The Current Situation Object-Oriented Introduction

› Basics, concepts, terminology & examples Object-Oriented Benefits

› Code re-use, portability, structure, meaning, control, separation of responsibility, time, reduce dependencies and more

Most scripts & tutorials all procedural or show bad understanding of OO

PHP’s unique history› Template language & PHP/FI 2.0› “evolved” over time with OO features

Good OO finally starting to emerge› PHP5 released in 2004› Zend Framework› Symfony Project

That was easy!Add “Object-Oriented PHP” to your resume!

It’s much more than just syntax – It’s a mindset

Object-Oriented programming gives meaning to your data› Represents real-world objects when

possible

Where have we seen this before?

Semantic markup Think:

› <blockquote> for quotes, not indentation› <address> for addresses, not <p> or

<div>› <cite> instead of <i> for citations

Goal is to for code to convey meaning

• Create meaning and structure• Separate responsibilities• Reduce/Isolate dependencies• Create common public interfaces• Clear, self-documenting code

Code objects cannot always represent real-world objects› Application flow› Structure› Delegation› Separation of responsibilities

How do we solve these problems?› Design Patterns

Model-View-Controller (MVC) Active Record Data Mapper Adapter Registry Factory Observer

What OO programming is not – where many PHP projects go wrong

Decorator

What is User?› A finder/utility class?› No clear definition or

purpose

“bob” is a User 1 instance = 1

user Properties of a

user Functions of a user

The power of applying object-oriented design to your application

Objects add automatic clarity Stick to standards and naming

conventions› camelCase› Zend Coding Standards

Function naming as verbose as possible› getPostBySlug($slug)› findPostsWithTag($tagName)

Parent > Child relationship between objects› Child extends Parent

Child inherits all parent methods› Child can override parent methods when

required Changes can be reflected across your

entire application with relative ease

Hides actual implementation Reduces or isolates dependencies to

lower levels Reduces or eliminates extensive future

changes in code base

› Adding extra headers is a mess (CC, BCC)› No built-in file attachment options› Limited configuration options

(Sendmail/SMTP)› Very inefficient for large amounts of email

› Custom Email() object› Clear, descriptive syntax› Unlimited configuration options

mail(), SMTP, database, external server, etc.

› File attachments can be easy with function

Did you notice the dependencies?

Remove the database dependencies by using a standard interface› PDO provides one (bundled with PHP5)

Use dependency injection to expose dependencies

Pass connection into constructor and store it as a class property

Replace mysql_* functions with standard functions from PDO using connection

Database adapters are interchangeable

Interchangeable code components› Standard interface› Single dependency

Separate “engine” from implementation

Different payment processors are a simple drop-in replacement

Objects should serve a single purpose› Separate code into manageable chunks

MVC – Good example› Model – Database› View – Display› Controller – Request/Flow

Resist temptation of globals everywhere› “global $var”, $_SESSION, $_REQUEST, etc

Building a Data Mapper with PHP5 and the Standard PHP Library› Friday Oct. 10 @ 10:30am

www.php.net/php5› Full official PHP5 feature documentation

Communities› Sitepoint – sitepoint.com› PHPit – phpit.com› PHP|Architect – phparch.com› Zend Developer Zone - devzone.zend.com

Vance Lucas, 23› Blog: www.vancelucas.com› Email: vance@vancelucas.com

Making websites since age 12› Started learning PHP when PHP3 was new

Oklahoma Baptist University – Shawee› Bachelor of Business Administration

Currently work at Back40 Design, Inc.› www.back40design.com