NoMethodError，未定义的方法“名称”，为nil：NilClass -rails 3

Question

I am getting NoMethodError in SitesController#index undefined method `subdomain' for nil:NilClass

I have an Accounts table that has a 'subdomain' field and a Site model which is a subclass of the Account Model that is:

class Site < Account

end

create_table "accounts", :force => true do |t|
  t.string   "subdomain"
  t.integer  "user_id"

end

and there is a current_account method defined in applications_controller like this

 def current_account
  if !is_root_domain?
   current_account = Account.find_by_subdomain(request.subdomains.first)
    if current_account.nil?
     redirect_to root_url(:account => false, :alert => "Unknown Account/subdomain")
  end
  else 
  current_account = nil
 end
return current_account

end

which calls is_root_domain? method below:

def is_root_domain?
  result = (request.subdomains.first.present? && request.subdomains.first != "www") ? false : true

end

I also chnaged the current_account method to this but got same error:

def current_account
    current_account = Account.find_by_subdomain(request.subdomains.first)
end

Under any of the above scenarios, i get the undefined method `subdomain' for nil:NilClass error on the SitesController#index. which is shown below while trying to access the url:

class SitesController < ApplicationController
  def index
    @site = Site.find_by_subdomain(current_account.subdomain)
  end

 def opps
   @site = Site.find_by_subdomain(current_account.subdomain)
 end

end

I have tried the various tricks of battling no method error that i know of, like adding 'attr_ccessible' and an initiliaze method but nothing seems to work. I also changed the Accounts table field from 'subdomain' to 'name', but no success. Any guide will be appreciated.

Answer 1

I think you might be confused by the 'redirect_to' in ApplicationController#current_account.

This redirect doesn't happen immediately, it happens when everything else is finished. So your current_account method will still return nil back to SitesController#index, where it is used to get the 'subdomain' and that's where you get your error.

If you call the redirect from a before_filter, it can handle this case before the code even enters your #index method. I would restructure the code something like this.

class ApplicationController

  # get the current account from the subdomain, calling find only if first time..
  def current_account
    unless is_root_domain?
      @current_account ||= Account.find_by_subdomain(request.subdomains.first)
    end
    @current_account
  end

end

And then:

class SitesController < ApplicationController
  before_filter :require_current_account

  def index
    @site = Site.find_by_subdomain(@current_account.subdomain)
  end

  private
  # makes sure @current_account is setup before using it elsewhere..
  def require_current_account
    if current_account.nil?
      redirect_to root_url(:account => false), :alert => "Unknown Account/subdomain"
    end
  end

end

Answer 2

Your problem is that current_account is nil. Make sure you are setting the variable to a valid (existing) object instance.