Web application framework, advantages, MVC

Web application framework

A web application framework is a software platform made of libraries, tools and conventions that supports the building of web applications. It provides ready-made code for common tasks (URL routing, database access, templating, sessions, authentication, security, form validation), so developers focus on the application's own logic. Examples: Laravel and CodeIgniter (PHP), Django and Flask (Python), Spring (Java), Ruby on Rails, ASP.NET, Express (Node.js).

Advantages

• Faster development: Reusable components avoid writing common code again.
• Structured code: A standard project layout, often MVC, makes code organised and maintainable.
• Security: Built-in protection against SQL injection, XSS and CSRF.
• Database abstraction: ORM lets code work with objects instead of raw SQL and supports several databases.
• Reusability and testing: Modular code and built-in testing tools.
• Community and support: Documentation, plugins and active communities.
• Scalability and team work: Clear separation allows large teams to work together.

MVC concept

Model-View-Controller divides an application into:

• Model: data and business logic, database operations.
• View: the user interface that shows data (HTML templates).
• Controller: receives requests, interacts with the model and selects the view.

 Request
    |
    v
+------------+  gets/saves  +-------+
| Controller |<------------>| Model |--> Database
+-----+------+              +-------+
      | passes data
      v
+------------+
|   View     |--> HTML response
+------------+

For example, in a library system a request for /books goes to BookController, which asks the Book model for all books and sends them to the books view that shows a table. MVC keeps code organised, testable and easy to change.