Compress images

example.php

<?php

$s = new smushit();
$smushed = $s->compress('http://thechronicleherald.ca/sites/default/files/imagecache/story_thumb/stories/photos/11-18-10_cl111710auditor2_1.jpg');
print_r($smushed);

smushed.dummy.class.php

<?php
/**
 * Just a dummy class so you know what you get back from the smushit compress function
 */
abstract class smushed {

	/**
	 * The url of the source image
	 * @var string
	 */
	public $src;
	/**
	 * The size of the file in bytes
	 * @var int
	 */
	public $src_size;
	/**
	 * The url of the smushed image
	 * @var string
	 */
	public $dest;
	/**
	 * The size of the smushed file in bytes
	 * @var int
	 */
	public $dest_size;
	/**
	 * The amount of compression
	 * @var float
	 */
	public $percent;
	/**
	 * Not sure...
	 * @var presumably an integer...?
	 */
	public $id;
}

smushed_exception.class.php

<?php
/**
 * Custom exception handler
 */
class Smush_exception extends Exception {

	/**
	 * Path to image
	 * @var string $image
	 */
	private $image = '';

	/**
	 * Overload the exception construct so we can provide an image name
	 * @param string $message
	 * @param string $image
	 */
	public function __construct($message, $image) {
		$this->image = $image;
		parent::__construct($message);
	}

	// Return image path.
	final function getImage() {
		return $this->image;
	}

}

smushit.class.php

<?php
/**
 * Description: Compresses images using Smush.it
 *
 * @license MIT
 * @author  Mathew Davies <thepixeldeveloper@googlemail.com>
 */
class smushit {
	const user_agent = 'Smush.it PHP Class (+http://mathew-davies.co.uk)';

	private $curl = NULL;

	/**
	 * Smush.it request URL
	 */
	const url = 'http://www.smushit.com/ysmush.it/ws.php';

	/**
	 * Make sure any prerequisite are installed.
	 */
	public function __construct() {
		if (!extension_loaded('json')) {
			throw new RuntimeException('The json extension was not found');
		}
		if (!extension_loaded('curl')) {
			throw new RuntimeException('The cURL extension was not found.');
		}

		// cURL handler
		$this->curl = curl_init();

		// Return HTTP response
		curl_setopt($this->curl, CURLOPT_RETURNTRANSFER, TRUE);
	}

	/**
	 * Compress image using smush.it. Image must be available online
	 *
	 * @param  string url to image.
	 * @throws Smush_exception
	 * @return smushed
	 */
	public function compress($image) {
		// Set appropriate URL.
		curl_setopt($this->curl, CURLOPT_URL, self::url . '?' . http_build_query(array('img' => $image)));

		// Set user agent
		curl_setopt($this->curl, CURLOPT_USERAGENT, self::user_agent);

		// Execute the HTTP request
		$request = curl_exec($this->curl);

		// JSON response
		$result = json_decode($request);

		if (isset($result->error)) {
			throw new Smush_exception($result->error, $image);
		}

		$result->dest = urldecode($result->dest);

		// Return response data
		return $result;
	}

}