Barby failing to generate some QR Codes - nil.rszf

Question

In irb

data = "2 1058 657682" barcode = Barby::QrCode.new(data) File.open('barcode.png', 'w+') {|f| f.write barcode.to_png(:height => 100, :margin => 25, :xdim => 100) }

Generates error:

ActionView::TemplateError (/Library/Ruby/Gems/1.8/gems/barby-    0.4.0/vendor/rqrcode/lib/rqrcode/qrcode/qr_code.rb:296:in `map_data': You have a nil     object when you didn't expect it!
The error occurred while evaluating nil.rszf) on line <a href="/toretore/barby/issues/#issue/1" class="internal">#1</a> of app/views/profile/ticket.rpdf:
1: pdf.font_families["Helvetica"] =
2: {
3:   "b"   => "Helvetica-Bold",
4:   "i"   => "Helvetica-Oblique"    
lib/pdf_render.rb:46:in `pdf'
barby (0.4.0) vendor/rqrcode/lib/rqrcode/qrcode/qr_code.rb:291:in `each'
barby (0.4.0) vendor/rqrcode/lib/rqrcode/qrcode/qr_code.rb:291:in `map_data'
barby (0.4.0) vendor/rqrcode/lib/rqrcode/qrcode/qr_code.rb:287:in `step'
barby (0.4.0) vendor/rqrcode/lib/rqrcode/qrcode/qr_code.rb:287:in `map_data'
barby (0.4.0) vendor/rqrcode/lib/rqrcode/qrcode/qr_code.rb:172:in `make_impl'
barby (0.4.0) vendor/rqrcode/lib/rqrcode/qrcode/qr_code.rb:196:in `get_best_mask_pattern'
barby (0.4.0) vendor/rqrcode/lib/rqrcode/qrcode/qr_code.rb:195:in `each'
barby (0.4.0) vendor/rqrcode/lib/rqrcode/qrcode/qr_code.rb:195:in `get_best_mask_pattern'
barby (0.4.0) vendor/rqrcode/lib/rqrcode/qrcode/qr_code.rb:145:in `make'
barby (0.4.0) vendor/rqrcode/lib/rqrcode/qrcode/qr_code.rb:85:in `initialize'
barby (0.4.0) lib/barby/barcode/qr_code.rb:94:in `new'
barby (0.4.0) lib/barby/barcode/qr_code.rb:94:in `rqrcode'
barby (0.4.0) lib/barby/barcode/qr_code.rb:55:in `encoding'
barby (0.4.0) lib/barby/outputter.rb:86:in `encoding'
barby (0.4.0) lib/barby/outputter/png_outputter.rb:67:in `height'
barby (0.4.0) lib/barby/outputter.rb:116:in `send'
barby (0.4.0) lib/barby/outputter.rb:116:in `with_options'
barby (0.4.0) lib/barby/outputter.rb:114:in `each'
barby (0.4.0) lib/barby/outputter.rb:114:in `inject'
barby (0.4.0) lib/barby/outputter.rb:114:in `with_options'
barby (0.4.0) lib/barby/outputter/png_outputter.rb:18:in `to_canvas'
barby (0.4.0) lib/barby/outputter/png_outputter.rb:58:in `to_png'
barby (0.4.0) lib/barby/barcode.rb:70:in `send'
barby (0.4.0) lib/barby/barcode.rb:70:in `method_missing'
(eval):107:in `pdf'
(eval):88:in `each'
(eval):88:in `pdf'
lib/pdf_render.rb:18:in `eval'
lib/pdf_render.rb:46:in `pdf'
lib/pdf_render.rb:18:in `render'
...

Whereas if I change data to "2 1058 657681" (replace the final '2' for a '1') it works fine.

Gems:

barby 0.4.0 png 1.1.0 (1.2.0 kept getting String::CompilationError)

Answer 1

Cheers! Looks like rqrcode and in turn Barby have been updated to fix this bug. toretore/barby

Answer 2

In line 295 of barby-<version>/vendor/rqrcode/lib/rqrcode/qrcode/qr_code.rb, change

if byte_index < data.size

into

if byte_index < data.size && ! data[byte_index].nil?

Have fun!

Answer 3

Tried with Barby 0.4.2 and it fails as well. The problem is in the RQRCode library which is still in version 0.3.2.

You can try and pass a :size parameter to override the dinamically calculated one but it will eventually fail on a different string.

The only way I found to bypass the problem was to try in one level and try another if it fails.

begin
  student_barcode = Barby::QrCode.new(content, :level => :q)
rescue NoMethodError
  student_barcode = Barby::QrCode.new(content, :level => :m)
end

An error generated in one level did not occur in another.. wierd but works.