getUploadMaxSize example

$form['#prefix'] = '<div id="editor-image-dialog-form">';
    $form['#suffix'] = '</div>';

    // Construct strings to use in the upload validators.     $image_upload = $editor->getImageUploadSettings();
    if (!empty($image_upload['max_dimensions']['width']) || !empty($image_upload['max_dimensions']['height'])) {
      $max_dimensions = $image_upload['max_dimensions']['width'] . 'x' . $image_upload['max_dimensions']['height'];
    }
    else {
      $max_dimensions = 0;
    }
    $max_filesize = min(Bytes::toNumber($image_upload['max_size']), Environment::getUploadMaxSize());
    $existing_file = isset($image_element['data-entity-uuid']) ? \Drupal::service('entity.repository')->loadEntityByUuid('file', $image_element['data-entity-uuid']) : NULL;
    $fid = $existing_file ? $existing_file->id() : NULL;

    $form['fid'] = [
      '#title' => $this->t('Image'),
      '#type' => 'managed_file',
      '#upload_location' => $image_upload['scheme'] . '://' . $image_upload['directory'],
      '#default_value' => $fid ? [$fid] : NULL,
      '#upload_validators' => [
        'file_validate_extensions' => ['gif png jpg jpeg'],
        'file_validate_size' => [$max_filesize],
        

  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.     $max_filesize = Bytes::toNumber(Environment::getUploadMaxSize());
    if (!empty($settings['max_filesize'])) {
      $max_filesize = min($max_filesize, Bytes::toNumber($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']];
    }

    

$filename = $upload->getClientOriginalName();

    $editor = $request->attributes->get('editor');
    $image_upload = $editor->getImageUploadSettings();
    $destination = $image_upload['scheme'] . '://' . $image_upload['directory'];

    // 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');
    }

    $max_filesize = min(Bytes::toNumber($image_upload['max_size']), Environment::getUploadMaxSize());
    if (!empty($image_upload['max_dimensions']['width']) || !empty($image_upload['max_dimensions']['height'])) {
      $max_dimensions = $image_upload['max_dimensions']['width'] . 'x' . $image_upload['max_dimensions']['height'];
    }
    else {
      $max_dimensions = 0;
    }

    $validators = [
      'file_validate_extensions' => ['gif png jpg jpeg'],
      'file_validate_size' => [$max_filesize],
      'file_validate_image_resolution' => [$max_dimensions],
    ];

  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.     $max_filesize = Bytes::toNumber(Environment::getUploadMaxSize());
    if (!empty($settings['max_filesize'])) {
      $max_filesize = min($max_filesize, Bytes::toNumber($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']];
    }

    

    else {
      $default = key($existing_languages);
      $language_options = [
        (string) $this->t('Existing languages') => $existing_languages,
        (string) $this->t('Languages not yet added') => $this->languageManager->getStandardLanguageListWithoutConfigured(),
      ];
    }

    $validators = [
      'file_validate_extensions' => ['po'],
      'file_validate_size' => [Environment::getUploadMaxSize()],
    ];
    $form['file'] = [
      '#type' => 'file',
      '#title' => $this->t('Translation file'),
      '#description' => [
        '#theme' => 'file_upload_help',
        '#description' => $this->t('A Gettext Portable Object file.'),
        '#upload_validators' => $validators,
      ],
      '#size' => 50,
      '#upload_validators' => $validators,
      

return FALSE;
  }

  /** * Wraps file_upload_max_size(). * * @return string * A translated string representation of the size of the file size limit * based on the PHP upload_max_filesize and post_max_size. */
  protected function getFileUploadMaxSize() {
    return Environment::getUploadMaxSize();
  }

  /** * Gets the current active user. * * @return \Drupal\Core\Session\AccountInterface * The current account. */
  protected function currentUser() {
    if (!$this->currentUser && \Drupal::hasService('current_user')) {
      $this->currentUser = \Drupal::currentUser();
    }

$this->fileUploadHandler = $this->container->get('file.upload_handler');
  }

  /** * Tests file size upload errors. */
  public function testFileSaveUploadSingleErrorFormSize() {
    $file_name = $this->randomMachineName();
    $file_info = $this->createMock(UploadedFileInterface::class);
    $file_info->expects($this->once())->method('getError')->willReturn(UPLOAD_ERR_FORM_SIZE);
    $file_info->expects($this->once())->method('getClientOriginalName')->willReturn($file_name);
    $file_info->expects($this->once())->method('getErrorMessage')->willReturn(sprintf('The file "%s" could not be saved because it exceeds %s, the maximum allowed size for uploads.', $file_name, format_size(Environment::getUploadMaxSize())));
    $this->expectException(FormSizeFileException::class);
    $this->expectExceptionMessage(sprintf('The file "%s" could not be saved because it exceeds %s, the maximum allowed size for uploads.', $file_name, format_size(Environment::getUploadMaxSize())));
    $this->fileUploadHandler->handleFileUpload($file_info);
  }

}

'#weight' => 1,
      '#maxlength' => 256,
      // By making this field required, we prevent a potential security issue       // that would allow files of any type to be uploaded.       '#required' => TRUE,
    ];

    $element['max_filesize'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Maximum upload size'),
      '#default_value' => $settings['max_filesize'],
      '#description' => $this->t('Enter a value like "512" (bytes), "80 KB" (kilobytes) or "50 MB" (megabytes) in order to restrict the allowed file size. If left empty the file sizes could be limited only by PHP\'s maximum post and file upload sizes (current limit <strong>%limit</strong>).', ['%limit' => format_size(Environment::getUploadMaxSize())]),
      '#size' => 10,
      '#element_validate' => [[static::class, 'validateMaxFilesize']],
      '#weight' => 5,
    ];

    $element['description_field'] = [
      '#type' => 'checkbox',
      '#title' => $this->t('Enable <em>Description</em> field'),
      '#default_value' => $settings['description_field'] ?? '',
      '#description' => $this->t('The description field allows users to enter a description about the uploaded file.'),
      '#weight' => 11,
    ];