PHP
5 Cookies
What
is a Cookie?
A cookie is
often used to identify a user. A cookie is a small file that the server embeds
on the user's computer. Each time the same computer requests a page with a
browser, it will send the cookie too. With PHP, you can both create and
retrieve cookie values.
Create
Cookies With PHP
A cookie is
created with the setcookie() function.
Syntax
setcookie(name,
value, expire, path, domain, secure, httponly);
Only the
name parameter is required. All other parameters are optional.
PHP
Create/Retrieve a Cookie
The
following example creates a cookie named "user" with the value
"John Doe". The cookie will expire after 30 days (86400 * 30). The
"/" means that the cookie is available in entire website (otherwise,
select the directory you prefer).
We then
retrieve the value of the cookie "user" (using the global variable
$_COOKIE). We also use the isset() function to find out if the cookie is set:
Example
<?php
$cookie_name
= "user";
$cookie_value
= "John Doe";
setcookie($cookie_name,
$cookie_value, time() + (86400 * 30), "/"); // 86400 = 1 day
?>
<html>
<body>
<?php
if(!isset($_COOKIE[$cookie_name]))
{
echo "Cookie named '" .
$cookie_name . "' is not set!";
}
else {
echo "Cookie '" . $cookie_name .
"' is set!<br>";
echo "Value is: " .
$_COOKIE[$cookie_name];
}
?>
</body>
</html>
Note: The
setcookie() function must appear BEFORE the <html> tag.
Note: The
value of the cookie is automatically URLencoded when sending the cookie, and
automatically decoded when received (to prevent URLencoding, use setrawcookie()
instead).
Modify a
Cookie Value
To modify a
cookie, just set (again) the cookie using the setcookie() function:
Example
<?php
$cookie_name
= "user";
$cookie_value
= "Alex Porter";
setcookie($cookie_name,
$cookie_value, time() + (86400 * 30), "/");
?>
<html>
<body>
<?php
if(!isset($_COOKIE[$cookie_name]))
{
echo "Cookie named '" .
$cookie_name . "' is not set!";
}
else {
echo "Cookie '" . $cookie_name .
"' is set!<br>";
echo "Value is: " .
$_COOKIE[$cookie_name];
}
?>
</body>
</html>
Delete a
Cookie
To delete a
cookie, use the setcookie() function with an expiration date in the past:
Example
<?php
//
set the expiration date to one hour ago
setcookie("user",
"", time() - 3600);
?>
<html>
<body>
<?php
echo
"Cookie 'user' is deleted.";
?>
</body>
</html>
Check if
Cookies are Enabled
The
following example creates a small script that checks whether cookies are
enabled. First, try to create a test cookie with the setcookie() function, then
count the $_COOKIE array variable:
Example
<?php
setcookie("test_cookie",
"test", time() + 3600, '/');
?>
<html>
<body>
<?php
if(count($_COOKIE)
> 0) {
echo "Cookies are enabled.";
}
else {
echo "Cookies are disabled.";
}
?>
</body>
</html>
Complete PHP
HTTP Reference
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