What's the right way to modify the params passed to controller in rails 3.1.0?

Question

In our Rails 3.1.0 app, we need to modify params passed to rfq controller in create and update. For example, we want to record the current user id under input_by_id. What we did was:

  @rfq.input_by_id = session[:user_id]

It worked as expected. Also when need_report field is false, then report_language field should be nil. We decide to add the following line in rfq controller to make sure the nil is passed to report_language when need_report is false:

  @rfq.report_language = nil unless params[:need_report]

However this addition causes the rspec case failure (in create/update of the controller) because of the data validation failure. However when we fire up the app, it behaves fine without saving the report_language when need_report is false. I am wondering if the line above is not the right way to use params[:need_report] for @rfq updating.

Thanks so much.

UPDATE:

Controller code:

  def create
    if has_create_right?
      @rfq = Rfq.new(params[:rfq], :as => :roles_new )
      @rfq.input_by_id = session[:user_id]
      #save sales_id selected
      if sales? && member? && !team_lead?
        @rfq.sales_id = session[:user_id]        
      end
      #view page may carry the hidden report language even if need_report == false
      @rfq.report_language = nil unless params[:need_report]
      #save into join table rfqs_standards
      params[:rfq][:standard_ids].each do |sid|  
        @rfq.standards << Standard.find(sid.to_i) if !sid.nil? && sid.to_i > 0 
      end unless params[:rfq][:standard_ids].nil?
      #save into join table rfqs_test_items
      params[:rfq][:test_item_ids].each do |tid|
        @rfq.test_items << TestItem.find(tid.to_i) if !tid.nil? && tid.to_i > 0 
      end unless params[:rfq][:test_item_ids].nil?
      if @rfq.save!
        redirect_to URI.escape("/view_handler?index=0&msg=RFQ saved!")
      else
        flash.now[:error] = "RFQ not saved!"
        render 'new'
      end
    else
       redirect_to URI.escape("/view_handler?index=0&msg=No rights!") 
    end
  end

Test case failed after addition of @rfq.report_language = nil unless params[:need_report]

   it "should be successful for corp head" do
      session[:corp_head] = true
      session[:user_id] = 1
      s = Factory(:standard)
      rfq = Factory.attributes_for(:rfq, :need_report => true, :report_language => 'EN')
      rfq[:standard_ids] = [s.id] # attach standard_id's to mimic the POST'ed form data
      get 'create', :rfq => rfq
      #response.should redirect_to URI.escape("/view_handler?index=0&msg=RFQ saved!")
      response.should render_template('new')
    end

Answer 1

the problem ist that you are simply not looking at the right value.

get 'create', :rfq => rfq will result in a params-hash like {:rfq => {...}}

so you need to @rfq.report_language = nil unless params[:rfq][:need_report] == 'true'