Let’s talk about how to implement cross-domain jump with cookies in PHP

PHP cross-domain jump with Cookie

When developing web pages, in many cases it is necessary to jump under different domain names, such as jumping from a web page under domain name A to a web page under domain name B. , which requires cross-domain access. However, if you need to retain the user's login information while crossing domains, you need to bring cookies with you during cross-domain jumps. Here is a PHP method for implementing cross-domain jumps with cookies.

1. Background knowledge

1. Cookie

Cookie refers to a small file sent by the server to the user's browser and stored on the user's computer . Each cookie has an expiration time and is automatically deleted after expiration.

When logging in to a web page, the user's login information is generally stored in a cookie, so that the user does not need to log in again when visiting other pages of the website.

2. Cross-domain access

When a web page under one domain name requests an interface or resource under another domain name, cross-domain access is required.

The traditional same-origin policy stipulates that only scripts with the same origin (that is, the same protocol, domain name, and port number) can access each other.

3. Cross-domain jump

In actual development, it is often necessary to jump under different domain names, which requires cross-domain jump. Cross-domain jumps require some additional configuration and code implementation to ensure that the jump is successful and the user's login information is retained.

2. PHP realizes cross-domain jump with Cookie

The following is a sample code. This code will jump from the web page under domain name A to the interface under domain name B, and will Cookie is passed to ensure that the user's login information is not lost.

header("Access-Control-Allow-Credentials: true"); // Allow cross-domain cookies
header("Access-Control-Allow-Origin: http ://www.b.com"); // Domain name that allows cross-domain access
setcookie("userid", "123456", time() 3600, "/", ".a.com"); / / Set Cookie
$target_url = "http://www.b.com/interface.php"; // Target jump address
header("Location: $target_url"); // Jump
?>

In the code, the domain name that allows cross-domain cookies and allows cross-domain access is first set through the header() function. Then the user information cookie is set through the setcookie() function. The fourth parameter "/" indicates that the entire website can access the cookie, and the fifth parameter ".a.com" indicates that the cookie can be accessed across subdomains.

Finally, use the header() function to jump and specify the target jump address $target_url.

3. Summary

To implement cross-domain jump with Cookie in PHP, many aspects need to be considered, including cross-domain access, cookie settings, implementation of cross-domain jump, etc. By using the header() function to implement the corresponding configuration, you can achieve cross-domain access and cross-domain jumps that maintain the user's login status.

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