diff --git a/lib/sinatra/base.rb b/lib/sinatra/base.rb
index b41e2cac..f2d60fb4 100644
--- a/lib/sinatra/base.rb
+++ b/lib/sinatra/base.rb
@@ -109,6 +109,23 @@ module Sinatra
       halt(*args)
     end
 
+    # Generates the absolute URI for a given path in the app.
+    # Takes Rack routers and reverse proxies into account.
+    def uri(addr = nil, absolute = true, add_script_name = true)
+      return addr if addr =~ /^https?:\/\//
+      uri = [host = ""]
+      if absolute
+        host << "#{request.scheme}://#{request.host}"
+        host << ":#{request.port}" unless request.port == (request.secure? ? 443 : 80)
+      end
+      uri << request.script_name.to_s if add_script_name
+      uri << (addr ? addr : request.path_info).to_s
+      File.join uri
+    end
+
+    alias url uri
+    alias to uri
+
     # Halt processing and return the error status provided.
     def error(code, body=nil)
       code, body    = 500, code.to_str if code.respond_to? :to_str
diff --git a/test/helpers_test.rb b/test/helpers_test.rb
index 612a9996..935cc2ab 100644
--- a/test/helpers_test.rb
+++ b/test/helpers_test.rb
@@ -694,6 +694,44 @@ class HelpersTest < Test::Unit::TestCase
     end
   end
 
+  describe 'uri' do
+    it 'generates absolute urls' do
+      mock_app { get('/') { uri }}
+      get '/'
+      assert_equal 'http://example.org/', body
+    end
+
+    it 'includes path_info' do
+      mock_app { get('/:name') { uri }}
+      get '/foo'
+      assert_equal 'http://example.org/foo', body
+    end
+
+    it 'allows passing an alternative to path_info' do
+      mock_app { get('/:name') { uri '/bar' }}
+      get '/foo'
+      assert_equal 'http://example.org/bar', body
+    end
+
+    it 'includes script_name' do
+      mock_app { get('/:name') { uri '/bar' }}
+      get '/foo', {}, { "SCRIPT_NAME" => '/foo' }
+      assert_equal 'http://example.org/foo/bar', body
+    end
+
+    it 'is aliased to #url' do
+      mock_app { get('/') { url }}
+      get '/'
+      assert_equal 'http://example.org/', body
+    end
+
+    it 'is aliased to #to' do
+      mock_app { get('/') { to }}
+      get '/'
+      assert_equal 'http://example.org/', body
+    end
+  end
+
   module ::HelperOne; def one; '1'; end; end
   module ::HelperTwo; def two; '2'; end; end