module ActionController::EtagWithTemplateDigest

def determine_template_etag(options) 

def determine_template_etag(options)
  if template = pick_template_for_etag(options)
    lookup_and_digest_template(template)
  end
end

def lookup_and_digest_template(template) 

def lookup_and_digest_template(template)
  ActionView::Digestor.digest name: template, format: nil, finder: lookup_context
end

def pick_template_for_etag(options)

template digest from the ETag.
the default controller/action template. If +:template+ is false, omit the
is present, use the named template. If +:template+ is +nil+ or absent, use
Pick the template digest to include in the ETag. If the +:template+ option 
def pick_template_for_etag(options)
  unless options[:template] == false
    options[:template] || lookup_context.find_all(action_name, _prefixes).first&.virtual_path
  end
end