1th chapter in-depth analysis of Web request process

The b/S architecture brings two benefits:
1. Clients use a unified browser, effectively shielding the different service providers to provide users with the difference of service. Most importantly, the interactive nature of the browser makes it easy for users to use it, and the user's behavior is highly inheritable.
2. The service side is based on a unified HTTP protocol, simplifying the development model, so that server developers can adopt a relatively standardized development model, which can greatly save development costs.

1.1 b/S Network architecture overview

b/S network architecture from the front end to the back end are simplified, based on the Unified Application layer protocol HTTP to interact with the data, the HTTP protocol uses a non-state short-link communication mode, typically, a single request to complete a data interaction, usually also corresponds to a business logic, and then the communication connection is disconnected. This is done in order to be able to serve more users at the same time, because the current Internet application processing hundreds of millions of user requests per day, it is not possible for each user to maintain this connection after one visit.

When a user enters www.taobao.com this URL in a browser, the following actions occur: First, the browser requests DNS to resolve the domain name to the corresponding IP address. Then, according to this IP address on the Internet to find the corresponding server, to the server to initiate a GET request, the server decided to return the default data resources to the user access. On the server side there is actually a complex business logic: The server may have more than one, exactly specify which server to process the request, which requires a load balancer device to evenly allocate all user requests;

1th chapter in-depth analysis of Web request process