Developing Web Applications with PHP RAD for the World Wide Web Jeff Jirsa [email protected].

Developing Web Developing Web Applications with PHPApplications with PHP

RAD for the World Wide Web

Jeff Jirsa [email protected]

AgendaAgenda

– Introduction– PHP Language Basics– Built-in Functions– PHP on Linux and Windows– Tricks and Tips– PHP 5– Examples– Questions?

IntroductionIntroduction

• What is PHP?– PHP stands for "PHP Hypertext

Preprocessor”– An embedded scripting language for HTML

like ASP or JSP– A language that combines elements of

Perl, C, and Java


• History of PHP– Created by Rasmus Lerdorf in 1995 for

tracking access to his resume– Originally a set of Perl scripts known as the

“Personal Home Page” tools– Rewritten in C with database functionality– Added a forms interpreter and released as

PHP/FI: includes Perl-like variables, and HTML embedded syntax


• History of PHP (cont.)– Rewritten again in and released as version 2.0

in November of 1997– Estimated user base in 1997 is several

thousand users and 50,000 web sites served– Rewritten again in late 1997 by Andi Gutmans

and Zeev Suraski– More functionality added, database support,

protocols and APIs


• History of PHP (cont.)– User base in 1998 estimated 10,000 users

and 100,000 web sites installed– Version 3.0 was released in June 1998 as

PHP– Estimated user base in tens of thousands

and hundreds of thousands of web sites served


• History of PHP (cont.)– Rewritten again in 1997 by Andi Gutmans

and Zeev Suraski– More functionality added (OOP features),

database support, protocols and APIs– PHP 3.0 is released in June 1998 with some

OO capability– The core is rewritten in 1998 for improved

performance of complex applications


• History of PHP (cont.)– The core is rewritten in 1998 by Zeev and

Andi and dubbed the “Zend Engine”– The engine is introduced in mid 1999 and

is released with version 4.0 in May of 2000– The estimated user base is hundreds of

thousands of developers and several million of web sites served


• History of PHP (cont.)– Version 5.0 will include version 2.0 of the

Zend Engine• New object model is more powerful and

intuitive• Objects will no longer be passed by value; they

now will be passed by reference• Increases performance and makes OOP more

attractive


• Netcraft Statistics– 11,869,645 Domains, 1,316,288 IP Addresses


• Performance*– Zdnet Statistics

• PHP pumped out about 47 pages/second • Microsoft ASP pumped out about 43 pages/second • Allaire ColdFusion pumped out about 29

pages/second • Sun Java JSP pumped out about 13 pages/second

* From PHP HOWTO, July 2001

PHP Language BasicsPHP Language Basics

• The Script Tags– All PHP code is contained in one of several

script tags:• <?

// Some code?>

• <?php// Some code here?>


• The Script Tags (cont.)• <script language=“PHP">

// Some code here</script>

– ASP-style tags• Introduced in 3.0; may be removed in the future • <%

// Some code here%>


• The Script Tags (cont.)– “Echo” Tags

– <table><tr> <td>Name:</td><td><?= $name ?></td></tr><tr> <td>Address:</td><td><?= $address ?></td></tr></table>


• Hello World!: An Example– Like Perl, there is more than one way to do

it• <?php echo “Hello World!”; ?> • <?php

$greeting = “Hello World!” printf(“%s”, $greeting);php?>


• Hello World!: An Example (cont.)• <script language=“PHP”>

$hello = “Hello”; $world = “World!”; print $hello . $world</script>


• Constants, Data Types and Variables– Constants define a string or numeric value– Constants do not begin with a dollar sign– Examples:

• define(“COMPANY”, “Acme Enterprises”);

• define(“YELLOW”, “#FFFF00”);

• define(“PI”, 3.14);

• define(“NL”, “<br>\n”);


• Constants, Data Types and Variables– Using a constant

• print(“Company name: “ . COMPANY . NL);


• Constants, Data Types and Variables– Data types

• Integers, doubles and strings– isValid = true; // Boolean– 25 // Integer– 3.14 // Double– ‘Four’ // String– “Total value” // Another string



• Strings and type conversion– $street = 123;– $street = $street . “ Main Street”;– $city = ‘Naperville’;

$state = ‘IL’;– $address = $street;– $address = $address . NL . “$city, $state”;– $number = $address + 1; // $number equals 124



• Arrays– Perl-like syntax

• $arr = array("foo" => "bar", 12 => true); – same as

• $arr[“foo”] = “bar”;• $arr[12] = true;


• Constants, Data Types and Variables

• Arrays (cont.)– <?php

$arr = array("somearray" => array(6 => 5, 13 => 9, "a" => 42));

echo $arr["somearray"][6]; // 5 echo $arr["somearray"][13]; // 9 echo $arr["somearray"]["a"]; // 42?>


• Constants, Data Types and Variables– Objects

– Currently not much more advanced than than associative arrays Using constants

– Before version 5.0, objects are passed by value• Slow• Functions can not easily change object variables


• Constants, Data Types and Variables– Operators

– Contains all of the operators like in C and Perl (even the ternary)

– Statements– if, if/elseif– Switch/case– for, while, and do/while loops– Include and require statements for code reuse

Built-in FunctionsBuilt-in Functions

• What comes In the box?– Array Manipulator Functions

• sort, merge, push, pop, slice, splice, keys, count

– CCVS: Interface to Red Hat’s credit system– COM functions: Interface to Windows COM

objects– Date and Time Functions

• getdate, mkdate, date, gettimeofday, localtime, strtotime, time


• What comes In the box?– Directory Functions

• Platform independent

– Error Handling Functions• Recover from warnings and errors

– Filesystem Functions• Access flat files• Check directory, link, and file status information• Copy, delete, and rename files


• What comes In the box?– IMAP Functions

• Manipulate mail boxes via the IMAP protocol

– LDAP Functions• Works with most LDAP servers

– Mail Functions• mail($recipient, $subject, $message)


• What comes In the box?– Database Functions

• dba: dbm-style abstraction layer• dBase• Frontbase• Informix• Ingres II• Interbase• mSQL


• What comes In the box?– Database Functions (cont.)

• MySQL• Oracle• PostgreSQL• SQL Server

– MING• Macromedia Flash

– PDF• Create/manipulate PDF files dynamically


• What comes In the box?– POSIX Functions

• Manipulate process information

– Regular Expression Functions• Uses POSIX regex

– Semaphore and Socket Functions• Available only on Unix

– Session Management Functions

PHP on Linux and WindowsPHP on Linux and Windows

• Code Portability– The obvious: don’t use Unix or Windows

specific functions– Create a reusable module for file system

differences, for example:– if( PHP_OS == "Linux" )

{ $ConfigPath = "/var/www/conf"; $DataPath = "/var/www/data";}

PHP on Linux and WindowsPHP on Linux and Windows

• Code Portability– if( ereg("WIN", PHP_OS) )

{ $ApachePath= “C:/Program Files/Apache Group/Apache”; $ConfigPath = ”$ApachePath/htdocs/conf"; $DataPath = "$ApachePath/htdocs/data";}

$ConfigFile = "$ConfigPath/paperwork.conf";$CountryList = "$DataPath/countries.txt";$StateAbbrList = "$DataPath/usstateabbrs.txt";$StateNameList= "$DataPath/usstatenames.txt";

Tricks and TipsTricks and Tips

• Coding– Prototype your web pages first

• Separate the design of the site from the coding

– Turn repetitive code into functions• Makes for more maintainable and reusable

code

– Turn grunt code into functions• Database access, configuration file access


• Debugging– Feature: PHP is not a strongly typed

language• Variables can be created anywhere in your

code

– Undocumented Feature: PHP is not a strongly typed language

• Typos in variable names will cause stuff to happen


• Debugging– Use scripts to dump form and session

variables• Write scripts to dump data to discover bad or

missing data


• Development Tools– Color coding editors

• vim, Emacs, Visual SlickEdit

– IDEs• Windows

– Macromedia Dreamweaver– Allaire Homesite

– Zend’s PHPEdit

• Linux– ???

PHP 5PHP 5

• Release Date– ???

• Features– Complete objects

• Objects with constructors

• Abstract classes

• Private, protected and abstract functions

• Private, protected and constant variables

• Namespaces

• Exception handling with try/catch blocks

ResourcesResources

• PHP Downloads and Online Documentation

– www.php.net

• Community– www.phpbuilder.com: articles on PHP, discussion

forums– www.phpresourceindex.com: over 1,000 PHP scripts– www.phpvolcano.com: PHP 5 information

• Newsgroups– comp.lang.php

Questions?Questions?

– Any Questions• www.php.net

– Community• www.phpbuilder.com: articles on PHP,

discussion forums

– Newsgroups• comp.lang.php

Developing Web Applications with PHP RAD for the World Wide Web Jeff Jirsa [email protected].

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