Optimize javascript using minify

"It combines multiple CSS or Javascript files, removes unnecessary whitespace and comments, and serves them with gzip encoding and optimal client-side cache headers."

Example of interesting urls:
* http://dev.bigproject/min/?f=static/map.js
* http://dev.bigproject/min/?b=static&f=map.js,taskpane.js,OpenLayers-2.8.js
* http://dev.bigproject/min/?g=js

Few challenges during setup
* 400 Bad Request -- check your path in config.php, especially $min_documentRoot
* watch for symbolic link for js/css files - you may need to update config $min_symlinks

In Minify Cookbook, it say YUICompressor = "Best Javascript Compression", but from my random test, Google Closure Compiler is better.

I created a php code for Minify Google Closure (80% copy paste from existing YUICompressor php code). To setup

function googleJs($js) {
require_once 'lib/Minify/GoogleClosure.php';
Minify_GoogleClosure::$jarFile = dirname(__FILE__) . '/lib/compiler.jar';
Minify_GoogleClosure::$tempDir = '/tmp';
return Minify_GoogleClosure::minifyJs($js);
}
$min_serveOptions['minifiers']['application/x-javascript'] = 'googleJs';


Since have problem attach the source code, so below is the code.


<?php
/**
* Class Minify_GoogleClosure
* @package Minify
*/

/**
* Compress Javascript/CSS using the GoogleClosure
*
* You must set $jarFile and $tempDir before calling the minify functions.
* Also, depending on your shell's environment, you may need to specify
* the full path to java in $javaExecutable or use putenv() to setup the
* Java environment.
*
*
* @package Minify
*/
class Minify_GoogleClosure {

/**
* Filepath of the Google Closure jar file. This must be set before
* calling minifyJs() or minifyCss().
*
* @var string
*/
public static $jarFile = null;

/**
* Writable temp directory. This must be set before calling minifyJs()
* or minifyCss().
*
* @var string
*/
public static $tempDir = null;

/**
* Filepath of "java" executable (may be needed if not in shell's PATH)
*
* @var string
*/
public static $javaExecutable = 'java';

/**
* Minify a Javascript string
*
* @param string $js
*
* @param array $options (verbose is ignored)
*
* @return string
*/
public static function minifyJs($js, $options = array())
{
return self::_minify('js', $js, $options);
}

/**
* Minify a CSS string
*
* @param string $css
*
* @param array $options (verbose is ignored)
*
* @return string
*/
public static function minifyCss($css, $options = array())
{
return self::_minify('css', $css, $options);
}

private static function _minify($type, $content, $options)
{
self::_prepare();
if (! ($tmpFile = tempnam(self::$tempDir, 'googlec_'))) {
throw new Exception('Minify_GoogleClosure : could not create temp file.');
}
file_put_contents($tmpFile, $content);
exec(self::_getCmd($options, $type, $tmpFile), $output);
unlink($tmpFile);
return implode("\n", $output);
}

private static function _getCmd($userOptions, $type, $tmpFile)
{
$cmd = self::$javaExecutable . ' -jar ' . escapeshellarg(self::$jarFile);
return $cmd . ' --js ' . escapeshellarg($tmpFile);
}

private static function _prepare()
{
if (! is_file(self::$jarFile)
|| ! is_dir(self::$tempDir)
|| ! is_writable(self::$tempDir)
) {
throw new Exception('Minify_GoogleClosure : $jarFile and $tempDir must be set.');
}
}
}