Fix a potential bug when user turn on AWS logging

This should fix an error when the user has turn on AWS logging while
and upload a file with non-English filename, as `aws-sdk` logger is not
encoding aware.

The problem was that the string returned from another logger methods
is in `US-ASCII`, while the string returned from Paperclip would be in
`UTF-8`. When the logger calls `#join` on those strings, Ruby would
raise an exception.

This solution is not the best, as it involves a monkey-patching, but
should make sure that the upload goes through without any hiccup. For
the long run, I'm going to send a patch to `aws-sdk` and also make
Paperclip require at least `aws-sdk > 1.4.1`

lib/paperclip/storage/s3.rb

@@ -85,6 +85,21 @@ module Paperclip
       def self.extended base
         begin
           require 'aws-sdk'
+
+          # Overriding AWS::Core::LogFormatter to make sure it return a UTF-8 string
+          if AWS::VERSION >= "1.3.9"
+            AWS::Core::LogFormatter.class_eval do
+              def summarize_hash(hash)
+                hash.map { |key, value| ":#{key}=>#{summarize_value(value)}".force_encoding('UTF-8') }.sort.join(',')
+              end
+            end
+          else
+            AWS::Core::ClientLogging.class_eval do
+              def sanitize_hash(hash)
+                hash.map { |key, value| "#{sanitize_value(key)}=>#{sanitize_value(value)}".force_encoding('UTF-8') }.sort.join(',')
+              end
+            end
+          end
         rescue LoadError => e
           e.message << " (You may need to install the aws-sdk gem)"
           raise e

test/integration_test.rb

+# encoding: utf-8
+
 require './test/helper'
 require 'open-uri'
 
@@ -635,6 +637,18 @@ class IntegrationTest < Test::Unit::TestCase
         headers = s3_headers_for(@dummy.avatar, :original)
         assert_equal 'image/png', headers['content-type']
       end
+
+      context "with non-english character in the file name" do
+        setup do
+
+          @file.stubs(:original_filename).returns("クリップ.png")
+          @dummy.avatar = @file
+        end
+
+        should "not raise any error" do
+          @dummy.save!
+        end
+      end
     end
   end
 end