KOReader Position Sync API Compatibility

[alexcash]

Idea Description

KOReader has a (default provided) plugin that implements reading position sync, given a compliant server. Source linked below:

https://github.com/koreader/koreader/tree/master/plugins/kosync.koplugin

Seems to be fairly simple in design: GET and PUT a percentage completed for a given document. It allows identification based on document checksum or filename.

I use OPDS-PS for manga while I'm on my home network, but for books I do full downloads (also via OPDS). That way I can turn on airplane mode and save battery, take my ereader out of the house, etc. But that means if I want to swap over to my computer, phone, or iPad I don't really have a way to pick up where I left off. If Kavita provided a KOReader sync compliant endpoint, it would make swapping between devices easier.

Duration of Using Kavita

2 Weeks

Idea Category

Feature Enhancement

Agreement

• I agree that this is solely for submitting ideas, and I will search for existing ideas before posting.

[majora2007]

I believe Kavita is already supported with KOReader.

See koreader/koreader#9750

[alexcash]

It's possible I'm mistaken, but I think that only works if you're using OPDS-PS. Support for the progress-sync API would work for books that had been downloaded for offline reading via OPDS (non page streaming).

[majora2007]

I don't think that's the case. Opds-PS doesn't work with epubs as it's a simple image based.

Would you mind testing? Last I spoke with KOReader, they informed there was syncing similar to tachiyomi.

[majora2007]

Linking this as this was my last discussion:
koreader/koreader#11105

[alexcash]

I'm pretty sure. If you look at the patch for koreader/koreader#9750 the methods are all namespaced under OPDS-PSE e.g. OPDSPSE:getLastPage and as far as I can tell getLastPage is only called from inside streamPages. This mirrors my experience using the app.

Here is a screenshot of what happens when you tap on a book listed in the Kavita OPDS library from KOReader. If it were manga, tapping "Page stream" would load up the book from the last read page. Additionally, when I close that Manga the last read page is saved to Kavita. That works like a charm. But as you say, you can't page stream an epub. Tapping those options simply loads an image of the koreader logo. "Book cover" and "Book information" show details about the book. All the remaining buttons pertain to downloading the book in its entirety. Once the book is downloaded, it doesn't appear to be any different than any other book dragged into the "Books" folder of the device internal storage. As far as I can tell it's totally untethered from Kavita. My progress isn't synced to Kavita, and as far as I can tell the only UI related to my reading position is labeled "Progress Sync" and prompts me to log into a KOReader sync server -- which I believe is the API I linked in my initial post.

[dandersch]

I don't think that's the case. Opds-PS doesn't work with epubs as it's a simple image based.

@majora2007 Is there a technical reason that makes page streaming support for epubs/pdfs infeasible? I saw that the OPDS-PS standard doesn't specify support for any other file types, but I don't see why a page streaming extension should remain exclusive to comic books.

[majora2007]

Yes. The spec was created and allows syncing on a page by page level. Epubs do not work on a page-by-page level, but rather are free form text, css, etc that are usually laid out in a manner to look like a page. But from your reader, pages 1-10 could actually be just the first page on that epub, or the whole chapter could just be one page.

The spec only allows for page level. While Kavita can support OPDS-PS, no epub client does support this due to the complexity and how bad the end result would be for them. Epubs cannot be streamed they are in fact html files, css, etc.

This is why there are no epubs that support syncing via OPDS-PS and I don't expect to see that to change. The best course of action is a dedicated API for these softwares that support OPDS (Calibre, Komga, Kavita, Stump).

The official spec is here: https://vaemendis.net/opds-pse/

Hope this helps.

[dandersch]

Thanks for the explanation. Am I right to assume that if the server knew about the readers screen size, font size, margins etc., then it could potentially construct the page layout and serve a single page epub for every streamed page?

What about PDFs? Shouldn't PS support be more straightforward to implement because ebook PDFs are usually page based?