pickles/classes/Dynamic.php

<?php

/**
 * Dynamic Content Class File for PICKLES
 *
 * PHP version 5
 *
 * Licensed under The MIT License 
 * Redistribution of these files must retain the above copyright notice.
 *
 * @author    Josh Sherman <josh@gravityblvd.com>
 * @copyright Copyright 2007-2010, Gravity Boulevard, LLC
 * @license   http://www.opensource.org/licenses/mit-license.html
 * @package   PICKLES
 * @link      http://p.ickl.es
 */

/**
 * Dynamic Class
 *
 * Handles generating links to static content that are a timestamp injected as
 * to avoid hard caching. Also minifies content where applicable.
 *
 * Note: you will want to add a mod_rewrite line to your .htaccess to support
 * the routing to the filenames with the timestamp injected:
 * 
 * RewriteRule ^(.+)\.([\d]+)\.(css|js|gif|png|jpg|jpeg)$ /$1.$3 [NC,QSA]
 */
class Dynamic extends Object
{
	/**
	 * Generate Reference
	 *
	 * Appends a dynamic piece of information to the passed reference in the
	 * form of a UNIX timestamp added to the query string.
	 *
	 * @param  string $reference URI reference of the file
	 * @return string URI reference reference with dynamic content
	 */
	public function ref($reference)
	{
		// Checks if the URI reference is absolute, and not relative
		if (substr($reference, 0, 1) == '/')
		{
			$query_string = '';

			// Checks for ? and extracts query string
			if (strstr($reference, '?'))
			{
				list($reference, $query_string) = explode('?', $reference);
			}

			// Adds the dot so the file functions can find the file
			$file = '.' . $reference;
			
			if (file_exists($file))
			{
				// Replaces the extension with time().extension
				$parts = explode('.', $reference);

				if (count($parts) == 1)
				{
					throw new Exception('Filename must have an extension (e.g. /path/to/file.png)');
				}
				else
				{
					end($parts);
					$parts[key($parts)] = filemtime($file) . '.' . current($parts);
					$reference = implode('.', $parts);
				}

				// Adds the query string back
				if ($query_string != '')
				{
					$reference .= '?' . $query_string;
				}
			}
			else
			{
				throw new Exception('Supplied reference does not exist');
			}
		}
		else
		{
			throw new Exception('Reference value must be absolute (e.g. /path/to/file.png)');
		}
		
		return $reference;
	}

	/**
	 * Generate Javascript Reference
	 *
	 * Attempts to minify the source with Google's Closure compiler, and then
	 * returns the reference URI for the file, minified or not.
	 *
	 * @link   http://code.google.com/closure/compiler/
	 * @param  string $reference URI reference of the Javascript file
	 * @return string URI reference reference with dynamic content
	 */
	public function js($original_reference, $level = 'simple')
	{
		$level = strtoupper($level);

		switch ($level)
		{
			CASE 'WHITESPACE':
			CASE 'SIMPLE':
			CASE 'ADVANCED':
				// Injects .min into the filename
				$parts = explode('.', $original_reference);

				if (count($parts) == 1)
				{
					throw new Exception('Filename must have an extension (e.g. /path/to/file.js)');
				}
				else
				{
					end($parts);
					$parts[key($parts)] = 'min.' . current($parts);
					$minified_reference = implode('.', $parts);
				}
				
				$original_filename = '.' . $original_reference;
				$minified_filename = '.' . $minified_reference;

				$path = dirname($original_filename);

				if (file_exists($original_filename))
				{
					$reference = $original_reference;

					if (is_writable($path) && (!file_exists($minified_filename) || filemtime($original_filename) > filemtime($minified_filename)) && extension_loaded('curl'))
					{
						// Sets up the options list
						$options = array(
							CURLOPT_URL             => 'http://closure-compiler.appspot.com/compile',
							CURLOPT_RETURNTRANSFER  => true,
							CURLOPT_HTTPHEADER      => array('Content-Type: application/x-www-form-urlencoded; charset=utf-8'),
							CURLOPT_POST            => true,
							CURLOPT_POSTFIELDS      => 'js_code=' . urlencode(file_get_contents($original_filename)) . '&compilation_level=' . ($level . '_' . ($level == 'WHITESPACE' ? 'ONLY' : 'OPTIMIZATIONS')) . '&output_format=text&output_info=compiled_code'
						);

						try
						{
							// Executes the request
							$curl = curl_init();
							curl_setopt_array($curl, $options);
							file_put_contents($minified_filename, curl_exec($curl));
							curl_close($curl);

							$reference = $minified_reference;
						}
						catch (Exception $exception)
						{
							$reference = $original_reference;
						}
					}
					elseif (file_exists($minified_filename))
					{
						$reference = $minified_reference;
					}
					else
					{
						Log::warning('Unable to minify ' . $original_reference . ' and a minified copy does not already exist');
					}

					$reference = $this->ref($reference);
				}
				else
				{
					throw new Exception('Supplied reference does not exist');
				}
				
				break;

			default:
				throw new Exception('The level "' . $level . '" is invalid. Valid levels include "whitespace", "simple" and "advanced"');
				break;
		}

		return $reference;
	}

	/**
	 * Generate Stylesheet Reference
	 *
	 * Attempts to minify the stylesheet and then  returns the reference URI
	 * for the file, minified or not.
	 *
	 * @param  string $reference URI reference of the Stylesheet
	 * @return string URI reference reference with dynamic content
	 */
	public function css($original_reference)
	{
		// Injects .min into the filename
		$parts = explode('.', $original_reference);

		if (count($parts) == 1)
		{
			throw new Exception('Filename must have an extension (e.g. /path/to/file.css)');
		}
		else
		{
			end($parts);
			$parts[key($parts)] = 'min.' . current($parts);
			$minified_reference = implode('.', $parts);
		}
		
		$original_filename = '.' . $original_reference;
		$minified_filename = '.' . $minified_reference;

		$path = dirname($original_filename);

		if (file_exists($original_filename))
		{
			$reference = $original_reference;

			if (is_writable($path) && (!file_exists($minified_filename) || filemtime($original_filename) > filemtime($minified_filename)))
			{
				// Minifies CSS with a few basic character replacements.
				$stylesheet = file_get_contents($original_filename);
				$stylesheet = str_replace(array("\t", "\n", ', ', ' {', ': ', ';}'), array('', '', ',', '{', ':', '}'), $stylesheet);
				$stylesheet = preg_replace('/\/\*.+?\*\//', '', $stylesheet);
				file_put_contents($minified_filename, $stylesheet);

				$reference = $minified_reference;
			}
			elseif (file_exists($minified_filename))
			{
				$reference = $minified_reference;
			}
			else
			{
				// @todo Log a warning
			}

			$reference = $this->ref($reference);
		}
		else
		{
			throw new Exception('Supplied reference does not exist');
		}

		return $reference;
	}
}

?>