undefined method `model_name' for ActiveModel::Errors:Class

Question

I have the following mongoid model class:

class Exercise
  include Mongoid::Document
  field :name, :type => String
  field :description, :type => String

  belongs_to :group

  validates_presence_of :name, :description, :group
end

And I have the following controller:

class ExercisesController < ApplicationController
  respond_to :json

  def create
    @exercise = Exercise.create(params[:exercise])
    if @exercise.save
      respond_with @exercise
    else
      respond_with(@exercise.errors, :status => :unprocessable_entity)
    end
  end
end

The model saves fine when valid but when the following line is ran:

respond_with(@exercise.errors, :status => :unprocessable_entity)

I get the following error

undefined method `model_name' for ActiveModel::Errors:Class

The errors collection is populated so I think my respond_with syntax is wrong.

shouldn't you `respond_with(@exercise, ....)` instead of `respond_with(@exercise.errors, ...)` — rubish, Jul 23 '12 at 20:51

score 2 · Answer 1 · answered Mar 21 '13 at 17:19

The rails respond_with helper expects to receive a rails model objects as the 1st parameter. So in this case you'd just want respond_with @exercise, status: :unprocessable_entity And then in your response view you would need to properly format the error data, I'm assuming you are doing this via ajax and responding with json, etc. Hope that helps.

undefined method `model_name' for ActiveModel::Errors:Class

1 Answers1