Character encoding detection in attachments is now automatic

app/helpers/attachments_helper.rb

@@ -12,6 +12,9 @@
 # See doc/COPYRIGHT.rdoc for more details.
 #++
 
+require 'rubygems'
+require 'UniversalDetector'
+
 module AttachmentsHelper
   # Displays view/delete links to the attachments of the given object
   # Options:
@@ -26,18 +29,16 @@ module AttachmentsHelper
   end
 
   def to_utf8_for_attachments(str)
-    if str.respond_to?(:force_encoding)
-      str.force_encoding('UTF-8')
-      return str if str.valid_encoding?
-    else
-      return str if /\A[\r\n\t\x20-\x7e]*\Z/n.match(str) # for us-ascii
-    end
-
-    begin
-      Iconv.conv('UTF-8//IGNORE', 'UTF-8', str + '  ')[0..-3]
-    rescue Iconv::InvalidEncoding
-      # "UTF-8//IGNORE" is not supported on some OS
-      str
-    end
+      return nil if str.nil?
+      iconv_str = str
+      detected = UniversalDetector::chardet(str)
+      enc = detected['encoding']
+      if !enc.nil?
+        begin
+          iconv_str = Iconv.conv('UTF-8', enc, str)
+        rescue Iconv::Failure => err
+        end
+      end
+      iconv_str
   end
 end