What is the operational principle of web API?

The working principle of Web API is based on communicating with the HTTP protocol. The specific principle is as follows:

1. The client sends an HTTP request to the server, which includes the URL, HTTP method (such as GET, POST, etc.), request headers, and request body.
2. After receiving the request, the server will call the corresponding Web API processing method based on the URL and HTTP method.
3. The Web API processing method performs the corresponding business logic based on the content of the request, which may include reading data from the database, processing data, and generating a response.
4. After processing is complete, the Web API will return an HTTP response to the client, which includes information such as the HTTP status code, response headers, and response body.
5. After receiving the response, the client processes it accordingly based on the HTTP status code, response body, and other information, which may involve parsing the response body data and displaying the data.

In summary, the operation principle of Web API involves communication between the client and server through the HTTP protocol. The client sends a request to the server, which then calls the Web API processing method to handle the business logic and returns an HTTP response to the client.