What are the responsibilities of Model, View, and Controller?

In the MVC (Model-View-Controller) pattern, each part of the system has strictly defined responsibilities so the application stays clear, flexible, and manageable.

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#1. Model - application data and logic

Responsibilities:

• Stores and manages data (for example, users, orders, products).
• Implements the system's business rules and behavior.
• Handles requests from the controller: "save", "change", "find".
• Notifies the view about data changes (in some implementations).

Example: A User class with register(), login(), change_password() methods and a users table in the database.

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#2. View - displaying data to the user

Responsibilities:

• Receives data from the model (through the controller).
• Builds the interface (HTML, JSON, an application window, a graphical element).
• Displays the result of the user's actions.
• Contains no processing or storage logic, only visualization.

Example: An HTML template of a user profile, a cart page, a PDF report, a React component.

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#3. Controller - connecting link and control logic

Responsibilities:

• Accepts user actions (a request, a click, a form input).
• Turns to the model to perform the needed action.
• Passes data to the view for display.
• Determines which view to use for the response.

Example: The method UserController.show(id) gets the user from UserModel and passes it to the profile.html template.

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#Overall structure of the work:

• Controller: manages the process.
• Model: performs business logic and data work.
• View: shows the result.

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Main principle:

Each component is responsible only for its own task. The controller manages, the model knows how to work, and the view knows how to show.