1 files changed, 31 insertions, 22 deletions

diff --git a/actionpack/lib/action_dispatch/http/url.rb b/actionpack/lib/action_dispatch/http/url.rb
index 64459836b5..4266ec042e 100644
--- a/actionpack/lib/action_dispatch/http/url.rb
+++ b/actionpack/lib/action_dispatch/http/url.rb
@@ -1,6 +1,8 @@
 module ActionDispatch
   module Http
     module URL
+      IP_HOST_REGEXP = /\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/
+
       mattr_accessor :tld_length
       self.tld_length = 1
 
@@ -21,38 +23,45 @@ module ActionDispatch
         end
 
         def url_for(options = {})
-          unless options[:host].present? || options[:only_path].present?
+          path = ""
+          path << options.delete(:script_name).to_s.chomp("/")
+          path << options.delete(:path).to_s
+
+          params = options[:params] || {}
+          params.reject! {|k,v| v.to_param.nil? }
+
+          result = build_host_url(options)
+
+          result << (options[:trailing_slash] ? path.sub(/\?|\z/) { "/" + $& } : path)
+          result << "?#{params.to_query}" unless params.empty?
+          result << "##{Journey::Router::Utils.escape_fragment(options[:anchor].to_param.to_s)}" if options[:anchor]
+          result
+        end
+
+        private
+
+        def build_host_url(options)
+          if options[:host].blank? && options[:only_path].blank?
             raise ArgumentError, 'Missing host to link to! Please provide the :host parameter, set default_url_options[:host], or set :only_path to true'
           end
 
-          rewritten_url = ""
+          result = ""
 
           unless options[:only_path]
             unless options[:protocol] == false
-              rewritten_url << (options[:protocol] || "http")
-              rewritten_url << ":" unless rewritten_url.match(%r{:|//})
+              result << (options[:protocol] || "http")
+              result << ":" unless result.match(%r{:|//})
             end
-            rewritten_url << "//" unless rewritten_url.match("//")
-            rewritten_url << rewrite_authentication(options)
-            rewritten_url << host_or_subdomain_and_domain(options)
-            rewritten_url << ":#{options.delete(:port)}" if options[:port]
+            result << "//" unless result.match("//")
+            result << rewrite_authentication(options)
+            result << host_or_subdomain_and_domain(options)
+            result << ":#{options.delete(:port)}" if options[:port]
           end
-
-          path = options.delete(:path) || ''
-
-          params = options[:params] || {}
-          params.reject! {|k,v| v.to_param.nil? }
-
-          rewritten_url << (options[:trailing_slash] ? path.sub(/\?|\z/) { "/" + $& } : path)
-          rewritten_url << "?#{params.to_query}" unless params.empty?
-          rewritten_url << "##{Journey::Router::Utils.escape_fragment(options[:anchor].to_param.to_s)}" if options[:anchor]
-          rewritten_url
+          result
         end
 
-        private
-
         def named_host?(host)
-          !(host.nil? || /\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/.match(host))
+          host && IP_HOST_REGEXP !~ host
         end
 
         def rewrite_authentication(options)
@@ -167,7 +176,7 @@ module ActionDispatch
       # such as 2 to catch <tt>"www"</tt> instead of <tt>"www.rubyonrails"</tt>
       # in "www.rubyonrails.co.uk".
       def subdomain(tld_length = @@tld_length)
-        subdomains(tld_length).join(".")
+        ActionDispatch::Http::URL.extract_subdomain(host, tld_length)
       end
     end
   end