Class
  def uploadfile
    # render :text => request.headers['X-File']
    render :text => env.inspect
  end
end

View Haml
= form_for :file, url: '/uploadfile', html: { multipart: true } do |f|
  = file_field_tag 'uploaded_files[]', required: true
  = f.submit 'Save'
end

Route
Rails.application.routes.draw do
  resources :files
  root 'files#index'
  match '/uploadfile' => 'files#uploadfile', via: [:get, :post]
end