LittleUtils.class.php

<?php
class LittleUtils{
 
    private static $systemRequirementsJsonFilePath;
 
    /**
     * Checks if system meets requirements
     * @return string If all the requirements are satisfied then it return  "Success" else "Error message" 
     */
    private function __checkSystemRequirements(){
 
        $result = array();
        
        //Get disabled php functions and check if "exec" command is disabled or not.
        $disabled = array_map('trim', explode(',', ini_get('disable_functions')));
        if(in_array('exec', $disabled)){
            $result['exec'] = array("success"=>false,"msg"=>"CW Image Optimizer requires exec(). Your system administrator has disabled this function.");
        }
        else{
            $result['exec'] = array("success"=>true,"msg"=>"");
        }
 
        //Check if required executable libraries are installed
        $missingLibraries = array();
        $requiredLibraries = array(
            'PNG' => 'opt-png',
            'JPG' => 'opt-jpg',
            'GIF' => 'opt-gif',
        );
        foreach($requiredLibraries as $imageType => $requiredLibrary){
            $res = trim(exec('which ' . $requiredLibrary));
            if(empty($res)){
                $missingLibraries[] = $requiredLibrary;
            }
        }
 
        $missingLibrariesString = implode(', ', $missingLibraries);
        if(!empty($missingLibrariesString)){
            $result['missing'] = array("success"=>false, "msg"=>"CW Image Optimizer requires http://sourceforge.net/projects/littleutils. You are missing: $missingLibrariesString.");
        }
        else{
            $result['missing'] = array("success"=>true,"msg"=>"All required libraries found");
        }
 
        if ( FALSE === is_writable(dirname(self::$systemRequirementsJsonFilePath)) ) {
            $result['file_write_perm'] = array("success"=> false, msg="Unable to write the requirements file ".self::$systemRequirementsJsonFilePath.". Please make sure the path is writable");
            //Utils::ErrorReportAndQuit(__LINE__, __FILE__, "Unable to write the requirements file ".self::$systemRequirementsJsonFilePath.". Please make sure the path is writable");
        }
        else{
            $result['file_write_perm'] = array("success"=> true, msg="");
        }
 
        $fHandle = file_put_contents(self::$systemRequirementsJsonFilePath,json_encode($result));
        if($fHandle)
            $result['file_write'] = array("success"=> true, msg="");
        else
            $result['file_write'] = array("success"=> false, msg="Unable to Write contents to ".self::$systemRequirementsJsonFilePath.". Please make sure the path is writable");
    
        foreach($result as $key=>$value){
            if(!$value['success']){
                return $value['msg'];
            }
        }
        return "Success";
    }
 
 
    /**
     * Checks if file already exists and if system requirements were already met or we should do a check
     */
    private function checkSystemRequirements(){
 
        // If requirements file doesn't exists check the requirements and write to file
        if ( FALSE === file_exists(self::$systemRequirementsJsonFilePath) || FALSE === is_file(self::$systemRequirementsJsonFilePath)) {
            return $this->__checkSystemRequirements() === "Success"?true:false; // Check the System Requirements and 
        }
        // File Exists
        //Read the file
        $content = json_decode(file_get_contents(self::$systemRequirementsJsonFilePath),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'])){
            return $this->__checkSystemRequirements() === "Success"?true:false;
        }
 
        // 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'];
 
            //***********TODO: this function is not well coded. What happens if the code reaches this point? ********
             
            // There is no additional check done. If the check fails again, the code will continue running.
            // here is the content is false that means the Little utils or php doesn't have required functions to continue,
            // so recursive checks are not needed, install the functions and packages then run the code again that should fix this
         
            return $this->__checkSystemRequirements() === "Success"?true:false;
        }
        // Passed all hurdles then it seems everything is passed, continue.
        return true;
 
 
    }
 
    public static function verifyFileNameElseQuit($fileName){
        // Changed to if not  << if file name has a-z and 1-2 it matches so this function always throws error for valid
        // file names, so changed to if not 
        if(!preg_match('/[^a-zA-Z0-9\-]+/',$fileName,$matches)){
            Utils::ErrorReportAndQuit(__LINE__, __FILE__, "Filename to save images contains invalid characters. Only alpha-numeric and dash are allowed: ". $fileName);
        }
    }
 
    /**
     * Optimizes an image given filepath. Works for gif, jpeg, and png
     * @param string $fileName
     * @return array
     */
    public function optimize($fileName){
 
        //Verify if filename doesn't have invalid characters, else quit
        $this->verifyFileNameElseQuit($fileName);
 
        $thisFolder =   dirname(__FILE__).DIRECTORY_SEPARATOR;
        self::$systemRequirementsJsonFilePath = $thisFolder.'check.json';
        if(!self::checkSystemRequirements())
             return false;
 
 
        //Force file path to be inside the cache folder
        $filePath = $thisFolder. "cache". DIRECTORY_SEPARATOR. $fileName;
 
        //Check if File Exists
        if ( FALSE === file_exists($filePath) || FALSE === is_file($filePath) ) {
            $msg = sprintf("Could not find %s", $filePath);
            return array("success"=>false, "message"=> $msg, "savings"=> NULL);
        }
 
        //Check that the file is writable
        if ( FALSE === is_writable($filePath) ) {
            $msg = sprintf("%s is not writable", $filePath);
            return array("success"=>false, "message"=> $msg, "savings"=> NULL);
        }
 
        if(function_exists('getimagesize')){
            $type = getimagesize($filePath);
            if(false !== $type){
                $type = $type['mime'];
            }
        }elseif(function_exists('mime_content_type')){
            $type = mime_content_type($filePath);
        }else{
            return array("success"=>false, "message"=> 'Missing getimagesize() and mime_content_type() PHP functions', "savings"=> NULL);
        }
 
        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"=>false, "message"=> 'Unknown type: ' . $type, "savings"=> NULL);
        }
 
        $result = exec($command . ' ' . escapeshellarg($filePath));
 
        $result = str_replace($filePath . ': ', '', $result);
 
        if($result == 'unchanged') {
            return array("success"=>true, "message"=> 'No savings', "savings"=>0);
        }
 
        if(strpos($result, ' vs. ') !== false) {
            $s = explode(' vs. ', $result);
 
            $savings = intval($s[0]) - intval($s[1]);
            $savingsString = $this->getBytesInHumanFriendlyFormat($savings, 1);
            $savingsString = str_replace(' ', '&nbsp;', $savingsString);
 
            $percent = 100 - (100 * ($s[1] / $s[0]));
 
            $resultMessage = sprintf("Reduced by %01.1f%% (%s)",$percent,$savingsString);
 
            return array("success"=>true, "message"=> $resultMessage, "savings"=>$percent);
 
        }
 
        return array("success"=>false, "message"=> 'Bad response from optimizer', "savings"=> NULL);
    }
 
    /**
     * Returns a string with a human friendly reading of bytes
     * @param int $bytes
     * @param int $precision
     * @return string
     */
    private function getBytesInHumanFriendlyFormat($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];
    }
}

    1  cd /usr/local/src/
    2  sudo wget http://downloads.sourceforge.net/project/littleutils/littleutils-source/1.0.27/littleutils-1.0.27.tar.bz2
    3  sudo tar jxvf littleutils-1.0.27.tar.bz2 && cd littleutils-1.0.27
    4  sudo ./configure --prefix=/usr
    5  sudo apt-get install python-software-properties
    6  sudo add-apt-repository ppa:ondrej/php
    7  sudo apt-get update
    8  sudo apt-get install -y php5.6 php5.6-common php5.6-gd
   

#Copy the above file

usage

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

a.gif will be image path