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• HELPERS are the group of functions that are USEFUL in ASSISTING the USER to perform SPECIFIC tasks.
• There are three types of helper files. They are:
  • URL helpers: Used for creating the links.
  • Text helpers: Used for the formatting of text.
  • Cookies helpers: Used to read and manage cookies.

Codeigniter is CALLED a loosely based MVC FRAMEWORK because it does not need to obey a strict MVC pattern during application CREATION. It is not important to create a model, we can use only view and controllers for creating an application. In addition, ONE can modify CodeIgniter to UTILIZE HMVC(Hierarchical Model View Controller) as well.

In CODEIGNITER, you can link images/CSS/JavaScript from a VIEW by using the absolute path to the resources required with respect to the ROOT FOLDER as given below:

• A DRIVER is a type of LIBRARY that has a parent class and multiple CHILD classes. These child classes can access their parent class, but they can’t access their siblings.
• Drivers can be found in the system/libraries folder.
• There are three steps for creating a driver:
  • Making FILE structure
  • Making driver list
  • Making driver(s)

• Routing is a technique used in CodeIgniter, by which you can define your URLs BASED on the REQUIREMENT INSTEAD of using the predefined URLs. So, WHENEVER there is a request made and MATCHES the URL pattern defined by us, it will automatically direct to the specified controller and function.
• A URL string and its corresponding controller class or method are in a one-to-one relationship here. The URI segments usually follow this pattern: example.com/class/function/id/. All routing rules are defined in the application/config/routes.php file of CodeIgniter.

There are 2 ways to check the CodeIgniter VERSION.

• The first method is to run the following code:

You can echo the constant value of CI_VERSION in the CodeIgniter CONTROLLER or view file.

• The second method is to navigate to the system/core/CodeIgniter.php DIRECTORY which stores the current version number of CodeIgniter in a global constant named ‘CI_VERSION’. Open the file and have a look at the lines:

An inhibitor in CODEIGNITER is an ERROR handler class. It will make use of PHP’s NATIVE functions like set_error_handler, set_exception_handler, register_shutdown_function to handle parse errors, exceptions, and fatal errors.

• CodeIgniter’s hooks will provide a way to change the internal workings or framework FUNCTIONALITIES without any need for hacking the CORE files. It permits script execution with a particular path within the CodeIgniter.
• We can globally enable/disable the hooks feature by setting the below-given item in the application/config/config.php file: $config['enable_hooks'] = TRUE;
• It is defined in application/config/hooks.php file. For example:

In the above code example, the ‘pre_controller‘ hook is called hook POINT. Various types of hook points are available in CodeIgniter.

CodeIgniter is an open-source and MVC-based framework used for WEB application development on PHP. This framework contains LIBRARIES, an easier interface with a LOGICAL structure to access these libraries, helpers, plug-ins, and other resources as well. It is easy to USE compared to other PHP FRAMEWORKS.