Question

I’m creating a Rails app for managing individual items. Each item has an item number (zero padded, 4 digit number, e.g. 0002 or 0212 or 1002), which I would like to use in the urls for the application. If I currently navigate to /items/2 I get the item with id = 2 and not the item with item_number = 2. My routes.rb file contains only resources :items; how would I go about allowing for this to pull out the items by item number?

Answer 1

Override the to_param method in your Item model:

def to_param
    item_number.to_s
end

You don’t have to change anything in your routes.
You’ll just have to find the items using find_by_item_number(params[:id])

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Just so you know: if you wanted to display the name of the item in the url, you could do the following:

def to_param
    "#{id}-#{name}".parameterize
end

What’s great about that, is that “1-item-name”.to_i is 1! So you would not have to change your find methods everywhere.