How data flows in Codeigniter

Basis

–Index.php file is the front controller and it must be existed to run codeigniter.

–Then router takes the advantages to decide what should be done with HTTP request.
–The cache file is sent to the browser with the normal system execution if a cache file is present
–then It is time for security check.The HTTP request is filtered for security.
–Here is now the main work to load model,libraries,helpers,plug-ins, and any other needed files according to HTTP request by the Controller,
-Then we can see the final out put on the web browser.