rails caching: expire_action in another namespace

My application is using a namespace for administrati开发者_Python百科ve purposes. I recently tried to start using action caching however I ran into some problems trying to expire the cache using expire_action. Basically I have a index action in my default namespace newsposts controller that is cached using action caching like this:

class NewspostsController < ApplicationController

  caches_action :index, :layout => false

  def index
    @posts = Newspost.includes(:author).order("created_at DESC").limit(5)
  end

end

This caches the view under views/host/newsposts.

The default namespace has no actions for modifying data, they are all in my admin namespace. In my Admin::NewspostsController I am trying to expire this cache in the create action like this:

expire_action(:controller => 'newsposts', :action => 'index')

however this will expire a cache file located under views/host/admin/newsposts. Obviously it can not work since im in the admin namespace and rails is (rightfully) looking to expire cache for this namespace. Sadly I can not pass a namespace parameter to the axpire_action method, so how can i expire the action cache in another namespace?

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after some more digging I finally found the solution. It's a bit hinted in the url_for method:

In particular, a leading slash ensures no namespace is assumed. Thus, while url_for :controller => 'users' may resolve to Admin::UsersController if the current controller lives under that module, url_for :controller => '/users' ensures you link to ::UsersController no matter what.

So basically,

expire_action(:controller => '/newsposts', :action => 'index')

Will expire in the default namespace, and

expire_action(:controller => 'admin/newsposts', :action => 'index')

in the admin namespace (when in default).

RailsCast

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One additional note I learned, if you want to expire a specific format, such as XML, JSON, etc., just

expire_action(:controller => '/newsposts', :action => 'index', :format => 'xml') 

or whatever format you want. It look me a while to figure out.