Installing CodeIgniter

First of all, we need to have a hosted PHP server (Version 5.3 or later) and a MySQL (one of the latest versions) server, where we know the database credentials. Local database access from the PHP is recommended for simplicity.

Note that the server will operate in a CGI (Common Gateway Interface) fashion in order to let CI operate. We can have a local web development environment on our PC or a remote server hosted and dedicated.

Once we've set up a local web development environment, we'll need to download the latest version of CI, which is Version 2.1.2 at the time of writing this book. The link to download the latest version is http://codeigniter.com/downloads/. Now, if we look inside the CI folder, we should see the following directory tree:

codeigniter/
  index.php
  application/
  cache/
  config/
  controllers/
  core/
  errors/
  helpers/
  hooks/
  language/
  libraries/
  logs/
  models/
  third_party/
  views/
  system/
  core/
  database/
  fonts/
  helpers/
  language/
  libraries/