Rails 3: Get current namespace?

问题:

using a method :layout_for_namespace I set my app's layout depending on whether I am in frontend or backend, as the backend is using an namespace "admin".

I could not find a pretty way to find out which namespace I am, the only way I found is by parsing the string from params[:controller]. Of course that's easy, seems to be fail-safe and working good. But I am just wondering if there's a better, prepared, way to do this. Does anyone know?

Currently I am just using the following method:

def is_backend_namespace?
  params[:controller].index("admin/") == 0
end

Thanks in advance

Arne

回答1:

You can use:

self.class.parent == Admin

回答2:

Outside the controller (e.g. in the views), use controller.class.name. You can turn this into a helper method like this:

module ApplicationHelper
  def admin?
    controller.class.name.split("::").first=="Admin"
  end
end

回答3:

In both the controller and the views, you can parse controller_path, eg.:

namespace = controller_path.split('/').first

回答4:

Not much more elegant, but it uses the class instead of the params hash. I am not aware of a "prepared" way to do this without some parsing.

self.class.to_s.split("::").first=="Admin"

回答5:

None of these solutions consider a constant with multiple parent modules. For instance:

A::B::C

As of Rails 3.2.x you can simply:

"A::B::C".deconstantize #=> "A::B"

As of Rails 3.1.x you can:

constant_name = "A::B::C"
constant_name.gsub( "::#{constant_name.demodulize}", '' )

This is because #demodulize is the opposite of #deconstantize:

"A::B::C".demodulize #=> "C"

If you really need to do this manually, try this:

constant_name = "A::B::C"
constant_name.split( '::' )[0,constant_name.split( '::' ).length-1]

回答6:

Setting the namespace in application controller:

path = self.controller_path.split('/')
@namespace = path.second ? path.first : nil

回答7:

Rails 6

Accessing the namespace in the view?

do not use: controller.namespace.parent == Admin

the parent method will be removed in Rails 6.1

DEPRECATION WARNING: `Module#parent` has been renamed to `module_parent`. `parent` is deprecated and will be removed in Rails 6.1.

use module_parent instead:

controller.namespace.module_parent == Admin

回答8:

In Rails 6, the controller class does not seem to have a namespace method on it.

The solution that seemed cleanest and worked for me in a view was: controller.class.module_parent

Specifically, if your namespace is Admin:: and you wanted 'admin', you'd do: controller.class.module_parent.to_s.downcase