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setcookie
Send a cookie
(PHP 4, PHP 5)
bool setcookie ( string name [, string value [, int expire [, string path [, string domain [, bool secure [, bool httponly]]]]]] )
setcookie() defines a cookie to be sent along with the
rest of the HTTP headers. Like other headers, cookies must be sent
before any output from your script (this is a
protocol restriction). This requires that you place calls to this function
prior to any output, including <html> and
<head> tags as well as any whitespace.
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.
$HTTP_COOKIE_VARS has existed since PHP 3. 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
$_COOKIE['cookiename']- expire
The time the cookie expires. This is a Unix timestamp so is in number of seconds since the epoch. In other words, you'll most likely set this with the time() function plus the number of seconds before you want it to expire. Or you might use mktime().
time()+60*60*24*30will set the cookie to expire in 30 days. If set to 0, or omitted, the cookie will expire at the end of the session (when the browser closes).Note:You may notice the expire parameter takes on a Unix timestamp, as opposed to the date format
Wdy, DD-Mon-YYYY HH:MM:SS GMT, this is because PHP does this conversion internally.expire is compared to the client's time which can differ from server's time.
- path
The path on the server in which the cookie will be available on. If set to
'/', the cookie will be available within the entire domain. If set to'/foo/', the cookie will only be available within the/foo/directory and all sub-directories such as/foo/bar/of domain. The default value is the current directory that the cookie is being set in.- domain
The domain that the cookie is available. To make the cookie available on all subdomains of example.com then you'd set it to
'.example.com'. The.is not required but makes it compatible with more browsers. Setting it towww.example.comwill make the cookie only available in thewwwsubdomain. Refer to tail matching in the » spec for details.- secure
Indicates that the cookie should only be transmitted over a secure HTTPS connection from the client. When set to
TRUE, the cookie will only be set if a secure connection exists. The default isFALSE. On the server-side, it's on the programmer to send this kind of cookie only on secure connection (e.g. with respect to$_SERVER["HTTPS"]).- httponly
When
TRUEthe 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.TRUEorFALSE
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 1609. 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:
<?php
// Print an individual cookie
echo $_COOKIE["TestCookie"];
echo $HTTP_COOKIE_VARS["TestCookie"];
// Another way to debug/test is to view all cookies
print_r($_COOKIE);
?>Example 1610. 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 1611. 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
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.
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
FALSEwill try to delete the cookie, you should not use boolean values. Instead, use 0 forFALSEand 1 forTRUE. - 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.
In PHP 3, multiple calls to setcookie() in the same script will be performed in reverse order. If you are trying to delete one cookie before inserting another you should put the insert before the delete. As of PHP 4, multiple calls to setcookie() are performed in the order called.
Microsoft Internet Explorer 4 with Service Pack 1 applied does not correctly deal with cookies that have their path parameter set.
Netscape Communicator 4.05 and Microsoft Internet Explorer 3.x appear to handle cookies incorrectly when the path and time are not set.