Vanishing custom metadata

[PurplePassion]

G'Day

New to Sigil.

I added some custom metadata to a book and saved it.

A few days later I've open it up and the custom meta data isn't visible int he meta data editor.

Is this expected behavior?

[KevinH]

Not unless the custom metadata is not structured properly, uses unknown namespaces, or unknown tags. The only piece of metadata that is shielded in the MetaData Editor is the bookid dc:identifier as changes to that element have ramifications for font obfuscation, ncx, and Checkpoints, etc. So user changes to that value are not shown or allowed in the Metadata Editor.

Did you open the OPF tab in CodeView to see it is still present in the metadata tag in the OPF?

What version of Sigil are you using?

Also was this epub2 or epub3?

Please show the exact custom metadata you tried to insert in this thread and I may be able to tell you more, and check to see if it is a bug.

[BeckyEbook]

I don't know what metadata entries the questioner is referring to, but there are indeed some that don't show up in the MetaData Editor window.

The best example would be the standard meta entry with Sigil version. In EPUB2 it is visible, but in EPUB3 it is no longer.

<meta name="Sigil version" content="2.6.0"/>

Similarly, any other entry with this structure, such as

<meta name="beckyid" content="BeckyLibrary-1234" />

Such an entry, however, officially (I think) cannot be obtained directly in the MetaData Editor window for an EPUB3 file, although in EPUB2 it can be done without a problem.

I'd be happy to read what entries @PurplePassion has made, as the key here is not just the metadata entry itself, but also whether such entries pass EpubCheck validation.

[KevinH]

epub2 metadata are allowed to still exist in epub3 but it must be ignored in epub3. Under epub3 the meta tag has different attributes and has actual content, so no meta tag generated by the Epub3 metadata editor should be using name and content attributes of the (epub2) meta tag metadata.

[KevinH]

After looking at the code for the epub3 metadata editor (just like the epub2 metadata editor), for safety it only allows you to edit the metadata tags it recognizes, ie. meta tags with known properties, dc metadata etc.

Yes you can create still custom metadata that will be stored in the opf using the metadata editor. But to then edit this unrecognized metadata, you would have to directly edit it in the opf, since you have added advanced tags that the Metadata Editor is unfamiliar with. But nothing should ever vanish from the OPF.

The main reason is that the OPF is pure xml, so custom attributes and custom tags would require adding the required namespaces and prefixes to the metadata tag itself. Sigil automatically handles that for opf, dc, dcterms namespaces (ie the ones it recognizes). If additional namespaces are required because of custom tags or custom attributes, the user would have to hand edit the OPF to add the appropriate namespaces and prefixes.

[BeckyEbook]

I get it, especially the metadata requirements in EPUB3. That's why I'm even more curious about the metadata of the user reporting the problem.

[KevinH]

So am I! That is why I asked. If they are common enough additions that others might use, we can certainly expand the list of recognized metadata for epub2 and/or epub3 and add the appropriate xmlns attributes as needed.