introductionto php
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Introduction to PHP scripting language
Lorenzo Tilve lvaro
List of topics
Basic concepts
Apache/CGI mode vs CLI
Installation & Configuration
Syntax
Web development with PHP
Security
Practices index
Basic concepts
PHP ( PHP Hypertext Preprocessor ) was born in 1994
Reference documentation
http://www.php.net
http://www.php.net/manual/en/langref.php
Characteristics:
Interpreted language
Implicit variable declaration
PHP stack
Basic concepts
Main advantages:
Lightweight
Ease of use and administration
Multiple library support
Fast learning curve
Multiplatform
Provides a lot of connectors
Basic concepts
Some disadvantages:
Complexity to handle large session data
Upgrade problems:
Issues with backwards compatibility
Certain package dependences
Lack of debugging tools
Handling of balance load
Basic concepts
Current releases state (Feb 08):
Stable branch 5.2.5
Compatibility support 4.4.8
Migration information
www.php.net/manual/en/migration5.php
Road to PHP 6
Apache/CGI mode vs CLI
PHP as a scripting language
Embed integration with HTML and use of templates
Programmed scripting process via cronjobs
Separated configuration files for different scenarios
Apache/CGI mode vs CLI
In CGI mode all PHP stack is regenerated with each request
Necessity of usage of GET, POST and SESSION variables to communication between requests
Cookie and user agent management
Alternatives for other technological components integration
Installation & Configuration
PHP multiplatform packages
Bundled packages of Apache+Mysql+PHP environment
For Ubuntu / Debian distributions
apt-get install php5 php5-common php5-cli
Specific compilation instructions
http://es.php.net/manual/en/install.unix.php
Configuration
Other important libraries:
php5-imap: IMAP module for php5
php5-ldap: LDAP module for php5
php5-mcrypt: MCRYPT module for php5
php5-mysql: MySQL module for php5
php5-gd: GD module for php5
php5-pear: PEAR - PHP Extension and Application
...
PHP accelerator
Zend extension
Configuration
Configuration files
/etc/php5/cli/etc.ini
/etc/php5/apache2/etc.ini
/etc/php5/cgi/etc.ini
For Apache usage
Apache configuration and virtualhosts setup with php_value directives
Configuration
Important configuration settings in php.ini:
safe_mode configuration
max_execution_time & memory_limit
register_globals
logging directories
Syntax
PHP code structure
Basic syntax
Types, variables and Constants
Expressions
Operators
Control Structures
Functions
Syntax
Basic syntax
PHP script
HTML embed
Syntax
Types, variables and Constants
// Constat declaration
define( "STRING_MAX_LENGTH", 25);
define( "USER", 1 );
define( "USER_GROUP", 2 );
define( "STANDARD_USER", "user" );
define( "ADMIN_USER", "admin" );
Syntax
Types, variables and Constants
// Arrays
$array = array( 'item1', 'item2', 'item3' );
$array2 = array( 'u1'=>'item1', 'u2'=>'item2' );
$arra2['u3'] = 'item3';
// Strings
$string = 'This is a string';
$string2 = "This is another string and $string";
$string3 = $string . " and " . $string2;
Syntax
Conditions
$user_id = 'login';
$ban_list = array( ) ;
// && and, || or, == equal operators
if ( empty( $user_id ) || in_array( $user_$ban_list ) )
{
exit( );
}
Syntax
Looping
$elements = array( one, two, three);
// Foreach, while and for loops
foreach ( $elements as $value ) {
$results[ ] = $value. "processed";
}
Syntax
Functions
// File requirements and inclussions
require_once(myclass.php);
include_once(myclass.php);
// Declaration
function foo ( $param1, $param2 = def_value, ...) {
// do some stuff
return $value;
}
Security
Safe mode
Limits execution of server-owned scriptsa and safe_mode_include_dir binaries
Register globals
Server validation
Unsafe client-side validation ( Javascript )
Filter SQL-injections
$id = mysql_real_escape_string($_POST['input']);
$SQL = 'SELECT * FROM table WHERE id = ' . $id;
Web development
PHP is extremely popular for CMS development on LAMP environments.
Typo3, eZPublish, Joomla, Drupal, phpNuke, Mambo, ...
www.cmsmatrix.com
Original web approach vs. specific PHP pages with presentation templates:
ModelViewController design pattern
Web development
Processing HTTP variables
Cookies and session handling
Connector for system integration
Web services using nusoap
Database handling
Image management
LDAP, Mail, etc, ...
Practices
Introductory practices
Basic PHP syntax and CLI mode
Configuration and security
Database and filesystem interaction
Data processing and sending mail
Teachers
Lorenzo Tilve. Igalia
Engineering group.
Xavier Castao. Igalia
Engineering group.
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