auth_request Module in Nginx

Overview of the auth_request Module in Nginx

The auth_request module in Nginx allows you to use requests for user authentication to control access to various resources. This module helps you assess the authentication status of a user based on another request (usually a backend URL). By doing this, you can utilize an external resource for user authentication and consequently manage your application more effectively.

For example, you can use this module for user authentication by utilizing external APIs, databases, or other authentication systems. This allows you to have more control over security and resource management in applications.

One of the key features of this module is that responses from the authentication requests can depend on different HTTP status codes. For instance, a response 200 means that the user is authenticated, while a response 401 indicates lack of authentication. With this structure, you can direct the user to suitable resources according to their authentication status.

Now, let’s consider a simple example of how to use the auth_request module. In this example, we will define a URL to check user authentication status and then only allow access to a specified resource for authenticated users.

location /protected {
    auth_request /auth;
    # Only authenticated users can access this location
    proxy_pass http://backend;
}

location = /auth {
    internal;
    # Check if the user is authenticated
    proxy_pass http://auth_backend;
    proxy_set_header Host $host;
}

Code Explanation

Here is an explanation of the Nginx code: