previewmanager.php

<?php
 
namespace Bitrix\Main\UI\Viewer;
 
use Bitrix\Main\Application;
use Bitrix\Main;
use Bitrix\Main\Context;
use Bitrix\Main\Event;
use Bitrix\Main\EventResult;
use Bitrix\Main\HttpRequest;
use Bitrix\Main\Loader;
use Bitrix\Main\SystemException;
use Bitrix\Main\Type\DateTime;
use Bitrix\Main\UI\Viewer\Transformation\TransformerManager;
use Bitrix\Main\Web\MimeType;
use Bitrix\Main\Web\Uri;
use Bitrix\Main\Security;
use Bitrix\Main\Engine\Response;
 
final class PreviewManager
{
    public const GET_KEY_TO_SEND_PREVIEW_CONTENT    = 'ibxPreview';
    public const GET_KEY_TO_SHOW_IMAGE              = 'ibxShowImage';
    public const HEADER_TO_SEND_PREVIEW             = 'BX-Viewer';
    public const HEADER_TO_RESIZE_IMAGE             = 'BX-Viewer-image';
    public const HEADER_TO_GET_SOURCE               = 'BX-Viewer-src';
    public const HEADER_TO_RUN_FORCE_TRANSFORMATION = 'BX-Viewer-force-transformation';
    public const HEADER_TO_CHECK_TRANSFORMATION     = 'BX-Viewer-check-transformation';
 
    private const SALT_FILE_ID = 'previewfile';
 
    private ?TransformerManager $transformer;
    private array $rendererList = [];
    private static bool $disableCatchingViewByUser = false;
 
    private $httpRequest;
 
    public function __construct(HttpRequest $httpRequest = null)
    {
        $this->httpRequest = $httpRequest? : Context::getCurrent()->getRequest();
        $this->transformer = $this->buildTransformer();
        $this->buildViewRendererList();
    }
 
    private function buildTransformer(): ?TransformerManager
    {
        if (!Loader::includeModule('transformer'))
        {
            return null;
        }
 
        return new TransformerManager();
    }
 
    private function buildViewRendererList(): void
    {
        $default = [
            Renderer\Pdf::class,
            Renderer\Video::class,
            Renderer\Audio::class,
            Renderer\Image::class,
            Renderer\Code::class,
        ];
 
        $event = new Event('main', 'onPreviewRendererBuildList');
        $event->send();
 
        $additionalList = [];
        foreach ($event->getResults() as $result)
        {
            if ($result->getType() != EventResult::SUCCESS)
            {
                continue;
            }
            $result = $result->getParameters();
            if (!\is_array($result))
            {
                throw new SystemException('Wrong event result. Must be array.');
            }
 
            foreach ($result as $class)
            {
                if (!\is_string($class) || !class_exists($class))
                {
                    throw new SystemException('Wrong event result. There is not a class.');
                }
 
                if (!is_subclass_of($class, Renderer\Renderer::class, true))
                {
                    throw new SystemException("Wrong event result. {$class} is not a subclass of " . Renderer\Renderer::class);
                }
 
                $additionalList[] = $class;
            }
        }
 
        $this->rendererList = array_merge($additionalList, $default);
    }
 
    public static function disableCatchingViewByUser(): void
    {
        self::$disableCatchingViewByUser = true;
    }
 
    public static function enableCatchingViewByUser(): void
    {
        self::$disableCatchingViewByUser = false;
    }
 
    public static function isDisabledCatchingViewByUser(): bool
    {
         return self::$disableCatchingViewByUser;
    }
 
    public function isInternalRequest($file, $options): bool
    {
        if (self::isDisabledCatchingViewByUser())
        {
            return false;
        }
 
        if (!\is_array($file) || empty($file['ID']))
        {
            return false;
        }
 
        if (!empty($options['prevent_work_with_preview']))
        {
            return false;
        }
 
        if ($this->httpRequest->get(self::GET_KEY_TO_SEND_PREVIEW_CONTENT))
        {
            return true;
        }
 
        if ($this->httpRequest->get(self::GET_KEY_TO_SHOW_IMAGE))
        {
            return true;
        }
 
        if ($this->httpRequest->getHeader(self::HEADER_TO_SEND_PREVIEW))
        {
            return true;
        }
 
        if ($this->httpRequest->getHeader(self::HEADER_TO_RUN_FORCE_TRANSFORMATION))
        {
            return true;
        }
 
        if ($this->httpRequest->getHeader(self::HEADER_TO_CHECK_TRANSFORMATION))
        {
            return true;
        }
 
        if ($this->httpRequest->getHeader(self::HEADER_TO_RESIZE_IMAGE))
        {
            return true;
        }
 
        return false;
    }
 
    public function processViewByUserRequest($file, $options): void
    {
        self::disableCatchingViewByUser();
 
        $response = null;
        if ($this->httpRequest->get(self::GET_KEY_TO_SEND_PREVIEW_CONTENT))
        {
            $response = $this->sendPreviewContent($file, $options);
        }
        elseif ($this->httpRequest->get(self::GET_KEY_TO_SHOW_IMAGE))
        {
            $this->showImage($file, $options);
        }
        elseif ($this->httpRequest->getHeader(self::HEADER_TO_RUN_FORCE_TRANSFORMATION))
        {
            $response = $this->sendPreview($file, true);
        }
        elseif ($this->httpRequest->getHeader(self::HEADER_TO_CHECK_TRANSFORMATION))
        {
            $response = $this->checkTransformation($file);
        }
        elseif ($this->httpRequest->getHeader(self::HEADER_TO_SEND_PREVIEW))
        {
            $response = $this->sendPreview($file);
        }
        elseif ($this->httpRequest->getHeader(self::HEADER_TO_RESIZE_IMAGE))
        {
            $response = $this->sendResizedImage($file);
        }
 
        if (($response instanceof Response\BFile) && isset($options['cache_time']))
        {
            $response->setCacheTime($options['cache_time']);
        }
 
        if ($response instanceof Main\Response)
        {
            global $APPLICATION;
 
            $APPLICATION->RestartBuffer();
 
            Application::getInstance()->end(0, $response);
        }
    }
 
    protected function sendPreviewContent($file, $options): ?Response\BFile
    {
        $possiblePreviewFileId = $this->unsignFileId($this->httpRequest->get(self::GET_KEY_TO_SEND_PREVIEW_CONTENT));
        $filePreview = $this->getFilePreviewEntryByFileId($file['ID']);
        if (!$filePreview || empty($filePreview['PREVIEW_ID']) || $filePreview['PREVIEW_ID'] != $possiblePreviewFileId)
        {
            return null;
        }
 
        FilePreviewTable::update($filePreview['ID'], [
            'TOUCHED_AT' => new DateTime(),
        ]);
 
        //get name for preview file
        return Response\BFile::createByFileId(
            $filePreview['PREVIEW_ID'],
            $file['ORIGINAL_NAME']
        );
    }
 
    protected function showImage($file, $options): void
    {
        if (!\is_array($options))
        {
            $options = [];
        }
        $options['force_download'] = false;
        $options['prevent_work_with_preview'] = true;
        \CFile::viewByUser($file, $options);
    }
 
    protected function sendResizedImage($file): ?Response\ResizedImage
    {
        $fileView = $this->getByImage($file['ID'], $this->getSourceUri());
 
        return $fileView?->render();
    }
 
    protected function prepareRenderParameters($file): array
    {
        $getContentType = function() use ($file){
            $filePreviewData = $this->getViewFileData($file);
            if (!$filePreviewData)
            {
                return null;
            }
 
            return $filePreviewData['CONTENT_TYPE'];
        };
 
        $getSourceUri = function() use ($file){
            $filePreviewData = $this->getViewFileData($file);
            if (!$filePreviewData)
            {
                return null;
            }
 
            return $this->getSourceUri()->addParams([
                self::GET_KEY_TO_SEND_PREVIEW_CONTENT => $this->signFileId($filePreviewData['ID']),
            ]);
        };
 
        return [
            'alt' => [
                'contentType' => $getContentType->bindTo($this, $this),
                'sourceUri' => $getSourceUri->bindTo($this, $this),
            ],
        ];
    }
 
    protected function checkTransformation($file): Response\AjaxJson
    {
        return new Response\AjaxJson([
            'transformation' => (bool)$this->getViewFileData($file),
        ]);
    }
 
    protected function sendPreview($file, bool $forceTransformation = false): Response\AjaxJson
    {
        $render = $this->buildRenderByFile(
            $file['ORIGINAL_NAME'],
            $file['CONTENT_TYPE'],
            $this->getSourceUri(),
            $this->prepareRenderParameters($file)
        );
        if ($render instanceof Renderer\Stub || $forceTransformation)
        {
            $filePreviewData = $this->getViewFileData($file);
            if ($filePreviewData)
            {
                $sourceUri = $this->getSourceUri()->addParams([
                    self::GET_KEY_TO_SEND_PREVIEW_CONTENT => $this->signFileId($filePreviewData['ID']),
                ]);
 
                $render = $this->buildRenderByFile(
                    $filePreviewData['ORIGINAL_NAME'],
                    $filePreviewData['CONTENT_TYPE'],
                    $sourceUri
                );
            }
            else
            {
                $generatePreview = $this->generatePreview($file['ID']);
                if ($generatePreview instanceof Main\Result)
                {
                    if ($generatePreview->isSuccess())
                    {
                        return Response\AjaxJson::createSuccess($generatePreview->getData());
                    }
 
                    return Response\AjaxJson::createError($generatePreview->getErrorCollection());
                }
 
                return Response\AjaxJson::createError();
            }
        }
 
        if ($render)
        {
            return Response\AjaxJson::createSuccess([
                'html' => $render->render(),
                'data' => $render->getData(),
            ]);
        }
 
        return Response\AjaxJson::createError();
    }
 
    public function attachPreviewToFileId(int $fileId, ?int $previewId, ?int $previewImageId): Main\ORM\Data\Result
    {
        $updatedFields = array_filter([
            'PREVIEW_IMAGE_ID' => $previewImageId,
            'PREVIEW_ID' => $previewId,
        ]);
 
        if (empty($updatedFields))
        {
            return new Main\ORM\Data\Result();
        }
 
        $alreadyPreview = $this->getFilePreviewEntryByFileId($fileId);
        if (isset($alreadyPreview['ID']))
        {
            $result = FilePreviewTable::update($alreadyPreview['ID'], $updatedFields);
        }
        else
        {
            $addedFields = $updatedFields;
            $addedFields['FILE_ID'] = $fileId;
 
            $result = FilePreviewTable::add($addedFields);
        }
 
        return $result;
    }
 
    public function setPreviewImageId(int $fileId, int $previewImageId): Main\ORM\Data\Result
    {
        return $this->attachPreviewToFileId($fileId, null, $previewImageId);
    }
 
    public function generatePreview($fileId): ?Main\Result
    {
        if (!$this->transformer)
        {
            return null;
        }
 
        //todo return status (OK, WAIT, ERROR) or some result.
 
        return $this->transformer->transform($fileId);
    }
 
    protected function getSourceUri(): Uri
    {
        $sourceSrc = $this->httpRequest->getHeader(self::HEADER_TO_GET_SOURCE);
        if (!$sourceSrc)
        {
            $sourceSrc = $this->httpRequest->getRequestUri();
        }
 
        return new Uri($sourceSrc);
    }
 
    protected function signFileId($fileId): string
    {
        $signer = new Security\Sign\Signer();
 
        return $signer->sign(
            base64_encode(serialize($fileId)),
            self::SALT_FILE_ID
        );
    }
 
    protected function unsignFileId($signedString)
    {
        $signer = new Security\Sign\Signer();
 
        $unsignedParameters = $signer->unsign(
            $signedString,
            self::SALT_FILE_ID
        );
 
        return unserialize(base64_decode($unsignedParameters), ['allowed_classes' => false]);
    }
 
    public function getByImage($fileId, Uri $sourceUri): ?Renderer\Image
    {
        $fileData = $this->getFileData($fileId);
        if (!$fileData)
        {
            return null;
        }
 
        $renderer = $this->buildRenderByFile(
            $fileData['ORIGINAL_NAME'],
            $fileData['CONTENT_TYPE'],
            $sourceUri,
            [
                'originalImage' => $fileData,
            ]
        );
        if (!($renderer instanceof Renderer\Image))
        {
            return null;
        }
 
        return $renderer;
    }
 
    protected function getViewFileData(array $fileData)
    {
        static $cache = [];
 
        if (empty($fileData['ID']))
        {
            return null;
        }
 
        if (isset($cache[$fileData['ID']]) || \array_key_exists($fileData['ID'], $cache))
        {
            return $cache[$fileData['ID']];
        }
 
        $filePreview = $this->getFilePreviewEntryByFileId($fileData['ID']);
        if (!$filePreview || empty($filePreview['PREVIEW_ID']))
        {
            $cache[$fileData['ID']] = null;
 
            return null;
        }
 
        $cache[$fileData['ID']] = $this->getFileData($filePreview['PREVIEW_ID']);
 
        return $cache[$fileData['ID']];
    }
 
    public function getFilePreviewEntryByFileId(int $fileId): ?array
    {
        $row = FilePreviewTable::getList([
            'filter' => [
                '=FILE_ID' => $fileId,
            ],
            'limit' => 1,
        ])->fetch();
 
        return $row ?: null;
    }
 
    protected function buildRenderByFile($originalName, $contentType, Uri $sourceUri, array $options = [])
    {
        $options['contentType'] = $contentType;
        $rendererClass = $this->getRenderClassByFile([
            'contentType' => $contentType,
            'originalName' => $originalName,
        ]);
 
        $reflectionClass = new \ReflectionClass($rendererClass);
        return $reflectionClass->newInstance($originalName, $sourceUri, $options);
    }
 
    public function getRenderClassByFile(array $file): string
    {
        $contentType = $file['contentType'];
        $originalName = $file['originalName'];
        $rendererClass = $this->findRenderClassByContentType($contentType);
        if (!$rendererClass)
        {
            $contentTypeByName = MimeType::getByFilename($originalName);
            $rendererClass = $this->findRenderClassByContentType($contentTypeByName);
        }
 
        $rendererClass = $rendererClass? : Renderer\Stub::class;
 
        if ($this->shouldRestrictBySize($file, $rendererClass))
        {
            return Renderer\RestrictedBySize::class;
        }
 
        return $rendererClass;
    }
 
    private function shouldRestrictBySize(array $file, $rendererClass): bool
    {
        if (!isset($file['size']))
        {
            return false;
        }
 
        $size = $file['size'];
        $restriction = $rendererClass::getSizeRestriction();
        if ($restriction !== null && $size > $restriction)
        {
            return true;
        }
 
        return false;
    }
 
    private function findRenderClassByContentType($contentType)
    {
        foreach ($this->rendererList as $rendererClass)
        {
            if (\in_array($contentType, $rendererClass::getAllowedContentTypes(), true))
            {
                return $rendererClass;
            }
        }
 
        return null;
    }
 
    protected function getFileData(int $fileId, bool $cacheCleaned = false): ?array
    {
        $fileData = \CFile::GetFileArray($fileId);
        if ($fileData === false && !$cacheCleaned)
        {
            global $DB;
            $strSql = "SELECT ID FROM b_file WHERE ID={$fileId}";
            $dbResult = $DB->Query($strSql);
            if ($dbResult->Fetch())
            {
                \CFile::CleanCache($fileId);
 
                return $this->getFileData($fileId, true);
            }
        }
 
        return $fileData ?: null;
    }
}