*Use Kraken.IO with TYPO3* - This post-processes every image generated by the frontend and stored in /_processed_/ regardless of the used StorageDriver - however, if the image could not be processed by Kraken.IO the processed image will remain untouched

ext_localconf.php

/** @var \TYPO3\CMS\Extbase\SignalSlot\Dispatcher $signalSlotDispatcher */
$signalSlotDispatcher = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\TYPO3\CMS\Extbase\SignalSlot\Dispatcher::class);
$signalSlotDispatcher->connect(
    \TYPO3\CMS\Core\Resource\ResourceStorage::class,
    \TYPO3\CMS\Core\Resource\Service\FileProcessingService::SIGNAL_PostFileProcess,
    \Dnp\DnpPlugins\ImageProcessing\KrakenIoPostProcessor::class,
    'process'
);

KrakenIoPostProcessor.php

<?php

namespace Dnp\DnpPlugins\ImageProcessing;

use TYPO3\CMS\Core\Http\RequestFactory;
use TYPO3\CMS\Core\Log\LogManager;
use TYPO3\CMS\Core\Resource;
use TYPO3\CMS\Core\Resource\Processing\ImageCropScaleMaskTask;
use TYPO3\CMS\Core\Utility\GeneralUtility;

/**
 * This post-processor slots in the FileProcessingService and optimizes the image generated by ImageMagick
 * with the Kraken.IO API right after a new /_processed_/* file is generated by TYPO3.
 *
 * @author Michael Feinbier <[email protected]>
 **/
class KrakenIoPostProcessor
{

    /**
     * @var \TYPO3\CMS\Core\Log\Logger
     */
    protected $logger;

    /**
     * @var RequestFactory
     */
    protected $requestFactory;

    /**
     * @var \Kraken
     */
    protected $krakenApi;

    public function __construct()
    {
        /** @var $logManager LogManager */
        $logManager = GeneralUtility::makeInstance(LogManager::class);
        $this->logger = $logManager->getLogger(__CLASS__);
        $this->requestFactory = GeneralUtility::makeInstance(RequestFactory::class);
        // Load API Credentials from Extension Configuration
        $apiCredentials = unserialize($GLOBALS['TYPO3_CONF_VARS']['EXT']['extConf']['dnp_plugins']);
        $this->krakenApi = GeneralUtility::makeInstance(\Kraken::class, $apiCredentials['apiKey'], $apiCredentials['apiSecret']);
    }

    /**
     * Post Process the image after the ImageCropScaleMaskTask generated a new image
     *
     * @param Resource\Service\FileProcessingService $fileProcessingService
     * @param Resource\Driver\DriverInterface        $driver
     * @param Resource\ProcessedFile                 $processedFile
     * @param Resource\FileInterface                 $fileObject
     * @param string                                 $taskType
     * @param array                                  $configuration
     */
    public function process(
        Resource\Service\FileProcessingService $fileProcessingService,
        Resource\Driver\DriverInterface $driver,
        Resource\ProcessedFile $processedFile,
        Resource\FileInterface $fileObject,
        $taskType,
        $configuration
    ) {
        // for now - we only process ImageCropScaleMaskTask
        $task = $processedFile->getTask();
        if (!$task instanceof ImageCropScaleMaskTask) {
            return;
        }

        // when a new image was generated, fetch a new updated image
        if ($task->isExecuted() && $task->isSuccessful() && $processedFile->isProcessed()) {
            $url = $this->getOptimizedImage($task->getTargetFile());
            if ($url) {
                $this->saveOptimizedFile($url, $processedFile);
                $task->setExecuted(true);
            }
        }
    }

    /**
     * @param Resource\FileInterface $file
     *
     * @return string|bool
     */
    protected function getOptimizedImage(Resource\FileInterface $file)
    {
        // @TODO maybe use $api->url() together with $file->getPublicUrl()
        $result = $this->krakenApi->upload([
            'lossy' => true,
            'wait' => true,
            'dev'  => false,
            'file' => $file->getForLocalProcessing(false),
        ]);
        if ($result['success']) {
            $this->logger->debug('kraken compress successful', $result);

            return $result['kraked_url'];
        }

        $this->logger->error('kraken error', $result);

        return false;
    }

    /**
     * @param string                 $url
     * @param Resource\ProcessedFile $targetFile
     */
    protected function saveOptimizedFile($url, Resource\ProcessedFile $targetFile)
    {
        $tempFile = GeneralUtility::tempnam('kraken');
        $this->requestFactory->request($url, 'GET', [
            'sink' => $tempFile,
        ]);

        $targetFile->updateWithLocalFile($tempFile);
        unlink($tempFile);
    }
}