View Full Version : Confusion about EPub dates in metadata

11-08-2010, 09:33 AM
Hello, I have some questions about the proper date tags to use when trying to setup the meta data for an EPub generated from scraping the chapters from fan-fiction sites. This means that stories can get updated/modified, and we will want to regenerate the story when that happens. We have 3 dates to be concerned with...
1) First posted date (initial publication date) (2010-11-01)
2) Last updated date (current publication date) (2010-11-03)
3) Date story was packaged (optional) (2010-11-08)

In Calibre, he defined a special tag named calibre:timestamp which is used for the publication date. For example:
<meta name="calibre:timestamp" content="2010-11-01T00:00:00"/>

The EPub specification suggests tags like this:
<dc:date event="publication">2010-11-01</dc:date>
<dc:date event="modification">2010-11-03</dc:date>
<dc:date event="creation">2010-11-08</dc:date>
However, ebook readers and calibre don't seem to recognize the above.

There doesn't seem to be any standard between various ebook readers as to what date to use for various things.. I can see the possibility of having event names like "1st printing", "2nd printing", ...

Why didn't the date entries get defined when defining the spec?

Or did they, and I didn't notice?

In that case why did the author of Calibre feel that he had to specify his own timestamp type?

What should I be using?

What do the various readers use?

Thank you,

11-08-2010, 10:47 AM
The specification says that "event" can be used, but it doesn't assign any meaning to them.

Personally, I use:

publication -> The original publication date
creation -> When I first created the ePUB version
modification -> The last time I modified the ePUB

and I add others if needed, like "translation".

11-13-2010, 11:11 AM
Also, the 'event' attribute doesn't have any effect on which date element a reading system will use--if it uses any; all the metadata other than identifier, title, and language is optional. The default for date is to use the first one listed, regardless of the 'event' attribute. So in your example above, the naked date element at the end is redundant.

There is no defined set of events ("vocabulary") in the epub spec. As Jellby mentioned, though, publication, creation, and modification are very commonly used (at least by us "amateur" epub makers).

11-13-2010, 12:31 PM
Also, the 'event' attribute doesn't have any effect on which date element a reading system will use--if it uses any

That would depend on the reading system, though it's probably true of all current ones.