Last annotation date

[Comfy.n]

Hi,

I'm running an Action Chain that filters a custom column with annotation count:true, then selects a View Manager preset that sorts the list by Last Action Date (from Last Modified plugin). This should give me in Library View a list of recently annotated titles in Calibre viewer.

However, as the Last Action column is also updated by other db changes, I thought of adding a custom column to display a book's last annotation date.

From looking at db\cache.py, I take it this might be possible...

@write_api
    def merge_annotations_for_book(self, book_id, fmt, annots_list, user_type='local', user='viewer'):
        '''
        Merge the specified annotations into the existing annotations for book_id, fm, user_type, and user.
        '''
        from calibre.utils.date import EPOCH
        from calibre.utils.iso8601 import parse_iso8601
        amap = self._annotations_map_for_book(book_id, fmt, user_type=user_type, user=user)
        merge_annotations(annots_list, amap)
        alist = []
        for val in itervalues(amap):
            for annot in val:
                ts = (parse_iso8601(annot['timestamp']) - EPOCH).total_seconds()
                alist.append((annot, ts))
        self._set_annotations_for_book(book_id, fmt, alist, user_type=user_type, user=user)

... because of that annot['timestamp'] reference.

Please help?

(I'm aware that the annotation browser sorts by last annotated titles but still thought this might be useful)

[Comfy.n]

hmm, I've tried adding a date column in Last Modified PI that should update on any changes to the #ac column (program: annotation_count()), but this didn't work.

[Comfy.n]

Originally Posted by Comfy.n

hmm, I've tried adding a date column in Last Modified PI that should update on any changes to the #ac column (program: annotation_count()), but this didn't work.

And that's because, I just noticed, the #ac count will only update on Calibre restart.

Would a PTM equivalent of...

program:  annotation_count()

refresh upon closing a just annotated book?

[kovidgoyal]

IIRC that template function basically directly queries the database using SQL for a count of annotations for the book id. Anytime the database is updated, the function should return the updated count. Closing the viewer causes it to update the database. But I dont recall the details of how custom columns cache values/when templates are re-evaluated etc.

[Comfy.n]

Originally Posted by kovidgoyal

Closing the viewer causes it to update the database.

In my case, I just noticed closing the viewer isn't enough. Reopening a just highlighted book (using a downloaded news standard epub for testing), does update the count instantaneously.

[chaley]

Composite column values are cached in the db layer. If the underlying data is changed then db.cache.clear_caches() should be called to tell the composite evaluator to re-evaluate the column on next use. Looking at the annotations code in cache, this isn't happening.

I see 3 choices:

• Do nothing. The caches will be cleared from time to time because of other operations.
• cache.clear_caches() whenever the annotations change. This is a rather large hammer.
• When annotations change, loop through the fields (columns) and clear the render cache for composites. This is a smaller hammer but requires more work to set up the loop.

A more targeted solution would be not to use a custom column for annotation count, instead calling the function directly. This avoids caching but requires that the processing be done on-demand. @Comfy.h: this might be possible depending on how your action chains work. Instead of referencing the a custom column to get the count, call the function directly.

[Comfy.n]

Will look more into it later, but I'll probably want to keep the annotation count column...

Another thing I noticed is that on my portable install, which has a setup closer to default settings (few plugins etc.), a Calibre restart is needed to get the annotation count updated. OTOH, on my main install, just reopening a recently highlighted book triggers the annotation count update.