Question

我一直收到DoubleRenderError，我无法弄明白为什么！基本上，我有一个动作，调用另一个动作，检查用户输入的查询错误，如果有错误，它停止并显示错误。但是当我输入一个带有错误的查询时，当我得到双重渲染时！有什么建议吗？

继承错误检查器操作：

def if_user_formulated_request_properly
    unless request.post?
      flash[:error] = "This page can only be accessed through the search page. (POST request only)"
 redirect_to(:action => "index") and return
    end

    if params[:query].blank?
      flash[:error] = "Search criteria can not be blank"
redirect_to(:action => "index") and  return
    end

    if !(params[:query] =~ /-/)
      flash[:error] = "( Format of search criteria is wrong.<br /> Should be [IXLSpecClass value][year]-[Message ID] for exam
ple GP07-8)"
redirect_to(:action => "index") and  return
    end

    if !(QueryParser.expression.match(params[:query]))
      flash[:error] = %( Format of search criteria is wrong.<br />Should be [IXLSpecClass value][year]-[Message ID] for examp
le GP07-8)
redirect_to(:action => "index") and return
  end
 yield

以防您需要调用此操作的操作..

 def show
        if_user_formulated_request_properly do
        @statuses = IXLStatus.find(:all)
        @input_messages = InputMessage.search_by(params[:query].stri
p) unless params[:query].blank?
        @query = params[:query]
        end
        respond_to do |format|
          format.html #default rendering
        end
        end
  end

更新

也忘了提一下，这最初是一个rails 2应用程序并且正在工作，当我升级到rails 3（我相信）时这个错误开始了，所以也许rails 3与and return做了不同的事情？

Answer 1

您只是从if_user_formulated_request_properly方法返回，这意味着redirect_to和respond_to都会进行渲染。

你可以试试这个：

def user_formulated_request_properly?
  unless request.post?
    flash[:error] = "This page can only be accessed through the search page. (POST request only)"
    return false
  end

  if params[:query].blank?
    flash[:error] = "Search criteria can not be blank"
    return false
  end

  if !(params[:query] =~ /-/)
    flash[:error] = "( Format of search criteria is wrong.<br /> Should be [IXLSpecClass value][year]-[Message ID] for example GP07-8)"
    return false
  end

  if !(QueryParser.expression.match(params[:query]))
    flash[:error] = %( Format of search criteria is wrong.<br />Should be [IXLSpecClass value][year]-[Message ID] for example GP07-8)
    return false
  end

  return true
end


def show
  if user_formulated_request_properly?
    @statuses = IXLStatus.find(:all)
    @input_messages = InputMessage.search_by(params[:query].strip) unless params[:query].blank?
    @query = params[:query]
  else
    redirect_to(:action => "index") and return
  end

  respond_to do |format|
    format.html #default rendering
  end
end

Answer 2

这是我的解决方案：

“根本原因是在触发错误之前分配了response_body的某些部分。

您可以在异常处理程序中调用render之前尝试清除响应主体。“

def render_400
  # Clear the previous response body to avoid a DoubleRenderError
  # when redirecting or rendering another view
  self.response_body = nil

  render(nothing: true, status: 400)
end

来源： DoubleRenderError in Rails 4.1 when rescuing from InvalidCrossOriginRequest

在此操作中多次调用渲染和/或重定向..？

2 个答案: