encoding error with ajax upload (qqfile) and paperclip - ruby-on-rails-3

Question

I'm trying to get an ajax upload working with rails 3.1.3 and paperclip.
I found this solution to my problem Rails 3 get raw post data and write it to tmp file, but using this, I get an 'encoding undefined conversion error "\xFF" from ASCII-8BIT to UTF-8.
The error occurs at the line #user.photo = #user.photo = QqFile.parse(params[:qqfile], request)
I have not edited the code supplied in the previous answer, but I'll include it here so you don't have to switch back and forth.
the gem list paperclip, returns 2.5.2, 2.4.5, 2.3.8
my controller
def create
#user = User.new(params[:user])
#user.photo = QqFile.parse(params[:qqfile], request)
if #user.save
return render :json => #user
else
return render :json => #user.errors
end
end
qq_file.rb
# encoding: utf-8
require 'digest/sha1'
require 'mime/types'
# Usage (paperclip example)
# #asset.data = QqFile.new(params[:qqfile], request)
class QqFile < ::Tempfile
def initialize(filename, request, tmpdir = Dir::tmpdir)
#original_filename = filename
#request = request
super Digest::SHA1.hexdigest(filename), tmpdir
fetch
end
def self.parse(*args)
return args.first unless args.first.is_a?(String)
new(*args)
end
def fetch
self.write #request.raw_post
self.rewind
self
end
def original_filename
#original_filename
end
def content_type
types = MIME::Types.type_for(#request.content_type)
types.empty? ? #request.content_type : types.first.to_s
end
end

Answer 1

This was an encoding error related to Ruby 1.9.2 (or I believe Ruby 1.9+).
this github post lead to the answer
https://github.com/lassebunk/webcam_app/issues/1
You must specify raw_post.force_encoding("UTF-8") when reading an upload as far as I could tell (I'm not a great programmer).