Flask View Functions: From Returning HTML to Dynamic Data

This article introduces the core role and usage of view functions in Flask. View functions are the core component that handles user requests and returns responses, acting as a bridge connecting user access and content generation. Firstly, view functions can return simple strings, and Flask will automatically convert them into HTML responses (such as the "Hello, Flask!" example). Secondly, `render_template` is used to load HTML templates from the `templates` folder, enabling static page rendering. Dynamic data processing is a key focus: by leveraging the Jinja2 templating engine, view functions can pass variables (e.g., current time) to templates for rendering using `{{ variable }}`. They also support loops (`{% for %}`) and conditional judgments (`{% if %}`) to display dynamic lists. Route parameters (e.g., `/profile/<user_id>`) can be used to obtain dynamic parameters from URLs, or the `request` object can handle request parameters (e.g., URL parameters, form data). In the comprehensive example, a dynamic blog list combines parameter processing with template rendering to implement article filtering by author. View functions support static content, dynamic data (variables, loops, conditions), and parameter handling, making them the foundation for building interactive web applications.