Save generated image file as a Paperclip attachment

Question

I have a method which is generating QR code for some string using rqrcode-rails3 gem:

def generate_qrcode(string, options={})
  format = options[:format] || :png
  size   = options[:size]   || RQRCode.minimum_qr_size_from_string(string)
  level  = options[:level]  || :h

  qrcode = RQRCode::QRCode.new(string, size: size, level: level)
  svg    = RQRCode::Renderers::SVG::render(qrcode, options)

  image = MiniMagick::Image.read(svg) { |i| i.format "svg" }
  image.format "png" if format == :png
  image
end

That newly generated image would be attached to the model object and stored in the database using paperclip:

has_attached_file :qrcode_png
has_attached_file :qrcode_svg

When I have been tried to attach the image:

label.qrcode_png = generate_qrcode(label.id.to_s)
label.save!

and got an exception Paperclip::AdapterRegistry::NoHandlerError

No handler found for MiniMagick::Image:0x007fa629e71388 @path="/var/folders/fs/yf7s27kj27n3lmdywp4tgcm80000gn/T/mini_magick20120816-2170-1w6vbz.png", @tempfile=#

What's a problem with my code?

Answer 1

Ok, I got it. I have to return a file object instead of MiniMagick::Image:

File.open(image.path)

Then paperclip can find and read a file from the file system and save it.