Tankōbon

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0025. Converting the CBR of the organized library to CBZ ​

  • Status: Accepted
  • Date: 2026-10-22

Context ​

A RAR can't be written by the libraries we use, so a CBR can't be cleaned (ADR 0023) or otherwise edited. Users want to turn their CBR into CBZ to get every option of the app, without losing what they recorded about the books (progress, rating, tags, lists).

Decision ​

  • Only the organized folder: the conversion moves and creates files, which the app only does in the folder it manages (ADR 0015). It needs the organization on and its folder reachable; a CBR elsewhere is left alone.
  • In the decoder process: convertCbrToCbz() (cbr-converter.ts) extracts the RAR's entries one at a time into <name>.cbz.converting.tmp with yazl (pages stored, other files compressed), reopens the result, checks its pages and entry count against the RAR's, and only then renames it. It never overwrites an existing file.
  • The entry keeps its id: once the CBZ exists, the main process (cbr-conversion.ts) moves the CBR into .deletedByTankobon at the root of the organized folder, then points the entry at the CBZ (updatePath(), updateFileStats()). The id, hence everything personal keyed on it, is unchanged. The cover and .nfo sidecars move to the CBZ's names. If the database refuses the new path the CBR goes back and the CBZ is deleted.
  • A holding folder, not the trash: the CBR leave the library folders but are not deleted; "Vider le dossier .deletedByTankobon…" deletes them for good after a confirmation. The library scan skips that folder (DELETED_BY_TANKOBON_FOLDER), otherwise the next resynchronization would add the CBR back.
  • One run at a time: it takes the LibraryRunLock (kind convert) shared with the other runs over the files.

Consequences ​

  • Converting needs the free disk space of a second copy of each book until the CBR is moved, and a CBR is read whole into memory (as when it is opened).
  • RAR-specific data that isn't a file (comments, recovery records) is not carried over.
  • The CBR are not recoverable from the app once the folder is emptied.

Alternatives considered ​

  • Converting in place and deleting the CBR: no safety net if the user dislikes the result.
  • Sending the CBR to the OS trash: works for a single file but is slow and noisy for a whole library, and the trash isn't visible to the library's own folder.
  • Converting any CBR of the library: would write files outside the folder the app manages.