Question

I currently have two models School and Course where School has_many courses, and Course belongs_to school. Additionally, School and Course are nested resources, where School is the parent resource, and Course the child.

I have created several test records in the Rails Console so that a query such as when the child calls upon the parent Course.first.school successfully executes and returns all the relevant information of the school Course.first is associated with.

However, when put into a controller function, I would instead get an error “undefined method `school’ for nil:NilClass” for the following line:

redirect_to school_course_path(@course.school, @course)

.. as if the .school part wasn’t recognized (where as it was in the console). Why is this the case, and how do I get past this error? Thanks!

Edit – as suggested, it could be that my @course instance variable isn’t passed from method to method in the controller. I have attempted at passing them through via a private method, but its still giving me the same error. Here is my code (background: the model Question belongs_to Course, with Course having many questions. Course isn’t part of the nested routes)

class QuestionsController < ApplicationController

  def new
    @course = Course.find(params[:course]) #confirmed working
    self.current_course = @course #I attempt to set current_course, a private method 
    @question = Question.new
  end

  def create
    @question = Question.new(params[:question]) #also works, in rails console all the questions confirms to have rails id
    if @question.save
      redirect_to school_course_path(current_course.school, current_course) #source of my frustrations - continues to returns same error message
    else
      render 'new'
    end
  end

  private 

  def current_course=(course)
    @current_school = course
  end


  def current_course
    @current_course
  end

end

Answer 1

Should work if your relationships are set up the way I think they are:

def create
  @question = Question.new(params[:question])
  @course = @question.course
  if @question.save
    redirect_to school_course_path(@course.school, @course)
  else
    render 'new'
  end
end