Rails 3: Get current namespace?

Question

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

Skimmia

Answer 1

You can use:

self.class.parent == Admin

Baldheaded

this answer should be first one! – Shorts

As many have pointed out this doesn't work for classes that have multiple levels of namespacing. However if you are just checking to see if you are in such a namespace (like the OP kind of was getting at) then you can use controller.class.parents.include?(Admin) and get at the similar thing without having to resort to string parsing – Islamite

@Islamite I get this error with that solution: NameError Exception: undefined local variable or method 'controller'. I'm on Rails 5.1. self.class.parents works and is equivalent. – Chromatophore

Answer 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

Brasher

Thanks. It's a simple and easy to use solution, especially when you need to check the namespace in Views. – Zippora

also in the views you can use controller.class.parent.name – Rokach

how to call this from the view? – Dwayne

looks like dirty code... I think more clear to use class.parent – Shorts

Answer 3

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

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

Fascism

this gives 'foo' back if I say 'foo'.split('/').first . A solution would be best if namespace is nil when checking a non-namespaced controller name – Swat

Answer 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"

Interjection

Hi. That's not what I meant, sorry. The controller's name is something else, "admin" is the namespace. It's Admin::MyController, so params[:controller] gives "admin/my_controller" or something, thats where I check if it is the admin namespace. Using controller_name I would have to do just the same, but I'd like to know a way to not parse it but get back the namespace only. – Skimmia

My fault, I didn't read the question closely. You clearly state namespace and not controller name. Answer updated with an alternative. – Interjection

More simply controller.class.name.start_with?('Admin'). – Ussery

Answer 5

Setting the namespace in application controller:

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

Handicraftsman

This would obviate the ternary: @namespace = (path.first if path.second) – Egoist

Answer 6

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]

Hypermeter

Answer 7

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

Voracity

Seems like module_parent is not available yet in Rails 6.0.3.2. So, I use controller.class.parent – Phila

This doesn't work if you have nested controllers ``` Admin::Accounts::SubAccountsController ``` gives you ``` Admin::Accounts ``` – Junkie

Answer 8

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

Saponin

Tried controller.namespace, but it says undefined method 'namespace'. I used rails 6.0 and controller.class.parent works – Phila

For me controller.class.module_parent worked – Adversary

Answer 9

In Rails 6 you can do:

controller.class.module_parent

to get the parent module. Haven't tried it with multiple nestings. But for one you can convert to a symbol like this:

controller.class.module_parent.to_s.underscore.to_sym

Adversary