php for hacks

Tom Praison tpraison@yahoo-inc.com

IIT-Delhi 16-Aug-2012

PHP for hacks

Sample Codes• The sample code is available for download

https://github.com/tompraison/php_sample

What we need to learn?• Enough PHP to handle simple request• How to talk to backend data store using PHP• How to parse XML/JSON in PHP• How to generate JSON in PHP

What is PHP?• Server side language• Very easy to learn• Available on LAMP stack (Linux Apache Mysql

PHP)• Does not require any special tools. Create a

file with .php extension and your done.

How it works?

Getting Started• You need a local server with PHP enabled.• XAMPP for windows• MAMP for Mac OSx• Linux has it by default

<?php $school="iit-delhi"; echo "Hello, World $school";?>

Create a file hello.php into htdocs and call it like this http://localhost:8888/hello.php

Getting Started

Basic Syntax• PHP blocks start with <?php and end with ?> -• Every line of PHP has to end with a

semicolon ";”• Variables in PHP start with a $• You print out content to the document in PHP

with the echo command.• $school is variable and it can be printed out• You can jump in and out of PHP anywhere in

the document. So if you intersperse PHP with HTML blocks, that is totally fine. For example:

<?php $origin = 'Outer Space'; $planet = 'Earth'; $plan = 9; $sceneryType = "awful";?><h1>Synopsis</h1><p>It was a peaceful time on planet <?php echo $planet;?> and people in the <?php echo $sceneryType;?> scenery were unaware of the diabolic plan <?php echo $plan;?> from <?php echo $origin;?> that will take their senses to the edge of what can be endured.</p>

Mix Match• You can mix and match HTML and PHP

demo1.php

Displaying more complex data

• You can define arrays in PHP using the array() method$lampstack = array('Linux','Apache','MySQL','PHP');

• If you simply want to display a complex datatype like this in PHP for debugging you can use the print_r() command

$lampstack = array('Linux','Apache','MySQL','PHP');print_r($lampstack);

demo2.php

Arrays• Accessing arrays using index

<ul><?php$lampstack = array('Linux','Apache','MySQL','PHP');echo '<li>Operating System:'.$lampstack[0] . '</li>';echo '<li>Server:' . $lampstack[1] . '</li>';echo '<li>Database:' . $lampstack[2] . '</li>';echo '<li>Language:' . $lampstack[3] . '</li>';?></ul>

demo3.php

Arrays• Iterating through arrays

<ul><?php$lampstack = array('Linux','Apache','MySQL','PHP');$labels = array('Operating System','Server','Database','Language');$length = sizeof($lampstack);for( $i = 0;$i < $length;$i++ ){ echo '<li>' . $labels[$i] . ':' . $lampstack[$i] . '</li>';}?></ul> sizeof($array) - this will return the size of the array

demo4.php

Associative Arrays• PHP has associative arrays with string keys<ul><?php$lampstack = array( 'Operating System' => 'Linux', 'Server' => 'Apache', 'Database' => 'MySQL', 'Language' => 'PHP');$length = sizeof($lampstack);$keys = array_keys($lampstack);for( $i = 0;$i < $length;$i++ ){ echo '<li>' . $keys[$i] . ':' . $lampstack[$keys[$i]] . '</li>';}?></ul>

demo5.php

Functions

<?phpfunction renderList($array){ if( sizeof($array) > 0 ){ echo '<ul>'; foreach( $array as $key => $item ){ echo '<li>' . $key . ':' . $item . '</li>'; } echo '</ul>'; }}$lampstack = array( 'Operating System' => 'Linux', 'Server' => 'Apache', 'Database' => 'MySQL', 'Language' => 'PHP');renderList($lampstack);?> demo6.php

Interacting with the web - URL parameters

<?php$name = 'Tom';

// if there is no language defined, switch to Englishif( !isset($_GET['language']) ){ $welcome = 'Oh, hello there, ';}if( $_GET['language'] == 'hindi' ){ $welcome = 'Namastae, ';}switch($_GET['font']){ case 'small': $size = 80; break; case 'medium': $size = 100; break; case 'large': $size = 120; break; default: $size = 100; break;}echo '<style>body{font-size:' . $size . '%;}</style>';echo '<h1>'.$welcome.$name.'</h1>';?>

demo7.php

Loading content from the web

<?php // define the URL to load $url = 'http://cricket.yahoo.com/player-profile/Sachin-Tendulkar_2962'; // start cURL $ch = curl_init(); // tell cURL what the URL is curl_setopt($ch, CURLOPT_URL, $url); // tell cURL that you want the data back from that URL curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); // run cURL $output = curl_exec($ch); // end the cURL call (this also cleans up memory so it is // important) curl_close($ch); // display the output echo $output;?>

demo8.php

Displaying XML content• Demo – Showing Twitter trends given a place– Displaying XML Content– Displaying JSON

demo9.php

Connecting to MySQL• Demo10.php from source code• Simple example to fetch data from DB

Further Referencehttp://www.php.net/

http://developer.yahoo.comhttp://isithackday.com/hackday-toolbox/phpforhacks/index.html

http://www.slideshare.net/tompraisonhttps://github.com/tompraison/php_sample