CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-4model-view-controllernomethoderror
Thibaud Clement
Thibaud Clement

Reputation: 6897

Rails 4: NoMethodError in <Model>Controller#index

In our Rails 4 app, there are four models:

class User < ActiveRecord::Base
  has_many :administrations, dependent: :destroy
  has_many :calendars, through: :administrations
end

class Administration < ActiveRecord::Base
  belongs_to :user
  belongs_to :calendar
end

class Calendar < ActiveRecord::Base
  has_many :administrations, dependent: :destroy
  has_many :users, through: :administrations
end

Here is our AdministrationsController: 

class AdministrationsController < ApplicationController

  def to_s
    role
  end

  def index
    @user = current_user
    @administrations = @user.administrations
    @calendar = Calendar.new
  end

  def show
    @administration = Administration.find(params[:id])
  end

  def destroy
    Administration.find(params[:id]).destroy
    flash[:success] = "You successfully quit this calendar"
    redirect_to dashboard_path
  end

end

When a new user signs up, ie: a new @user is created, he is redirected to his dashboard, which corresponds to the Administration index.html.erb view:

<% provide(:title, 'Dashboard') %>

<h1>Dashboard</h1>

<div class="container-fluid">

    <div class="row">

        <div class="col-md-4 col-md-offset-4">
            <% if @user.administrations.any? %>
                <h2>My Calendars</h2>
                <table>
                    <%= render @administrations %>
                </table>
            <% end %>

            <section class="calendar_form">
                <%= render 'shared/calendar_form' %>
            </section>
        </div>

    </div>

</div>

At this moment, a user has no calendar and no administration.

So, logically, after we sign up a new user, we get the following error:

NoMethodError in AdministrationsController#index

undefined method `administrations' for nil:NilClass

def index
  @user = current_user
  @administrations = @user.administrations
  @calendar = Calendar.new
end

We tried to do something like:

def index
  @user = current_user
  @administrations = @user.administrations if @user.administrations.exists?
  @calendar = Calendar.new
end

but it did not work, and returned a similar error.

How can we fix this?

Upvotes: 0

Views: 975

Answers (2)

Fred Willmore
Fred Willmore

Reputation: 4604

the problem is that current_user is returning nil, not a user object. Maybe you have created a user but not logged in.

Upvotes: 2

PhilVarg
PhilVarg

Reputation: 4821

you can utilize the #respond_to? method

@administrations = @user.administrations if @user.respond_to? :admininstrations

Upvotes: 0

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