[GUI Plugin] EpubSplit

[Rellwood]

Originally Posted by JimmXinu

That error indicates that no TOC was found in the epub.

EpubSplit currently only handles EPUB2, not EPUB3, which will give that error.

If that's not the issue, I'd have to see the epub.

How do I know if it is ebup3? Is it only created in polishing?

yes it was an epub3..works now!

[JimmXinu]

I've been looking at epub3 and here's what I've found so far:

- EpubSplit(and EpubMerge) don't look at the epub version number, but they do look for the TOC in a ncx file (or more precisely, file with media-type='application/x-dtbncx+xml'). Apparently, this is not uncommon among epub readers from what I've seen.

- Calibre's Polish->Upgrade book internals, Edit book->Tools->Upgrade book internals and Convert->Epub->Output Version:3 features all currently write only the epub3 nav.xhtml and no toc.ncx.

- Calibre's Edit TOC (both from Calibre directly and inside Edit book) will write both the epub3 nav.xhtml and epub2 toc.ncx.

With a small (2-3 line) change, Calibre can be made to write the epub2 toc.ncx for "Upgrade book internals" and Convert->Epub using the same mechanism as Edit TOC that looks to work correctly to me. I haven't decided yet if I should submit it to Kovid or not--and he may or may not want it.

That would help with Calibre generated epub3s, but doesn't directly do anything for epub3s from other sources. So I'm still considering what changes EpubSplit/EpubMerge should have as well. Native epub3 support? Prompts to generate toc.ncx if absent? Prompts and instructions for the user to generate toc.ncx?

[JimmXinu]

New Version Released

Version 2.9.0 - 10 Feb 2020
- Update translations.
- Add check and error message for unsupported epub3.
- Changes for eventual Python3 migration of Calibre.

[kazbates]

Hi! I've been using both epubsplit and epubmerge since the beginning and have found the plugins very helpful. I'm not sure what changed within the last month, but I am now receiving the "epub3 detected error" when trying to execute epubsplit on a file that I have previously been able to split. I was able to successfully split this particular epub file at the beginning of February. Do I need to go back to a previous version of Calibre and/or the plugins?

[JimmXinu]

kazbates:

The major difference between epub2 and epub3 (for EpubSplit) is that the Table of Contents is in different files using different formats.

The previous version of EpubSplit could handle epub2 and some epub3 also include epub2 Table of Contents(TOC). This is a thing that some epub3s include specifically for backward compatibility.

However, Calibre doesn't normally include that older/back-compatible TOC file when writing or converting epub3. Those just failed in EpubSplit with a non-descriptive error. (See back a few posts.)

Calibre's output is the only source of epub3 examples I've yet found, and they all use the same code. That's not a large enough sample for me to add epub3 code to EpubSplit yet.

I did consider looking for existence of the older TOC file, but there's no guarantee in back-compatible epub3s that both TOCs are the same.

So your choices are to down-convert your epub3s to epub2--Calibre Convert's epub output has that option; or, as you asked, use an older version.

Past versions of EpubSplit are available here:
https://github.com/JimmXinu/EpubSplit/releases

[kazbates]

JimmXinu,
Thank you so much for the information. Having Calibre convert it to an epub2 worked perfectly!

[iamallmight]

Hiya folks!

So, I just got hold of a huge ePub file and wanting to split it, I installed the ePub Split plugin. While Calibre did tell me that it is installed and I should restart, after restarting I can't find it in the title bar or can't access it! After snooping a bit in Preferences, I found that while ePub Split IS listed as a "User interface action plugins", it is absent in the "Toolbars & Menus" under Preferences. Thus, I cannot use it.

What is even more strange is that, ePub Merge installed successfully and is present in the toolbar! I tried removing the ePub Split plugin a couple times, installed it from file and yet no success.

So yeah,

[BetterRed]

I'm moving this to the EpubSplit thread, there's Sticky index at top of sub-forum

[JimmXinu]

Uninstall and reinstall the plugin?

You might also try restarting Calibre into debug mode (Preferences dropdown) before installing it to see if there are any issues reported.

Despite what BR says, that's outside the plugin's own code. But we do sometimes see plugins not download/install perfectly.

[BetterRed]

Uninstall won't remove everything for a plugin, firstly it will leave any plugin specific settings in place, these will be used on a re-install, and secondly on re-install the popup about which toolbars and menus should show the the plugin won't be popped (not sure if this is always true).

The plugin specific settings are easy to remove, after removing the plugin from calibre, look for a <pluginname>.* files in the calibre configuration folders plugins subdirectory; if found, delete them. Some plugins wont have any files, and many will only have a .json file, but some have extra files like an .html file for help etc.

The popop issue is harder, IIRC you have to edit the gui.json file and exorcise relevant entries. If on first install you chose to not show the plugin in any menus or toolbars then on subsequent re-installs that choice will still be in effect.

Would be nice if the plugin management sub-system had a Nuke Plugin option.

BR

[JimmXinu]

Originally Posted by BetterRed

The plugin specific settings are easy to remove, after removing the plugin from calibre, look for a <pluginname>.* files in the calibre configuration folders plugins subdirectory; if found, delete them. Some plugins wont have any files, and many will only have a .json file, but some have extra files like an .html file for help etc.

Some plugins (like mine) keep their settings inside the current library's prefs database instead of in a separate JSON file. FYI.

[BetterRed]

Originally Posted by JimmXinu

Some plugins (like mine) keep their settings inside the current library's prefs database instead of in a separate JSON file. FYI.

I knew that of course, but the guy who wrote the post forgot about it

I think the JobSpy plugin "might" have something to remove them, I'll have a look. Otherwise the only way I know to remove them is by editing the library metadata_db_prefs_backup.json file and rebuilding the database.

Is there a better way?

BR

[JimmXinu]

I don't know. I've never see a need to be quite that draconian about it.

I suspect that iamallmight's problem is more likely an incomplete or corrupted zip file than settings.

[BetterRed]

Maybe

But before they do it all again, they should go into Preferences->Toolbars and menus->Main toolbar, if its in the left hand list they should move it over to the right hand list

BR

[JimmXinu]

Originally Posted by iamallmight

... After snooping a bit in Preferences, I found that while ePub Split IS listed as a "User interface action plugins", it is absent in the "Toolbars & Menus" under Preferences. Thus, I cannot use it. ...

I chose to believe iamallmight knew what they were talking about.

Although I will confess I missed the part where they tried re-installing the plugin already.

Nothing in EpubSplit settings should keep it from appearing as an 'action' to Calibre. Especially on first install when it doesn't have any settings yet.

I'd like to see a debug log from iamallmight before speculating more.