class.ilQtiMatImageSecurity.php

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<?php
/* Copyright (c) 1998-2013 ILIAS open source, Extended GPL, see docs/LICENSE */

require_once 'Modules/TestQuestionPool/classes/class.assQuestion.php';
require_once 'Services/Utilities/classes/class.ilFileUtils.php';
require_once 'Services/QTI/exceptions/class.ilQtiException.php';

class ilQtiMatImageSecurity
{
        protected $imageMaterial;
        
        protected $detectedMimeType;
        
        public function __construct(ilQTIMatimage $imageMaterial)
        {
                $this->setImageMaterial($imageMaterial);
                
                if( !strlen($this->getImageMaterial()->getRawContent()) )
                {
                        throw new ilQtiException('cannot import image without content');
                }
                
                $this->setDetectedMimeType(
                        $this->determineMimeType($this->getImageMaterial()->getRawContent())
                );
        }
        
        public function getImageMaterial()
        {
                return $this->imageMaterial;
        }
        
        public function setImageMaterial($imageMaterial)
        {
                $this->imageMaterial = $imageMaterial;
        }
        
        protected function getDetectedMimeType()
        {
                return $this->detectedMimeType;
        }
        
        protected function setDetectedMimeType($detectedMimeType)
        {
                $this->detectedMimeType = $detectedMimeType;
        }
        
        public function validate()
        {
                if( !$this->validateLabel() )
                {
                        return false;
                }
                
                if( !$this->validateContent() )
                {
                        return false;
                }
                
                return true;
        }
        
        protected function validateContent()
        {
                if($this->getImageMaterial()->getImagetype() && !assQuestion::isAllowedImageMimeType($this->getImageMaterial()->getImagetype()) )
                {
                        return false;
                }

                if( !assQuestion::isAllowedImageMimeType($this->getDetectedMimeType()) )
                {
                        return false;
                }

                if ($this->getImageMaterial()->getImagetype())
                {
                        $declaredMimeType = assQuestion::fetchMimeTypeIdentifier($this->getImageMaterial()->getImagetype());
                        $detectedMimeType = assQuestion::fetchMimeTypeIdentifier($this->getDetectedMimeType());

                        if( $declaredMimeType != $detectedMimeType )
                        {
                                // since ilias exports jpeg declared pngs itself, we skip this validation ^^
                                // return false;
                                
                                /* @var ilComponentLogger $log */
                                $log = $GLOBALS['DIC'] ? $GLOBALS['DIC']['ilLog'] : $GLOBALS['ilLog'];
                                $log->log(
                                        'QPL: imported image with declared mime ('.$declaredMimeType.') '
                                        .'and detected mime ('.$detectedMimeType.')'
                                );
                        }
                }

                return true;
        }
        
        protected function validateLabel()
        {
                if ($this->getImageMaterial()->getUri())
                {
                        $extension = $this->determineFileExtension($this->getImageMaterial()->getUri());
                }
                else
                {
                        $extension = $this->determineFileExtension($this->getImageMaterial()->getLabel());
                }

                return assQuestion::isAllowedImageFileExtension($this->getDetectedMimeType(), $extension);
        }
        
        public function sanitizeLabel()
        {
                $label = $this->getImageMaterial()->getLabel();
                
                $label = basename($label);
                $label = ilUtil::stripSlashes($label);
                $label = ilUtil::getASCIIFilename($label);
                
                $this->getImageMaterial()->setLabel($label);
        }
        
        protected function determineMimeType($content)
        {
                return ilFileUtils::lookupContentMimeType($content);
        }
        
        protected function determineFileExtension($label)
        {
                list($dirname, $basename, $extension, $filename) = array_values( pathinfo($label) );
                return $extension;
        }
}