Chapter 3. Controller Usage and Scope

This chapter covers the CI controller scope and the various controller usage categories with several code examples of web applications. The controllers are the front-line decision makers of how to process or route a request and how to respond to actions, such as a rendered view sending back to the browser as an HTML page, an AJAX response to let the current requesting page update certain selector areas by the response, or even just to update the database seamlessly. The controllers use the available models, helpers, libraries, and views to respond to the caller, be it a web browser URL or a cron process issuing the cURL types POST/GET requests automatically.

The CI built-in controller behaves like an abstract class in the project scope so any of our project controllers must be extensions of a built-in CI controller. Our developed controller will inherit the CI built-in controller capabilities and built-in resources, such as auto-loaded helpers, libraries...