rails-action-controller-patterns

Strong parameters in Rails controllers filter and whitelist incoming request data before passing it to models. Use `permit` to define allowed attributes in nested hashes, protecting against mass assignment vulnerabilities while maintaining RESTful action patterns like index, show, create, update, and destroy.

Before_action filters are lifecycle callbacks that run before controller actions execute. Use them to authenticate users, authorize resource access, or set up shared data—for example, `before_action :authenticate_user` runs on every action unless skipped, centralizing security logic across your controller.

Routing in Rails maps HTTP requests to controller actions; namespaced controllers organize related resources under a module path. Define routes in `config/routes.rb` with `namespace :admin` to group admin controllers, reducing naming conflicts and structuring large apps logically.

API-only controllers skip view rendering and session handling, responding with JSON instead. Rails generates these with `--api` flag, removing unnecessary middleware and focus on data serialization, making them ideal for headless or microservice architectures.

Authorization checks who can perform an action on a resource using filters or gems like Pundit. Time-zone management leverages Rails' `Time.zone` and controller-level configuration to ensure consistent timestamp handling across user sessions and background jobs.

Filters centralize repeated logic—authentication, logging, parameter validation—reducing duplication and maintenance burden. They execute consistently across actions, making your controller code cleaner and security policies easier to audit and modify.