```ruby
require 'spreadsheet'

module Spreadsheet
  module Rails
    module SpreadsheetHelper

      def excel_document(opts={})
        download = opts.delete(:force_download)
        filename = opts.delete(:filename)
        template_path = opts.delete(:template_path)
        workbook_class = opts.delete(:renderer) || Spreadsheet::Workbook
        workbook = template_path ? Spreadsheet.open(template_path) : workbook_class.new
        yield(workbook)
        disposition(download, filename) if (download || filename)
        workbook
      end

      def disposition(download, filename)
        download = true if (filename && download == nil)
        disposition = download ? "attachment;" : "inline;"
        disposition += " filename=#{filename}" if filename
        headers["Content-Disposition"] = disposition
      end
    end

    class TemplateHandler
      class_attribute :default_format
      self.default_format = :xls
      def self.call(template)
        "sio = StringIO.new; #{template.source.strip}.write(sio); sio.string"
      end
    end
  end
end

unless Mime::Type.lookup_by_extension :xls
  Mime::Type.register_alias "application/xls", :xls
end
ActionView::Template.register_template_handler(:rxls, Spreadsheet::Rails::TemplateHandler)
ActionView::Base.send(:include, Spreadsheet::Rails::SpreadsheetHelper)
```

Add quoting to filename part of Content-Disposition header.
user
```ruby
require 'spreadsheet'

module Spreadsheet
  module Rails
    module SpreadsheetHelper

      def excel_document(opts={})
        download = opts.delete(:force_download)
        filename = opts.delete(:filename)
        template_path = opts.delete(:template_path)
        workbook_class = opts.delete(:renderer) || Spreadsheet::Workbook
        workbook = template_path ? Spreadsheet.open(template_path) : workbook_class.new
        yield(workbook)
        disposition(download, filename) if (download || filename)
        workbook
      end

      def disposition(download, filename)
        download = true if (filename && download == nil)
        disposition = download ? "attachment;" : "inline;"
        disposition += " filename=\"#{filename}\"" if filename
        headers["Content-Disposition"] = disposition
      end
    end

    class TemplateHandler
      class_attribute :default_format
      self.default_format = :xls
      def self.call(template)
        "sio = StringIO.new; #{template.source.strip}.write(sio); sio.string"
      end
    end
  end
end

unless Mime::Type.lookup_by_extension :xls
  Mime::Type.register_alias "application/xls", :xls
end
ActionView::Template.register_template_handler(:rxls, Spreadsheet::Rails::TemplateHandler)
ActionView::Base.send(:include, Spreadsheet::Rails::SpreadsheetHelper)
```
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