I'm working on implementing Ajax-Upload for uploading photos in my Rails 3 app. The documentation says:

1. For IE6-8, Opera, older versions of other browsers you get the file as you normally do with regular form-base uploads.

2. For browsers which upload file with progress bar, you will need to get the raw post data and write it to the file.

So, how can I receive the raw post data in my controller and write it to a tmp file so my controller can then process it? (In my case the controller is doing some image manipulation and saving to S3.)

Some additional info:

As I'm configured right now the post is passing these parameters:

Parameters:
{"authenticity_token"=>"...", "qqfile"=>"IMG_0064.jpg"}

... and the CREATE action looks like this:

def create
    @attachment = Attachment.new
    @attachment.user = current_user
    @attachment.file = params[:qqfile]
    if @attachment.save!
        respond_to do |format|
            format.js { render :text => '{"success":true}' }
        end
    end
end

... but I get this error:

ActiveRecord::RecordInvalid (Validation failed: File file name must be set.):
  app/controllers/attachments_controller.rb:7:in `create'