"Save Date" Metadata?

[Clancolin]

This may seem a daft question, and I suspect the answer is no, but web searching was of no help...

Word has a "last saved" metadata element, that updates automatically when a doc is saved


I'd like to convert Word/pdf/text docs to epub, but retain the info about when that epub was last altered/checked and saved. Is there some sort of "save date" code that I could use in an epub?*

*(even if it needs to be updated by hand).



Thanks.

[KevinH]

the modification date/time metadata is always updated when a svae is done in Sigil. It is actually part of the epub3 spec, as the full unique id of an epub3 is its uuid dc:identifier plus the modification date and time. Open the opf of the epub in Sigil to see the metadata in its current form.

[Clancolin]

Hi Kevin.
I open an epub and this is in the opf:

<dc:identifier id="BookID" opf:scheme="UUID">urn:uuid:2c3272a4-731b-4348-909d-6f38b97b18eb</dc:identifier>

That looks pretty meaningless to me, so I opened a second epub opf and this is in there:

<dc:date>2014-07-17</dc:date>

A much more recognisable date code, but it looks more like an "initial creation" date to me than a "last saved" form. In the same opf however, there is this

<dc:identifier id="a9781444792997">urn:uuid:655e14c9-6567-420b-a802-5555d899f567</dc:identifier>

Is that last bit of the "id=" the date 29th Sep 1997 in American format?

So I saved the file to see what changed in Sigil and got this:

<meta name="Sigil version" content="0.9.17" />
<dc:date xmlnspf="http://www.idpf.org/2007/opf" opf:event="modification">2020-04-21</dc:date>

Much clearer and I suspect that this is what you meant by " date/time metadata is always updated when a svae is done in Sigil. ", but do all/most epub creators update the code on saving? It wasn't something I spotted before, and does it apply to Epub 2 and 3?

[KevinH]

Sigil has always updated the modification date on save. The dc:identifier is a unique number that represents that epub and it is autogenerated once and only once. You can think of it like a isbn of a sort. See here for a description of a uuid. https://en.wikipedia.org/wiki/Univer...que_identifier

Under epub2 just the modification date is set. Under epub3, the modification date and time are set. Under epub3, the spec calls for the combination of uuid (identifier) and modification date/time to always completely identify an epub publication.


I would assume calibre does something similar, as does ibooks author, especially for epub3, as it is spec.

[Clancolin]

Super. Thanks KevinH.