PHP for hacks


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PHP primer for hacking

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PHP for hacks

  1. 1. PHP for hacks Tom Praison IIT-Delhi 16-Aug-2012
  2. 2. Sample Codes• The sample code is available for download
  3. 3. 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
  4. 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. 5. How it works?
  6. 6. Getting Started• You need a local server with PHP enabled.• XAMPP for windows• MAMP for Mac OSx• Linux has it by default
  7. 7. Getting StartedCreate a file hello.php into htdocs and call it like thishttp://localhost:8888/hello.php <?php $school="iit-delhi"; echo "Hello, World $school"; ?>
  8. 8. 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:
  9. 9. Mix Match• You can mix and match HTML and PHP <?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. 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. 11. 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
  12. 12. 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($array) - this will return the size of the array demo4.php
  13. 13. Associative Arrays• PHP has associative arrays with string keys<ul><?php$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[$i]] . </li>;}?></ul> demo5.php
  14. 14. Functions<?phpfunction renderList($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($lampstack);?> demo6.php
  15. 15. Interacting with the web - URL parameters<?php$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
  16. 16. Loading content from the web<?php // define the URL to load $url =; // 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. 17. Displaying XML content• Demo – Showing Twitter trends given a place – Displaying XML Content – Displaying JSONdemo9.php
  18. 18. Connecting to MySQL• Demo10.php from source code• Simple example to fetch data from DB
  19. 19. Further Reference toolbox/phpforhacks/index.html
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