Epub "error opening file"

Panels
#1

I just downloaded some epub files from Dynamite’s online store, but Panels will not open them.

Strangely, Panels is able to extract the cover images and show them in the file manager.

It would not totally surprise me if the files were constructed incorrectly, because Dynamite’s online store is pretty janky. However, YACReader (on mac desktop) will open them, so they can’t be completely screwed up.

I will email one of the files to support@panels.app

If you discover that the file is malformed, could you tell me what is wrong with it? I’m willing and capable of unzipping the epub and fixing it. (I could also just rip out the images and create a cbz instead…)

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#2

I plugged my file into an epub validator (Free EPUB Validator - Bookery).

It found a handful of warnings, and the following errors:

  • OEBPS/content.opf

    • Add the missing OPF xml:lang attribute
    • Add a ‘schema:accessMode’ metadata property to the Package Document
    • Add a ‘schema:accessibilityFeature’ metadata property to the Package Document
    • Add a ‘schema:accessibilityHazard’ metadata property to the Package Document

  • Every page xml file

    • element must have a lang attribute

Are you able to see Panels choking on one of these errors specifically?

#3

Hey @GrantB

sorry for the late reply.

I checked the file you sent us to reproduce the issue, and I assume is this one:
image

That does not prevent the app from opening the ePUB, only triggers a warning because Panels assumes it’s an eBook not a comic ePUB.

Unfortunately, there is no official way to identify a comic from an ebook, so we had to come up with our own method to try to identify them.
The logic we use is to check the table of contents and the number of spine references. If they match, that means the editor created an entry in the table of contents for each spine reference.
That is the normal structure of a text ebook, where each chapter appears in the TOC. But for comics, as content is static and cannot flow, editors normally dedicate one spine reference per page instead of chapter.

The file you sent us has a TOC reference per page. As if every page was a different chapter. That’s why our logic fails in this case.

If you tap on “Continue Anyway” it should open it normally.

We plan to improve ePUB support in the future, and this warning won’t be needed anymore.

Until then, you can put up with it and tap “Continue Anyway”, or edit the ePUB so pages don’t have references in the table of contents as chapters.

#4

I don’t get that popup. I only get a popup that says “X - Error opening file”.

I just tried a second file (same publisher), and got the same thing.

I just updated to Version 3.6.5 Build 742, same result.

Here’s a pic of what I see when I tap the epub file:

IMG_6819
IMG_68191920×2560 218 KB

#5

Ok, I see what’s going on. I was able to reproduce it.

That error should be an upsell, because Comic ePUB support was added in Panels 3, and I guess you have Panels 2 or a free account.

I just fixed it for the next release, but it should show like this when you have access:

In the next version, it will show the upsell instead of that error.

#6

Oh, no kidding, I didn’t even know Panels 3 existed. I’ve had Panels 2 since 2023.

I guess that upsell dialog should be pretty valuable for you :slightly_smiling_face:

Thanks!

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#7

I can confirm that I see the upsell after the latest update.

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