This chapter brings together a few CI helpers and classes with similar themes. They help you to:
Write and read files on your system with minimal coding, while CI locks and unlocks the files in the background
Download files, rather than show them as HTML on the screen—with CI providing the HTTP headers and worrying about MIME types for you
Upload files to your site, allowing you to specify security constraints such as the size and type of files you allow
Easily manipulate images, to resize them
Compress your files before you download them to your users
This is what frameworks are all about. Instead of a lot of tedious coding, they let you get on with building an application that works. They give you a standard and easy interface, and worry about the details for you.