The system/ folder is where all the action happens. This folder contains all the CodeIgniter code of
consequence, organized into various folders:
application — The application foldercontains the application you ’ re building. Basically, this
folder contains your models, views, controllers, and other code (like helpers and class
extensions). In other words, this folder is where you ’ ll do 99 percent of your work.
cache — The cache foldercontains all cached pages for your application. In Chapter 9 , you learn
more about caching and how to turn your super - speedy development application into a
blazingly fast live application.
codeigniter — The codeigniter folderis where CodeIgniter ’ s core classes live. You have almost no
reason to go in here. All of your work will occur in the application folder. Even if your intent is
to extend the CodeIgniter core, you would do it with hooks, and hooks live in the application
folder.
database — The database foldercontains core database drivers and other database utilities. Again,
there ’ s no good reason for you to be in this folder.
fonts — The fonts foldercontains font - related information and utilities. Again, there ’ s no reason
to spend any time here.
helpers — The helpers foldercontains standard CodeIgniter helpers (such as date, cookie, and
URL helpers). You ’ ll make frequent use of helpers in your CodeIgniter career and can even
extend helpers thanks to improvements introduced in CodeIgniter version 1.6.
language — The language foldercontains language files. You can ignore it for now.
libraries — The libraries foldercontains standard CodeIgniter libraries (to help you with e - mail,
calendars, file uploads, and more). You can create your own libraries or extend (and even
replace) standard ones, but those will be saved in the application/libraries directory to keep
them separate from the standard CodeIgniter libraries saved in this particular folder.
logs — The logs folderis the folder CodeIgniter uses to write error and other logs to.
plugins — The plugins foldercontains plugins. Plugins and helpers are very similar, in that they
both allow developers to quickly address an issue or create content like forms, links, etc..
However, the main difference between them is that plugins usually consist of one function,
while helpers often have many functions bundled inside them.
consequence, organized into various folders:
application — The application foldercontains the application you ’ re building. Basically, this
folder contains your models, views, controllers, and other code (like helpers and class
extensions). In other words, this folder is where you ’ ll do 99 percent of your work.
cache — The cache foldercontains all cached pages for your application. In Chapter 9 , you learn
more about caching and how to turn your super - speedy development application into a
blazingly fast live application.
codeigniter — The codeigniter folderis where CodeIgniter ’ s core classes live. You have almost no
reason to go in here. All of your work will occur in the application folder. Even if your intent is
to extend the CodeIgniter core, you would do it with hooks, and hooks live in the application
folder.
database — The database foldercontains core database drivers and other database utilities. Again,
there ’ s no good reason for you to be in this folder.
fonts — The fonts foldercontains font - related information and utilities. Again, there ’ s no reason
to spend any time here.
helpers — The helpers foldercontains standard CodeIgniter helpers (such as date, cookie, and
URL helpers). You ’ ll make frequent use of helpers in your CodeIgniter career and can even
extend helpers thanks to improvements introduced in CodeIgniter version 1.6.
language — The language foldercontains language files. You can ignore it for now.
libraries — The libraries foldercontains standard CodeIgniter libraries (to help you with e - mail,
calendars, file uploads, and more). You can create your own libraries or extend (and even
replace) standard ones, but those will be saved in the application/libraries directory to keep
them separate from the standard CodeIgniter libraries saved in this particular folder.
logs — The logs folderis the folder CodeIgniter uses to write error and other logs to.
plugins — The plugins foldercontains plugins. Plugins and helpers are very similar, in that they
both allow developers to quickly address an issue or create content like forms, links, etc..
However, the main difference between them is that plugins usually consist of one function,
while helpers often have many functions bundled inside them.
