TemporaryJsonapiFileFieldUploader.php

<?php

namespace Drupal\jsonapi\Controller;

use Drupal\Component\Utility\Crypt;
use Drupal\Core\Config\ConfigFactoryInterface;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Field\FieldDefinitionInterface;
use Drupal\Core\File\Event\FileUploadSanitizeNameEvent;
use Drupal\Core\File\Exception\FileException;
use Drupal\Core\File\FileExists;
use Drupal\Core\File\FileSystemInterface;
use Drupal\Core\Lock\LockBackendInterface;
use Drupal\Core\Session\AccountInterface;
use Drupal\Core\Utility\Token;
use Drupal\file\Entity\File;
use Drupal\file\FileInterface;
use Drupal\file\Plugin\Field\FieldType\FileFieldItemList;
use Drupal\file\Upload\FileUploadLocationTrait;
use Drupal\file\Upload\InputStreamFileWriterInterface;
use Drupal\file\Validation\FileValidatorInterface;
use Drupal\file\Validation\FileValidatorSettingsTrait;
use Psr\Log\LoggerInterface;
use Symfony\Component\HttpFoundation\File\Exception\CannotWriteFileException;
use Symfony\Component\HttpFoundation\File\Exception\NoFileException;
use Symfony\Component\HttpFoundation\File\Exception\UploadException;
use Symfony\Component\HttpKernel\Exception\HttpException;
use Symfony\Contracts\EventDispatcher\EventDispatcherInterface;
use Symfony\Component\Mime\MimeTypeGuesserInterface;

/**
 * Reads data from an upload stream and creates a corresponding file entity.
 *
 * This is implemented at the field level for the following reasons:
 *   - Validation for uploaded files is tied to fields (allowed extensions, max
 *     size, etc..).
 *   - The actual files do not need to be stored in another temporary location,
 *     to be later moved when they are referenced from a file field.
 *   - Permission to upload a file can be determined by a user's field- and
 *     entity-level access.
 *
 * @internal This will be removed once https://www.drupal.org/project/drupal/issues/2940383 lands.
 */
class TemporaryJsonapiFileFieldUploader {
    use FileValidatorSettingsTrait;
    use FileUploadLocationTrait {
        getUploadLocation as getUploadDestination;
    }
    public function __construct(LoggerInterface $logger, FileSystemInterface $fileSystem, MimeTypeGuesserInterface $mimeTypeGuesser, Token $token, LockBackendInterface $lock, ConfigFactoryInterface $configFactory, EventDispatcherInterface $eventDispatcher, FileValidatorInterface $fileValidator, InputStreamFileWriterInterface $inputStreamFileWriter) {
    }
    
    /**
     * Creates and validates a file entity for a file field from a file stream.
     *
     * @param \Drupal\Core\Field\FieldDefinitionInterface $field_definition
     *   The field definition of the field for which the file is to be uploaded.
     * @param string $filename
     *   The name of the file.
     * @param \Drupal\Core\Session\AccountInterface $owner
     *   The owner of the file. Note, it is the responsibility of the caller to
     *   enforce access.
     *
     * @return \Drupal\file\FileInterface|\Drupal\Core\Entity\EntityConstraintViolationListInterface
     *   The newly uploaded file entity, or a list of validation constraint
     *   violations
     *
     * @throws \Symfony\Component\HttpKernel\Exception\HttpException
     *   Thrown when temporary files cannot be written, a lock cannot be acquired,
     *   or when temporary files cannot be moved to their new location.
     */
    public function handleFileUploadForField(FieldDefinitionInterface $field_definition, $filename, AccountInterface $owner) {
        assert(is_a($field_definition->getClass(), FileFieldItemList::class, TRUE));
        $settings = $field_definition->getSettings();
        $destination = $this->getUploadDestination($field_definition);
        // Check the destination file path is writable.
        if (!$this->fileSystem
            ->prepareDirectory($destination, FileSystemInterface::CREATE_DIRECTORY)) {
            throw new HttpException(500, 'Destination file path is not writable');
        }
        $validators = $this->getFileUploadValidators($field_definition->getSettings());
        $prepared_filename = $this->prepareFilename($filename, $validators);
        // Create the file.
        $file_uri = "{$destination}/{$prepared_filename}";
        if ($destination === $settings['uri_scheme'] . '://') {
            $file_uri = "{$destination}{$prepared_filename}";
        }
        $temp_file_path = $this->streamUploadData();
        $file_uri = $this->fileSystem
            ->getDestinationFilename($file_uri, FileExists::Rename);
        // Lock based on the prepared file URI.
        $lock_id = $this->generateLockIdFromFileUri($file_uri);
        if (!$this->lock
            ->acquire($lock_id)) {
            throw new HttpException(503, sprintf('File "%s" is already locked for writing.', $file_uri), NULL, [
                'Retry-After' => 1,
            ]);
        }
        // Begin building file entity.
        $file = File::create([]);
        $file->setOwnerId($owner->id());
        $file->setFilename($prepared_filename);
        $file->setMimeType($this->mimeTypeGuesser
            ->guessMimeType($prepared_filename));
        $file->setFileUri($temp_file_path);
        // Set the size. This is done in File::preSave() but we validate the file
        // before it is saved.
        $file->setSize(@filesize($temp_file_path));
        // Validate the file against field-level validators first while the file is
        // still a temporary file. Validation is split up in 2 steps to be the same
        // as in \Drupal\file\Upload\FileUploadHandler::handleFileUpload().
        // For backwards compatibility this part is copied from ::validate() to
        // leave that method behavior unchanged.
        // @todo Improve this with a file uploader service in
        //   https://www.drupal.org/project/drupal/issues/2940383
        $violations = $this->fileValidator
            ->validate($file, $validators);
        if (count($violations) > 0) {
            return $violations;
        }
        $file->setFileUri($file_uri);
        // Update the filename with any changes as a result of security or renaming
        // due to an existing file.
        // @todo Remove this duplication by replacing with FileUploadHandler. See
        // https://www.drupal.org/project/drupal/issues/3401734
        $file->setFilename($this->fileSystem
            ->basename($file->getFileUri()));
        // Move the file to the correct location after validation. Use
        // FileExists::Error as the file location has already been
        // determined above in FileSystem::getDestinationFilename().
        try {
            $this->fileSystem
                ->move($temp_file_path, $file_uri, FileExists::Error);
        } catch (FileException $e) {
            throw new HttpException(500, 'Temporary file could not be moved to file location');
        }
        // Second step of the validation on the file object itself now.
        $violations = $file->validate();
        // Remove violations of inaccessible fields as they cannot stem from our
        // changes.
        $violations->filterByFieldAccess();
        if ($violations->count() > 0) {
            return $violations;
        }
        $file->save();
        $this->lock
            ->release($lock_id);
        return $file;
    }
    
    /**
     * Checks if the current user has access to upload the file.
     *
     * @param \Drupal\Core\Session\AccountInterface $account
     *   The account for which file upload access should be checked.
     * @param \Drupal\Core\Field\FieldDefinitionInterface $field_definition
     *   The field definition for which to get validators.
     * @param \Drupal\Core\Entity\EntityInterface $entity
     *   (optional) The entity to which the file is to be uploaded, if it exists.
     *   If the entity does not exist and it is not given, create access to the
     *   entity the file is attached to will be checked.
     *
     * @return \Drupal\Core\Access\AccessResultInterface
     *   The file upload access result.
     */
    public static function checkFileUploadAccess(AccountInterface $account, FieldDefinitionInterface $field_definition, EntityInterface $entity = NULL) {
        assert(is_null($entity) || $field_definition->getTargetEntityTypeId() === $entity->getEntityTypeId() && (is_null($field_definition->getTargetBundle()) || $field_definition->getTargetBundle() === $entity->bundle()));
        $entity_type_manager = \Drupal::entityTypeManager();
        $entity_access_control_handler = $entity_type_manager->getAccessControlHandler($field_definition->getTargetEntityTypeId());
        $bundle = $entity_type_manager->getDefinition($field_definition->getTargetEntityTypeId())
            ->hasKey('bundle') ? $field_definition->getTargetBundle() : NULL;
        $entity_access_result = $entity ? $entity_access_control_handler->access($entity, 'update', $account, TRUE) : $entity_access_control_handler->createAccess($bundle, $account, [], TRUE);
        $field_access_result = $entity_access_control_handler->fieldAccess('edit', $field_definition, NULL, NULL, TRUE);
        return $entity_access_result->andIf($field_access_result);
    }
    
    /**
     * Streams file upload data to temporary file and moves to file destination.
     *
     * @return string
     *   The temp file path.
     *
     * @throws \Symfony\Component\HttpKernel\Exception\HttpException
     *   Thrown when input data cannot be read, the temporary file cannot be
     *   opened, or the temporary file cannot be written.
     */
    protected function streamUploadData() {
        // Catch and throw the exceptions that JSON API module expects.
        try {
            $temp_file_path = $this->inputStreamFileWriter
                ->writeStreamToFile();
        } catch (UploadException $e) {
            $this->logger
                ->error('Input data could not be read');
            throw new HttpException(500, 'Input file data could not be read', $e);
        } catch (CannotWriteFileException $e) {
            $this->logger
                ->error('Temporary file data for could not be written');
            throw new HttpException(500, 'Temporary file data could not be written', $e);
        } catch (NoFileException $e) {
            $this->logger
                ->error('Temporary file could not be opened for file upload');
            throw new HttpException(500, 'Temporary file could not be opened', $e);
        }
        return $temp_file_path;
    }
    
    /**
     * Validates the file.
     *
     * @todo this method is unused in this class because file validation needs to
     *   be split up in 2 steps in ::handleFileUploadForField(). Add a deprecation
     *   notice as soon as a central core file upload service can be used in this
     *   class. See https://www.drupal.org/project/drupal/issues/2940383
     *
     * @param \Drupal\file\FileInterface $file
     *   The file entity to validate.
     * @param array $validators
     *   An array of upload validators to pass to FileValidator.
     *
     * @return \Drupal\Core\Entity\EntityConstraintViolationListInterface
     *   The list of constraint violations, if any.
     */
    protected function validate(FileInterface $file, array $validators) {
        $violations = $file->validate();
        // Remove violations of inaccessible fields as they cannot stem from our
        // changes.
        $violations->filterByFieldAccess();
        // Validate the file based on the field definition configuration.
        $violations->addAll($this->fileValidator
            ->validate($file, $validators));
        return $violations;
    }
    
    /**
     * Prepares the filename to strip out any malicious extensions.
     *
     * @param string $filename
     *   The file name.
     * @param array $validators
     *   The array of upload validators.
     *
     * @return string
     *   The prepared/munged filename.
     */
    protected function prepareFilename($filename, array &$validators) {
        // The actual extension validation occurs in
        // \Drupal\jsonapi\Controller\TemporaryJsonapiFileFieldUploader::validate().
        $extensions = $validators['FileExtension']['extensions'] ?? '';
        $event = new FileUploadSanitizeNameEvent($filename, $extensions);
        $this->eventDispatcher
            ->dispatch($event);
        return $event->getFilename();
    }
    
    /**
     * Generates a lock ID based on the file URI.
     *
     * @param string $file_uri
     *   The file URI.
     *
     * @return string
     *   The generated lock ID.
     */
    protected static function generateLockIdFromFileUri($file_uri) {
        return 'file:jsonapi:' . Crypt::hashBase64($file_uri);
    }

}