rails sha1 hash for route to object?

Question

I want to my controller in my app to not just respond to the id of the object sent from it's route, but actually a sha1 hash, i've generated using Digest::SHA1.hexdigest.

So instead of:

/client/invoice/1

I want the url to be something like:

/client/invoice/0beec7b5ea3f0fdbc95d0

Answer 1

Invoice.first(:conditions=>["SHA(id) = ?",params[:id]])

Answer 2

Changing the URL for an object in Rails generally involves two things:

First, change relevant controller actions to use a finder that works the way you want it to. In your case you probably want to write a custom finder in your Invoice model, like:

def self.find_by_id_or_sha1(id)
  Invoice.find_by_id(id) || Invoice.find_by_sha1(id)
end

and then use Invoice.find_by_id_or_sha1(params[:id]) in your controller actions (show, edit, update, destroy).

Second, change generated URLs to follow your new design (if desired). So, if you want link_to("Jan 1, 2010", @invoice) to go to /client/invoice/0beec7b5ea3f0fdbc95d0, override the default to_param method in your Invoice model. For example:

def to_param
  sha1
end

(That assumes your invoice's SHA1 hash is stored in the sha1 attribute.)