Topic: Save zip to db then extract it later

So I upload a zipfile and in my controller do

 infile = params[:file]
 @job = BackgroundJob.new
 @job.filename = infile.original_filename
 @job.content_type = infile.content_type
 @job.data = infile.read 
 @job.save

Then I want to read that @job.data and do some stuff with it

f=BackgroundJob.find 59
@junk=unzip(f.data)

The unzip function

def unzip(zip_source)
    first_time=true
    Zip::ZipFile.open(zip_source) do |zip_file|
      zip_file.each do |f|
        if first_time
          first_time=false
          return f.get_input_stream.read
        end        
      end
    end
    nil
  end

But gems/rubyzip-0.9.9/lib/zip/zip_file.rb:65 returns the error string contains null byte
Can someone help me?