Ruby on Rails: How to store and retrieve a MRU item in a cookie
It is convenient to display items that the user has visited recently, MRU (Most Recently Used) items.
Preparation
No special preparation is required.
Database
It is assumed only that you have a database table with an identifying column. In this example, the table is called items.
Model
No model changes are required.
Controller
To store an item in the cookie, add something like the following to your show method:
cookies[:item] = params[:id]
:item is simply a key that should be used consistently when setting or retrieving the value of the cookie. The key will be different for each controller. params[:id] retrieves the identifier of the shown element from the URL.
To retrieve an item from the cookie, add something like the following to your controller. Add it to a particular method that retrieves values for display, or add it to the application controller to make the MRU item always available for display.
if (nil == cookies[:item])Â
@recentitem = nil
else
begin
@recentitem = Item.find(cookies[:item])
rescue ActiveRecord::RecordNotFound
@recentitem = nil
end
end
View
You will need to display the item after it is retrieved by the controller.
<% if (@recentitem) %> <%= link_to(@recentitem.name, @recentitem) %> <% end %>