fangxing

If you using this for ISBN, you can make use of [check digit](https://en.wikipedia.org/wiki/International_Standard_Book_Number#Check_digits)

@ericblade Thanks, I realized the barcode is too small(ISBN), then I set a [zoom value] (https://github.com/serratus/quaggaJS/issues/307), the accuracy has boosted dramatically.

Rails has similar function now [.annotate_template_file_names annotates HTML output with template file names](https://github.com/rails/rails/pull/38848)， haml support this since 5.2.2 https://github.com/haml/haml/releases/tag/v5.2.2

It seems Rails expects a url or path as a string, so we can convert it to string: ``` post request.uri.to_s, params: request.body, headers: request.headers ```