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Working with Controllers in Rails

Working with controllers in the Rails framework is integral to web application development. Essentially, the controller is the C in MVC (Model-View-Controller), acting as a middleman between models and views. In Rails, developers craft controllers as Ruby classes inheriting from the Application Controller.

Controllers are responsible for making sense of the user’s request and producing the appropriate output. They mediate the data traffic between the user and the system.

Whether you’re a beginner or an experienced developer, grasping the nuances of rails working controllers is fundamental to crafting robust web applications.

Naming Convention

Generally, the naming convention of controllers in Rails favors the pluralization of the last word in the controller’s name. For instance, a controller dealing with user-related processes would likely be named UsersController.

Inheritance in Controllers

An important point to note is that controllers in Rails are essentially Ruby classes that inherit from the Application Controller.

The Application Controller inherits from Action Controller::Base, which defines several helpful methods. You can view all these methods in the API documentation.

Parameters in Rails Controllers

Another significant aspect of rails working controllers is understanding how parameters work. Parameters are available to Rails’ actions via the params hash object.

Multi-Dimensional Parameters

With params, you’re not strictly limited to one-dimensional keys and values. In fact, it can contain nested arrays and hashes. While convenient, handling such multi-dimensional parameters may be challenging, requiring an additional level of checks and balances.

Interchangeable Keys

The params object allows you to use symbols and strings interchangeably as keys. If your request’s “Content-Type” header is set to “application/json”, Rails will automatically load your parameters into the params hash.

Special Parameters

The params hash will always contain the :controller and :action keys, reflecting the current controller’s name and the action’s name.

Filtering and Permission

With strong parameters, Action Controller parameters are forbidden to be used in Active Model mass assignments until they have been explicitly allowed. Extreme care should be taken when using permit! as it will allow all current and future model attributes to be mass-assigned.

The Session and the Flash

Your application maintains a session for each user in which you can store small amounts of data between requests. Plotting its course, the session uses a cookie to store a unique ID for each session.

Flash Messages

The flash is a part of the session that is cleared with each request. Values stored in the flash will only be available in the next request. For instance, if an action sets a notice message, this message will appear in the user’s next request after the action ends.

Dealing with Cookies

In Rails, you can access the value of cookies via the cookies method, which behaves like a hash object. Rails also provides a signed cookie jar and an encrypted cookie jar for storing sensitive data.


Controllers are indispensable components of Rails applications, managing user requests, handling parameters, and managing sessions and flash messages. Mastery of controllers is fundamental to becoming proficient in Rails programming. Keep exploring and building with Rails!

If you found this article insightful, you might want to check out our previous article on Understanding MVC Pattern in Rails.

In the upcoming tutorials, we will dive deeper into the world of Rails programming. Stay tuned!


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