Add `:restricted_characters` default options

Introducing `:restricted_characters` in Paperclip::Attachment.default_options  so people can override their blacklist characters by override that setting.

ChangeLog

 2012-01-27  Prem Sichanugrist <psichanugrist@thoughtbot.com>
 
+* Introducing `:restricted_characters` in Paperclip::Attachment.default_options
+  so people can override their blacklist characters by override that setting.
+
 * Paperclip will now replace all the special characters in the filename to an
   underscore. This is a more desired behavior against having to deal with URL
   escaping and unescaping later. You can see the list of blacklist characters

lib/paperclip/attachment.rb

@@ -14,6 +14,7 @@ module Paperclip
         :convert_options       => {},
         :default_style         => :original,
         :default_url           => "/:attachment/:style/missing.png",
+        :restricted_characters => /[&$+,\/:;=?@<>\[\]\{\}\|\\\^~%# ]/,
         :hash_data             => ":class/:attachment/:id/:style/:updated_at",
         :hash_digest           => "SHA1",
         :interpolator          => Paperclip::Interpolations,
@@ -25,10 +26,10 @@ module Paperclip
         :storage               => :filesystem,
         :styles                => {},
         :url                   => "/system/:attachment/:id/:style/:filename",
-        :url_generator         => Paperclip::UrlGenerator
+        :url_generator         => Paperclip::UrlGenerator,
         :use_default_time_zone => true,
         :use_timestamp         => true,
-        :whiny                 => Paperclip.options[:whiny] || Paperclip.options[:whiny_thumbnails],
+        :whiny                 => Paperclip.options[:whiny] || Paperclip.options[:whiny_thumbnails]
       }
     end
 
@@ -479,7 +480,9 @@ module Paperclip
     end
 
     def cleanup_filename(filename)
-      filename.gsub(/[&$+,\/:;=?@<>\[\]\{\}\|\\\^~%# ]/, '_')
+      if @options[:restricted_characters]
+        filename.gsub(@options[:restricted_characters], '_')
+      end
     end
   end
 end

test/attachment_test.rb

@@ -714,15 +714,18 @@ class AttachmentTest < Test::Unit::TestCase
   end
 
   context "Attachment with reserved filename" do
-    "&$+,/:;=?@<>[]{}|\^~%# ".split(//).each do |character|
-      context "with character #{character}" do
     setup do
       rebuild_model
+      @file = StringIO.new(".")
+    end
 
-          file = StringIO.new(".")
-          file.stubs(:original_filename).returns("file#{character}name.png")
+    context "with default configuration" do
+      "&$+,/:;=?@<>[]{}|\^~%# ".split(//).each do |character|
+        context "with character #{character}" do
+          setup do
+            @file.stubs(:original_filename).returns("file#{character}name.png")
             @dummy = Dummy.new
-          @dummy.avatar = file
+            @dummy.avatar = @file
           end
 
           should "convert special character into underscore" do
@@ -732,6 +735,26 @@ class AttachmentTest < Test::Unit::TestCase
       end
     end
 
+    context "with specified regexp replacement" do
+      setup do
+        @old_defaults = Paperclip::Attachment.default_options.dup
+        Paperclip::Attachment.default_options.merge! :restricted_characters => /o/
+
+        @file.stubs(:original_filename).returns("goood.png")
+        @dummy = Dummy.new
+        @dummy.avatar = @file
+      end
+
+      teardown do
+        Paperclip::Attachment.default_options.merge! @old_defaults
+      end
+
+      should "match and convert that character" do
+        assert_equal "g___d.png", @dummy.avatar.original_filename
+      end
+    end
+  end
+
   context "Attachment with uppercase extension and a default style" do
     setup do
       @old_defaults = Paperclip::Attachment.default_options.dup