dc:date metadata importing from EPUB

[eevan]

I know there's been a lot discussion regarding published date meatadata.

But I haven't found an answer to this.
I author my EPUB books in Sigil. Here is an extract of the date metadata from opf file inside the EPUB:

<dc:date opf:event="publication">1995-03-23</dc:date>
<dc:date opf:event="creation">1967-05-08</dc:date>

So, I have created two date fileds that have the following meaning:
publication: date of the publication of this edition (translation)
creation: date of the publication of original book.

When I import this book in Calibre, pubdate field gets the value from <dc:date opf:event="creation"> (May 1967).

Is there a way to control which date gets mapped to pubdate?
Or a way to import this "creation" date into some user defined field (column).

Otherwise one has to manually change the pubdate to other value.

[thiago.eec]

According to the specs, we have this:

The date element has one optional OPF event attribute. The set of values for event are not defined by this specification; possible values may include: creation, publication, and modification.

Readium uses it like this:

EPUB 2.x
The string is the value of the <dc:date> element whose opf:event attribute has the value publication.

EPUB 3.x
The string is the value of the <dc:date> element.

Calibre, on the other hand, seems to ignore altogether the opf:event property. It just uses the oldest date, regardless of its attribute.

[kovidgoyal]

Calibre will basically consider only one DC:date you can put dates into Calibre custom columns the easiest way to do so is to add the date to Calibre and then use save to disk to see how Calibre saves the matadata in the exported epub. Use the same technique in your epubs

[eevan]

Thanks a lot for clarification guys!

[eevan]

OK, I have tried. Created a custom column named #original.
Filled it with date, and saved EPUB to disk. The resulting meta tag in the EPUB is a bit impractical for use, because it's content is a long JSON string with a full description of a custom column, not just the date value. It is just one line of course, I have broken it just for better display in a code block.

<meta name="calibre:user_metadata:#original" content="{&quot;link_column&quot;:
&quot;value&quot;, &quot;is_multiple2&quot;: {}, 
&quot;search_terms&quot;: [&quot;#original&quot;], 
&quot;is_csp&quot;: false, &quot;rec_index&quot;: 22,
 &quot;column&quot;: &quot;value&quot;, 
&quot;datatype&quot;: &quot;datetime&quot;, 
&quot;label&quot;: &quot;original&quot;, 
&quot;name&quot;: &quot;Originaly published&quot;, 
&quot;kind&quot;: &quot;field&quot;, 
&quot;is_custom&quot;: true, &quot;is_category&quot;: false,
&quot;#extra#&quot;: null, &quot;is_editable&quot;: true, 
&quot;display&quot;: {&quot;description&quot;: 
&quot;Date of original publishing&quot;, &quot;date_format&quot;: 
&quot;dd.MM.yyyy.&quot;}, &quot;is_multiple&quot;: null, 
&quot;table&quot;: &quot;custom_column_4&quot;, 
&quot;category_sort&quot;: &quot;value&quot;, 
&quot;#value#&quot;: null, &quot;colnum&quot;: 4}"/>

But thanks anyway for your help!

[thiago.eec]

Hi, eevan.

Looks like you didn't put any value on the custom field before saving it, right? If you had, there would be a date there on the #value# attribute, like this:

"#value#": {"__value__": "2019-09-25T12:31:45.812000+00:00", "__class__": "datetime.datetime"}

The full date set in this example is the bold text. If you edit this on your files BEFORE adding to calibre, it will be imported automatically to the #original column.