HTTP Requests and Responses: Fundamental Core Concepts in Python Web Development

In Python web development, HTTP is the core for communication between the client (e.g., a browser) and the server, based on the "request-response" mechanism. The client generates an HTTP request, which includes methods (GET/POST, etc.), URLs, header information (e.g., User-Agent, Cookie), and a request body (POST data). After processing, the server returns an HTTP response, which contains a status code (e.g., 200 for success, 404 for not found), response headers (e.g., Content-Type), and a response body (web pages/data). The process is: client sends a request → server parses and processes it → returns a response → client renders the response (e.g., HTML to render a web page). Python frameworks (e.g., Flask) simplify this process. In the example, Flask uses `request` to access the request and `return` to directly send back the response content. Understanding this mechanism is fundamental to web development and lays the foundation for advanced studies such as HTTPS and Cookies.