Allow loading external route files from the router

This feature enables the ability to load an
external routes file from the router via:
  draw :filename

External routes files go in +config/routes+. This
feature works in both engines and applications.

2 files changed, 18 insertions, 0 deletions

diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index fdc0bfb686..716e2d2271 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -1305,6 +1305,21 @@ module ActionDispatch
           parent_resource.instance_of?(Resource) && @scope[:shallow]
         end
 
+        def draw(name)
+          path = @draw_paths.find do |path|
+            path.join("#{name}.rb").file?
+          end
+
+          unless path
+            msg  = "Your router tried to #draw the external file #{name}.rb,\n" \
+                   "but the file was not found in:\n\n"
+            msg += @draw_paths.map { |path| " * #{path}" }.join("\n")
+            raise msg
+          end
+
+          instance_eval(path.join("#{name}.rb").read)
+        end
+
         # match 'path' => 'controller#action'
         # match 'path', to: 'controller#action'
         # match 'path', 'otherpath', on: :member, via: :get
@@ -1554,6 +1569,7 @@ module ActionDispatch
 
       def initialize(set) #:nodoc:
         @set = set
+        @draw_paths = set.draw_paths
         @scope = { :path_names => @set.resources_path_names }
       end
 
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index f1aa131cbb..7a7810a95c 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -255,6 +255,7 @@ module ActionDispatch
       attr_accessor :formatter, :set, :named_routes, :default_scope, :router
       attr_accessor :disable_clear_and_finalize, :resources_path_names
       attr_accessor :default_url_options, :request_class, :valid_conditions
+      attr_accessor :draw_paths
 
       alias :routes :set
 
@@ -266,6 +267,7 @@ module ActionDispatch
         self.named_routes = NamedRouteCollection.new
         self.resources_path_names = self.class.default_resources_path_names.dup
         self.default_url_options = {}
+        self.draw_paths = []
 
         self.request_class = request_class
         @valid_conditions = {}