Custom columns not being set when adding books programmatically

[Howlingwolf]

I was testing an idea for programmatically adding books to a Calibre library and encountered a problem with custom columns.

I'm using mi.set('#subtitle', Subtitle) - following this with mi.get('#subtitle') shows the data is being set correctly - but this is not being 'carried over' into the library metadata.

This is a 'standalone' script run using calibre-debug, not a plugin.

Is this related to the metadata plugin issue I've seen mentioned elsewhere or something I'm doing wrong?

[chaley]

Originally Posted by Howlingwolf

I was testing an idea for programmatically adding books to a Calibre library and encountered a problem with custom columns.

I'm using mi.set('#subtitle', Subtitle) - following this with mi.get('#subtitle') shows the data is being set correctly - but this is not being 'carried over' into the library metadata.

This is a 'standalone' script run using calibre-debug, not a plugin.

Is this related to the metadata plugin issue I've seen mentioned elsewhere or something I'm doing wrong?

You are doing something wrong.

mi.set changes the value in the metadata instance (in memory). It does not write that value to the database. To write to the database you should use new_api.set_field() (db.cache.py) if you are writing only a few fields or set_metadata() (db.legacy.py or cache.py) if you are changing many fields. Both assume that you have access to a database instance.

The thread https://www.mobileread.com/forums/sho...d.php?t=241680 has an example of using set_field.

[Howlingwolf]

Umm...

Perhaps we need a new forum rule.

DO NOT... Post requests for help while suffering from severe flu symptoms



To clarify what I'm trying to achieve.


I start with a list of filenames in the following format:

<Author> - <Series_Name> <Series_Index> - <Title> (<Subtitle and/or Other Info>).<fmt>


This is split and formatted into the following:

Author (FN LN)
Author_Sort (LN, FN)
Series
Series_Index
Title
Subtitle


I then read the metadata from the source file, update it as appropriate with the above and call add_books() passing the updated metadata.

This works almost exactly as intended. The book is added with the correct metadata except for the missing custom column data.

[chaley]

Originally Posted by Howlingwolf

Umm...

Perhaps we need a new forum rule.

DO NOT... Post requests for help while suffering from severe flu symptoms

I am going out on a limb here because I haven't ever done what you are trying to do.

I assume you got the mi instance by something like mi = Metadata(). The problem is that this metadata instance will not contain any of the custom column metadata, which means that when you set a value for #foobar, you aren't actually setting the value for a custom column. Instead you are setting a local value in a dict that calibre will ignore.

So, you need to add the custom metadata to the mi instance. What (I think) you should do is something like (fixing names and imports as needed):

custom_metadata = db.field_metadata.custom_field_metadata()

for each book:
    mi = Metadata(...)
    mi.set_all_user_metadata(custom_metadata)
    # do what you need to do to prepare to add the book
    # now when you do mi.set('#foobar', val) it knows that you are working with a custom column.
    db.add_books(....) # this should now add the custom column data

[Howlingwolf]

Ah... What light through yonder window breaks...


I'm reading the metadata from the source file like this:

with open(src_file, 'rb') as tmp_file:
	src_metadata = get_metadata(tmp_file, src_type, force_read_metadata=True)

So naturally it won't contain the custom field...

OK. So if I'm interpreting this correctly. I need to add the custom field 'definition' to the source metadata object, THEN set the field data using .set()



EDIT:

That worked perfectly.

Thanks for your help. It's much appreciated.