The Power of SFRA Controllers
SFRA controllers are the foundational infrastructure for handling user interactions and processing data in your storefront. They enable developers to handle requests, execute business logic, and create dynamic personalised experiences — managing everything from displaying a product page to processing a checkout.
Default Controllers in SFRA
The framework ships with several built-in controllers that handle the core commerce flows:
- ProductController — Displays product details and variations
- CartController — Manages shopping cart operations: adding, updating, and removing items
- CheckoutController — Guides users through the checkout process, handling validation and payment
- SearchController — Retrieves and displays products based on user search queries
- AccountController — Manages registration, login, and customer profile functions
Extending Controllers
One of SFRA’s most powerful patterns is the ability to customise controller behaviour without altering the core platform code. Extensions are achieved through three approaches:
Appending
Adds functionality at the end of an existing function. Use this when you want to perform additional logic after the base controller has completed its work — for example, tracking an event after a product is added to cart.
Prepending
Inserts code at the beginning of an existing function. Useful when you need to validate or transform data before the base logic executes.
Replacing
Substitutes an existing function entirely with a custom implementation. This is the most powerful option but should be used sparingly — replacing core logic means you own the maintenance of that behaviour going forward.
All three approaches let you modify storefront behaviour without creating upgrade risk, since your customisations live in a separate cartridge rather than inside the base code.
Best Practices
Single Responsibility Principle
Each controller should have a clear, focused purpose. If a controller is growing large, it is usually a sign that business logic should be moved into helper scripts.
Keep Controllers Lightweight
Controllers should coordinate — not compute. Delegate complex operations like data retrieval, calculations, and external API calls to helper scripts in the Scripts folder. This keeps controllers readable and maintainable.
Plan for Scalability
Design with a modular mindset. Controllers that are cleanly scoped are much easier to extend or replace as requirements evolve.
Comprehensive Error Handling
Every controller action that touches external data or user input should handle errors gracefully. Uncaught exceptions in controllers surface directly to customers.
Thorough Testing
Controller logic sits at the intersection of user requests and business logic — test it thoroughly. Both unit tests and integration tests are valuable here.
Summary
SFRA controllers are the backbone of your storefront’s request handling. Understanding the default controllers, knowing when to append versus replace, and keeping your implementations clean and focused will set you up for a maintainable, scalable SFCC codebase. In Part 3, we’ll explore the Scripts folder in depth.