Beginning PHP

Beginning PHPWeb Talk Series[2]

Contents Why PHP ?

Coding.

Limitations.

Pros & Cons .

Language constructors.

OO Aspects.

Fear of PHP.

Line of culture .

Why PHP ?PHP is an excellent choice for Web programming.

It has many advantages over other languages, including other Weboriented languages.

To get a very general understanding of how the common Web programming languages compare, let’s compare them.

PHP ASP Java Perl

Why PHP ?

ASP

Microsoft’s Web programming environment.

It’s not a language itself because it allows the programmer to choose from a few actual languages, such as VBScript or Jscript.

ASP is simple, but too simple for programs that use complex logic or algorithms.

Many companies find it hard to budget forthe expense of Microsoft licenses.

Why PHP ?

Java

Java is platform independent.

It has serious downsides in development time, development cost, and execution speed.

Java development is timeconsuming because projects in Java must follow strict rules (imposed by Java) that require extensive planning.

Java developers are expensive to hire!

Why PHP ?

Perl

Perl has been around longer than PHP. Before PHP, Perl was generally accepted as the best Web programming language.

You have to download separate modules to get the same functionality in Perl.

This leads to problems when programs are transferredfrom one system to another .

Why PHP ?PHP’s primary use certainly isn’t to track résumés anymore.

It has grown to be able to do that and just about anything else.

PHP's common uses:

• Feedback forms • Shopping carts and other types of ecommerce systems • User registration, access control, and management for online subscription services • Guest books • Discussion and message boards

CodingCreating a PHP program requires that you actually work with the source code of the file as opposed to a “what you see is what you get” (WYSIWYG) approach.

“Installing the environment and web scenario”

The process you would use to create a PHP program is much the same:

1. Create your HTML file (containing text, tables, images, or sounds) and insert PHP code where desired. 2. Save your PHP file as filename.php. 3. Use an FTP program to upload your file to the Web server. 4. Point your browser to the address of the file on your Web server (suchas http://www.example.com/filename.php).

Coding

<html><head><title> Example 1/title></head> HTML<body bgcolor="white" text="black"><h4>Chapter 1 :: Example 1</h4> <?php/* Display a text message */echo "Hello, world! This is my first PHP program.";?> </body> </html>

Save. Upload to web server . Test.

Coding

Coding

The PHP interpreter (or parser) is the program that performs the processing mentioned previously.

It reads the PHP program file and executes thecommands it understands.

If PHP happens to find a command it doesn’t understand, it stops parsing the file and sends an error message back to the browser.

This is quite different from a compiled language, such as C or C++, which is only interpreted from a humanreadable form once.

Coding

The most important limitations are :

Statement:must be correct commands.

Syntax :ex: echo “Hi” > will not work.But

echo “Hi”; > will work.

Limitations

Like the most of programming languages , but PHP has some tweaks:

●Variables & Constants.●Program Input & Output.●Arithmetic and String manipulations.●Control Structures.●Functions.●Classes and Objects.●Creating dynamic contents with PHP & MySQL.●Password protection.●Uploading files.●Cookies and Sessions.

Language Constructors

It's simple , so that there's no unified structure in writing code,like Java for example..!

Hard to debug and maintain .. !

Hard for team oriented projects.

But , developers made somethings called “Frameworks” , following some design patterns to unify the way all programmers work with.

Cons

PHP has the ability to “include” files within a web page.

This reduces initial work and ongoing maintenance.

Imagine a website contains a menu at the top of each web page, and this menu is identical throughout the site. You could cut and paste the appropriate code into every page, but this is both cumbersome and counterproductive.

This is the simple OO aspect in PHP.But there's more.

Object Oriented Aspects

You could summarize this approach as “include and reuse; don’t rewrite.”

Objectoriented programming (OOP) is just an extension of this concept.

Objects simplify web development by eliminating the need to cut,paste, and adapt existing code.

Object Oriented Aspects

1. It's just a scripting language. “Some scripting languages simply string together a series of commands and for this reason are sometimes referred to as glue”.

An OO scripting language is a contradiction in terms; it’s a language that’s“getting above itself.”

The limited OO capabilities of PHP 4 reinforced the view that a scripting language shouldn’t attempt to be object oriented.

Arguments for OO PHP

2.Object Orientation Is for Large Software Shops

OOP is something best left to the large shops.

If a number of programmers are involved in the same project, an OO approach is a necessary evil, but it’s not much use for the lone developer.

Arguments for OO PHP

OOP doesn’t replace procedural programming or make it obsolete.

Nor is an OO approach always the right approach, as some OO enthusiasts might have you believe.

However,some web problems require an OO solution.

without a minimal understanding of the basics of OOP, you can’t make full use of the capabilities of PHP 5.

Example: if you want to create a SOAP client, there is really no other way to do it than by using the SOAPClient class.

Replies

Fear of PHP becoming overly complex is often a more subtly stated objection to an OO PHP.

There’s no doubt that OOP can sometimes introduce unwanted complexity.

This hasn’t happened with PHP, and there’s good reasonto suspect that it won’t.

PHP is first and foremost a web development language (which is probably why it has taken so long for PHP to adopt an OO approach).

Fear of PHP

The point of object orientation in PHP is not to turn PHP into Java or something similar, but to provide the proper tools for web developers.

Object orientation is another strategy for adapting to the current circumstances of “web development”.

Fear of PHP

(KISS) : Keep IT Simple , Stupid !

There will be a learning curve for a procedural programmer adopting an OO approach to web development,

In fact, you’ll probably find that some of the tasks you’re used to doing procedurally are more easily done in an OOmanner.

A line of culture

Questions?!

Thanks!

Technology

Beginning PHP