I do not actively maintain this repository. There are a couple of forks that might work for you.

How to use

// INCLUDE COMPRESSOR CLASS
include('yuicompressor.php');

// INVOKE CLASS
$yui = new YUICompressor(JAR_PATH, TEMP_FILES_DIR, $options);

// ADD FILES
$yui->addFile($absolute_path_to_file);

// ADD STRING
$yui->addString($string);

// COMPRESS
$code = $yui->compress();