This section describes two other cookie properties, domain and path, which tells the browser to send back the cookie only to the specified domain and path.
A cookie also has two other properties:
1. "domain" - A property that defines the domain of Web servers to which this cookie should be made available.
Web browsers will send a cookie back to a Web server when the Web server matches its defined domain.
Web browsers will never send back a cookie to a domain other than its defined domain.
For example, if a cookie's domain is www.google.com, the browser will send back this cookie to the server
only when the browser is visiting www.google.com. The browser will never send back this cookie to www.yahoo.com.
To make a cookie available for all sub domains of a top level domain, set the domain property
to the top level domain name. For example, if a cookie's domain is set to ".google.com", this cookie will be
available to all google sub domains, like groups.google.com and gmail.google.com.
2."path" - A property that defines a Web server path to which this cookie should be made available.
Web browsers will send a cookie back to a Web server when the Web server matches its defined domain, and
the requested page matches its defined path. Web browsers will never send back a cookie to requested path
other than its defined path.
Note that the defined path also includes all its sub paths. For example, if a cookie's domain is "www.amazon.com",
and path is "/order/", then a browser will send back this cookie for requests like
"http://www.amazon.com/order/checkout.html", and "http://www.amazon.com/order/report/invoice.html".
But a browser should not send back this cookie for requests like "http://www.amazon.com/catelog/book.html".
The setcookie() function offers two more parameters to allow you to set "domain" and "path" properties on a cookie
as in the following syntax:
where "path" specifies the cookie's path property, and "domain" specifies the cookie's domain property.
If "path" is not given, the cookie will have "/" as the default path.
If "domain" is not given, the cookie will have the current domain as the default domain.
Okay. Let's play the properties with the following script, CookieProperties.php:
<?php #CookieProperties.php
# Copyright (c) 2005 by Dr. Herong Yang, http://www.herongyang.com/
#
print("<pre>\n");
print("\nAdding a cookie with default properties:\n");
$cookieName = "User";
$cookieValue = "Herong Yang";
$expiration = time()+60*60*24*30;
setcookie($cookieName, $cookieValue, $expiration);
print(" Name: $cookieName\n");
print(" Value: $cookieValue\n");
print(" Expiration: $expiration\n");
print("\nAdding a cookie with non-default properties:\n");
$cookieName = "Book";
$cookieValue = "Herong's Tutorial Notes on PHP";
$expiration = time()+60*60*24*30;
$path = "/";
$domain = "localhost";
setcookie($cookieName, $cookieValue, $expiration, $path, $domain);
print(" Name: $cookieName\n");
print(" Value: $cookieValue\n");
print(" Expiration: $expiration\n");
print(" Path: $path\n");
print(" Domain: $domain\n");
print("\nCookies received by the server:\n");
foreach ($_COOKIE as $k => $v) {
print " $k = $v\n";
}
print "</pre>\n";
?>
Ran this script in IE, I got:
Adding a cookie with default properties:
Name: User
Value: Herong Yang
Expiration: 1134622043
Adding a cookie with non-default properties:
Name: Book
Value: Herong's Tutorial Notes on PHP
Expiration: 1134622043
Path: /
Domain: localhost
Clicked the refresh button on IE, I got:
Adding a cookie with default properties:
Name: User
Value: Herong Yang
Expiration: 1134622059
Adding a cookie with non-default properties:
Name: Book
Value: Herong's Tutorial Notes on PHP
Expiration: 1134622059
Path: /
Domain: localhost
Cookies received by the server:
User = Herong Yang
Apparently, my script did not set the properties correctly. The browser should have sent back my second cookie also.
So either the "path=/" or "domain=localhost" did not match my local IIS environment. I could not figure it out why.
