instance method `preview`

Ruby on Rails 7.2.3

Since v5.2.8.1

Available in: v5.2.8.1 v6.0.6 v6.1.7.10 v7.0.10 v7.1.6 v7.2.3 v8.0.4 v8.1.2

Compare with:

preview(transformations)

Returns an ActiveStorage::Preview instance with the set of transformations provided. A preview is an image generated from a non-image blob. Active Storage comes with built-in previewers for videos and PDF documents. The video previewer extracts the first frame from a video and the PDF previewer extracts the first page from a PDF document.

blob.preview(resize_to_limit: [100, 100]).processed.url

Avoid processing previews synchronously in views. Instead, link to a controller action that processes them on demand. Active Storage provides one, but you may want to create your own (for example, if you need authentication). Here’s how to use the built-in version:

<%= image_tag video.preview(resize_to_limit: [100, 100]) %>

This method raises ActiveStorage::UnpreviewableError if no previewer accepts the receiving blob. To determine whether a blob is accepted by any previewer, call ActiveStorage::Blob#previewable?.

Parameters

transformations req

Source

# File activestorage/app/models/active_storage/blob/representable.rb, line 129
  def preview(transformations)
    if previewable?
      ActiveStorage::Preview.new(self, transformations)
    else
      raise ActiveStorage::UnpreviewableError
    end
  end

Defined in activestorage/app/models/active_storage/blob/representable.rb line 129 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveStorage::Blob::Representable

Signature

Parameters