Expose auth cache helpers as module functions

Quick reminder: module functions are available on the module itself and
also added as `private` methods when the module is included. It is best
that they are stateless, or rely on a more global state,  due to this
dual accessibility.

This is in preparation for providing a new set of RSpec auth helpers
targeting API endpoints. Most APIs are stateless and the newer Rails 5
`ActionController::API` base class does not mix in cookie or session
support by default. Because of this the existing `sign_in` helper is not
properly suited for these controllers.

Additionally, for API endpoints the `sign_in` helper hides the fact that
authentication _must_ be provided through the `Authorization` header;
instead of assuming it was set previously in the session. This could
cause some edge cases bugs to slip through where authorization isn't
getting set, checked, or goes through the proper process.

Author: cupakromer

lib/kracken/controllers/token_authenticatable.rb

@@ -29,6 +29,27 @@ def request_http_token_authentication(realm = 'Application')
         end
       end
 
+    module_function
+
+      def cache_valid_auth(token, &generate_cache)
+        cache_key = "auth/token/#{token}"
+        val = Rails.cache.read(cache_key)
+        val ||= store_valid_auth(cache_key, &generate_cache)
+        shallow_freeze(val)
+      end
+
+      def shallow_freeze(val)
+        # `nil` is frozen in Ruby 2.2 but not in Ruby 2.1
+        return val if val.frozen? || val.nil?
+        val.each { |_k, v| v.freeze }.freeze
+      end
+
+      def store_valid_auth(cache_key)
+        val = yield
+        Rails.cache.write(cache_key, val, CACHE_TTL_OPTS) if val
+        val
+      end
+
     private
 
       CACHE_TTL_OPTS = {
@@ -51,19 +72,6 @@ def authenticate_user_with_token!
         }
       end
 
-      def cache_valid_auth(token, &generate_cache)
-        cache_key = "auth/token/#{token}"
-        val = Rails.cache.read(cache_key)
-        val ||= store_valid_auth(cache_key, &generate_cache)
-        shallow_freeze(val)
-      end
-
-      def shallow_freeze(val)
-        # `nil` is frozen in Ruby 2.2 but not in Ruby 2.1
-        return val if val.frozen? || val.nil?
-        val.each { |_k, v| v.freeze }.freeze
-      end
-
       def current_auth_info
         @_auth_info ||= {}
       end
@@ -96,12 +104,6 @@ def munge_header_auth_token!
       def realm
         self.class.realm
       end
-
-      def store_valid_auth(cache_key)
-        val = yield
-        Rails.cache.write(cache_key, val, CACHE_TTL_OPTS) if val
-        val
-      end
     end
 
   end