eCan Crusher gone? What alternative?

[Inélsòre]

Hello there,

I am in need of inspecting an EPUB which—you guess—is giving me issues with being uploaded to Apple Books (yes, I'm doing the same thing, the same process that worked until yesterday, and it is giving me a stupid error of "too big image" when they are all SVGs and they've been set up with a script to Export Tag and to keep original format). 

The tool I used on the Intel Mac, eCanCrusher, is said to be a closed project as of March 2022 on its GitHub page. Is it still being actively developed? Is there an alternative? 

I'm now on an Apple Silicon Mac, though that should not be a problem per se.

Thank you!

[James Gifford—NitroPress]

As far as I know, the only truly valid EPUB validator is epubcheck, which is a bit of a pain to use since it's a command-line tool. It's 100% standards-compliant, though, and somewhere between most and all other 'validators' use it as the engine, wrapped in various UIs and with "helpful" if nonstandard checking added.

The raw check is to open the EPUB and look in the images folder. If what you say (and have said over time) is true, there should be NO images in there except perhaps a few things like logos and decorations. (I am not sure if that's where SVGs are stored, but you should be able to look down the list and see if any of them are anomalous.

And FXL EPUB remains a real pain to diagnose and fix after export. I know you have your reasons for using it.

[Inélsòre]

Eventually I used the app "The Unarchiver" to open the EPUB and look inside it. 

InDesign apparently adds a bunch of blank PNGs during export, and some of them are just huge in resolution (not in size!), and Apple already generously (*cough*) updated the pixel count from 4mi to 5.6mi.

In the Conversion page of the EPUB export dialog, I've set the conversion to PNG and the resolution to 72ppi. Since they are blank PNGs, this didn't change their appearance, but reduced their resolution enough to have the test pass.

Since the "pagina EPUB checker" app is crashing on launch on macOS Sonoma (and the devs I've written to are not replying to my queries), I've been using this portal: https://www.epubvalidation.com/ 

Still, the test passed there, and not on Apple Books, because Apple adds a few custom rules...

[James Gifford—NitroPress]

Well, we've established over time that your project requirements — FXL, with content requiring high resolution, and to Apple Books — is a difficult road. I would have thought you'd ironed out the workflow by now, though. 😛

[Inélsòre]

Hehe! I had, but some part of it are kind of ... random?! 

Plus, as said above, the issue this time was the tool I used on the Intel Mac that appears to be discontinued. 

I can uncompress the epub archive, but without eCanCrusher, I cannot compress it again into epub format. Or can I? 

[James Gifford—NitroPress]

From past discussions — I believe there are ZIP archivers that will work on the Mac without applying compression to the MIMETYPE file (that being the usual fault at validation — the MIMETYPE declaration must be uncompressed, and why Macs see the need to compress a 20-30 byte file is exasperating), but the information here and from Macsperts I queried was not helpful.

If you can locate such an archiver, one that allows selective control of compression, you could unzip the EPUB, edit as necessary, re-compress, and then (if necessary) update the MIMETYPE file with specific instruction to leave it uncompressed. A bit messy, but a typical workaround for Macs when doing low-level file operations.

[Derek Cross]

Try BBEdit https://www.barebones.com/products/bbedit/index.html

[James Gifford—NitroPress]

Most EPUB editors have one or more critical flaws (like not re-writing files in fully compatible ways); they have their roots firmly in the Lego/Build-a-Bear model of EPUB development and bring too much "help" and "improvement" to the tasks.

BBEdit is probably worth looking into for this, and for any Mac-based book creator, but I am recalling from a long history of working through these outer-fringe problems of this OP that only direct file surgery answers some of the issues.

[Inélsòre]

Unfortunately, I have no idea what a MIMETYPE file is, as I've always been more concerned about the content looking good, leaving those issues to the softwares, until things like this started to happen. 

eCanCrusher was built for this purpose: expand, edit, drop the folder on the app's icon, and enjoy your new EPUB that will pass all validations. I wonder why the project has been closed.

I use BBEdit from time to time, but had no idea it could work with EPUB archives. Could you please elaborate on how it does that, @Derek Cross ? 

Thank you both!

@James Gifford—NitroPress : please forgive me if this problem comes back now and then... I even saved PDFs of the previous forum posts for reference, but new things seem to come by... thank you for your patience!

[James Gifford—NitroPress]

Again, I am working from what may be a slightly fuzzy recollection of the many threads related to your projects and workflow. I recall that simply unzipping an EPUB, making changes and re-archiving led to a validation fault regarding the MIMETYPE file, which is short code declaration in the top folder of an EPUB structure:

and containing a simple text string much like this:

application/epub+zip

It's a nothing little bit, and most archivers will leave it uncompressed since there's next to nothing that could be gained (or lost) from compression. But we established that the default Mac archiving process was applying compression to this file, which is a serious validation fault.

So the need, last time I recall this discussion, was to be able to re-archive an EPUB without applying compression to this file... which the EPUB tools do, of course, but for which a straight archiver with this level of control on the Mac was not identified.

The UI editors like Calibre can be a great help, but they often manage things in nonstandard ways that suited the time of their development, or, more likely, their developer's 'better ideas.' So along with CSS editing, one of the really essential tools for successful EPUB development, when ID doesn't get it exactly right, is the ability to unpack the EPUB file, make any changes, and then repack it in a way that conforms to standard and passes validation.

I don't know if BBEdit can/do that.

[Inélsòre]

I believe we didn't have issues with the MIMETYPE file, at least not in my experience.

The main issue was 

a) understand Apple thrown errors

b) identify that ID was creating blank PNGs of inappropriate size

Also Sigil was a good app to simply open and re-save EPUBs, but sometimes it was causing issues greater than those it solved. 

[James Gifford—NitroPress]

Okay. I remember an encoding/compression error in there, but I won't claim to have retained every detail. 🙂

[emin.roblack]

I just hit a similar wall and found this little open-sourced software that did the trick 👌

https://sigil-ebook.com/sigil/download/

It is also present in homebrew: https://formulae.brew.sh/cask/sigil#default

[James Gifford—NitroPress]

The OP mentioned Sigil. It's widely used but I have many reservations about both its approach (the obsolete "lego" or "build-a-bear" approach to book development), and as the OP notes, it's not a flawless app even when used in simple modes.

[emin.roblack]

Don't know about possible issues but I managed to replace a cover and remove several chapters without causing issues for Apple books so that's something.

It is a tad hardcore as you neet to remove chapters rather manually so not perfect but 🤷‍:male_sign: It works 😅

[James Gifford—NitroPress]

I won't say any workflow that works is wrong, but the era of editing EPUB files is long past. The correct approach is to generate them properly in the first place, not perform surgery on them later.

(FWIW, note that I am extremely hard on the methods of a decade ago, building e-books like a web page or computer program,  techniques that are still promulgated by 'gurus' who should have long since learned better. We don't go move slugs of lead type around any more, either, or peel and rearrange blueline layouts. EPUB no longer needs these crude, old-school methods.)