File API

Per-option reference for the file field. For setup and worked examples, see the File guide.

Options are passed to the field declaration in an Avo resource, such as app/avo/resources/user.rb:

field :avatar, as: :file, accept: "image/*", direct_upload: true

Shared options such as formatting, visibility, and read-only behavior are documented in Common field options.

Uploads

-> accept

The HTML accept attribute on the file input. It filters the browser's file picker, not the server's upload handling.

field :avatar, as: :file, accept: "image/*"

• Type: String or nil
• Default: nil
• Values: MIME types, wildcard MIME types such as image/* or audio/*, or file extensions, including comma-separated lists, as defined by the HTML specification.
• Validation: No server-side content-type or size validation is added by this option.

-> direct_upload

Enables Active Storage direct uploads on the file input. Requires the application's Rails direct-upload setup and a storage service configured to accept those uploads.

field :avatar, as: :file, direct_upload: true

• Type: Boolean
• Default: false

Attachment display

-> display_filename

Controls the filename caption below attachment previews on Show and forms, and the image lightbox caption. It does not hide the filename used for non-image, non-audio files on Index.

field :avatar, as: :file, display_filename: false

• Type: Boolean
• Default: true (also when explicitly passed nil)

-> lightbox

Enables the in-page lightbox for representable image attachments on Show. Forms retain plain thumbnails. Audio, video, and documents do not open in the image lightbox. The original-file link is included only when the user is authorized to download the attachment.

field :avatar, as: :file, lightbox: false

• Type: Boolean
• Default: true (also when explicitly passed nil)

-> link_to_record

Wraps image and audio previews on Index in a link to the record's Show page. It does not affect Show or form previews, or filename-only cells on Index.

field :avatar, as: :file, link_to_record: true

• Type: Boolean
• Default: false