使用元搜索来渲染xml

Question

Metasearch gem产生如下内容：

Started GET "/isbns/onixxml?utf8=%E2%9C%93&search%5Btitle_contains%5D=flickers&5D=&commit=Search" for 127.0.0.1 at 2011-08-14 09:40:39 +0100
  Processing by IsbnsController#onixxml as HTML
  Parameters: {"utf8"=>"✓", "search"=>{"title_contains"=>"flickers", "commit"=>"Search"}
  Isbn Load (8.1ms)  SELECT "isbns".* FROM "isbns" WHERE "isbns"."client_id" = 4 AND ("isbns"."title" LIKE '%flickers%')
Completed 406 Not Acceptable in 54ms

但是我收到406错误，因为我希望表单呈现onixxml.xml.builder。它只是想呈现html。查看代码：

  = semantic_form_for @search, :url => onixxml_isbns_path, :action => :onixxml, :html => {:method => :get}  do |f|
    %ol.search#slickbox
      = f.input :title_contains, :label => "Title"          
      = f.buttons do
        = f.submit 'Search'

控制器：

  def onix
    @title = "ISBNs"
    @search = Isbn.where(:client_id => current_user.client_id).search(params[:search])
    @filename = 'report.csv'
     @isbns = @search.order(sort_column + " " + sort_direction)
    if @search.nil? 
       @isbns = Isbn.where(:client_id => current_user.client_id) 
    end    
    session[:query] = @isbns.map(&:id)
    respond_to do |format|
      format.html
    end
  end

  def onixxml
    @title = "ISBNs"
    @search = Isbn.where(:client_id => current_user.client_id).search(params[:search])
     @isbns = @search.order(sort_column + " " + sort_direction)
    if @search.nil? 
       @isbns = Isbn.where(:client_id => current_user.client_id) 
    end
    session[:query] = @isbns.map(&:id)
    respond_to do |format|
      format.xml  
    end           
  end

我可以使用Metasearch呈现该XML吗？