Named routes in mounted rails engine
I'm making a small rails engine which I mount like this:
mount BasicApp::Engine => "/app"
Using this answer I have verified that all the routes in the engine are as the should be:
However - when I (inside the engine) link to a named route (defined inside the engine) I get this error
undefined local variable or method `new_post_path' for #<#<Class:0x000000065e0c08>:0x000000065d71d0>
Running "rake route" clearly verifies that "new_post" should be a named path, so I have no idea why Rails (3.1.0) can't figure it out. Any help is welcome
my config/route.rb (for the engine) look like this
BasicApp::Engine.routes.draw do
resources :posts, :path => '' do
resources :post_comments
resources :post_images
end
end
I should add that it is and isolated engine. However paths like main_app.root_path works fine - while root_path does not
Solution 1:
The right way
I believe the best solution is to call new_post_path
on the Engine's routes proxy, which is available as a helper method. In your case, the helper method will default to basic_app_engine
, so you can call basic_app_engine.new_post_path
in your views or helpers.
If you want, you can set the name in one of two ways.
# in engine/lib/basic_app/engine.rb:
module BasicApp
class Engine < ::Rails::Engine
engine_name 'basic'
end
end
or
# in app/config/routes.rb:
mount BasicApp::Engine => '/app', :as => 'basic'
In either case, you could then call basic.new_posts_path
in your views or helpers.
Another way
Another option is to not use a mounted engine and instead have the engine add the routes directly to the app. Thoughtbot's HighVoltage does this. I don't love this solution because it is likely to cause namespace conflicts when you add many engines, but it does work.
# in engine/config/routes.rb
Rails.application.routes.draw do
resources :posts, :path => '' do
resources :post_comments
resources :post_images
end
end
# in app/config/routes.rb:
# (no mention of the engine)
Solution 2:
On Rails 4 the engine_name
directive did not work for me.
To access a named route defined in engine's routes from engine's own view or controller, I ended up using the verbose
BasicApp::Engine.routes.url_helpers.new_post_path
I recommend defining a simple helper method to make this more usable
# in /helpers/basic_app/application_helper.rb
module BasicApp::ApplicationHelper
def basic_app_engine
@@basic_app_engine_url_helpers ||= BasicApp::Engine.routes.url_helpers
end
end
With this in place you can now use
basic_app_engine.new_post_path
In case you need to access your main application helper from the engine you can just use main_app
:
main_app.root_path
Solution 3:
use the below in you app to access the engine routes
MyApp::Engine.routes.url_helpers.new_post_path