CodeIgniter is an application development framework, which can be used to develop websites, using PHP. It is an Open Source framework. It has a very rich set of functionality, which will increase the speed of website development work.
The architecture of CodeIgniter application is shown below.
1. As per the above figure, whenever a request comes to CodeIgniter, it will first go to index.php page.
2. In the second step, Routing will decide whether to pass this request to step-3 for caching or to pass this request to step-4 for security check.
3. If the requested page is already in Caching, then Routing will pass the request to step-3 and the response will go back to the user.
4. If the requested page does not exist in Caching, then Routing will pass the requested page to step-4 for Security checks.
5. Before passing the request to Application Controller, the Security of the submitted data is checked. After the Security check, the Application Controller loads necessary Models, Libraries, Helpers, Plugins and Scripts and pass it on to View.
6. The View will render the page with available data and pass it on for Caching. As the requested page was not cached before so this time it will be cached in Caching, to process this page quickly for future requests.
