# config/initializers/writeexcel_template_handler.rb
class ActionView::Template
  module Handlers
    class WriteExcelTemplateHandler
      def call(template)
        %{
          Tempfile.open('writeexcel').tap do |tmp|
            WriteExcel.new(tmp.path).tap do |workbook|
              #{template.source}
            end.close
          end.tap(&:rewind).read
        }
      end
    end
  end

  register_template_handler(:writeexcel, Handlers::WriteExcelTemplateHandler.new)
end