Automatic JavaScript and CSS Packer

class AssetHelper extends Helper {
//Cake debug = 0 packed js/css returned. $this->debug doesn't do anything.
//Cake debug > 0, $this->debug = false essentially turns the helper off. js/css not packed. Good for debugging your js/css files.
//Cake debug > 0, $this->debug = true packed js/css returned. Good for debugging this helper.
var $debug = false;

//there is a *minimal* perfomance hit associated with looking up the filemtimes
//if you clean out your cached dir (as set below) on builds then you don't need this.
var $checkTS = true;

//the packed files are named by stringing together all the individual file names
//this can generate really long names, so by setting this option to true
//the long name is md5'd, producing a resonable length file name.
var $md5FileName = false;

//you can change this if you want to store the files in a different location.
//this is relative to your webroot/js and webroot/css paths
var $cachePath = 'packed/';

//set the css compression level
//options: default, low_compression, high_compression, highest_compression
//default is no compression
//I like high_compression because it still leaves the file readable.
var $cssCompression = 'high_compression';

var $helpers = array('Html', 'Javascript');
var $viewScriptCount = 0;

//flag so we know the view is done rendering and it's the layouts turn
function afterRender() {
$view =& ClassRegistry::getObject('view');
$this->viewScriptCount = count($view->__scripts);
}

function scripts_for_layout() {
$view =& ClassRegistry::getObject('view');

//nothing to do
if (!$view->__scripts) {
return;
}

//move the layout scripts to the front
$view->__scripts = array_merge(
array_slice($view->__scripts, $this->viewScriptCount),
array_slice($view->__scripts, 0, $this->viewScriptCount)
);

if (Configure::read('debug') && $this->debug == false) {
return join("\n\t", $view->__scripts);
}

//split the scripts into js and css
foreach ($view->__scripts as $i => $script) {
if (preg_match('/js\/(.*).js/', $script, $match)) {
$temp = array();
$temp['script'] = $match[1];
$temp['name'] = basename($match[1]);
$js[] = $temp;

//remove the script since it will become part of the merged script
unset($view->__scripts[$i]);
} else if (preg_match('/css\/(.*).css/', $script, $match)) {
$temp = array();
$temp['script'] = $match[1];
$temp['name'] = basename($match[1]);
$css[] = $temp;

//remove the script since it will become part of the merged script
unset($view->__scripts[$i]);
}
}

$scripts_for_layout = '';
//first the css
if (!empty($css)) {
$scripts_for_layout .= $this->Html->css($this->cachePath . $this->process('css', $css));
$scripts_for_layout .= "\n\t";
}

//then the js
if (!empty($js)) {
$scripts_for_layout .= $this->Javascript->link($this->cachePath . $this->process('js', $js));
}

//finally anything that was left over, usually codeBlocks
$scripts_for_layout .= join("\n\t", $view->__scripts);

return $scripts_for_layout;
}

function process($type, $data) {
switch ($type) {
case 'js':
$path = JS;
break;
case 'css':
$path = CSS;
break;
}

$folder = new Folder;

//make sure the cache folder exists
if ($folder->create($path . $this->cachePath, "777")) {
trigger_error('Could not create ' . $path . $this->cachePath
. '. Please create it manually with 777 permissions', E_USER_WARNING);
}

//check if the cached file exists
$names = Set::extract($data, '{n}.name');
$folder->cd($path . $this->cachePath);
$fileName = $folder->find($this->__generateFileName($names) . '_([0-9]{10}).' . $type);
if ($fileName) {
//take the first file...really should only be one.
$fileName = $fileName[0];
}

//make sure all the pieces that went into the packed script
//are OLDER then the packed version
if ($this->checkTS && $fileName) {
$packed_ts = filemtime($path . $this->cachePath . $fileName);

$latest_ts = 0;
$scripts = Set::extract($data, '{n}.script');
foreach($scripts as $script) {
$latest_ts = max($latest_ts, filemtime($path . $script . '.' . $type));
}

//an original file is newer. need to rebuild
if ($latest_ts > $packed_ts) {
unlink($path . $this->cachePath . $fileName);
$fileName = null;
}
}

//file doesn't exist. create it.
if (!$fileName) {
$ts = time();

//merge the script
$scriptBuffer = '';
$scripts = Set::extract($data, '{n}.script');
foreach($scripts as $script) {
$buffer = file_get_contents($path . $script . '.' . $type);

switch ($type) {
case 'js':
//jsmin only works with PHP5
if (PHP5) {
vendor('jsmin/jsmin');
$buffer = trim(JSMin::minify($buffer));
}
break;

case 'css':
vendor('csstidy/class.csstidy');
$tidy = new csstidy();
$tidy->load_template($this->cssCompression);
$tidy->parse($buffer);
$buffer = $tidy->print->plain();
break;
}

$scriptBuffer .= "\n/* $script.$type */\n" . $buffer;
}

//write the file
$fileName = $this->__generateFileName($names) . '_' . $ts . '.' . $type;
$file = new File($path . $this->cachePath . $fileName);
$file->write(trim($scriptBuffer));
}

if ($type == 'css') {
//$html->css doesn't check if the file already has
//the .css extension and adds it automatically, so we need to remove it.
$fileName = str_replace('.css', '', $fileName);
}

return $fileName;
}

function __generateFileName($names) {
$fileName = str_replace('.', '-', implode('_', $names));

if ($this->md5FileName) {
$fileName = md5($fileName);
}