rails 3，如何通过不保存的Controller＃create动作设置和传递查询字符串

Question

I have 3 views that the users sees in an order, first they select a location, next then select a category, then they get sent to a form. The first view sends the location info to the category select view. From the category select view, I am using a query string to send the category id through to a form. In the Controller#new action I am putting the query string into an instance variable: @award = Award.find(params[:award])

the issue is that if the user does not fill in the appropriate fields, then the form doesn't save, and the query string no longer exists. Which in my case means that a recommendation doesn't have a category anymore which will then continue to make the form fail.

How can I persist the query string through a failed create action?

def create
    @recommendation = Recommendation.new(params[:recommendation])
    @recommendation.user_id = current_user.id


    respond_to do |format|
      if @recommendation.save
        format.html { redirect_to location_path, notice: 'Recommendation was successfully created.' }
        format.json { render json: @recommendation, status: :created, location: @recommendation }
      else
        format.html { render action: "new" }
        format.json { render json: @recommendation.errors, status: :unprocessable_entity }
      end
    end
  end

EDIT _

I figured I could share the new action to:

def new
    @recommendation = Recommendation.new
    @award = Award.find(params[:award])
    @recommendation.approvals.build
    respond_to do |format|
      format.html # new.html.erb
      format.json { render json: @recommendation }
    end
  end

Answer 1

well, since the querystring is already being passed from the new action to the create action, if the create action fails, it will hit your 'format.html { render action: "new" }' line.

you could do something like this:

format.html {redirect_to thing_path(@thing, :foo => params[:foo])}