uninitialized constant CustomersController::CSV - ruby-on-rails

Question

I'm following the tutorial http://www.funonrails.com/2012/01/csv-file-importexport-in-rails-3.html]for upload files in rails 3, because I need that my app's user could upload csv files but when I tried to save the file I get: uninitialized constant CustomersController::CSV message, before change my routes to get "customers/import" to post "customers/import" I had other error No route matches [POST] "/customers/import" what Im doing wrong? thanks in advance.
MY CONTROLLER:
class CustomersController < ApplicationController
def import
if request.post? && params[:file].present?
infile = params[:file].read
n, errs = 0, []
CSV.parse(infile) do |row|
n += 1
# SKIP: header i.e. first row OR blank row
next if n == 1 or row.join.blank?
# build_from_csv method will map customer attributes &
# build new customer record
customer = Customer.build_from_csv(row)
# Save upon valid
# otherwise collect error records to export
if customer.valid?
customer.save
else
errs << row
end
end
# Export Error file for later upload upon correction
if errs.any?
errFile ="errors_#{Date.today.strftime('%d%b%y')}.csv"
errs.insert(0, Customer.csv_header)
errCSV = CSV.generate do |csv|
errs.each {|row| csv << row}
end
send_data errCSV,
:type => 'text/csv; charset=iso-8859-1; header=present',
:disposition => "attachment; filename=#{errFile}.csv"
else
flash[:notice] = I18n.t('customer.import.success')
redirect_to import_url #GET
end
end
end
end
MY MODEL:
class Customer < ActiveRecord::Base
scope :active, where(:active => true)
scope :latest, order('created_at desc')
def self.csv_header
"First Name,Last Name,Email,Phone,Mobile, Address, FAX, City".split(',')
end
def self.build_from_csv(row)
# find existing customer from email or create new
cust = find_or_initialize_by_email(row[2])
cust.attributes ={:first_name => row[0],
:last_name => row[1],
:email => row[3],
:phone => row[4],
:mobile => row[5],
:address => row[6],
:fax => row[7],
:city => row[8]}
return cust
end
def to_csv
[first_name, last_name, email, phone, mobile, address, fax, city]
end
end
*MY VIEW:
<h1>Subir Archivos</h1>
<%= form_tag('import', :multipart => true) do %>
<p>
File:<br />
<%= file_field_tag 'file' %><br />
</p>
<p>
<%= submit_tag "subir" %>
</p>
<% end %>
MY ROUTES:
Pruebaupcsv::Application.routes.draw do
post "customers/import"

Answer 1

You need to add a require 'csv' before you use it, either in an initializer, or at the top of your controller.