embedded_svg helper for Rails

embedded_svg_helper.rb

module ApplicationHelper
  # Using raw files
  def embedded_svg filename, options = {}
    root = options[:root] || Rails.root.join("app", "assets", "svgs")
    file = File.read(File.join(root, filename))
    doc = Nokogiri::HTML::DocumentFragment.parse file
    svg = doc.at_css 'svg'
    svg['class'] = options[:class] if options[:class].present?
    doc.to_html.html_safe
  end
end

embedded_svg_v2_helper.rb

module ApplicationHelper
  # Using Sprockets (AssetPipeline) to fetch the files
  def embedded_svg_v2 filename, options = {}
    content = Rails.application.assets.find_asset(filename).body.force_encoding("UTF-8")
    doc = Nokogiri::HTML::DocumentFragment.parse content
    svg = doc.at_css 'svg'
    svg['class'] = options[:class] if options[:class].present?
    doc.to_html.html_safe
  end
end

sample.svg

usage_sample.html.erb

<%= embedded_svg "sample.svg", class: "svg-icons signal" %>
<%= embedded_svg "dir_inside_root/sample.svg", class: "svg-icons signal" %>

@tulios second example does not work on rails (4.2.4) :(

for svg v2 i needed to change
content = Rails.application.assets.find_asset(filename).body.force_encoding("UTF-8")
to
content = Rails.application.assets.find_asset(filename).source.force_encoding("UTF-8")

Although it works fine, unfortunately it is pretty slow. I am seeing that rendering takes an additional 1ms PER svg.
If SVGs are used extensively in your application, I would look for another solution.