Merb::Router.prepare do |r|
  r.resources :channels do |channels|
    channels.resources :shows do |shows|
      shows.resources :episodes
    end
  end
end

But after updating to the latest version of Merb, I got links looking like:

http://localhost:4000/channels/#<Channel:0x27b7300>/shows

The first thing to do is to read Carl’s wiki about the latest Router changes.

Carl explains that things got cleaned up in the router code and my routes should now look like:

Merb::Router.prepare do |r|
  r.resources :channels do
    resources :shows do |shows|
      resources :episodes
    end
  end
end

However that won’t be enough.. You see my url used to look like that:

url(:channel_shows, :channel_id => channel)

Now I can simplify it to:

url(:channel_shows, channel)

That still won’t fix the problem, since the real problem comes from the fact that I was on Merb HEAD but not DataMapper HEAD. Updating DM clears things up. That’s the price to pay to be on HEAD

FYI the problem comes from the fact that DM doesn’t add a to_params method to its objects. Rails users might recognize that method used to convert an object into a string to create a route, something not really ORM agnostic and frowned upon by the DM/Merb teams.

Merb lets you specify the param to use for your routes using the identify method. Read Carl’s wiki page for more cool stuff and see how to create some cool stuff like url slugs etc..

Note that even if you are using ActiveRecord, you’ll need to update merb_activerecord as the new identify rules were updated in the ORM plugins.