Same gap-fill rule as the EPUB path, against the PDF's embedded Info
dictionary via a readPDFInfoDict helper reusing extractPDFMetadata's
field conventions (creator falls back to author, subject maps to
description, producer to publisher, keywords to tags, plus page count).
Sidecar values always win; unopenable PDFs skip silently.
TestMergeMetadataPDFGapFill uses an Info-bearing hand-built PDF fixture
(shared with the sidecar-cover test) and asserts the sidecar title is
kept while author/description/publisher/tags/page count fill in.
A sparse metadata.opf/metadata.json (title only, no description) left
books thin even when the file itself carried rich data: the embedded
extractors only ran when no sidecar existed at all. Now mergeMetadata
fills blanks from the book's own OPF - title, author, description,
publisher, language, ISBN, ASIN, series/number, publish date, tags,
contributors - while sidecar values always win and unparseable files
skip silently. Also covers .kepub, which the merge previously ignored
while the extractor already supported it.
Adds TestMergeMetadataEPUBGapFill asserting both directions: sidecar
title/author survive, embedded description/publisher/language fill in.
A full rescan wiped cover_image_path for every PDF/EPUB living in a
metadata.json (or metadata.opf-less) folder with no cover.jpg next to
the book: the sidecar branches returned early after findSidecarCover
missed, and mergeMetadata has no PDF/EPUB cover logic of its own. Four
books lost their thumbnails while their {file}.cover.jpg files still sat
on disk - most visibly the Audiobookshelf-managed No Starch titles.
Both sidecar branches now fall through to an embedded-cover fallback
(PDF via extractPDFCover, EPUB/KEPUB via extractEPUBCover) whenever no
sidecar cover file exists. Comics are untouched: mergeMetadata already
extracts their covers from the archive.
Adds TestSidecarCoverFallback with a hand-built one-page PDF carrying a
JPEG XObject plus a metadata.json sidecar, asserting the sidecar title
wins while the cover still comes from the file. Verified live: rescans
restored all four dereferenced covers with no leftover rows.
Libraries managed by Audiobookshelf keep a metadata.json next to each
book (title, authors, series+sequence, genres/tags, publisher,
description, isbn/asin, language, published year/date) - and no
metadata.opf. The scanner silently ignored those files: deleting them
changed nothing, and their data never reached the database.
Parse them as a first-class sidecar in extractMetadata, priority
metadata.opf -> metadata.json -> embedded media. Only fields with a
matching media_items column are mapped; narrators, subtitle, explicit,
abridged, and chapters are deliberately skipped.
Cover handling is unchanged: the existing findSidecarCover priority
(cover.jpg / folder.jpg / {basename}.jpg) applies to the sidecar branch
exactly as it does for Calibre.
go-epub's ReadBook parses every spine chapter and fails the entire call
if any single chapter (or the TOC) is malformed, discarding already-parsed
OPF metadata. For books like Pragmatic's 'A Common-Sense Guide' the OPF
holds good title/author/publisher/ISBN metadata that rescans then wrote
as blanks - success toast, no (visible) change.
Refactor to parse the EPUB's own OPF document with the same Dublin Core
machinery used for Calibre sidecars: parseCalibreMetadataOPF is now a thin
file wrapper around a reusable parseOPFContent([]byte), and the OPF lookup
previously inline in extractEPUBCover is shared via findOPFPathInZip. Since
metadata never touches chapter bodies, chapter damage cannot blank it.
Also picked up along the way: dc:language mapping and scheme-less
dc:identifier values that normalize to a valid ISBN (EPUB3 style).
Tests cover a Pragmatic-style EPUB (dc namespace on <metadata>, no
identifier scheme, deliberately malformed chapter) that must still yield
full metadata, plus series/date/subject OPF parsing.
John O'Keefe