Your comments

You have several options. You can either:

  • For Ubooquity 2: launch Ubooquity in headless mode (details here), Ubooquity will not try to use Java FX. But you will not have any desktop UI.
  • For Ubooquity 2: use an Oracle JRE that contains Java FX
  • Use Ubooquity latest version (3 beta) and any JDK over version 17

Indeed, looks like a dependency issue.

I didn't change anything around this lib recently, but there must be some side effect, perhaps from the Java version increase (8 to 17 was a pretty big jump).

I'll look at it so that it's fixed in the next update.

Thanks for the investigation, it helps a lot. :)

This error comes from the network call (to my server) that checks if a new Ubooquity version is available.

The server had an issue for a few days, it's been fixed now.

However, this error does not prevent Ubooquity from running at all.

Thanks for the lead, it'll help the investigation !

That's because the PDF pages are rendered as images on the server before being sent to your browser (whereas Epubs chapters are sent as HTML files, including links).

Ungfortunately this means links will never be functional when the PDF is read online, page by page.

For PDF links to works, the PDF file has to be opened in a PDF reader. So you have to download it instead of reading it online.

I tried reproducing the issue by recreating the structure you described, but I don't have the probblem.

Same offer as for Pseudocomicnerd in the messages above: would you be able to send me the database file of a Ubooquity instance that have this issue ?

I don't know what might be causing this behaviour, but if you send me your Ubooquity database I'll take a look.

This is the ubooquity-6.mv.db file. Just be sure to stop Ubooquity before copying it.
You can upload it to any file sharing service (e.g. Wormhole) and send me the link at: tom 'at' vaemendis.net

Note that I will be able to see the names of all your files (but not access the files themselves).

I'm glad it worked out in the end, although I would have prefered to understand why. :D

The interface is now a web interface not the previous folder navigation
style, but that maybe because the url is simply
host:port/collection/opds

You mean in Moon Reader ? You don't have something like that ?

Image 805

Image 806

I get the same error

I'm missing something there.

Do you think you could send me your database file ? 
This is the ubooquity-6.mv.db file. Just be sure to stop Ubooquity before copying it.

Note that I will be able to see the names of all your files (but not access the files themselves).
If you prefer and are willing to work a bit more, you can create another database (just launch Ubooquity in another folder) and recreate the issue with just a few files/folder before sending me the database.

However that has opened a new problem authentication fails everytime. I
have a special character in my password, so removed that and tried just
alphanumeric numeric and no password and they all fail with the 2
android apps I use moonreader & fbreader for OPDS feeds. If i try a
browser though the opds url works everytime.

I have had the exact same issue in the past with Moon Reader and FBReader. I don't know where it comes from, although I suspect some credential caching issue on client side (since, as you noticed, the browser never has the issue).

UnfortunateIy I don't remember how the problem went away. Since it was in the middle of big changes, I wiped and reconfigured both my Ubooquity instance and the readers a lot of times. 

the “reader application” has to design the opds to work with ubooquity

No, OPDS is a standard, so (in theory) all clients should be able to work with all servers as long as the specifications of the format are correctly implemented.


It is however rarely that easy with software, as you can see. :)


As far as I can tell, Ubooquity serves valid OPDS (I checked again with this validator today). But from what you tell me, there must be a difference between the feed provided by Ubooquity and the feeds provided by other servers.


The following could help me invetigate further:

  • The version of KOReader you use, as well as the platform (Kindle, Kobo, Android...).
  • Some examples of OPDS pages (XML files) that work correctly for you. You can get them by navigating the feed directly in your browser (to get clickable links, display the page source once the feed is displayed, using the CTRL+U shortcut in your browser)