ability to define custom sanitizers for filenames

lib/paperclip/attachment.rb

@@ -14,6 +14,7 @@ module Paperclip
         :default_url           => "/:attachment/:style/missing.png",
         :escape_url            => true,
         :restricted_characters => /[&$+,\/:;=?@<>\[\]\{\}\|\\\^~%# ]/,
+        :filename_sanitizer    => nil,
         :hash_data             => ":class/:attachment/:id/:style/:updated_at",
         :hash_digest           => "SHA1",
         :interpolator          => Paperclip::Interpolations,
@@ -98,7 +99,12 @@ module Paperclip
       return nil if file.nil?
 
       @queued_for_write[:original]   = file
-      instance_write(:file_name,       cleanup_filename(file.original_filename))
+      cleaned_filename = if @options[:filename_sanitizer]
+        @options[:filename_sanitizer].call(file.original_filename, self)
+      else
+        cleanup_filename(file.original_filename)
+      end
+      instance_write(:file_name,       cleaned_filename)
       instance_write(:content_type,    file.content_type.to_s.strip)
       instance_write(:file_size,       file.size)
       instance_write(:fingerprint,     file.fingerprint) if instance_respond_to?(:fingerprint)
@@ -360,6 +366,14 @@ module Paperclip
       end
     end
 
+    def cleanup_filename(filename)
+      if @options[:restricted_characters]
+        filename.gsub(@options[:restricted_characters], '_')
+      else
+        filename
+      end
+    end
+
     private
 
     def path_option
@@ -480,14 +494,6 @@ module Paperclip
        end
     end
 
-    def cleanup_filename(filename)
-      if @options[:restricted_characters]
-        filename.gsub(@options[:restricted_characters], '_')
-      else
-        filename
-      end
-    end
-
     # Check if attachment database table has a created_at field
     def able_to_store_created_at?
       @instance.respond_to?("#{name}_created_at".to_sym)

test/attachment_test.rb

@@ -916,6 +916,40 @@ class AttachmentTest < Test::Unit::TestCase
         end
       end
     end
+
+    context 'with specified sanitizer proc' do
+      setup do
+        @old_defaults = Paperclip::Attachment.default_options.dup
+      end
+
+      teardown do
+        Paperclip::Attachment.default_options.merge! @old_defaults
+      end
+
+      should 'call proc and take it result as cleaned filename' do
+        proc = Proc.new do |str, attachment|
+          "from_proc_#{str}"
+        end
+        Paperclip::Attachment.default_options[:filename_sanitizer] = proc
+
+        @file.stubs(:original_filename).returns("goood.png")
+        @dummy = Dummy.new
+        @dummy.avatar = @file
+        assert_equal "from_proc_goood.png", @dummy.avatar.original_filename
+      end
+
+      should 'be able to call cleanup_filename from proc' do
+        proc = Proc.new do |str, attachment|
+          attachment.cleanup_filename "from_proc_#{str}"
+        end
+        Paperclip::Attachment.default_options[:filename_sanitizer] = proc
+
+        @file.stubs(:original_filename).returns("go/ood.png")
+        @dummy = Dummy.new
+        @dummy.avatar = @file
+        assert_equal "from_proc_go_ood.png", @dummy.avatar.original_filename
+      end
+    end
   end
 
   context "Attachment with uppercase extension and a default style" do