I built the site using Ruby on Rails, and ended up trying all the PDF libraries I could find. In the end I had to use six different libraries and tools to solve various problems with parsing or transforming PDFs.
The libraries I use are: pdf-reader [1], prawn [2], prawn-templates [3], origami [4], qpdf [5], and pdftk [6].
There's a new PDF library for Ruby called hexapdf [7], and it looks really promising. I think it might even be able to replace all six of these libraries, but it's released under the AGPL license, and commercial licenses are not available yet.
The libraries I use are: pdf-reader [1], prawn [2], prawn-templates [3], origami [4], qpdf [5], and pdftk [6].
There's a new PDF library for Ruby called hexapdf [7], and it looks really promising. I think it might even be able to replace all six of these libraries, but it's released under the AGPL license, and commercial licenses are not available yet.
[1] https://github.com/yob/pdf-reader
[2] https://github.com/prawnpdf/prawn
[3] https://github.com/prawnpdf/prawn-templates
[4] https://github.com/gdelugre/origami
[5] http://qpdf.sourceforge.net/
[6] https://www.pdflabs.com/tools/pdftk-the-pdf-toolkit/
[7] https://hexapdf.gettalong.org/