class TemporaryJsonapiFileFieldUploader in Drupal 8

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.

Hierarchy

• class \Drupal\jsonapi\Controller\TemporaryJsonapiFileFieldUploader

1 string reference to 'TemporaryJsonapiFileFieldUploader'

jsonapi.services.yml in core/modules/jsonapi/jsonapi.services.yml

core/modules/jsonapi/jsonapi.services.yml

1 service uses TemporaryJsonapiFileFieldUploader

jsonapi.file.uploader.field in core/modules/jsonapi/jsonapi.services.yml

Drupal\jsonapi\Controller\TemporaryJsonapiFileFieldUploader

File

core/modules/jsonapi/src/Controller/TemporaryJsonapiFileFieldUploader.php, line 43

Namespace

Drupal\jsonapi\Controller

class TemporaryJsonapiFileFieldUploader {

  /**
   * The regex used to extract the filename from the content disposition header.
   *
   * @var string
   */
  const REQUEST_HEADER_FILENAME_REGEX = '@\\bfilename(?<star>\\*?)=\\"(?<filename>.+)\\"@';

  /**
   * The amount of bytes to read in each iteration when streaming file data.
   *
   * @var int
   */
  const BYTES_TO_READ = 8192;

  /**
   * A logger instance.
   *
   * @var \Psr\Log\LoggerInterface
   */
  protected $logger;

  /**
   * The file system service.
   *
   * @var \Drupal\Core\File\FileSystemInterface
   */
  protected $fileSystem;

  /**
   * The MIME type guesser.
   *
   * @var \Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface
   */
  protected $mimeTypeGuesser;

  /**
   * The token replacement instance.
   *
   * @var \Drupal\Core\Utility\Token
   */
  protected $token;

  /**
   * The lock service.
   *
   * @var \Drupal\Core\Lock\LockBackendInterface
   */
  protected $lock;

  /**
   * System file configuration.
   *
   * @var \Drupal\Core\Config\ImmutableConfig
   */
  protected $systemFileConfig;

  /**
   * Constructs a FileUploadResource instance.
   *
   * @param \Psr\Log\LoggerInterface $logger
   *   A logger instance.
   * @param \Drupal\Core\File\FileSystemInterface $file_system
   *   The file system service.
   * @param \Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface $mime_type_guesser
   *   The MIME type guesser.
   * @param \Drupal\Core\Utility\Token $token
   *   The token replacement instance.
   * @param \Drupal\Core\Lock\LockBackendInterface $lock
   *   The lock service.
   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
   *   The config factory.
   */
  public function __construct(LoggerInterface $logger, FileSystemInterface $file_system, MimeTypeGuesserInterface $mime_type_guesser, Token $token, LockBackendInterface $lock, ConfigFactoryInterface $config_factory) {
    $this->logger = $logger;
    $this->fileSystem = $file_system;
    $this->mimeTypeGuesser = $mime_type_guesser;
    $this->token = $token;
    $this->lock = $lock;
    $this->systemFileConfig = $config_factory
      ->get('system.file');
  }

  /**
   * 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));
    $destination = $this
      ->getUploadLocation($field_definition
      ->getSettings());

    // 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 = $this
      ->getUploadValidators($field_definition);
    $prepared_filename = $this
      ->prepareFilename($filename, $validators);

    // Create the file.
    $file_uri = "{$destination}/{$prepared_filename}";
    $temp_file_path = $this
      ->streamUploadData();
    $file_uri = $this->fileSystem
      ->getDestinationFilename($file_uri, FileSystemInterface::EXISTS_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.'), NULL, [
        'Retry-After' => 1,
      ]);
    }

    // Begin building file entity.
    $file = File::create([]);
    $file
      ->setOwnerId($owner
      ->id());
    $file
      ->setFilename($prepared_filename);
    $file
      ->setMimeType($this->mimeTypeGuesser
      ->guess($prepared_filename));
    $file
      ->setFileUri($file_uri);

    // 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 entity against entity-level validation and field-level
    // validators.
    $violations = $this
      ->validate($file, $validators);
    if ($violations
      ->count() > 0) {
      return $violations;
    }

    // Move the file to the correct location after validation. Use
    // FileSystemInterface::EXISTS_ERROR as the file location has already been
    // determined above in FileSystem::getDestinationFilename().
    try {
      $this->fileSystem
        ->move($temp_file_path, $file_uri, FileSystemInterface::EXISTS_ERROR);
    } catch (FileException $e) {
      throw new HttpException(500, 'Temporary file could not be moved to file location');
    }
    $file
      ->save();
    $this->lock
      ->release($lock_id);
    return $file;
  }

  /**
   * Validates and extracts the filename from the Content-Disposition header.
   *
   * @param \Symfony\Component\HttpFoundation\Request $request
   *   The request object.
   *
   * @return string
   *   The filename extracted from the header.
   *
   * @throws \Symfony\Component\HttpKernel\Exception\BadRequestHttpException
   *   Thrown when the 'Content-Disposition' request header is invalid.
   */
  public function validateAndParseContentDispositionHeader(Request $request) {

    // First, check the header exists.
    if (!$request->headers
      ->has('content-disposition')) {
      throw new BadRequestHttpException('"Content-Disposition" header is required. A file name in the format "filename=FILENAME" must be provided.');
    }
    $content_disposition = $request->headers
      ->get('content-disposition');

    // Parse the header value. This regex does not allow an empty filename.
    // i.e. 'filename=""'. This also matches on a word boundary so other keys
    // like 'not_a_filename' don't work.
    if (!preg_match(static::REQUEST_HEADER_FILENAME_REGEX, $content_disposition, $matches)) {
      throw new BadRequestHttpException('No filename found in "Content-Disposition" header. A file name in the format "filename=FILENAME" must be provided.');
    }

    // Check for the "filename*" format. This is currently unsupported.
    if (!empty($matches['star'])) {
      throw new BadRequestHttpException('The extended "filename*" format is currently not supported in the "Content-Disposition" header.');
    }

    // Don't validate the actual filename here, that will be done by the upload
    // validators in validate().
    // @see \Drupal\file\Plugin\rest\resource\FileUploadResource::validate()
    $filename = $matches['filename'];

    // Make sure only the filename component is returned. Path information is
    // stripped as per https://tools.ietf.org/html/rfc6266#section-4.3.
    return $this->fileSystem
      ->basename($filename);
  }

  /**
   * 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
   *   file 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() && $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() {

    // 'rb' is needed so reading works correctly on Windows environments too.
    $file_data = fopen('php://input', 'rb');
    $temp_file_path = $this->fileSystem
      ->tempnam('temporary://', 'file');
    if ($temp_file_path === FALSE) {
      $this->logger
        ->error('Temporary file could not be created for file upload.');
      throw new HttpException(500, 'Temporary file could not be created');
    }
    $temp_file = fopen($temp_file_path, 'wb');
    if ($temp_file) {
      while (!feof($file_data)) {
        $read = fread($file_data, static::BYTES_TO_READ);
        if ($read === FALSE) {

          // Close the file streams.
          fclose($temp_file);
          fclose($file_data);
          $this->logger
            ->error('Input data could not be read');
          throw new HttpException(500, 'Input file data could not be read.');
        }
        if (fwrite($temp_file, $read) === FALSE) {

          // Close the file streams.
          fclose($temp_file);
          fclose($file_data);
          $this->logger
            ->error('Temporary file data for "%path" could not be written', [
            '%path' => $temp_file_path,
          ]);
          throw new HttpException(500, 'Temporary file data could not be written.');
        }
      }

      // Close the temp file stream.
      fclose($temp_file);
    }
    else {

      // Close the input file stream since we can't proceed with the upload.
      // Don't try to close $temp_file since it's FALSE at this point.
      fclose($file_data);
      $this->logger
        ->error('Temporary file "%path" could not be opened for file upload.', [
        '%path' => $temp_file_path,
      ]);
      throw new HttpException(500, 'Temporary file could not be opened');
    }

    // Close the input stream.
    fclose($file_data);
    return $temp_file_path;
  }

  /**
   * Validates the file.
   *
   * @param \Drupal\file\FileInterface $file
   *   The file entity to validate.
   * @param array $validators
   *   An array of upload validators to pass to file_validate().
   *
   * @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.
    $errors = file_validate($file, $validators);
    if (!empty($errors)) {
      $translator = new DrupalTranslator();
      foreach ($errors as $error) {
        $violation = new ConstraintViolation($translator
          ->trans($error), $error, [], EntityAdapter::createFromEntity($file), '', NULL);
        $violations
          ->add($violation);
      }
    }
    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) {

    //  Don't rename if 'allow_insecure_uploads' evaluates to TRUE.
    if (!$this->systemFileConfig
      ->get('allow_insecure_uploads')) {
      if (!empty($validators['file_validate_extensions'][0])) {

        // If there is a file_validate_extensions validator and a list of
        // valid extensions, munge the filename to protect against possible
        // malicious extension hiding within an unknown file type. For example,
        // "filename.html.foo".
        $filename = file_munge_filename($filename, $validators['file_validate_extensions'][0]);
      }

      // Rename potentially executable files, to help prevent exploits (i.e.
      // will rename filename.php.foo and filename.php to filename._php._foo.txt
      // and filename._php.txt, respectively).
      if (preg_match(FILE_INSECURE_EXTENSION_REGEX, $filename)) {

        // If the file will be rejected anyway due to a disallowed extension, it
        // should not be renamed; rather, we'll let file_validate_extensions()
        // reject it below.
        $passes_validation = FALSE;
        if (!empty($validators['file_validate_extensions'][0])) {
          $file = File::create([]);
          $file
            ->setFilename($filename);
          $passes_validation = empty(file_validate_extensions($file, $validators['file_validate_extensions'][0]));
        }
        if (empty($validators['file_validate_extensions'][0]) || $passes_validation) {
          if (substr($filename, -4) != '.txt') {

            // The destination filename will also later be used to create the URI.
            $filename .= '.txt';
          }
          $filename = file_munge_filename($filename, $validators['file_validate_extensions'][0] ?? '');

          // The .txt extension may not be in the allowed list of extensions. We
          // have to add it here or else the file upload will fail.
          if (!empty($validators['file_validate_extensions'][0])) {
            $validators['file_validate_extensions'][0] .= ' txt';
          }
        }
      }
    }
    return $filename;
  }

  /**
   * Determines the URI for a file field.
   *
   * @param array $settings
   *   The array of field settings.
   *
   * @return string
   *   An un-sanitized file directory URI with tokens replaced. The result of
   *   the token replacement is then converted to plain text and returned.
   */
  protected function getUploadLocation(array $settings) {
    $destination = trim($settings['file_directory'], '/');

    // Replace tokens. As the tokens might contain HTML we convert it to plain
    // text.
    $destination = PlainTextOutput::renderFromHtml($this->token
      ->replace($destination, [], [], new BubbleableMetadata()));
    return $settings['uri_scheme'] . '://' . $destination;
  }

  /**
   * Retrieves the upload validators for a field definition.
   *
   * This is copied from \Drupal\file\Plugin\Field\FieldType\FileItem as there
   * is no entity instance available here that a FileItem would exist for.
   *
   * @param \Drupal\Core\Field\FieldDefinitionInterface $field_definition
   *   The field definition for which to get validators.
   *
   * @return array
   *   An array suitable for passing to file_save_upload() or the file field
   *   element's '#upload_validators' property.
   */
  protected function getUploadValidators(FieldDefinitionInterface $field_definition) {
    $validators = [
      // Add in our check of the file name length.
      'file_validate_name_length' => [],
    ];
    $settings = $field_definition
      ->getSettings();

    // Cap the upload size according to the PHP limit.
    $max_filesize = Bytes::toInt(Environment::getUploadMaxSize());
    if (!empty($settings['max_filesize'])) {
      $max_filesize = min($max_filesize, Bytes::toInt($settings['max_filesize']));
    }

    // There is always a file size limit due to the PHP server limit.
    $validators['file_validate_size'] = [
      $max_filesize,
    ];

    // Add the extension check if necessary.
    if (!empty($settings['file_extensions'])) {
      $validators['file_validate_extensions'] = [
        $settings['file_extensions'],
      ];
    }
    return $validators;
  }

  /**
   * 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);
  }

}

Members

Name	Modifiers	Type	Description	Overrides
TemporaryJsonapiFileFieldUploader::$fileSystem	protected	property	The file system service.
TemporaryJsonapiFileFieldUploader::$lock	protected	property	The lock service.
TemporaryJsonapiFileFieldUploader::$logger	protected	property	A logger instance.
TemporaryJsonapiFileFieldUploader::$mimeTypeGuesser	protected	property	The MIME type guesser.
TemporaryJsonapiFileFieldUploader::$systemFileConfig	protected	property	System file configuration.
TemporaryJsonapiFileFieldUploader::$token	protected	property	The token replacement instance.
TemporaryJsonapiFileFieldUploader::BYTES_TO_READ		constant	The amount of bytes to read in each iteration when streaming file data.
TemporaryJsonapiFileFieldUploader::checkFileUploadAccess	public static	function	Checks if the current user has access to upload the file.
TemporaryJsonapiFileFieldUploader::generateLockIdFromFileUri	protected static	function	Generates a lock ID based on the file URI.
TemporaryJsonapiFileFieldUploader::getUploadLocation	protected	function	Determines the URI for a file field.
TemporaryJsonapiFileFieldUploader::getUploadValidators	protected	function	Retrieves the upload validators for a field definition.
TemporaryJsonapiFileFieldUploader::handleFileUploadForField	public	function	Creates and validates a file entity for a file field from a file stream.
TemporaryJsonapiFileFieldUploader::prepareFilename	protected	function	Prepares the filename to strip out any malicious extensions.
TemporaryJsonapiFileFieldUploader::REQUEST_HEADER_FILENAME_REGEX		constant	The regex used to extract the filename from the content disposition header.
TemporaryJsonapiFileFieldUploader::streamUploadData	protected	function	Streams file upload data to temporary file and moves to file destination.
TemporaryJsonapiFileFieldUploader::validate	protected	function	Validates the file.
TemporaryJsonapiFileFieldUploader::validateAndParseContentDispositionHeader	public	function	Validates and extracts the filename from the Content-Disposition header.
TemporaryJsonapiFileFieldUploader::__construct	public	function	Constructs a FileUploadResource instance.