问题
From 'Agile Web Development with Rails 4' pag.272.
If an incoming request has a controller named (say) admin/book, Rails will look for the controller called book_controller in the directory app/controllers/admin. That is, the final part of the controller name will always resolve to a file called name_controller.rb, and any leading path information will be used to navigate through subdirectories, starting in the app/controllers directory.
Imagine that our program has two such groups of controllers (say, admin/xxx and content/xxx) and that both groups define a book controller. There’d be a file called book_controller.rb in both the admin and content subdirectories of app/controllers. Both of these controller files would define a class named BookController. If Rails took no further steps, these two classes would clash. To deal with this, Rails assumes that controllers in subdirectories of the directory app/controllers are in Ruby modules named after the subdirectory.
My question is: how could the two book_controller.rb files clash?
I have two different URLs: ..../admin/book and ..../content/book, how can they clash? In the previous paragraph it explicit says
[..] any leading path information will be used to navigate through subdirectories, starting in the app/controllers directory
回答1:
The file names do not matter. What matter are the constant names.
It's totally okay to have two files with identical names, like controllers/admin/books_controller.rb, and controllers/books_controller.rb.
However, the class names inside those controller should be different. You can add namespace to differentiate them. For example
class Admin::BooksController
class BooksController
回答2:
Imagine the filepaths like this
../app/controllers/admin/book_controller.rb
&&
../app/controllers/content/book_controller.rb
Rails uses convention over configuration: http://en.wikipedia.org/wiki/Convention_over_configuration
Like it states in the last paragraph
If Rails took no further steps, these two classes would clash. To deal with this, Rails assumes that controllers in subdirectories of the directory app/controllers are in Ruby modules named after the subdirectory.
Someone please correct me if I'm wrong but rails would look for models named admin.rb and content.rb
来源：https://stackoverflow.com/questions/20162628/same-controller-name-in-two-different-directories