Question

Here is my unaltered controller:

  def create
    @user = User.new(params[:user])

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

And here are my routes:

  root :to => "songs#index"
  match '/votes/:song_id/:user_id' => "votes#create"
  resources :votes

  resource :session

  resources :users

  resources :songs

  match '/login' => "sessions#new", :as => "login" 
  match '/logout' => "sessions#destroy", :as => "logout" 

And the error:

undefined method `user' for #<User:0x00000102b42a00>


Application Trace | Framework Trace | Full Trace
app/controllers/users_controller.rb:46:in `block in create'
app/controllers/users_controller.rb:45:in `create'
Request

Parameters:

{"utf8"=>"✓",
 "authenticity_token"=>"oOzmpsbEJtnHC4YGeAf4N6pVxfK+Zf4W9ec+0E/Eds0=",
 "user"=>{"email"=>"[e-mail]",
 "password"=>"[FILTERED]"},
 "commit"=>"Create User"}

model:

class User < ActiveRecord::Base
  attr_accessible :email, :password
  validates_uniqueness_of :user
  validates_presence_of :password

  has_many :votes


end

Answer 1

http://guides.rubyonrails.org/active_record_validations_callbacks.html#uniqueness

This helper validates that the attribute’s value is unique

Your problem is in your validations; validates_uniqueness_of checks the uniqueness of a model attribute, so validates_uniqueness_of :user is trying to check that the user’s user attribute is unique. In the process, it calls @user.user, which produces the NoMethodError.

Edited to add: As @Amar says, the way to fix this is by validating the uniqueness of some attribute or set of attributes that will be unique for each user record (such as :email).