PHP 5.4.31 Released

setcookie

(PHP 4, PHP 5)

setcookieSend a cookie

Description

bool setcookie ( string $name [, string $value [, int $expire = 0 [, string $path [, string $domain [, bool $secure = false [, bool $httponly = false ]]]]]] )

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. 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.

» RFC 6265 provides the normative reference on how each setcookie() parameter is interpreted.

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.

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. Setting the domain to 'www.example.com' will make the cookie available in the www subdomain and higher subdomains. Cookies available to a lower domain, such as 'example.com' will be available to higher subdomains, such as 'www.example.com'. Older browsers still implementing the deprecated » RFC 2109 may require a leading . to match all subdomains.

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. 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. It has been suggested that this setting can effectively help to reduce identity theft through XSS attacks (although it is not supported by all browsers), but that claim is often disputed. 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"$value);
setcookie("TestCookie"$valuetime()+3600);  /* expire in 1 hour */
setcookie("TestCookie"$valuetime()+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 #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) {
        
$name htmlspecialchars($name);
        
$value htmlspecialchars($value);
        echo 
"$name : $value <br />\n";
    }
}
?>

The above example will output:

three : cookiethree
two : cookietwo
one : cookieone

Changelog

Version Description
5.5.0 A Max-Age attribute is now included in the Set-Cookie header sent to the client.
5.2.0 The httponly parameter was added.

Notes

Note:

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. This is internally achieved by setting value to 'deleted' and expiration time to one year in past.
  • 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 user's 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.

See Also

add a note add a note

User Contributed Notes 49 notes

up
84
walterquez
1 year ago
Instead of this:
<?php setcookie( "TestCookie", $value, time()+(60*60*24*30) ); ?>

You can this:
<?php setcookie( "TestCookie", $value, strtotime( '+30 days' ) ); ?>
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6
jdknock (at) gMaIl (dot) com
3 years ago
IE7 can have trouble with settings cookies that are embedded in an iframe. The problem lies with a W3C standard called Platform for Privacy Preferences or P3P for short.

To overcome, include the header:

header('P3P:CP="IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT"');

before setting the cookie.
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14
jonathan dot bergeron at rve dot ulaval dot ca
7 years ago
About the delete part, I found that Firefox only remove the cookie when you submit the same values for all parameters, except the date, which sould be in the past. Submiting blank values didn't work for me.

Example :
- set -

<?php setcookie( "name", "value", "future_timestamp", "path", "domain" ); ?>

- delete -
<?php setcookie( "name", "value", "past_timestamp", "path", "domain" ); ?>

Jonathan
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4
bluewaterbob
7 years ago
if you are having problems seeing cookies sometimes or deleting cookies sometimes, despite following the advice below, make sure you are setting the cookie with the domain argument. Set it with the dot before the domain as the examples show: ".example.com".  I wasn't specifying the domain, and finally realized I was setting the cookie when the browser url had the http://www.example.com and later trying to delete it when the url didn't have the www. ie. http://example.com. This also caused the page to be unable to find the cookie when the www. wasn't in the domain.  (When you add the domain argument to the setcookie code that creates the cookie, make sure you also add it to the code that deletes the cookie.)
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6
Eric
4 years ago
The server my php code is running on has sessions disabled so I am forced to store a fair bit of arbitrary data in cookies.  Using array names was impractical and problematic, so I implemented a splitting routine.  I do not serialize any class instances, just arrays and simple objects.

In a nutshell, when setting a cookie value, I serialize it, gzcompress it, base64 encode it, break it into pieces and store it as a set of cookies.  To fetch the cookie value I get the named piece then iterate through piece names rebuilding the base64 data, then reverse the rest of the process.  The only other trick is deleting the pieces correctly.

Sessions are better, but if they are not available this is a viable alternative.  I chose gz over bz for compression because it looked faster with only slightly worse ratios.

Here is a simplified version of my implementation.  This is a good starting point but is not suitable for most uses.  For example, the domain and path are hard coded and no return values are checked for validity.

<?php
define
( 'COOKIE_PORTIONS' , '_piece_' );

function
clearpieces( $inKey , $inFirst ) {
   
$expire = time()-3600;
   
    for (
$index = $inFirst ; array_key_exists( $inKey.COOKIE_PORTIONS.$index , $_COOKIE ) ; $index += 1 ) {
       
setcookie( $inKey.COOKIE_PORTIONS.$index , '' , $expire , '/' , '' , 0 );
        unset(
$_COOKIE[$inKey.COOKIE_PORTIONS.$index] );
    }
}

function
clearcookie( $inKey ) {
   
clearpieces( $inKey , 1 );
   
setcookie( $inKey , '' , time()-3600 , '/' , '' , 0 );
    unset(
$_COOKIE[$inKey] );
}

function
storecookie( $inKey , $inValue , $inExpire ) {
   
$decode = serialize( $inValue );
   
$decode = gzcompress( $decode );
   
$decode = base64_encode( $decode );
   
   
$split = str_split( $decode , 4000 );//4k pieces
   
$count = count( $split );
   
    for (
$index = 0 ; $index < $count ; $index += 1 ) {
       
$result = setcookie( ( $index > 0 ) ? $inKey.COOKIE_PORTIONS.$index : $inKey , $split[$index] , $inExpire , '/' , '' , 0 );
    }
   
   
clearpieces( $inKey , $count );
}

function
fetchcookie( $inKey ) {
   
$decode = $_COOKIE[$inKey];
   
    for (
$index = 1 ; array_key_exists( $inKey.COOKIE_PORTIONS.$index , $_COOKIE ) ; $index += 1 ) {
       
$decode .= $_COOKIE[$inKey.COOKIE_PORTIONS.$index];
    }
   
   
$decode = base64_decode( $decode );
   
$decode = gzuncompress( $decode );
   
    return
unserialize( $decode );
}
?>
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6
Carl V
9 years ago
If you want to delete all the cookies set by your domain, you may run the following:

<?php
$cookiesSet
= array_keys($_COOKIE);
for (
$x=0;$x<count($cookiesSet);$x++) setcookie($cookiesSet[$x],"",time()-1);
?>

Very useful when doing logout scripts and the cookie name may have changed (long story).
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6
Jörg Aldinger
10 years ago
When using your cookies on a webserver that is not on the standard port 80, you should NOT include the :[port] in the "Cookie domain" parameter, since this would not be recognized correctly.
I had the issue working on a project that runs on multiple servers (development, production, etc.). One of the servers is running on a different port (together with other websites that run on the same server but on different ports).
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3
stovenator at gmail dot com
7 years ago
If you are having issues with IE7 and setcookie(), be sure to verify that the cookie is set via http for http sites, and https for https site.

Also, if the time is incorrect on your server, IE7 will also disallow those cookies from being set.
up
3
terry at scribendi dot com
9 years ago
A few comments have suggested using serialize() to set object or array data into a cookie.  There are a couple of reasons to be carefull with that technique:

Security: If the cookie is human readable, then it is also fairly easy for end users to play around with it.  Wrapping your cookie setting and getting in an encryption routine will prevent tampering, and make sure that your cookies don't make any sense to any client-side exploits or other sites they get sent to thanks to browser bugs.

Bulk: If you serialize even a fairly simple class, then you get a lot of data.  Large cookies will make browser requests fat and slow, and some browsers have a limit on cookie size, so think about what data you really need to persist, and create __sleep() and __wakeup() methods to package the data into the shortest possible form.  You can get better and faster results when you write your own __sleep() and __wakup() to implode() or pack() your data, than by using zlib compress() on the serialized object.
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3
MrXCol
3 years ago
If you're having problem with IE not accepting session cookies this could help:

It seems the IE (6, 7, 8 and 9) do not accept the part 'Expire=0' when setting a session cookie. To fix it just don't put any expire at all. The default behavior when the 'Expire' is not set is to set the cookie as a session one.

(Firefox doesn't complains, btw.)
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2
paul nospam AT nospam sitepoint dot com
7 years ago
Note when setting "array cookies" that a separate cookie is set for each element of the array.

On high traffic sites, this can substantially increase the size of subsequent HTTP requests from clients (including requests for static content on the same domain).

More importantly though, the cookie specification says that browsers need only accept 20 cookies per domain.  This limit is increased to 50 by Firefox, and to 30 by Opera, but IE6 and IE7 enforce the limit of 20 cookie per domain.  Any cookies beyond this limit will either knock out an older cookie or be ignored/rejected by the browser.
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2
hansel at gretel dot com
7 years ago
The following code snippet combines abdullah's and Charles Martin's examples into a powerful combination function (and fixes at least one bug in the process):

<?php
 
function set_cookie_fix_domain($Name, $Value = '', $Expires = 0, $Path = '', $Domain = '', $Secure = false, $HTTPOnly = false)
  {
    if (!empty(
$Domain))
    {
     
// Fix the domain to accept domains with and without 'www.'.
     
if (strtolower(substr($Domain, 0, 4)) == 'www.'$Domain = substr($Domain, 4);
     
$Domain = '.' . $Domain;

     
// Remove port information.
     
$Port = strpos($Domain, ':');
      if (
$Port !== false$Domain = substr($Domain, 0, $Port);
    }

   
header('Set-Cookie: ' . rawurlencode($Name) . '=' . rawurlencode($Value)
                          . (empty(
$Expires) ? '' : '; expires=' . gmdate('D, d-M-Y H:i:s', $Expires) . ' GMT')
                          . (empty(
$Path) ? '' : '; path=' . $Path)
                          . (empty(
$Domain) ? '' : '; domain=' . $Domain)
                          . (!
$Secure ? '' : '; secure')
                          . (!
$HTTPOnly ? '' : '; HttpOnly'), false);
  }
?>

Basically, if the domain parameter is supplied, it is converted to support a broader range of domains.  This behavior may or may not be desireable (e.g. could be a security problem depending on the server) but it makes cookie handling oh-so-much-nicer (IMO).
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5
mkmohsinali at gmail dot com
2 years ago
#cookies.php
/*This code will demonstrate use of cookies with PHP
It is very easy to understand and is better for beginner to
understand and get idea about power of cookies when used
with PHP.Here we give user a form to choose colors he/she
likes for website and when he/she visits site again within one
hour his/her settings are saved and read from cookie
and he/she doesn't have to set the page color and page
text color again.You can change time from 3600
seconds to whatever you deem appropriate in your case.
if you don't understand anything please email me*/

<?php
#checking if form has been submitted
if (isset($_POST['submitted'])){
#if yes (form is submitted) assign values from POST array to variables
$newbgColor=$_POST['bgColor'];
$newtxtColor=$_POST['txtColor'];
#set cookies
setcookie("bgColor",$newbgColor,time()+3600);
setcookie("txtColor",$newtxtColor,time()+3600);

}
#in case user has come for first time and cookies are not set then
if ((!isset($_COOKIE['bgColor']) ) && (!isset($_COOKIE['txtColor']))){
$bgColor = "Black";
$txtColor="White";
}
#if cookies are set then use them
else{
$bgColor = $_COOKIE['bgColor'];
$txtColor = $_COOKIE['txtColor'];
}
?>
<!-- HTML Page-->
<html>
<body bgcolor="<?php echo $bgColor ?>" text="<?php echo $txtColor ?>">
<form action= "<?php echo $_SERVER['PHP_SELF']; ?>" method ="POST">
<p>Body Color:</p>
<select name=bgColor>
<option value ="Red">Red</option>
<option value ="Green" selected>Green</option>
<option value ="Blue">Blue</option>
<option value ="Yellow">Yellow</option>
<option value ="Black">Black</option>
<option value ="Brown">Brown</option>
<option value ="White">White</option>
</select>
<p>Text Color:</p>
<select name=txtColor>
<tion value ="Red">Red</option>
<option value ="Green" selected>Green</option>
<option value ="Blue">Blue</option>
<option value ="Yellow">Yellow</option>
<option value ="Black">Black</option>
<option value ="Brown">Brown</option>
<option value ="White">White</option>
</select>
<input type ="hidden" name="submitted" value="true"></br>
<input type="submit" value="remind">
</form>
</body>
</html>
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5
bocian941 at pawno dot pl
3 years ago
My 2 functions to use "live cookies":

<?php
   
function SetCookieLive($name, $value='', $expire = 0, $path = '', $domain='', $secure=false, $httponly=false)
    {
       
$_COOKIE[$name] = $value;
        return
setcookie($name, $value, $expire, $path, $domain, $secure, $httponly);
    }

    function
RemoveCookieLive($name)
    {
        unset(
$_COOKIE[$name]);
        return
setcookie($name, NULL, -1);
    }
?>
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4
Anonymous
7 years ago
something that wasn't made clear to me here and totally confused me for a while was that domain names must contain at least two dots (.), hence 'localhost' is invalid and the browser will refuse to set the cookie! instead for localhost you should use false.

to make your code work on both localhost and a proper domain, you can do this:

<?php

$domain
= ($_SERVER['HTTP_HOST'] != 'localhost') ? $_SERVER['HTTP_HOST'] : false;
setcookie('cookiename', 'data', time()+60*60*24*365, '/', $domain, false);

?>
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3
jay at w3prodigy dot com
4 years ago
You can also delete cookies by supplying setcookie an empty value.

setcookie("w3p_cookie", "");
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2
Anonymous
3 years ago
A period in a cookie name (like user.name) seems to show up in the $_COOKIE array as an underscore (so user_name). This means that for example $_COOKIE["user_name"] must be used to read a cookie that has been set with setcookie("user.name" ...), which is already rather confusing.

Furthermore the variable $_COOKIE["user_name"] will retain the value set by setcookie("user.name" ...) and no amount of calling setcookie("user_name" ...) will alter this value. This is rather trivially fixed by clearing the "user.name" cookie, but it can take a while to realize this since there's only "user_name" in $_COOKIE.

Hope this saves someone some time.
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3
chris at styl dot ee
3 years ago
I was searching for a simple example of creating a cookie, storing a random number and updating it on refresh. I couldn't find one so I had to figure it out on my own....

- - - -
One thing to *NOTE* is technically you can't update a cookie, you can only overwrite it with a new one with the same name.

- - - -

This creates a random number, stores it in a cookie, then references it on refresh, checks for duplicates and does necessary correction, then stores it again, rinse and repeat...

<?php
ob_start
();
$MaxCount = 4;// set the max of the counter, in my tests "4" = (0,1,2,3) I adjusted below (+1) to get a "real" 4 (0,1,2,3,4) this is in reality 5 keys to humans, you can adjust script to eliminate "0", but my script makes use of the "0"

$random =(rand()%($MaxCount+1));//give me a random number limited by the max, adding "1" because computers start counting at "0"

if(!isset($_COOKIE['random'])){// check if random number cookie is not set
    //echo"not set";
   
setcookie('random', $random);//set the cookie for the first time
   
}else{
   
$lastRandom= $_COOKIE['random']; //hold the last number if it was set before
   
if($lastRandom == $random){//some logic to avoid repeats
    
if($random < $MaxCount){//if below max, add 1
       
$random++;
       
//echo "under the max, adding 1, ";   
   
}elseif($random >= ($MaxCount-1)){// if for some reason the random number is more than max or equal to it -1, and an additional -1 for max count in initial var (so in reality this -1 from intial max var, and -1 from $random which should be the same number)
           
$random--;
           
//echo "hit the max, subtracting 1, ";
       
}else{
       
$random++;
       
//echo "no case match, adding 1, ";   
       
}
   
//echo "(".$lastRandom.", ".$random. "), they matched initally - was it fixed?";
   
}else{
   
//echo "(".$lastRandom.", ".$random. "), they DO NOT match";
   
setcookie('random', $random);   
    }
   
//echo"is set: {$_COOKIE['random']}";
}

ob_end_flush();

?>
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3
laffen
5 years ago
Note that the $_COOKIE variable not will hold multiple cookies with the same name. It is legitimate to set two cookies with the same name to the same host where the sub domain is different.
<?php
setcookie
("testcookie", "value1hostonly", time(), "/", ".example.com", 0, true);
setcookie("testcookie", "value2subdom", time(), "/", "subdom.example.com", 0, true);
?>
The next request from the browser will have both cookies in the $_SERVER['HTTP_COOKIE'] variable, but only one of them will be found in the $_COOKIE variable. Requests to subdom.example.com will have both cookies, while browser request to example.com or www.example.com only sends the cookie with the "value1hostonly" value.

<?php
$kaker
= explode(";", $_SERVER['HTTP_COOKIE']);
foreach(
$kaker as $val){
   
$k = explode("=", $val);
    echo
trim($k[0]) . " => " . $k[1];
}

// output
testcookie => value1hostonly
testcookie
=> value2subdom

?>
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2
mike
7 years ago
Be careful of using the same cookie name in subdirectories. Setting a simple cookie

<?php setcookie("region", $_GET['set_region']); ?>

both in the root / and for instance in this case /admin/ will create 2 cookies with different paths. In reading the cookies back only the first one is read regardless of path.
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1
gabe at fijiwebdesign dot com
7 years ago
If you want to delete all cookies on your domain, you may want to use the value of:

<?php $_SERVER['HTTP_COOKIE'] ?>

rather than:

<?php $_COOKIE ?>

to dertermine the cookie names.
If cookie names are in Array notation, eg: user[username]
Then PHP will automatically create a corresponding array in $_COOKIE. Instead use $_SERVER['HTTP_COOKIE'] as it mirrors the actual HTTP Request header.

<?php

// unset cookies
if (isset($_SERVER['HTTP_COOKIE'])) {
   
$cookies = explode(';', $_SERVER['HTTP_COOKIE']);
    foreach(
$cookies as $cookie) {
       
$parts = explode('=', $cookie);
       
$name = trim($parts[0]);
       
setcookie($name, '', time()-1000);
       
setcookie($name, '', time()-1000, '/');
    }
}

?>
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3
ahmetantmen at msn dot com
7 years ago
You can be sure about the cookie files contents weren't changed.

<?php

$Seperator
= '--';
$uniqueID = 'Ju?hG&F0yh9?=/6*GVfd-d8u6f86hp';
$Data = 'Ahmet '.md5('123456789');

setcookie('VerifyUser', $Data.$Seperator.md5($Data.$uniqueID));

if (
$_COOKIE) {
  
$Cut = explode($Seperator, $_COOKIE['VerifyUser']);
   if (
md5($Cut[0].$uniqueID) === $Cut[1]) {
      
$_COOKIE['VerifyUser'] = $Cut[0];
   } else {
       die(
'Cookie data is invalid!!!');
   }
}

echo
$_COOKIE['VerifyUser'];

?>

Create a unique id for your site and create a hash with md5($Data.$uniqueID). Attacker can understant that it must be re-hash after change cookie content.
But doesn't. Because cannot guess your unique id. Seperate your hash and data with seperator and send that cookie. Control that hash of returned value and your unique id's is same returned hash. Otherwise you have to stop attack. Sorry for my poor english!
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1
gareth at gw126 dot com
8 years ago
You can use cookies to prevent a browser refresh repeating some action from a form post... (providing the client is cookie enabled!)

<?php
//Flag up repeat actions (like credit card transaction, etc)
if(count($_POST)>0) {
   
$lastpost= isset($_COOKIE['lastpost']) ? $_COOKIE['lastpost'] : '';
    if(
$lastpost!=md5(serialize($_POST))) {
       
setcookie('lastpost', md5(serialize($_POST)));
       
$_POST['_REPEATED']=0;
    } else {
       
$_POST['_REPEATED']=1;
    }
}

//At this point, if $_POST['_REPEATED']==1, then  the user
//has hit the refresh button; so don't do any actions that you don't
//want to repeat!
?>

Hope that helps :)

Gareth
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1
Bachsau
2 years ago
Want to remove a cookie?

Many people do it the complicated way:
setcookie('name', 'content', time()-3600);

But why do you make it so complicated and risk it not working, when the client's time is wrong? Why fiddle around with time();

Here's the easiest way to unset a cookie:
setcookie('name', 'content', 1);

Thats it.
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ellert at vankoperen dot nl
14 days ago
Caveat: if you use URL RewriteRules to get stuff like this: domain.com/bla/stuf/etc into parameters, you might run into a hickup when setting cookies.
At least in my setup a change in one of the parameters resulted in the cookie not being 'there' anymore.
The fix is simple: specify the domain. '/' will usualy do fine.
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cwillard at fastmail dot fm
6 years ago
If you're looking to set multiple values in your cookie (rather than setting multiple cookies) you might find these useful.

<?php
function build_cookie($var_array) {
  if (
is_array($var_array)) {
    foreach (
$var_array as $index => $data) {
     
$out.= ($data!="") ? $index."=".$data."|" : "";
    }
  }
  return
rtrim($out,"|");
}

function
break_cookie ($cookie_string) {
 
$array=explode("|",$cookie_string);
  foreach (
$array as $i=>$stuff) {
   
$stuff=explode("=",$stuff);
   
$array[$stuff[0]]=$stuff[1];
    unset(
$array[$i]);
  }
  return
$array;
}
?>
Hopefully someone finds these useful.
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Anonymous
7 years ago
if you only want to do something once per unique visitor, you can test if a cookie is set, and if not, set the cookie and perform the action. This being the poorman's version, it has a problem, where if a user is blocking cookies they will appear as a first time visitor each time. What you can do to avoid this is to set a test cookie first and check that it exists. If it exists, then check to see if your second cookie has been set. If the first one is set, but the second isn't, then you know this is a first time visitor.
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Anonymous
7 years ago
If you ever find yourself in a situation where you need to overwrite a non-PHP application's session cookie, you can do that with the following line:

<?php
header
("Set-Cookie: SIDNAME=$overwrite; path=/; secure");
?>

I couldn't get setcookie() to do this for all major web browsers, but manually sending the header did the trick. Note: Remove secure if you aren't mandating SSL connections.
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apex at xepa dot nl
10 years ago
Note on setting cookies allowing access to sites:

If you are not using something "personal" from the computer that you are sending the cookie too watch out.  Via javascript it is possible to steal cookies from other users.  Thus allowing the stealer to login to your site as another user that might not have access otherwise.  Try to add something like the user's ip in the cookie and allowing access from that ip only with the stored cookie data.

[Editor's note: ... or simply use sessions. You can't be sure that the visitor will use the same IP the next visit. Not even on the next request (thanks to proxy servers)]
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dave at fubra dot com
10 years ago
There are several characters that dont work correctly if part of the cookie name, I in particular ran into problems using = as part of the cookie name ie/

<?php setcookie('dE4fR=', $foo); ?>

this was as a result of base64_encode() ing a variable to use as the name. The cookie was being set fine but the = is stored as a little square character in the cookie which prevent proper retreival.

The solution for me was to use md5() instead of base64_encode() but any other method which avoids the = sign should also solve the problem
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adruff at gmail dot com
7 years ago
If you intend to use persistent cookies (vice session cookies that are deleted when the browser is closed) be aware:
1) Firefox appears to require that you include all paramaters, or it will ignore the expiration and treat the cookie as a session cookie
2) My version of firefox (1.5.0.6) defaults to 'keep cookies until i close firefox' , which essentially makes every cookie a session cookie. This of course sucks for devs, but i suppose is supposed to be a security feature for the end user. If the user wants to configure firefox to respect the expiration date and retain cookies beyond the session, the user must change it to 'keep cookies until they expire'.
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Alchaemist
9 years ago
setcookie + header Location + IIS 5 = Trouble

It took me a long time to figure out what was causing a missing cookie in one system while it worked perfectly in another...

See this one: http://support.microsoft.com/kb/q176113/

In short, this WILL NEVER WORK IN IIS 5:
<?php
header
("Pragma: no-cache");
header('Location: http://www.example.com/');
setcookie('AA','1',0,'/');
setcookie('BB','2',time() + 24 * 3600,'/');
?>

You will ONLY get the Location Header, everything else will be "cut out" by IIS 5 CGI implementation.

Solutions:
1- Migrate to Apache/IIS6/Whatever
2- Use a Non Parsed Header Script (nph-*.php)
3- Try with header('Refresh: 0; $URL');

I hope this helps somebody not to spend hours knocking his/her head.

Alchaemist
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RC
3 years ago
For those of your banging your head as to why a cookie is not present when Internet Explorer 6 prints, the explanation is quite interesting. After a bit of investigation, a cookie with an expiration time other than 0 fails to be passed from IE6 to the server when printing. A cookie with an expiration time of 0 is sent.

Therefore:

setcookie("TestCookie", $value, time()+3600); //will not be sent from Print / Print Preview in IE6

setcookie("TestCookie", $value, 0); //will be sent from Print / Print Preview in IE6

I'll let everyone figure out who's bright idea it was to not send normal expiring cookies when printing in IE6...
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vanclute at gmail dot com
2 years ago
I have been tearing my hair out wondering why a cookie would not delete.  Despite countless discussions of reasons this can happen all over the internet, none of them addresses my case.  Here is what was happening:

My cookies have been formed kindof as an array, and the name of the cookie to be deleted is being passed in a variable, so I was using this to attempt to delete the cookie (stripped to the minimum for simplicity of the example):

<?php
    setcookie
("$cookiename[id]");
?>

But it simply would not work.  Ultimately what DID work was this:

<?php
    setcookie
($cookiename."[id]");
?>

So I had to concatenate the variable to the "element id" and then the cookies deleted without any issue.

I hope this saves someone else from a sleepless night!!

Jonathan
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danielpopescu93 at gmail dot com
1 year ago
Hei, so here is what problem I had, maybe it will help someone in the future:
I couldn't delete a cookie, not even set it a different value. I think that is because it had a name following the rule FirstSecondThird. So it had uppercase letters.
After I modified the name everithing worked.

Another note:
Just for safety you should put what you want to put in the cookie in a var first.
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herrkampfgarten at gmail dot com
1 year ago
Please note that setting the expiry to some timestamp in the past is a common way to get rid of a cookie. However, depending on the value you might set to "invalidate" a cookie immediately, this may pose a threat to the privacy of your user's data, especially when it comes to session cookies.

If you write "0" and "expire-in-the-past" into a session cookie, it remains on the client-side until the clean-up mechanism of the browser hits. (That might be anything from no-time to a very long time. I'm not even thinking of app-based mobile browsers that won't close properly or do their best to ignore standards and RFCs and stuff...)

So, if you have sufficiently messed up your ways of picking up existing session IDs and write-closing their data to your server, the session's data might move from file "sess_(random)" to "sess_0", because that is exactly the identifier that is referred in the cookie.

From now on (at least until your server decides to clean up) there is data laying open wide to anyone requesting the session "0". Which may happen by accident (i.e. another user gains an own "0"-cookie) or malice (i.e. forgery).

Long story short, ALWAYS use an empty string instead of a "0" value for invalidating a session cookie.
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dbessoudo at gmail dot com
4 years ago
setcookie - value = "deleted" on IE

  setcookie(session_name(), '', time()-42000, '/');

When "setcookie" is passed an empty value (ie, ''), it changes the value to the string "deleted" and sets the date to exactly one year and one second in the past, ignoring the expiration parameter.*

So, I'm guessing that if a client machine has its time set to more than a year in the past or if the browser is somehow broken, then a site visitor could potentially send a PHPSESSID with a value of "deleted".  This will cause PHP to create a "sess_deleted" file in the sessions directory.

In my case, I was seeing several incidents per minute, with each user clobbering the other's session data causing all kinds of security and identity issues.  Two changes seemed to have solved the problem:

1) Use session_id() in place of '' in setcookie, as well as pick a date that's far in the past (in this case Jan 1, 1970, 8:00:01AM):

    setcookie(session_name(), session_id(), 1, '/');

2) Use session_regenerate_id() when logging a user in or otherwise changing their authority level.

Hope this helps somebody.

Rob

* Here is the relevant code in head.c:

    if (value && value_len == 0) {
        /*                                                                                                                                                                                                     
         * MSIE doesn't delete a cookie when you set it to a null value                                                                                                                                        
         * so in order to force cookies to be deleted, even on MSIE, we                                                                                                                                        
         * pick an expiry date 1 year and 1 second in the past                                                                                                                                                 
         */
        time_t t = time(NULL) - 31536001;
        dt = php_format_date("D, d-M-Y H:i:s T", sizeof("D, d-M-Y H:i:s T")-1, t, 0 TSRMLS_CC);
        sprintf(cookie, "Set-Cookie: %s=deleted; expires=%s", name, dt);
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soeren dot spreng at gmail dot com
6 years ago
Beware: The Internet Explorer doesn't accept Cookies with an expiretime, which is to long. time() + time() for example doesn't work and the Cookie won't be created!
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jacobkamphansen at gmail dot com
3 years ago
I've been pulling my hair for a couple of minutes (read: hours) and finally figured out why setcookie in my case, returned the "headers already sent"-error:

The file in question was orignally saved as ANSI in Notepad and worked flawlessly, but when saved with UTF-8-encoding, it didn't work. So after trying phpDesigner 7, I was able to both save the file in UTF-8 AND remove the BOM (byte-order-mark which is output BEFORE the cookie is set and thereby fails everything).
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Marcin Wiazowski
7 years ago
'session.cookie_domain' should be set to empty string for all local domain names, not only for 'localhost' (but should not be empty for local IP addresses):

<?php
ini_set
('session.cookie_domain', (strpos($_SERVER['HTTP_HOST'],'.') !== false) ? $_SERVER['HTTP_HOST'] : '');
?>
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kurtubba at gmail dot com
7 years ago
When setting a top level domain ex ".mydomain.com" you must add the secure arg so it should look like

<?php
setcookie
("TestCookie", $value, time()+3600, "/", ".example.com", 0);
?>


ignoring the secure arg makes IE ignores the cookie
to get the top level domain use

<?php
$myDomain
= ereg_replace('^[^\.]*\.([^\.]*)\.(.*)$', '\1.\2',$_SERVER['HTTP_HOST']);
?>


to avoid localhost switch use

<?php
$phpCkDmn
= $_SERVER['HTTP_HOST'] != "localhost" ? $myDomain : false;
?>
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simon at ruderich dot com
8 years ago
If you want to delete a session cookie, you can do it with this code:

<?php
  session_start
();

 
// many code

 
$sessionName = session_name();
 
$sessionCookie = session_get_cookie_params();

 
session_destroy();

 
setcookie($sessionName, false, $sessionCookie['lifetime'], $sessionCookie['path'], $sessionCookie['domain'], $sessionCookie['secure']);
?>

This works also well if the session cookie params or the session name were changed.
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soreman at abv dot bg
11 years ago
If you experience problems on Microsoft Information Server (IIS) when setting a cookie via PHP and when PHP is running as a CGI binary it is not setting the cookie. After spending many hours on what the problem is here is what happens:

When you invoke setcookie and redirect to another page you will not have your cookie set, because it seems that IIS doesn't set the cookie unless you actually send some contents to the browser. Therefore if you want to set a cookie and then redirect to another page you will have to do the redirection via JavaScript and/or HTML if you want your script to work on IIS.
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mleer at sp dot nl
11 years ago
P3P is a good idea. But.
IE 6 features an inadequate definition of third party cookies.
If your site is hosted on server A and your PHP stuff is coming in a framesetting from server B your setcookie-attempts will be blocked when default privacy settings are deployed. Your secondparty-cookie will be regarded as a thirdparty-cookie.

So what you do is not read the P3P-Internet Explorer 6-manual at MS but send a header like

<?php
header
('P3P: CP="NOI ADM DEV PSAi COM NAV OUR OTRo STP IND DEM"');
?>

before doing the setcookie-thing. This will enable your cookie to survive any IE-6 privacy settings.

You won't do this if you're working for some doubleclick institution, because if you do, you... you...well... you are not a very nice person!
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karamfil dot pc at gmail dot com
3 years ago
Beware of underscores in the hostname, because IE won't save cookies.
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php at gigadepot dot com
5 years ago
If you use a multiple cookie name with the function bellow

example :

createcookie("member[name]","jack");

don't work with array

error with "rawurlencode($name)"

I'm use : createcookie(array('member'=>'name'),'jack');

<?php
createCookie
($name, $value='', $maxage=0, $path='',$domain='', $secure=false, $HTTPOnly=false)
    {
        if(
is_array($name))
        {
            list(
$k,$v)    =    each($name);

               
$name    =    $k.'['.$v.']';

        }
       
$ob = ini_get('output_buffering');
       
// Abort the method if headers have already been sent, except when output buffering has been enabled
       
if ( headers_sent() && (bool) $ob === false || strtolower($ob) == 'off' )
            return
false;
        if ( !empty(
$domain) )
        {
           
// Fix the domain to accept domains with and without 'www.'.
           
if ( strtolower( substr($domain, 0, 4) ) == 'www.' ) $domain = substr($domain, 4);
           
// Add the dot prefix to ensure compatibility with subdomains
           
if ( substr($domain, 0, 1) != '.' ) $domain = '.'.$domain;
           
// Remove port information.
           
$port = strpos($domain, ':');
            if (
$port !== false ) $domain = substr($domain, 0, $port);
        }
       
// Prevent "headers already sent" error with utf8 support (BOM)
        //if ( utf8_support ) header('Content-Type: text/html; charset=utf-8');
       
if(is_array($name))
        {
           
header('Set-Cookie: '.$name.'='.rawurlencode($value)
                                    .(empty(
$domain) ? '' : '; Domain='.$domain)
                                    .(empty(
$maxage) ? '' : '; Max-Age='.$maxage)
                                    .(empty(
$path) ? '' : '; Path='.$path)
                                    .(!
$secure ? '' : '; Secure')
                                    .(!
$HTTPOnly ? '' : '; HttpOnly'), false);
        }else{
           
header('Set-Cookie: '.rawurlencode($name).'='.rawurlencode($value)
                                    .(empty(
$domain) ? '' : '; Domain='.$domain)
                                    .(empty(
$maxage) ? '' : '; Max-Age='.$maxage)
                                    .(empty(
$path) ? '' : '; Path='.$path)
                                    .(!
$secure ? '' : '; Secure')
                                    .(!
$HTTPOnly ? '' : '; HttpOnly'), false);
        }
        return
true;
    }
?>
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isooik at gmail-antispam dot com
6 years ago
Here's a more advanced version of the php setcookie() alternative function:

<?php

   
/**
     * A better alternative (RFC 2109 compatible) to the php setcookie() function
     *
     * @param string Name of the cookie
     * @param string Value of the cookie
     * @param int Lifetime of the cookie
     * @param string Path where the cookie can be used
     * @param string Domain which can read the cookie
     * @param bool Secure mode?
     * @param bool Only allow HTTP usage?
     * @return bool True or false whether the method has successfully run
     */
   
function createCookie($name, $value='', $maxage=0, $path='', $domain='', $secure=false, $HTTPOnly=false)
    {
       
$ob = ini_get('output_buffering');

       
// Abort the method if headers have already been sent, except when output buffering has been enabled
       
if ( headers_sent() && (bool) $ob === false || strtolower($ob) == 'off' )
            return
false;

        if ( !empty(
$domain) )
        {
           
// Fix the domain to accept domains with and without 'www.'.
           
if ( strtolower( substr($domain, 0, 4) ) == 'www.' ) $domain = substr($domain, 4);
           
// Add the dot prefix to ensure compatibility with subdomains
           
if ( substr($domain, 0, 1) != '.' ) $domain = '.'.$domain;

           
// Remove port information.
           
$port = strpos($domain, ':');

            if (
$port !== false ) $domain = substr($domain, 0, $port);
        }

       
// Prevent "headers already sent" error with utf8 support (BOM)
        //if ( utf8_support ) header('Content-Type: text/html; charset=utf-8');

       
header('Set-Cookie: '.rawurlencode($name).'='.rawurlencode($value)
                                    .(empty(
$domain) ? '' : '; Domain='.$domain)
                                    .(empty(
$maxage) ? '' : '; Max-Age='.$maxage)
                                    .(empty(
$path) ? '' : '; Path='.$path)
                                    .(!
$secure ? '' : '; Secure')
                                    .(!
$HTTPOnly ? '' : '; HttpOnly'), false);
        return
true;
    }

?>

Regards,
Isaak
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mikeh at view22 dot com
6 years ago
Observed: session cookies were expiring even though the session was still active.  (To test, set a cookie expiry of 5 seconds and keep hitting the page every second.  The session will expire and create a new SESSID after 5 seconds despite the fact that you hit the page only a second ago.)

Calling this function before starting the session fixed it.  It copies the cookie contents back to itself while forcing an update to the expiry time in the cookie.

<?php
function FreshenSessionCookie($lifetimeSeconds, $cookieName = 'PHPSESSID')
{
    if (isset(
$_COOKIE[$cookieName]))
        {
       
$data = $_COOKIE[$cookieName];
       
$timeout = time()+$lifetimeSeconds;
       
setcookie($cookieName, $data$timeout);
        }
}
?>
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jbouvet at absolunet dot com
9 months ago
When deleting a cookie that was set in Javascript, add the path to the setcookie function, like so :

setCookie('cookie_name', '', time()-3600, '/');
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