Briefly describe the architecture principle of WEB system

Generally speaking, the WEB system mainly refers to the back end, and the front end is various browsers.

So simply speaking, as long as it can interact with the browser through the network, it can be regarded as a WEB system. The simplest thing is to write an echo with NODEJS, that is, what the client sends back.

In practical application, the architecture of WEB system generally includes several parts: load balancing, authorization verification (optional), static content service, dynamic content service (business logic), database and operation and maintenance background.

1) Load balancing is to improve user experience and make full use of server resources. Its main function is to forward new requests to less busy servers for processing.

2) Authorization verification is to verify the authorization of the request initiated by the browser. If it is not a legitimate request, it will be rejected or redirected to the login page.

3) Static content service refers to static content, such as pictures and CSS, which will not change according to different users and will be returned directly to users. Because there is no need for logical judgment, the performance mainly depends on I/O reading and writing, and the response can be very fast. Super-large websites will also deal with some dynamic content statically, such as news pages with large visits, to improve the response speed. The typical static content service is CDN.

4) Dynamic content service is a business logic processing that responds to different users' requests. Such as CRUD (add, delete, check and modify) of user data. This is the core of most WEB systems, which is usually called database and data cache. The specific implementation will change according to the business requirements, and it may also become very complicated.

5) The database where the data is located includes both the classic relational traditional database system and the main memory database, so as to improve the access performance and reduce the workload.

6) The operation and maintenance background is for the convenience of monitoring the operation status, upgrading and maintaining the system, and does not directly participate in external services.

Let's write so much first. You can ask specific questions again.