Developing Web Applications with PHP

1
Developing Web Applications with PHP

• RAD for the World Wide Web
• Jeff Jirsa jjirsa_at_xnet.com

2
Agenda

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

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

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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

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Introduction

• 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

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Introduction

• 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

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Introduction

• 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

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Introduction

• 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

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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

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Introduction

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

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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

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PHP Language Basics

• The Script Tags
• All PHP code is contained in one of several
  script tags
• lt?// Some code?gt
• lt?php// Some code here?gt

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PHP Language Basics

• The Script Tags (cont.)
• ltscript languagePHP"gt // Some code
  herelt/scriptgt
• ASP-style tags
• Introduced in 3.0 may be removed in the future
• lt // Some code heregt

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PHP Language Basics

• The Script Tags (cont.)
• Echo Tags
• lttablegtlttrgt lttdgtNamelt/tdgtlttdgtlt? name
  ?gtlt/tdgtlt/trgtlttrgt lttdgtAddresslt/tdgtlttdgtlt?
  address ?gtlt/tdgtlt/trgtlt/tablegt

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PHP Language Basics

• Hello World! An Example
• Like Perl, there is more than one way to do it
• lt?php echo Hello World! ?gt
• lt?php greeting Hello World!
  printf(s, greeting)php?gt

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PHP Language Basics

• Hello World! An Example (cont.)
• ltscript languagePHPgt hello Hello
  world World! print hello .
  worldlt/scriptgt

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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, ltbrgt\n)

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PHP Language Basics

• Constants, Data Types and Variables
• Using a constant
• print(Company name . COMPANY . NL)

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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

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PHP Language Basics

• Constants, Data Types and Variables
• Data types
• Strings and type conversion
• street 123
• street street . Main Street
• city Napervillestate IL
• address street
• address address . NL . city, state
• number address 1 // number equals
  124

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PHP Language Basics

• Constants, Data Types and Variables
• Data types
• Arrays
• Perl-like syntax
• arr array("foo" gt "bar", 12 gt true)
• same as
• arrfoo bar
• arr12 true

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PHP Language Basics

• Constants, Data Types and Variables
• Arrays (cont.)
• lt?php arr array("somearray" gt array(6 gt
  5, 13 gt 9, "a" gt
  42)) echo arr"somearray"6 // 5
  echo arr"somearray"13 // 9 echo
  arr"somearray""a" // 42?gt

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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

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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

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Built-in Functions

• What comes In the box?
• Array Manipulator Functions
• sort, merge, push, pop, slice, splice, keys,
  count
• CCVS Interface to Red Hats credit system
• COM functions Interface to Windows COM objects
• Date and Time Functions
• getdate, mkdate, date, gettimeofday, localtime,
  strtotime, time

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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

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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)

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Built-in Functions

• What comes In the box?
• Database Functions
• dba dbm-style abstraction layer
• dBase
• Frontbase
• Informix
• Ingres II
• Interbase
• mSQL

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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

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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

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PHP on Linux and Windows

• Code Portability
• The obvious dont 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"

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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"ConfigF
  ile "ConfigPath/paperwork.conf"CountryList
  "DataPath/countries.txt"StateAbbrList
  "DataPath/usstateabbrs.txt"StateNameList
  "DataPath/usstatenames.txt"

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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

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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

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Tricks and Tips

• Debugging
• Use scripts to dump form and session variables
• Write scripts to dump data to discover bad or
  missing data

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Tricks and Tips

• Development Tools
• Color coding editors
• vim, Emacs, Visual SlickEdit
• IDEs
• Windows
• Macromedia Dreamweaver
• Allaire Homesite
• Zends PHPEdit
• Linux
• ???

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PHP 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

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Resources

• 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

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Questions?

• Any Questions
• www.php.net
• Community
• www.phpbuilder.com articles on PHP, discussion
  forums
• Newsgroups
• comp.lang.php