A general request process

A general request process

When a user enters the URL www.taobao.com in a browser, many operations will occur. First, it requests DNS to resolve the domain name to the corresponding IP address, then finds the corresponding server on the Internet based on the IP address, and initiates a get request to the server, the server decides to return the default data resource to the accessed user. There is actually a complicated business logic on the server side: there may be many servers. Which server should be designated to process the requests? This requires a Server Load balancer device to evenly distribute requests from all users; in addition, the requested data is stored in the distributed cache, in a static file, or in a database. when the data is returned to the browser, when the browser parses the data and finds that there are still some static resources (such as CSS, JS, or images), it will initiate another HTTP request, which is likely to be on the CDN, then the CDN server will process the user's request again. In general, a user request will involve so many operations. Every detail affects whether the request is successful.