How to override Rails app routes from an engine?

Question

I have a Rails app that I am trying to integrate a Rails engine in to.

The host app has some catch all routes:

  # magic urls
  match '/' => 'admin/rendering#show'
  match '*path/edit' => 'admin/rendering#show', :defaults => { :editing => true }
  match '*path' => 'admin/rendering#show'

It looks like the engine routes are loaded after the application catches all routes.

/sitemap.xml(.:format)                                            {:format=>"xml", :controller=>"admin/sitemaps", :action=>"show"}
                              /(.:format)                                                       {:controller=>"admin/rendering", :action=>"show"}
                              /*path/edit(.:format)                                             {:controller=>"admin/rendering", :action=>"show"}
                              /*path                                                            {:controller=>"admin/rendering", :action=>"show"}
           engine_envs GET    /engine/envs/:id(.:format)                                       {:controller=>"engine/envs", :action=>"show"}
                       PUT    /engine/envs/:id(.:format)                                       {:controller=>"engine/envs", :action=>"update"}
                jammit        /assets/:package.:extension(.:format)                             {:extension=>/.+/, :controller=>"jammit", :action=>"package"}

So far, everything is hitting the /engine/envs routes are getting caught by the application catch all routes. However I see that the jammit route is loaded after the engine and I don't believe those are getting caught. Any way to override the app routes?

Answer 1

You could stick your engine routes in a method and then call that in your host app.

# engine routes.rb
module ActionDispatch::Routing
  class Mapper
    def engine_routes
      engine_envs GET    /engine/envs/:id(.:format)
      # ...
    end 
# ...

and then in your host app add the method before the catch-all route

# host app routes.rb
MyTestApp::Application.routes.draw do
  # ... 

  engine_routes

  match '/' => 'admin/rendering#show'
  match '*path/edit' => 'admin/rendering#show', :defaults => { :editing => true }
  match '*path' => 'admin/rendering#show'
end

Answer 2

Routes are used in the order they are defined. The first routes to be read are the one of the host application, then of your engine.

As soon as a matching route is found, the search for a route is stopped.

As far as I know, there are no way (I may be wrong about this) to override this feature other than to change your "mag

UPDATE: So that means that the order you see them in "rake routes" is the order they are processed. As soon as a matching route is found, there you go.