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setcookie
(PHP 4, PHP 5) setcookie — Send a cookie
Description
bool setcookie
( string $name
[, string $value
[, int $expire
[, string $path
[, string $domain
[, bool $secure
[, bool $httponly
]]]]]] )
Once the cookies have been set, they can be accessed on the next page load
with the $_COOKIE or
$HTTP_COOKIE_VARS arrays. Note,
superglobals
such as $_COOKIE became available in PHP 4.1.0.
Cookie
values also exist in $_REQUEST.
Parameters
All the arguments except the name
argument are
optional. You may also replace an argument with an empty string
("") in order to skip that argument.
Because the expire
argument is integer, it cannot
be skipped with an empty string, use a zero (0)
instead.
See » Netscape cookie specification for
specifics on how each setcookie() parameter works
-
name
-
The name of the cookie.
-
value
-
The value of the cookie. This value is stored on the clients
computer; do not store sensitive information.
Assuming the name
is 'cookiename', this
value is retrieved through $_COOKIE['cookiename']
-
expire
-
The time the cookie expires. This is a Unix timestamp so is
in number of seconds since the epoch. In other words, you'll
most likely set this with the time() function
plus the number of seconds before you want it to expire. Or
you might use mktime().
time()+60*60*24*30 will set the cookie to
expire in 30 days. If set to 0, or omitted, the cookie will expire at
the end of the session (when the browser closes).
Note:
You may notice the expire
parameter takes on a
Unix timestamp, as opposed to the date format Wdy, DD-Mon-YYYY
HH:MM:SS GMT, this is because PHP does this conversion
internally.
expire
is compared to the client's time which can
differ from server's time.
-
path
-
The path on the server in which the cookie will be available on.
If set to '/', the cookie will be available
within the entire domain
. If set to
'/foo/', the cookie will only be available
within the /foo/ directory and all
sub-directories such as /foo/bar/ of
domain
. The default value is the
current directory that the cookie is being set in.
-
domain
-
The domain that the cookie is available.
To make the cookie available on all subdomains of example.com
then you'd set it to '.example.com'. The
. is not required but makes it compatible
with more browsers. Setting it to www.example.com
will make the cookie only available in the www
subdomain. Refer to tail matching in the
» spec for details.
-
secure
-
Indicates that the cookie should only be transmitted over a
secure HTTPS connection from the client. When set to TRUE, the
cookie will only be set if a secure connection exists. The default
is FALSE. On the server-side, it's on the programmer to send this
kind of cookie only on secure connection (e.g. with respect to
$_SERVER["HTTPS"]).
-
httponly
-
When TRUE the cookie will be made accessible only through the HTTP
protocol. This means that the cookie won't be accessible by
scripting languages, such as JavaScript. This setting can effectly
help to reduce identity theft through XSS attacks (although it is
not supported by all browsers). Added in PHP 5.2.0.
TRUE or FALSE
Return Values
If output exists prior to calling this function,
setcookie() will fail and return FALSE. If
setcookie() successfully runs, it will return TRUE.
This does not indicate whether the user accepted the cookie.
Examples
Some examples follow how to send cookies:
Example #1 setcookie() send example
<?php
$value = 'something from somewhere';
setcookie("TestCookie", $value);
setcookie("TestCookie", $value, time()+3600); /* expire in 1 hour */
setcookie("TestCookie", $value, time()+3600, "/~rasmus/", ".example.com", 1);
?>
Note that the value portion of the cookie will automatically be
urlencoded when you send the cookie, and when it is received, it
is automatically decoded and assigned to a variable by the same
name as the cookie name. If you don't want this, you can use
setrawcookie() instead if you are using PHP 5. To see
the contents of our test cookie in a script, simply use one of the
following examples:
Example #2 setcookie() delete example
When deleting a cookie you should assure that the expiration date
is in the past, to trigger the removal mechanism in your browser.
Examples follow how to delete cookies sent in previous example:
<?php
// set the expiration date to one hour ago
setcookie ("TestCookie", "", time() - 3600);
setcookie ("TestCookie", "", time() - 3600, "/~rasmus/", ".example.com", 1);
?>
Example #3 setcookie() and arrays
You may also set array cookies by using array notation in the
cookie name. This has the effect of setting as many cookies as
you have array elements, but when the cookie is received by your
script, the values are all placed in an array with the cookie's
name:
<?php
// set the cookies
setcookie("cookie[three]", "cookiethree");
setcookie("cookie[two]", "cookietwo");
setcookie("cookie[one]", "cookieone");
// after the page reloads, print them out
if (isset($_COOKIE['cookie'])) {
foreach ($_COOKIE['cookie'] as $name => $value) {
echo "$name : $value <br />\n";
}
}
?>
The above example will output:
three : cookiethree
two : cookietwo
one : cookieone
Notes
Note:
As of PHP 4, you can use output buffering to send output prior to the
call of this function, with the overhead of all of your output to the
browser being buffered in the server until you send it. You can do this
by calling ob_start() and
ob_end_flush() in your script, or setting the
output_buffering configuration directive on in your
php.ini or server configuration files.
Note:
If the PHP directive register_globals
is set to on then cookie values will also be made into
variables. In our examples below, $TestCookie will
exist. It's recommended to use $_COOKIE.
Common Pitfalls:
-
Cookies will not become visible until the next loading of a page that
the cookie should be visible for. To test if a cookie was successfully
set, check for the cookie on a next loading page before the cookie
expires. Expire time is set via the expire
parameter. A nice way to debug the existence of cookies is by
simply calling print_r($_COOKIE);.
-
Cookies must be deleted with the same parameters as they were set with.
If the value argument is an empty string, or FALSE, and all other arguments
match a previous call to setcookie, then the cookie with the specified
name will be deleted from the remote client.
-
Because setting a cookie with a value of FALSE will try to delete the cookie,
you should not use boolean values. Instead, use 0 for FALSE
and 1 for TRUE.
-
Cookies names can be set as array names and will be available to your
PHP scripts as arrays but separate cookies are stored on the users
system. Consider explode() to set one cookie with
multiple names and values. It is not recommended to use
serialize() for this purpose, because it can result
in security holes.
Multiple calls to setcookie() are performed in the order called.
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