'NoMethodError: undefined method `scan' for nil:NilClass' when functional testing with rails

Question

This is not a question, it a solution that I found.

I am developing an application with Ruby on Rails 4.1 that displays text in Spanish, English and Japanese.

When I started the Functional Testing, I keep getting the following error:

NoMethodError: undefined method `scan' for nil:NilClass

Surffing I saw several posts with the same error, but none work for me.

This is the code original code:

application_controller.rb:

class ApplicationController < ActionController::Base

  protect_from_forgery with: :exception

  before_action :set_locale

  def set_locale
    I18n.locale = params[:locale] || I18n.default_locale
    navegador = extract_locale_from_accept_language_header
    ruta = params[:locale] || nil
    unless ruta.blank?
      I18n.locale = ruta if IDIOMAS.flatten.include? ruta
    else
      I18n.locale = navegador if IDIOMAS.flatten.include? navegador
    end
  end

  private

  def extract_locale_from_accept_language_header
    request.env['HTTP_ACCEPT_LANGUAGE'].scan(/^[a-z]{2}/).first
  end

  def ajusta_pagina_filtro
    if defined? params[:post][:filtrar_por]
      buscar = params[:post][:filtrar_por]
    else
      buscar = ''
    end
    page = params[:pagina] || 1
    [page, buscar]
  end

end

So this is the code for /test/controllers/homes_controller_test.rb at:

require 'test_helper'

class HomesControllerTest < ActionController::TestCase
  test "should get index" do
    get :index
    assert_response :success
  end
end

So, when I 'rake test', I got:

  1) Error:
HomesControllerTest#test_should_get_index:
NoMethodError: undefined method `scan' for nil:NilClass
    app/controllers/application_controller.rb:22:in `extract_locale_from_accept_language_header'
    app/controllers/application_controller.rb:9:in `set_locale'
    test/controllers/homes_controller_test.rb:5:in `block in <class:HomesControllerTest>'

possible duplicate of [What is a Null Pointer Exception, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception-and-how-do-i-fix-it) — Uri Agassi, May 14 '14 at 18:30

score 5 · Answer 1 · answered May 14 '14 at 18:34

5

The following solutions will also work without a begin rescue block

def extract_locale_from_accept_language_header
   accept_language = (request.env['HTTP_ACCEPT_LANGUAGE'] || 'es').scan(/^[a-z]{2}/).first
end

Or

def extract_locale_from_accept_language_header
  return 'es' unless request.env['HTTP_ACCEPT_LANGUAGE']
  request.env['HTTP_ACCEPT_LANGUAGE'].scan(/^[a-z]{2}/).first
end

answered May 14 '14 at 18:34

engineersmnky

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That is right. I had not thought about it. Thanks engineersmnky – OfficeYA May 15 '14 at 04:52

score 1 · Answer 2 · answered May 14 '14 at 18:26

The problem whas that at application_controller.rb, the method extract_locale_from_accept_language_header is failling. It is not getting the lananguage header from the request.

So I change it to:

  def extract_locale_from_accept_language_header
    begin
      request.env['HTTP_ACCEPT_LANGUAGE'].scan(/^[a-z]{2}/).first
    rescue
      'es'
    end
  end

I hope you find this usefull.

'NoMethodError: undefined method `scan' for nil:NilClass' when functional testing with rails

2 Answers2