Little Utils from bountify

optimize.php

<?php
/*
Make sure that /tmp/check.json has permissions to read and write
It is better to create /tmp/check.json manually
type below commands if you are using only php 

sudo echo > /tmp/check.json
sudo chmod 777 /tmp/check.json
sudo chown www-data:www-data /tmp/check.json

now call the below class 

$lu = new LittleUtils();
$lu->optimize('file.gif');

$lu->optimize('file.jpg');

$lu->optimize('file.png');



Expected Output if image size is reduced 
Array
(
    [0] => 1
    [1] => Reduced by 30.2% (258.2&nbsp;KB)
)

if already reduced 

Array
(
    [0] =>
    [1] => No savings
)

*/
class LittleUtils{

	private static $jsonFile = '/tmp/check.json';

	private function check(){

		$result = array();

		$required = array(
		    'PNG' => 'opt-png',
		    'JPG' => 'opt-jpg',
		    'GIF' => 'opt-gif',
		);

		$disabled = array_map('trim', explode(',', ini_get('disable_functions')));
		if(in_array('exec', $disabled)){
		    $result['exec'] = array("success"=>false,"msg"=>"<p><strong>CW Image Optimizer requires exec().</strong> Your system administrator has disabled this function.</p>");
		}
		else{
			$result['exec'] = array("success"=>true,"msg"=>"");
		}
		$missing = array();
		foreach($required as $key => $req){
		    $res = trim(exec('which ' . $req));
		    if(empty($res)){
		        $missing[] = $req;
		    }
		}

		$msg = implode(', ', $missing);

		if(!empty($msg)){
		    //echo "<p><strong>CW Image Optimizer requires <a href=\"http://sourceforge.net/projects/littleutils/\">littleutils</a>.</strong> You are missing: $msg.</p>";
		    //die();
		    $result['missing'] = array("success"=>false, "msg"=>"<p><strong>CW Image Optimizer requires <a href=\"http://sourceforge.net/projects/littleutils/\">littleutils</a>.</strong> You are missing: $msg.</p>");
		}
		else{
			$result['missing'] = array("success"=>true,"msg"=>"");
		}
		if (!is_writable(self::$jsonFile) ) {
            
            return "Unable to write the requirements file ".self::$jsonFile.". Please make sure the path is writable";
        }

		return file_put_contents(self::$jsonFile,json_encode($result));


	}


	private function checkSystemRequirements(){

		// If requirements file doesn't exists check the requirements and write to file
		if (!file_exists(self::$jsonFile) && !is_file(self::$jsonFile)) {
			$this->check();
		}


		$content = json_decode(file_get_contents(self::$jsonFile),true);


		// if the requirement file exists but if doesn't have required info check requirements again and rewrite the fresh file
		if(!isset($content['exec']) || !isset($content['missing'])){
			$this->check();
		}

		// if the requirements file exists and if the requirements are false check again.
		if($content['exec']['success'] === false || $content['missing']['success'] === false){
			echo $content['exec']['msg']."<br/>".$content['missing']['msg'];
			$this->check();			
		}


	}

	public function optimize($file){

		$success = false;

		self::checkSystemRequirements();

		$file_path = $file;

		//check if File Exists
		if ( FALSE === file_exists($file_path) || FALSE === is_file($file_path) ) {
			$msg = sprintf("Could not find <span class='code'>%s</span>", $file_path);
			return array($success, $msg);
		}

		// check that the file is writable
        if ( FALSE === is_writable($file_path) ) {
            $msg = sprintf("<span class='code'>%s</span> is not writable", $file_path);
            return array($success, $msg);
        }

        if(function_exists('getimagesize')){
            $type = getimagesize($file_path);
            if(false !== $type){
                $type = $type['mime'];
            }
        }elseif(function_exists('mime_content_type')){
            $type = mime_content_type($file_path);
        }else{
            $type = 'Missing getimagesize() and mime_content_type() PHP functions';
        }

        switch($type){
            case 'image/jpeg':
                $command = 'opt-jpg';
                break;
            case 'image/png':
                $command = 'opt-png';
                break;
            case 'image/gif':
                $command = 'opt-gif';
                break;
            default:
                return array($success, 'Unknown type: ' . $type);
        }

        $result = exec($command . ' ' . escapeshellarg($file));

        $result = str_replace($file . ': ', '', $result);

        if($result == 'unchanged') {
            return array($success, 'No savings');
        }

        if(strpos($result, ' vs. ') !== false) {
            $s = explode(' vs. ', $result);

            $savings = intval($s[0]) - intval($s[1]);
            $savings_str = $this->cw_image_optimizer_format_bytes($savings, 1);
            $savings_str = str_replace(' ', '&nbsp;', $savings_str);

            $percent = 100 - (100 * ($s[1] / $s[0]));

            $results_msg = sprintf("Reduced by %01.1f%% (%s)",$percent,$savings_str);

            return array(true, $results_msg);
        }

        return array($success, 'Bad response from optimizer');
    }


    function cw_image_optimizer_format_bytes($bytes, $precision = 2) {
        $units = array('B', 'KB', 'MB', 'GB', 'TB');
        $bytes = max($bytes, 0);
        $pow = floor(($bytes ? log($bytes) : 0) / log(1024));
        $pow = min($pow, count($units) - 1);
        $bytes /= pow(1024, $pow);
        return round($bytes, $precision) . ' ' . $units[$pow];
    }




}
?>