undefined method `scard' for nil:NilClass - ruby-on-rails

Question

app/models/user.rb:51:in `cart_count'
app/views/layouts/_header.html.erb:24:in `block in _app_views_layouts__header_html_erb__3312865121531214569_70179387150260'
app/views/layouts/_header.html.erb:23:in `_app_views_layouts__header_html_erb__3312865121531214569_70179387150260'
app/views/users/show.html.erb:40:in `_app_views_users_show_html_erb___592785710009336321_70179415740600'
When I attempt to view page after identification, I get the error above.
Here's my layouts/header.html.erb code:
<% if signed_in? %>
<%= link_to accueilconnect_path do%>
<li class="forma">Accueil</li>
<% end %>
<%= link_to nosformations_path do%>
<li class="contac">Formations</li>
<% end %>
<%= link_to devenirformateur_path do%>
<li class="contac">Devenir formateur</li>
<% end %>
<%= link_to contacts_path do%>
<li class="contac">Contact</li>
<% end %>
<%= link_to cart_path do%>
<i class="fi-shopping-cart"></i> My Cart (<span class="cart-count"><%=current_user.cart_count%></span>)
<%end%>
<%= link_to image_tag('user2.png', :class => "user_icon"), current_user %>
<% end %>
and here is my User Model :
class User < ActiveRecord::Base
attr_accessor :password
before_save { self.email = email.downcase }
attr_accessible :name, :email, :login, :password, :password_confirmation
email_regex = /\A[\w+\-.]+#[a-z\d\-.]+\.[a-z]+\z/i
validates :name, :presence => true,
:length => { :maximum => 50 }
validates :email, :presence => true,
:format => { :with => email_regex },
:uniqueness => { :case_sensitive => false }
validates :login, :presence => true,
:length => { :maximum => 20 }
validates :password, :presence => true,
:confirmation => true,
:length => { :within => 6..40 }
before_create :confirmation_token
before_create :encrypt_password
# Retour true (vrai) si le mot de passe correspond.
def has_password?(password_soumis)
encrypted_password == encrypt(password_soumis)
# Compare encrypted_password avec la version cryptée de
# password_soumis.
end
def authenticate(submitted_password)
self.has_password?(submitted_password)
end
def self.authenticate_with_salt(id, cookie_salt)
user = find_by_id(id)
(user && user.salt == cookie_salt) ? user : nil
end
def email_activate
self.email_confirmed = true
self.confirm_token = nil
save!(:validate => false)
end
def cart_count
$redis.scard "cart#{id}"
end
private
def encrypt_password
self.salt = make_salt if new_record?
self.encrypted_password = encrypt(password)
end
def encrypt(string)
secure_hash("#{salt}--#{string}")
end
def make_salt
secure_hash("#{Time.now.utc}--#{password}")
end
def secure_hash(string)
Digest::SHA2.hexdigest(string)
end
def confirmation_token
if self.confirm_token.blank?
self.confirm_token = SecureRandom.urlsafe_base64.to_s
end
end
end
problem is in :
def cart_count
$redis.scard "cart#{id}"
end
any idea ?

Answer 1

Did you installed Redis Server:
http://redis.io/download
and Run it locallay go to where redis folder exist and write
redis-server
and define it in intalizers:
$redis = Redis.new