Added the beginnings of the observe_field helper

actionpack/lib/action_view/helpers/ajax_helper.rb

@@ -33,7 +33,19 @@ module ActionView
         
         tag(:input, html_options)
       end
-      
+
+      def observe_field(name, options = {}, html_options = {})
+        url = options.delete(:url)
+        url = url_for(url) if url.is_a?(Hash)
+
+        if frequency = options.delete(:frequency)
+          html_options[:"data-frequency"] = frequency
+        end
+
+        html_options.merge!(:"data-observe" => true, :"data-url" => url)
+        tag(:input, html_options)
+      end
+
       module Rails2Compatibility
         def set_callbacks(options, html)
           [:complete, :failure, :success, :interactive, :loaded, :loading].each do |type|

actionpack/test/template/ajax_test.rb

@@ -112,3 +112,58 @@ class ButtonToRemoteTest < AjaxTestCase
     end
   end
 end
+
+class ObserveFieldTest < AjaxTestCase
+  def url_for(hash)
+    "/blog/update"
+  end
+
+  def protect_against_forgery?
+    false
+  end
+
+  def field(options = {})
+    observe_field("title", options)
+  end
+
+  test "basic" do
+    assert_html field,
+      %w(data-observe="true")
+  end
+
+  test "with a :frequency option" do
+    assert_html field(:frequency => 5.minutes),
+      %w(data-observe="true" data-frequency="300")
+  end
+
+  test "using a url string" do
+    assert_html field(:url => "/some/other/url"),
+      %w(data-observe="true" data-url="/some/other/url")
+  end
+
+  test "using a url hash" do
+    assert_html field(:url => {:controller => :blog, :action => :update}),
+      %w(data-observe="true" data-url="/blog/update")
+  end
+
+#  def test_observe_field
+#    assert_dom_equal %(<script type=\"text/javascript\">\n//<![CDATA[\nnew Form.Element.Observer('glass', 300, function(element, value) {new Ajax.Request('http://www.example.com/reorder_if_empty', {asynchronous:true, evalScripts:true, parameters:value})})\n//]]>\n</script>),
+#      observe_field("glass", :frequency => 5.minutes, :url => { :action => "reorder_if_empty" })
+#  end
+#
+#  def test_observe_field_using_with_option
+#    expected = %(<script type=\"text/javascript\">\n//<![CDATA[\nnew Form.Element.Observer('glass', 300, function(element, value) {new Ajax.Request('http://www.example.com/check_value', {asynchronous:true, evalScripts:true, parameters:'id=' + encodeURIComponent(value)})})\n//]]>\n</script>)
+#    assert_dom_equal expected, observe_field("glass", :frequency => 5.minutes, :url => { :action => "check_value" }, :with => 'id')
+#    assert_dom_equal expected, observe_field("glass", :frequency => 5.minutes, :url => { :action => "check_value" }, :with => "'id=' + encodeURIComponent(value)")
+#  end
+#
+#  def test_observe_field_using_json_in_with_option
+#    expected = %(<script type=\"text/javascript\">\n//<![CDATA[\nnew Form.Element.Observer('glass', 300, function(element, value) {new Ajax.Request('http://www.example.com/check_value', {asynchronous:true, evalScripts:true, parameters:{'id':value}})})\n//]]>\n</script>)
+#    assert_dom_equal expected, observe_field("glass", :frequency => 5.minutes, :url => { :action => "check_value" }, :with => "{'id':value}")
+#  end
+#
+#  def test_observe_field_using_function_for_callback
+#    assert_dom_equal %(<script type=\"text/javascript\">\n//<![CDATA[\nnew Form.Element.Observer('glass', 300, function(element, value) {alert('Element changed')})\n//]]>\n</script>),
+#      observe_field("glass", :frequency => 5.minutes, :function => "alert('Element changed')")
+#  end
+end