How do I reference an image inside my custom module directory?

Question

I want to ship a default image in my custom module. I know I can reference images in the files directory with public://, but how can I properly reference my module's URL path?

Update: I need to pass this URI to image_style so a raw path to the module directory won't be enough:

  $render_image = [
    '#theme' => 'image_style',
    '#style_name' => 'blah',
    '#uri' => $uri,
    ...
  ];

Answer 1

Drupal needs a URI (not just a URL or filepath) to generate an image style derivative. All URIs begin with a stream wrapper like "public://" or "private://". The stream wrapper tells Drupal how to handle the resource; for example, "public" typically means "treat this resource as a local file within sites/default/files."

You won't be able to use the "public" stream wrapper for assets in a module directory, because that module does not live in sites/default/files.

Drupal doesn't come with a stream wrapper for module or theme assets, but there's a contributed module to add that functionality at https://www.drupal.org/project/system_stream_wrapper.

Answer 2

The value passed as #uri can be either the image URI or an image relative path. template_preprocess_image_style() passes the value of $variables['uri'] to ImageStyle::buildUrl() which as first parameter accepts either the image relative path or its URI.

  $style = ImageStyle::load($variables['style_name']);

  // Determine the dimensions of the styled image.
  $dimensions = [
    'width' => $variables['width'],
    'height' => $variables['height'],
  ];
  $style->transformDimensions($dimensions, $variables['uri']);
  $variables['image'] = [
    '#theme' => 'image',
    '#width' => $dimensions['width'],
    '#height' => $dimensions['height'],
    '#attributes' => $variables['attributes'],
    '#style_name' => $variables['style_name'],
  ];

  // If the current image toolkit supports this file type, prepare the URI for
  // the derivative image. If not, just use the original image resized to the
  // dimensions specified by the style.
  if ($style->supportsUri($variables['uri'])) {
    $variables['image']['#uri'] = $style->buildUrl($variables['uri']);
  }

To get the module path, both drupal_get_path('module', $module_name), which is still implemented even in Drupal 9.3.x, and \Drupal::moduleHandler()->getModule($module_name)->getPath() return the same value. Deprecate drupal_get_path() and drupal_get_filename() and replace with ExtensionList::getPath() and ExtensionList::getPathname() and drupal_get_path() and drupal_get_filename() have been deprecated in favor of extension listing services (the associated change record) suggest to use either \Drupal::service('extension.list.module')->getPath($module_name) or \Drupal::service('extension.path.resolver')->getPath('module', $module_name), to get a module path.

Answer 3

The \Drupal class has many useful static functions such as moduleHandler. I recommend (for future issues) to first search there, then in the core.services.yml & system.services.yml files for a service or a method that could help.

\Drupal::moduleHandler()->getModule('foo')->getPath()

Answer 4

I think following is easy method to do this

Create private file path

$settings['file_private_path'] = 'give path to you /private-files'; \Drupal::service('file_system')->realpath("private://");

Now you can use this to upload your module related file also custom file for custom form.

Ref: https://www.drupal.org/docs/8/modules/skilling/installation/set-up-a-private-file-path