Introduction To Code Igniter

Introduction To CodeIgniter Mohammad Amzad Hossain Softwork Solutions [email_address]

Prerequisite

OOP – Object Oriented Programming

PHP

MySQL

Index

Introduction

Evolution Of Web Development

Basic Idea Of Web Framework

Why Framework not Scratch?

MVC ( Model View Controller) Architecture

What is CodeIgniter ????

Installation of CodeIgniter

Application Flow of CodeIgniter

CodeIgniter URL

Controllers

Views

Models

CodeIgniter Libraries

Helpers

A Basic Application Development Of Codeigniter

Application Flow

Q/A

Reference

Evolution of Web Development How you first started building websites.

Evolution of Web Development How you’re building websites now.

Evolution of Web Development How you build websites with a framework

Basic Idea Of Web Framework

A web application framework

Is a Software framework

Designed to support the development of

Dynamic websites

Web applications

Web services

Aims to alleviate the overhead associated with common activities used in Web development.

Libraries for database access

Templating frameworks

Session management

Often promote code reuse

Many more …….

Why Framework Not Scratch ?

Key Factors of a Development

Interface Design

Business Logic

Database Manipulation

User Access Control

Advantage of Framework

Templating

Provide Solutions to Common problems

Abstract Levels of functionality

Make Rapid Development Easier

Disadvantage of Scratch Development

Make your own Abstract Layer

Solve Common Problems Yourself

The more Typing Speed the more faster

MVC Architecture

Separates User Interface From Business Logic

Model - Encapsulates core application data and functionality Business Logic.

View - obtains data from the model and presents it to the user.

Controller - receives and translates input to requests on the model or the view

Figure : 01

What is CodeIgniter ???

An Open Source Web Application Framework

Nearly Zero Configuration

MVC ( Model View Controller ) Architecture

Multiple DB (Database) support

DB Objects

Templating

Caching

Modules

Validation

Rich Sets of Libraries for Commonly Needed Tasks

Has a Clear, Thorough documentation

Installation of CodeIgniter

Requirments

Web Server - Download & Install Apache

PHP – 4.3.2 or Higher

Database – MySQL ( support for other DB exists )

Installation

Download the latest version from www.codeigniter.com and unzip into your web root directory.

Open “application/config/config.php” and change base_url value to base url. For example: http://localhost/myci/

To Use Database open “application/config/database.php” and change necessary values. Usually you have to change: ‘hostname’, ‘username’, ‘password’, ‘datbase’.

Start Your Web Server and Database Server and go to http:// localhot/myci

Application Flow Of CodeIgniter Figure : 2 [ Application Flow of CodeIgniter]

CodeIgniter URL

URL in CodeIgniter is Segment Based.

Segments in a URI CodeIgniter Optionally Supports Query String URL www.your-site.com/ news / article / my_article www.your-site.com/ class / function / ID www.your-site.com/index.php? c=news & m=article & ID=345

Controllers

A Class file resides under “application/controllers”

www.your-site.com/index.php/ first <?php class First extends Controller{ function First() { parent::Controller(); } function index () { echo “<h1> Hello CUET !! </h1> “; } } ?> // Output Will be “Hello CUET!!”

Note:

Class names must start with an Uppercase Letter.

In case of “constructor” you must use “parent::Controller();”

Controllers

In This Particular Code

<?php class First extends Controller{ function index() { echo “<h1> Hello CUET !! </h1> “; } function bdosdn ( $location ) { echo “<h2> Hello $location !! </h2>”; } } ?> // Output Will be “Hello world !!” www.your-site.com/index.php/ first / bdosdn/ world

Note:

The ‘Index’ Function always loads by default. Unless there is a second segment in the URL

VIEWS

A Webpage or A page Fragment

Should be placed under “application/views”

Never Called Directly

<html> <title> My First CodeIgniter Project</title> <body> <h1> Welcome ALL … To My .. ::: First Project ::: . . . </h1> </body> </html> web_root/myci/system/application/views/myview.php

VIEWS

Calling a VIEW from Controller

Data Passing to a VIEW from Controller $this->load->view(‘myview’); function index() { $var = array( ‘ full_name’ => ‘Amzad Hossain’, ‘ email’ => ‘tohi1000@yahoo.com’ ); $this->load->view(‘myview’, $var); } <html> <title> ..::Personal Info::.. </title> <body> Full Name : <?php echo $full_name;?> <br /> E-mail : <?=email;?> <br /> </body> </html>

VIEWS

There are 3 mechanism that can be utilize to show Dynamic Data inside a VIEW File

- Pure PHP

- PHP’s Alternative Syntax

- CodeIgniter’s Template Engine

<?php if( $for_this == true ):?> <h1> For This </h1> <?php elseif( $for_that == true ): ?> <h1> For That </h1> <?php else: ?> <h1> What </h1> <?php endif; ?>

Note:

There are other alternative syntax ‘for’, ‘foreach’, ‘while’

Models

Designed to work with Information of Database

Models Should be placed Under “application/models/”

Loading a Model inside a Controller <?php class Mymodel extend Model{ function Mymodel() { parent::Model(); } function get_info () { $query = $this->db->get(‘name’, 10); /*Using ActiveRecord*/ return $query->result(); } } ?> $this->load->model(‘mymodel’); $data = $this->mymodel->get_info();

CodeIgniter Libraries Special Purpose Classes Loading CodeIgniter Library Benchmarking Database Encryption Calendaring FTP Table File Uploading Email Image Manipulation Pagination Input and Security HTML Trackback Parser Session Template Unit Testing User Agent URI Validation $this->load->library(‘database’);

CodeIgniter Libraries

Database Library

Abstract Database Class support traditional structures and Active Record Pattern.

Active Record Pattern General Approach function index() { $this->load->library(‘database’); $rslt = $this->db->query (“ select first_name from user_name ”); foreach( $rslt->result() as $row_data) echo $row_data->first_name . “<br />”; } function index() { $this->load->library(‘database’); $this->db->select(“first_name”); $rslt = $this->db->get (“ user_name ”); foreach( $rslt->result() as $row_data) echo $row_data->first_name . “<br />”; }

Helpers

Simply a collection of functions in a particular category.

Loading A Helper Inside a Controller Array Date File HTML Smiley Text URL Cookie Download Form Security String Directory E-mail Inflector XML Parser Typography $this->load->helper(‘helper_name’); $this->load->helper(array(‘form’,’url’) );

Helpers