Codeigniter Work Flow Structure

1. The index.php is the front controller, initializing the bottom resources required to run CodeIgniter.
2. The Router examines the HTTP request to work out what ought to be finished it.
3. If a cache file exists, it's sent on to the browser, bypassing the traditional system execution.
4. Security.
5. Before the applying controller is loaded, the HTTP request and any user-submitted data are filtered for security.
6. The Controller masses the model, core libraries, helpers, and any other resources needed to process the specific request.
7. The finalized read is rendered then sent to the online browser to be seen.

If caching is enabled, the read is cached 1st in order that on succeeding requests it may be served.