In-depth understanding of PHP 401 Unauthorized and authorization mechanism

The 401 Unauthorized error in PHP indicates that the request is unauthorized, which may be due to: 1. The client did not provide credentials; 2. The credentials are invalid; 3. The client does not have permission to access the resource. To prevent unauthorized access, PHP provides authorization mechanisms, including: 1. Basic authorization (HTTP authentication); 2. Token authorization (JWT/OAuth); 3. Session (storage of authenticated user information).

In-depth understanding of PHP 401 Unauthorized and authorization mechanism

Introduction

PHP Medium The 401 Unauthorized error means that the request is unauthorized. This error is usually due to one of the following reasons:

• The client did not provide credentials.
• The credentials provided are invalid.
• The client does not have permission to access the specified resource.

Authorization mechanism

In order to prevent unauthorized access, PHP provides a variety of authorization mechanisms, including:

• Basic Authorization: Use username and password for HTTP authentication.
• Token Authorization: Use JSON Web Tokens (JWT) or OAuth 2.0 tokens for authentication.
• Session: Use a PHP session to store the details of the authenticated user.

Practical case:

Suppose we have a PHP application and need to protect a file named "secret.php". We can use basic authorization to achieve this:

<?php

if (!isset($_SERVER['PHP_AUTH_USER']) || !isset($_SERVER['PHP_AUTH_PW'])) {
    // 拒绝访问并显示错误消息
    header('HTTP/1.1 401 Unauthorized');
    exit;
}

// 验证凭据
if ($_SERVER['PHP_AUTH_USER'] != 'username' || $_SERVER['PHP_AUTH_PW'] != 'password') {
    // 验证失败
    header('HTTP/1.1 401 Unauthorized');
    exit;
}

// 允许访问
// ...

Note:

• Basic authorization is a simple and commonly used authorization mechanism, but it is not very secure , because the credentials are transmitted in clear text.
• For a more secure option, consider using tokens or sessions as they do not transmit credentials.

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