The document introduces PHP as a server-side scripting language that is easy to learn and commonly used with the LAMP stack. It provides examples of basic PHP syntax for variables, arrays, functions, and interacting with URLs and external data sources. The goal is to teach enough PHP to handle simple requests and parse/generate XML and JSON through practical code examples.

1. PHP for hacks
Tom Praison
(tpraison@yahoo-inc.com)

4. 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.

5. 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

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

7. Getting Started
Create a file hello.php into htdocs and call it like this
http://localhost:8888/hello.php
<?php
$school="iit-kgp";
echo "Hello, World $school";
?>

8. • 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:

9. Mix Match
<?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>
demo1.php

10. 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

11. Arrays
<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

12. Arrays
<ul>
<?php
$lampstack = array('Linux','Apache','MySQL','PHP');
$labels = array('OperatingSystem','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

13. Associative Arrays
<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

14. Functions
<?php
function 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

15. Interacting with the web - URL
parameters
<?php
$name = 'Tom';
// if there is no language defined, switch to English
if( !isset($_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

16. 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

17. Displaying XML content
• Demo
demo9.php

18. Displaying JSON content
• Demo
demo9.php

19. Putting all together

20. Further Reference
http://www.php.net/
http://developer.yahoo.com
http://isithackday.com/hackday-
toolbox/phpforhacks/index.html
http://www.slideshare.net/tompraison