Introduction to PHP OOP

PREPARED BY FAKHRUL HASAN COMPUTER PROGRAMMER DAFFODIL INTERNATIONAL UNIVERSITY EXPERTISE AREA: WEB DESIGNING, WEB DEVELOPMENT, PHP, C#, ASP.NET, MYSQLAND MS SQL.

TOPICS WHAT IS PHP? HISTORY HOW WORKS WHAT PHP CAN DO? WHY PHP USED? HOW STUDENTS GET BENEFITED PHP – BASIC PROGRAMMING PHP – OBJECT ORIENTED PROGRAMMING GET AND POST METHOD SESSIONS AND COOKIES

PHP (Hypertext Pre- Processor) is a widely-used open source scripting language that is used for web development. It can be embedded in HTML Document. Currently, PHP support both Procedural and OOP WHAT IS PHP?

HISTORY PHP/FI – Personal Home Page – Developed in1994 by Rasmus Lerdorf. Support: DBM, mSQL, and Postgres95 databases, cookies, user-defined function support, and much more. PHP 3 – Hyper Text Pre-Processor – Released in 1998 Developed by Andi, Rasmus, and Zeev. Features: Multiple database support, OOP Support PHP 4 – Developed by Zeev And ANDI. Designed based on Zend Engine. Released in 2000. Support Multiple Databases, Many Web Servers, HTTP Sessions etc. PHP 5 – Released in 2004. Fully OOP, Support Multiple Databases and some advance features.

HOW WORKS PHP Pre-Processor Database Client Browser Page Request HTML HTML Passed Put Data Get Data

WHAT PHP CAN DO? • Main target field of PHP. Server Side Scripting: • PHP scripts can run on command prompt without server.Command Line Scripting: • Not best. But can be developed using PHP- GTK php extension. Writing Desktop Application:

WHY PHP USED? Easy to use. Code is embedded into HTML. Easy to built informative website, e-commerce, high-level management system and so on. Runs on almost any web server, many databases and operating systems. Supported Web-Servers: Apache, Microsoft IIS, Netscape Enterprise Server. Supported Operating Systems: Mac-Os, Windows, Linux (Solaries) etc. Database Supported: MS-SQL, MySQL, Oracle, PostgreSQL, SQLite, FilePro, dBase etc.

HOW STUDENTS GET BENEFITED WITH LEARNING PHP Students who learn PHP for web-development will get following advantages Cost Effective Development Easily Integration Flexible to use Available Learning Resources Can easily involve in outsourcing Available popular CMS

PHP – BASIC PROGRAMMING Variables: Variables are used to store data. PHP supports different data-type. But it is not necessary to declare data-type. PHP uses $ sign to declare a variable. Syntax: <?php $a = “hello php”; ?> Arrays: Array is a process to store multiple values to a single variable in php. The values are identified by key. Syntax: <?php $students = array(‘hasan’, ‘kabir’); ?> or <?php $students = array(‘first’=>’hasan’, ‘second’=>’kabir’); ?>

PHP – BASIC PROGRAMMING Loop: A sequence of instructions that repeated until reached to a certain condition. Loops in PHP: for, while, do..while and foreach. Example:

PHP – BASIC PROGRAMMING Functions: Functions are special block of code which can re-use again and again. Used to minimize code and better performance. Basically Two Types: Built-in functions, User-defined functions. Functions are executed, when it is called. Sample Example:

PHP- BASIC PROGRAMMING Conditional Statements: Conditional Statements are used to perform different action on different decision. Conditional Statements are if, if…else, if…..else if…..else if….else, switch…case Example:

OBJECT ORIENTED PROGRAMMING PHP Classes and Objects Methods and Properties Scope Inheritance Static methods and properties Constants Abstraction and interfaces Overriding Object Iteration Serialization Namespaces Concept of OOP is to move the application architecture closer to real world. The OOP features of PHP is described below:

OBJECT ORIENTED PROGRAMMING PHP Classes and Objects  Classes are type of entity and objects are single units of a given class  If human is a class, then Mr. Karim, Rahim are objects of human class.  Examples:

CONSTRUCTOR Each class has one constructor. Constructor is called when object is initialized.

PROPERTIES A class may have unlimited number of properties

ACCESS MODIFIER Each property and method has access modifier/scope in PHP class. It defines who can access it. Access modifiers are: Public • It can be accessed from any outside file through object Protected • Protected can be accessed by descendant class Private • Private can be accessed by a class itself.

INHERITANCE • A class can inherit another class. • When a class inherit another class, it inherit all public an protected properties of inherited class. But can’t inherit private property.

STATIC METHOD AND PROPERTY  Defining static to a property or method makes them accessible without creating object.  Class can access static property with self keyword. Outside world can access it with class name.  Example:

CONSTANTS Normally constants are declared in PHP with define() function. But in a class constants are declared with const keyword and not using $ sing. Class constant can’t be called with object. Example:

ABSTRACT CLASS AND METHOD Abstract class can defined with abstract keyword and can’t be instantiated. This type of class must be used by inheritance. Abstract class may have several abstract method. If abstract class has abstract method definition. Child class must have the implementation of abstract method.

ABSTRACT CLASS AND METHOD Examples:

INTERFACE Interfaces allow what a child class must implement. No methods in interface have implementation. Classes can implement interface instead of extends. Interface can only have public method.

OVERRIDING When a class inherit another class, it can declare methods that override parent class method. Two class method names are same, parameter may differ. An Example is following:

OBJECT ITERATION PHP provides facility to iterate an object as item of an array. Example is following:

NAMESPACE PHP Namespace after 5.3 version allow create class with same name in same application or page under different namespaces. Example Code is following:

PHP – GET AND POST VARIABLE GET and POST create an array with key and value pair, where key contains name of the form field and value contains the value of the field. • GET is treated as $_GET in PHP, which holds all information passed through URL as array. • Information sent through GET Method is visible to users. • GET has limitation highest 2000 characters GET • POST is treated as $_POST in PHP, which holds all information passed through form post as array. • Information sent through POST Method is not visible to users. • POST has no limitation. POST

COOKIES Cookie is piece of text file that web servers can store on user’s browser. It allows server to store information to user machine and later retrieve it. Can store file up to 4 kb. Maximum 20 cookies can be stored on user’s PC per server.

SESSIONS Session is a mechanism to store information to be used in multiple pages on the server. PHP Session variable holds information about a single user (browser) and it available on multiple pages. Basically made up of two components. Client Side Session ID and Server Side Session Data. To use session in PHP, developer must call the function session_start(); at the top.

PHP FRAMEWORKS Some popular frameworks of PHP are following: Laravel Symfony Code Igniter Yii Cake PHP Zend Phalcon Popular CMS build using PHP: Wordpress Joomla Drupal Exponent CMS Magento PHP Nuke

Introduction to PHP OOP

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