EPUB schema metadata/date/event and metadata/identifier/scheme attributes are not being parsed

[vers-one]

Description

opf:event and opf:scheme attributes in the following example are always skipped during the parsing:

<package xmlns="http://www.idpf.org/2007/opf"
         xmlns:opf="http://www.idpf.org/2007/opf"
         xmlns:dc="http://purl.org/dc/elements/1.1/" ...>
  <metadata>
    <dc:date opf:event="...">...</dc:date>
    <dc:identifier ... opf:scheme="...">...</dc:identifier>
    ...

This is due to the fact that those attributes are not part of DC (Dublin Core Metadata Element Set) XML namespace. Instead, they are extra attributes added by the EPUB 2 standard which is why they appear in the opf XML namespace in the example above. EpubReader didn't account for this fact, so the values of those attributes were always null after parsing.

Sample EPUB file

test.epub

EPUB specification links

• date metadata element: https://idpf.org/epub/20/spec/OPF_2.0.1_draft.htm#Section2.2.7
• identifier metadata element: https://idpf.org/epub/20/spec/OPF_2.0.1_draft.htm#Section2.2.10

[vers-one]

Fixed in PR #54.