From the page request sent by the user browser to the server response, which middleware are used in the middle and what are their functions

Before the user's browser sends a page request to the server's response, the following middleware may be used:

1. DNS server: resolves the domain name into an IP address, which is convenient for browsers to access.

2. Load Balancer: Distribute user requests to different servers to avoid performance degradation or downtime caused by excessive load on a single server.

3. Reverse Proxy Server (Reverse Proxy Server): Receiving requests on behalf of the server and forwarding them to the real server, hiding the information of the real server, increasing the security and maintainability of the system.

4. CDN (Content Delivery Network): Cache static resources, such as pictures, videos, JS, etc., so that users can access the website faster and improve website performance.

5. Firewall (Firewall): Control the traffic entering and leaving the network to ensure network security.

6. SSL/TLS: Encrypts HTTP requests and responses to provide higher security. It is often used in online payment, login and other scenarios.

7. Web servers (such as Apache, Nginx, etc.): process HTTP requests and return responses, often used for dynamic page generation, static resource caching, etc.

In short, the role of these middleware is to ensure system security, high availability and performance optimization, and improve user experience.