Where to set session default value? - ruby-on-rails-3

Question

guys!
Prior to asking i should mention, that i`m working without ActiveRecord or any self-hosted-database. So thats why i have to store some values in the session.
From the very begining i desided to set session value of the users city in the layout. - i supposed it would be loaded before anything else. So i`ve done something like this:
<% session[:city] ||= {:name => 'City-Name', :lat => '40', :lng => '40'}%>
But when i`m loading directly to inner page it occurs that session[:city is nil *(
How should i set the session properely, so that it wouldn`t be nil???

Answer 1

I had similar needs in one of the applications I worked on. It needed the users data to be loaded on sign-in and stored in the session. So, wrote a module called session_helpers.rb with the following:
module SessionHelpers
def get_value(key)
session[key.to_sym]
end
protected
def store_data(*objects)
objects.each do |object|
if object.is_a?(Hash)
object.each do |key, value|
session[key.to_sym] = value
end
end
end
end
def remove_data(*objects)
objects.each do |object|
if object.is_a?(String)
key = to_id(object)
else
key = to_id(object.class.name)
end
session[key] = nil
end
end
def update_data(key, value)
session[key.to_sym] = value
end
private
def to_id(name)
"#{name.parameterize('_').foreign_key}".to_sym
end
end
You can make any or all the methods available to views as well:
# application_controller.rb
helper_method :get_value
From the model I would retrieve a hash of the data that needs to be put up in the session about the user:
def common_data
#data = Hash.new
#data.merge!( { 'news' => self.news.count } )
...
#data
end
As I wanted to do this after sign-in I overrode the devise method to do this:
def after_sign_in_path_for(resource_or_scope)
store_data( '_count', current_user.common_data )
dashboard_path
end
This way I was able to load important data about the user on sign-in and store it in the session and retrieve whenever I wanted. Hope this helps.