Course Content
Introduction to CodeIgniter 4
CodeIgniter is an Application Development Framework. CodeIgniter is a popular and powerful MVC (Model-View-Controller) framework that is used to develop web applications. It is a free and Open-source PHP framework.
MVC (Model-View-Controller)
MVC stands for Model-View-Controller. MVC is an application design model consisting of three interconnected parts. They include the model (data), the view (user interface), and the controller (processes that handle input).
The Session class allows you to maintain a user’s "state" and track their activity while they browse your site.
URI Routing
There is a one-to-one relationship between a URL string and its corresponding controller class/method.
Working with Database
Like any other framework, we need to interact with the database very often and CodeIgniter makes this job easy for us. It provides a rich set of functionalities to interact with the database.
PhpSpreadsheet is a PHP library for reading and writing spreadsheet files. Importing Excel and CSV into MySQL help to save the user time and avoid repetitive work.
CodeIgniter 4
About Lesson

Routing rules are defined in your /app/Config/Routes.php file.

There is a one-to-one relationship between a URL string and its corresponding controller class/method. The segments in a URI normally follow this pattern:


$routes->add('from', 'to', $options);

In some cases, you may want to remap this relationship so that a different class/method can be called instead of the one corresponding to the URL.

To learn how to implement routers on a real-world project, we will assume that we are creating an application for managing contact details. The following table shows the URLs that will be working with.

No. URL Route Controller Method
1 / $route->add(‘Contacts::index’) Contacts index
2 /contacts $route->add(‘Contacts::list’) Contacts list
3 /contacts/add $route->add(‘Contacts::contacts/add’) Contacts add
4 /contacts/create $route->post(‘Contacts::contacts/create’) Contacts add
5 /contacts/edit/id $route->get(‘Contacts::contacts/edit/(:num)’) Contacts edit
6 /contacts/update $route->post(‘Contacts::contacts/update’) Contacts update
7 /contacts/delete/id $route->get(‘Contacts::contacts/delete/(:num)’) welcome delete


Create URLs for Applications

create routes for our project. Open /app/Config/Routes.php

$routes->add('/', 'Contacts::index');
$routes->add('contacts/list', 'Contacts::list');
$routes->add('contacts/add', 'Contacts::add');
$routes->post('contacts/create', 'Contacts::create');
$routes->get('contacts/edit/(:any)', 'Contacts::edit/$1');
$routes->post('contacts/update', 'Contacts::update');
$routes->get('contacts/delete/(:any)', 'Contacts::delete/$1');

The following table shows the respective URLs obtained from the above-defined routes

No. Route URL
1 $routes->add(‘/’, ‘Contacts::index’); http://localhost
2 $routes->add(‘contacts/list’, ‘Contacts::list’) http://localhost/contacts/list
3 $routes->add(‘contacts/add’, ‘Contacts::add’); http://localhost/contacts/add
3 $routes->post(‘contacts/create’, ‘Contacts::create’); http://localhost/contacts/create
4 $routes->get(‘contacts/edit/(:any)’, ‘Contacts::edit/$1’); http://localhost/contacts/edit/1
5 $routes->post(‘contacts/update’, ‘Contacts::update’); http://localhost/contacts/update/1
6 $routes->get(‘contacts/delete/(:any)’, ‘Contacts::delete/$1’); http://localhost/contacts/delete/1


Directory structure

	+ contacts
		- add.php
		- list.php
		- edit.php

	+ innerpages
		- header.php
		- footer.php
		- template.php
	- home.php


Global Options

The methods for creating a route (add, get, post, resource, etc.) can take an array of options that can modify the generated routes or further restrict them. The $options an array is always the last parameter:

$routes->get('from', 'to', $options);
$routes->post('from', 'to', $options);
$routes->put('from', 'to', $options);
$routes->head('from', 'to', $options);
$routes->options('from', 'to', $options);
$routes->delete('from', 'to', $options);
$routes->patch('from', 'to', $options);
$routes->match(['get', 'put'], 'from', 'to', $options);
$routes->resource('photos', $options);
$routes->map($array, $options);
$routes->group('name', $options, function());