I use this method to retrieve some JSON and prepare the objects for NanoStore.

json_to_nano_object.rb

def self.update(username, &block)
  BW::HTTP.get("#{Constants::API_endpoint}/events/#{username}") do |response|
    if response.ok?
      events = BW::JSON.parse(response.body)
      
      ::Event.delete
      events.each { |e|
        eventdata = e.each_with_object({}){ |(k,v), h| h[k.to_sym] = v }
        eventData.each { |k,v| eventData.delete(k) if v.nil? }
        ::Event.create(eventData)
      }
        
      block.call if block
    else
      alert = UIAlertView.alloc.initWithTitle('Events error',
        message:'There was an error getting your events.',
        delegate:nil,
        cancelButtonTitle:'OK',
        otherButtonTitles:nil)
      alert.show
      block.call(true) if block
    end
  end
end