some changes

config/initializers/sunspot.rb

@@ -0,0 +1,74 @@
+# config/initializers/sunspot.rb
+module Sunspot
+  # 
+  # DataExtractors present an internal API for the indexer to use to extract
+  # field values from models for indexing. They must implement the #value_for
+  # method, which takes an object and returns the value extracted from it.
+  #
+  module DataExtractor #:nodoc: all
+    # 
+    # AttributeExtractors extract data by simply calling a method on the block.
+    #
+    class AttributeExtractor
+      def initialize(attribute_name)
+        @attribute_name = attribute_name
+      end
+
+      def value_for(object)
+        Filter.new( object.send(@attribute_name) ).value
+      end
+    end
+   # 
+    # BlockExtractors extract data by evaluating a block in the context of the
+    # object instance, or if the block takes an argument, by passing the object
+    # as the argument to the block. Either way, the return value of the block is
+    # the value returned by the extractor.
+    #
+    class BlockExtractor
+      def initialize(&block)
+        @block = block
+      end
+
+      def value_for(object)
+        Filter.new( Util.instance_eval_or_call(object, &@block) ).value
+      end
+    end
+
+    # 
+    # Constant data extractors simply return the same value for every object.
+    #
+    class Constant
+      def initialize(value)
+        @value = value
+      end
+
+      def value_for(object)
+        Filter.new(@value).value
+      end
+    end
+
+    # 
+    # A Filter to allow easy value cleaning
+    #
+    class Filter
+      def initialize(value)
+        @value = value
+      end
+      def value
+        strip_control_characters @value
+      end
+      def strip_control_characters(value)
+        return value unless value.is_a? String
+
+        value.chars.inject("") do |str, char|
+          unless char.ascii_only? and (char.ord < 32 or char.ord == 127)
+            str << char
+          end
+          str
+        end
+
+      end
+    end
+
+  end
+end