Refactor ActionDispatch::RemoteIp

Refactored IP address checking in ActionDispatch::RemoteIp to rely on
the IPAddr class instead of the unwieldly regular expression to match
IP addresses. This commit keeps the same api but allows users to pass
IPAddr objects to config.action_dispatch.trusted_proxies in addition
to passing strings and regular expressions.

Example:

    # config/environments/production.rb
    config.action_dispatch.trusted_proxies = IPAddr.new('4.8.15.0/16')

1 files changed, 15 insertions, 1 deletions

diff --git a/railties/test/application/middleware/remote_ip_test.rb b/railties/test/application/middleware/remote_ip_test.rb
index 946b82eeb3..97d5b5c698 100644
--- a/railties/test/application/middleware/remote_ip_test.rb
+++ b/railties/test/application/middleware/remote_ip_test.rb
@@ -1,3 +1,4 @@
+require 'ipaddr'
 require 'isolation/abstract_unit'
 require 'active_support/key_generator'
 
@@ -53,12 +54,25 @@ module ApplicationTests
       end
     end
 
+    test "remote_ip works with HTTP_X_FORWARDED_FOR" do
+      make_basic_app
+      assert_equal "4.2.42.42", remote_ip("REMOTE_ADDR" => "1.1.1.1", "HTTP_X_FORWARDED_FOR" => "4.2.42.42")
+    end
+
     test "the user can set trusted proxies" do
       make_basic_app do |app|
         app.config.action_dispatch.trusted_proxies = /^4\.2\.42\.42$/
       end
 
-      assert_equal "1.1.1.1", remote_ip("REMOTE_ADDR" => "4.2.42.42,1.1.1.1")
+      assert_equal "1.1.1.1", remote_ip("REMOTE_ADDR" => "1.1.1.1", "HTTP_X_FORWARDED_FOR" => "4.2.42.42")
+    end
+
+    test "the user can set trusted proxies with an IPAddr argument" do
+      make_basic_app do |app|
+        app.config.action_dispatch.trusted_proxies = IPAddr.new('4.2.42.0/24')
+      end
+
+      assert_equal "1.1.1.1", remote_ip("REMOTE_ADDR" => "1.1.1.1", "HTTP_X_FORWARDED_FOR" => "10.0.0.0,4.2.42.42")
     end
   end
 end