CODEWITHSUNDEEP
ruby-on-railsvalidationcontroller
gonzalo2000
gonzalo2000

Reputation: 648

updating resource undefined method `valid?' for false:FalseClass

I have some validations for my Lesson model, and I'm able to highlight validation problems on the controller under the create action with the valid? method. However, if I try to valid? in an analogous manner, I get undefined methodvalid?' for false:FalseClass` How can I go about validating my edit form upon submission, such that it renders the edit form again if the validation doesn't pass?

Lesson model:

class Lesson < ActiveRecord::Base
  belongs_to :user
  has_many :words, dependent: :destroy

  validates :title, presence: true, length: { maximum: 55 }
  validates :description, presence: true, length: { maximum: 500 }
  validates :subject, presence: true, length: { maximum: 55 }
  validates :difficulty, presence: true, numericality: { less_than_or_equal_to: 5 }
end

Controller:

class Teacher::LessonsController < ApplicationController
  before_action :authenticate_user!
  before_action :require_authorized_for_current_lesson, only: [:show, :edit, :update]

  def show
    @lesson = Lesson.find(params[:id])
  end

  def new
    @lesson = Lesson.new
  end

  def edit
    @lesson = Lesson.find(params[:id])
  end

  def create
    @lesson = current_user.lessons.create(lesson_params)
    if @lesson.valid?
      redirect_to teacher_lesson_path(@lesson)
    else
      render :new, status: :unprocessable_entity
    end
  end

  def update
    @lesson = current_lesson.update_attributes(lesson_params)
    if @lesson.valid?
      redirect_to teacher_lesson_path(current_lesson)
    else
      render :edit, status: :unprocessable_entity
    end
  end

  private
    def require_authorized_for_current_lesson
      if current_lesson.user != current_user
        render text: "Unauthorized", status: :unauthorized
      end
    end

    def current_lesson
      @current_lesson ||= Lesson.find(params[:id])
    end

    def lesson_params
      params.require(:lesson).permit(:title, :description, :subject, :difficulty)
    end
end

Upvotes: 3

Views: 1049

Answers (1)

BananaNeil
BananaNeil

Reputation: 10762

If you see an error that looks like undefined method 'valid?' for 'false:FalseClass

That means that wherever you call the method :valid?, the object on which you are calling it is not the object you expect, it is instead just false

So you have two instances in your code where you are calling @lesson.valid?, which means one or both of the assignments of @lesson is sometimes returning false.

In the docs of create, it says: The resulting object is returned whether the object was saved successfully to the database or not.

In the docs of update_attributes, it says: If the object is invalid, the saving will fail and false will be returned.

So it looks like your problem is with update_attributes, which apparently just returns false if your update was unsuccessful.

Upvotes: 3

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