ucf

https://github.com/myGrid/ruby-ucf

A Ruby library for working with Universal Container Format files - a type of EPUB document. See the UCF specification (https://learn.adobe.com/wiki/display/PDFNAV/Universal+Container+Format) for details. They are very similar, although not as restrictive, as the EPUB Open Container Format (OCF) (http://www.idpf.org/epub/30/spec/epub30-ocf.html).