[ruby-on-rails] Rails: Check output of path helper from console

Rails defines a bunch of magic with named routes that make helpers for your routes. Sometimes, especially with nested routes, it can get a little confusing to keep track of what URL you'll get for a given route helper method call. Is it possible to, using the Ruby console, see what link a given helper function will generate? For example, given a named helper like post_path(post) I want to see what URL is generated.

Remember if your route is name-spaced, Like:

product GET  /products/:id(.:format)  spree/products#show

Then try :

helper.link_to("test", app.spree.product_path(Spree::Product.first), method: :get)

output

Spree::Product Load (0.4ms)  SELECT  "spree_products".* FROM "spree_products"  WHERE "spree_products"."deleted_at" IS NULL  ORDER BY "spree_products"."id" ASC LIMIT 1
=> "<a data-method=\"get\" href=\"/products/this-is-the-title\">test</a>" 

You can always check the output of path_helpers in console. Just use the helper with app

app.post_path(3)
#=> "/posts/3"

app.posts_path
#=> "/posts"

app.posts_url
#=> "http://www.example.com/posts"

you can also

include Rails.application.routes.url_helpers

from inside a console sessions to access the helpers:

url_for controller: :users, only_path: true
users_path
# => '/users'

or

Rails.application.routes.url_helpers.users_path

In the Rails console, the variable app holds a session object on which you can call path and URL helpers as instance methods.

app.users_path

For Rails 5.2.4.1, I had to

app.extend app._routes.named_routes.path_helpers_module
app.whatever_path