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using the activerecord session_store for session tracking

Here’s what you need to do to take advantage of AR’s SessionStore. The following was tested with Rails 3.2.5.

1. Run rake db:sessions:create
2. Run rake db:migrate
3. Modify config/initializers/session_store.rb to this:

    YourApp.config.session_store :active_record_store

 

• Add the following in application.rb:

   config.action_dispatch.session_store = :active_record_store  

 

This will setup the default session tracking mechanism. I wanted to have a custom Session class, which held the user_id ( if he’s logged in ). Here’s the additional things I’ve done:

1. I added in config/initializers/session_store.rb the following line:

    ActiveRecord::SessionStore.session_class = Session

 

• I added the following code in app/models/session.rb :

   
  class Session < ActiveRecord::SessionStore::Session 
    belongs_to :user 
    before_save :ensure_user_is_set 
    
    def self.find_by_session_id(session_id) 
      find(:first,:conditions => ["session_id = ?",session_id]) 
    end 
    
    private 
    def ensure_user_is_set 
      warden_data = self.data["warden.user.user.key"] 
      if warden_data 
        user_id = warden_data[1][0] 
        self.user = User.find(user_id) 
      end 
    end 
  end 

 

 

creating a postgresql schema from inside a rails migration

If you ever need to create a schema from inside a migration, write this:

def up
  execute "CREATE SCHEMA some_schema"
end

def down
  execute "DROP SCHEMA some_schema"
end

change timezone without changing time

t = DateTime.now
t.change(:offset => "+0800")

will change the timezone to a +0800 one.

rendering a jbuilder template to a string

Here’s how:

#controllers/users_controller.rb
def index
  @users = User.all
  @users_json = render_to_string( template: 'users.json.jbuilder', locals: { users: @users})
end

#views/users/users.json.jbuilder
json.array!(users) do |json, user|
  json.(user, :id, :name)
end

Thanks to Aaron Renoir

Dalli unmarshal error

I’ve kept receiving errors like: DalliError: unable to unmarshal value.
The solution was to add all the unmarshable classes in the relevant controllers, like this:

require_dependency "some_model_that_cannot_be_unmarshalled"

rails delete table from console

ActiveRecord::Migration.drop_table(:users)