Solution to PHP Session cross-domain problem

Solution to PHP Session cross-domain problem

In development where the front and back ends are separated, cross-domain requests have become the norm. When dealing with cross-domain issues, we usually involve the use and management of sessions. However, due to browser origin policy restrictions, sessions cannot be shared by default across domains. In order to solve this problem, we need to use some techniques and methods to achieve cross-domain sharing of sessions.

1. Use cookies to share sessions across domains

The most common solution is to use cookies to share sessions across domains. Since cookies are not restricted by the same-origin policy, session information can be transferred and shared between different domain names.

The specific steps are as follows:

1. Set the session on the server side, such as:

session_start();
$_SESSION['user'] = 'example';

2. Store the session identification information in the cookie, For example:

setcookie(session_name(), session_id(), time() + 60*60*24*30, '/', 'www.example.com', false, true);

Among them, www.example.com is the domain name of the current server and needs to be modified according to the actual situation.

3. In the client of cross-domain request, send a request with cookie, such as:

fetch('http://www.example.com/api', {
  credentials: 'include',
})

Among them, credentials: 'include' Use This tells the browser to send credentials, including cookies, to the server.

4. The server parses the cookie and resets the session, such as:

session_id($_COOKIE[session_name()]);
session_start();
if(isset($_SESSION['user'])){
    // session 跨域共享成功
}else{
    // session 跨域共享失败
}

2. Use token to share the session across domains

Another solution Token is used to achieve cross-domain sharing of sessions. The specific steps are as follows:

1. When logging in, a token is generated and stored in the database, associated with the user, such as:

$token = bin2hex(random_bytes(16));
// 将 token 存储到数据库中
// 返回 token 给客户端

2. In The client stores the token in local localStorage or sessionStorage.
3. When making a cross-domain request, send the token to the server as a parameter or in the request header.
4. The server parses the token, verifies the validity of the token by querying the database, and performs corresponding session settings and management.

It should be noted that in order to ensure security, the token needs to set a validity period and be refreshed within a certain period of time. On the server side, expired tokens need to be cleared regularly.

Summary:

The above are two common methods to solve PHP Session cross-domain problems. You can choose a suitable solution according to your actual situation. Whether using cookies or tokens, corresponding processing needs to be performed on the server side to achieve cross-domain sharing of sessions. At the same time, in order to ensure security, we also need to take some measures to protect the security of session data.

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