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Developing Web Developing Web Applications with PHPApplications with PHP
RAD for the World Wide Web
AgendaAgenda
– Introduction– PHP Language Basics– Built-in Functions– Tricks and Tips– PHP 5
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
IntroductionIntroduction
• 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
IntroductionIntroduction
• 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
IntroductionIntroduction
• Netcraft Statistics– 11,869,645 Domains, 1,316,288 IP Addresses
IntroductionIntroduction
• 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?>
PHP Language BasicsPHP Language Basics
• 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%>
PHP Language BasicsPHP Language Basics
• The Script Tags (cont.)– “Echo” Tags
– <table><tr> <td>Name:</td><td><?= $name ?></td></tr><tr> <td>Address:</td><td><?= $address ?></td></tr></table>
PHP Language BasicsPHP Language Basics
• 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?>
PHP Language BasicsPHP Language Basics
• Hello World!: An Example (cont.)• <script language=“PHP”>
$hello = “Hello”; $world = “World!”; print $hello . $world</script>
PHP Language BasicsPHP 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”, “<br>\n”);
PHP Language BasicsPHP Language Basics
• Constants, Data Types and Variables– Using a constant
• print(“Company name: “ . COMPANY . NL);
PHP Language BasicsPHP 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
PHP Language BasicsPHP 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
PHP Language BasicsPHP 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;
PHP Language BasicsPHP Language Basics
• 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 $arr["somearray"]["a"]; // 42?>
PHP Language BasicsPHP Language Basics
• Constants, Data Types and Variables– Objects
– Currently not much more advanced than than associative arrays Using constants
– Before version 5.0, objects are passed by value• Slow• Functions can not easily change object variables
PHP Language BasicsPHP Language Basics
• Constants, Data Types and Variables– Operators
– Contains all of the operators like in C and Perl (even the ternary)
– Statements– if, if/elseif– Switch/case– for, while, and do/while loops– Include and require statements for code reuse
Built-in FunctionsBuilt-in Functions
• What comes In the box?– Array Manipulator Functions
• sort, merge, push, pop, slice, splice, keys, count
– CCVS: Interface to Red Hat’s credit system– COM functions: Interface to Windows COM
objects– Date and Time Functions
• getdate, mkdate, date, gettimeofday, localtime, strtotime, time
Built-in FunctionsBuilt-in Functions
• What comes In the box?– Directory Functions
• Platform independent
– Error Handling Functions• Recover from warnings and errors
– Filesystem Functions• Access flat files• Check directory, link, and file status information• Copy, delete, and rename files
Built-in FunctionsBuilt-in Functions
• What comes In the box?– IMAP Functions
• Manipulate mail boxes via the IMAP protocol
– LDAP Functions• Works with most LDAP servers
– Mail Functions• mail($recipient, $subject, $message)
Built-in FunctionsBuilt-in Functions
• What comes In the box?– Database Functions
• dba: dbm-style abstraction layer• dBase• Frontbase• Informix• Ingres II• Interbase• mSQL
Built-in FunctionsBuilt-in Functions
• What comes In the box?– Database Functions (cont.)
• MySQL• Oracle• PostgreSQL• SQL Server
– MING• Macromedia Flash
– PDF• Create/manipulate PDF files dynamically
Built-in FunctionsBuilt-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
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
Tricks and TipsTricks 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
Tricks and TipsTricks and Tips
• Debugging– Use scripts to dump form and session
variables• Write scripts to dump data to discover bad or
missing data
Tricks and TipsTricks and Tips
• Development Tools– Color coding editors
• vim, Emacs, Visual SlickEdit
– IDEs• Windows
– Macromedia Dreamweaver– Allaire Homesite
– Zend’s PHPEdit
• Linux– ???
PHP 5PHP 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