How do I cache a value daily in rails?

Let's say you have widget_price

one that you want to update every 24 hours. You usually use Widget.calculate_daily_price

to get the daily price, but it takes too long to slow down your web pages.

widget_price = Widget.calculate_daily_price

      

        
        
        
      

    

Wrap this call with Rails.cache.fetch and complete the results in 24 hours.

widget_price = Rails.cache.fetch('widget_price', expires_in: 24.hours) do
  Widget.calculate_daily_price
end

      

        
        
        
      

    

Now, if widget_price is already cached, the cached value will be used and the block will be ignored. If the cache expired while it is running, the block will be executed and the cache will be set to a new value for another 24 hours.