1. Developing Web Applications with PHP RAD for the World Wide Web

2. Agenda –Introduction –PHP Language Basics –Built-in Functions –Tricks and Tips –PHP 5

3. Introduction 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

4. Introduction 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

5. Introduction 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

6. Introduction Netcraft Statistics –11,869,645 Domains, 1,316,288 IP Addresses

7. Introduction 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

8. PHP Language Basics The Script Tags –All PHP code is contained in one of several script tags:

9. PHP Language Basics The Script Tags (cont.) // Some code here –ASP-style tags Introduced in 3.0; may be removed in the future

10. PHP Language Basics The Script Tags (cont.) –“Echo” Tags – Name: Address:

11. PHP Language Basics Hello World!: An Example –Like Perl, there is more than one way to do it

12. PHP Language Basics Hello World!: An Example (cont.) $hello = “Hello”; $world = “World!”; print $hello. $world

13. PHP Language Basics 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”, “ \n”);

14. PHP Language Basics Constants, Data Types and Variables –Using a constant print(“Company name: “. COMPANY. NL);

15. PHP Language Basics 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

16. PHP Language Basics Constants, Data Types and Variables –Data types 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

17. PHP Language Basics Constants, Data Types and Variables –Data types Arrays –Perl-like syntax $arr = array("foo" => "bar", 12 => true); –same as $arr[“foo”] = “bar”; $arr[12] = true;

18. PHP Language Basics Constants, Data Types and Variables Arrays (cont.) – array(6 => 5, 13 => 9, "a" => 42)); echo $arr["somearray"][6]; // 5 echo $arr["somearray"][13]; // 9 echo $arr["somearray"]["a"]; // 42 ?>

19. PHP Language Basics 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

20. PHP Language Basics 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

21. Built-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

22. Built-in Functions 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

23. Built-in Functions 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)

24. Built-in Functions What comes In the box? –Database Functions dba: dbm-style abstraction layer dBase Frontbase Informix Ingres II Interbase mSQL

25. Built-in Functions What comes In the box? –Database Functions (cont.) MySQL Oracle PostgreSQL SQL Server –MING Macromedia Flash –PDF Create/manipulate PDF files dynamically

26. Built-in Functions 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

27. PHP 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"; }

28. PHP 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";

29. Tricks 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

30. Tricks and Tips 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

31. Tricks and Tips Debugging –Use scripts to dump form and session variables Write scripts to dump data to discover bad or missing data

32. Tricks and Tips Development Tools –Color coding editors vim, Emacs, Visual SlickEdit –IDEs Windows –Macromedia Dreamweaver –Allaire Homesite –Zend’s PHPEdit Linux –???

33. PHP 5 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