pm is not required or used by this module.
167
168       Under mod_perl, pass in an Apache request object:
169
170         $c->bake($r);
171
172       If you want to set the cookie yourself, Within a CGI script you can
173       send a cookie to the browser by creating one or more Set-Cookie: fields
174       in the HTTP header.  Here is a typical sequence:
175
176         my $c = CGI::Cookie->new(-name    =>  'foo',
177                                 -value   =>  ['bar','baz'],
178                                 -expires =>  '+3M');
179
180         print "Set-Cookie: $c\n";
181         print "Content-Type: text/html\n\n";
182
183       To send more than one cookie, create several Set-Cookie: fields.
184
185       If you are using CGI.pm, you send cookies by providing a -cookie
186       argument to the header() method:
187
188         print header(-cookie=>$c);
189
190       Mod_perl users can set cookies using the request object's header_out()
191       method:
192
193         $r->err_headers_out->add('Set-Cookie' => $c);
194
195       Internally, Cookie overloads the "" operator to call its as_string()
196       method when incorporated into the HTTP header.  as_string() turns the
197       Cookie's internal representation into an RFC-compliant text
198       representation.  You may call as_string() yourself if you prefer:
199
200         print "Set-Cookie: ",$c->as_string,"\n";
201
202   Recovering Previous Cookies
203               %cookies = CGI::Cookie->fetch;
204
205       fetch returns an associative array consisting of all cookies returned
206       by the browser.  The keys of the array are the cookie names.  You can
207       iterate through the cookies this way:
208
209               %cookies = CGI::Cookie->fetch;
210               for (keys %cookies) {
211                  do_something($cookies{$_});
212               }
213
214       In a scalar context, fetch() returns a hash reference, which may be
215       more efficient if you are manipulating multiple cookies.
216
217       CGI.pm uses the URL escaping methods to save and restore reserved
218       characters in its cookies.  If you are trying to retrieve a cookie set
219       by a foreign server, this escaping method may trip you up.  Use
220       raw_fetch() instead, which has the same semantics as fetch(), but
221       performs no unescaping.
222
223       You may also retrieve cookies that were stored in some external form
224       using the parse() class method:
225
226              $COOKIES = `cat /usr/tmp/Cookie_stash`;
227              %cookies = CGI::Cookie->parse($COOKIES);
228
229       If you are in a mod_perl environment, you can save some overhead by
230       passing the request object to fetch() like this:
231
232          CGI::Cookie->fetch($r);
233
234       If the value passed to parse() is undefined, an empty array will
235       returned in list context, and an empty hashref will be returned in
236       scalar context.
237
238   Manipulating Cookies
239       Cookie objects have a series of accessor methods to get and set cookie
240       attributes.  Each accessor has a similar syntax.  Called without
241       arguments, the accessor returns the current value of the attribute.
242       Called with an argument, the accessor changes the attribute and returns
243       its new value.
244
245       name()
246           Get or set the cookie's name.  Example:
247
248                   $name = $c->name;
249                   $new_name = $c->name('fred');
250
251       value()
252           Get or set the cookie's value.  Example:
253
254                   $value = $c->value;
255                   @new_value = $c->value(['a','b','c','d']);
256
257           value() is context sensitive.  In a list context it will return the
258           current value of the cookie as an array.  In a scalar context it
259           will return the first value of a multivalued cookie.
260
261       domain()
262           Get or set the cookie's domain.
263
264       path()
265           Get or set the cookie's path.
266
267       expires()
268           Get or set the cookie's expiration time.
269
270       max_age()
271           Get or set the cookie's max_age value.
272

AUTHOR INFORMATION

274       The CGI.pm distribution is copyright 1995-2007, Lincoln D. Stein. It is
275       distributed under the Artistic License 2.0. It is currently maintained
276       by Lee Johnson with help from many contributors.
277
278       Address bug reports and comments to:
279       https://github.com/leejo/CGI.pm/issues
280
281       The original bug tracker can be found at:
282       https://rt.cpan.org/Public/Dist/Display.html?Queue=CGI.pm
283
284       When sending bug reports, please provide the version of CGI.pm, the
285       version of Perl, the name and version of your Web server, and the name
286       and version of the operating system you are using.  If the problem is
287       even remotely browser dependent, please provide information about the
288       affected browsers as well.
289

BUGS

291       This section intentionally left blank.
292

NAME

SYNOPSIS

DESCRIPTION

USING CGI::Cookie

AUTHOR INFORMATION

BUGS

SEE ALSO