Zipping files into an epub

[PenguinCEO]

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[Doitsu]

Originally Posted by PenguinCEO

I would like to compare that code with a possible "standard". Where can I find a document that describes the standard of internal structure and file compression levels within an epub?

It's in the EPUB Open Container Format specification.

[Jellby]

My base script:

zip -X0 "${FILENAME}.epub" mimetype
zip -X9Dr "${FILENAME}.epub" META-INF OEBPS
advzip -z -4 "${FILENAME}.epub"

[KevinH]

FWIW, epub3 spec does not require an OEBPS folder or even any folder at all.

[PenguinCEO]

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[DNSB]

Originally Posted by Jellby

My base script:

zip -X0 "${FILENAME}.epub" mimetype
zip -X9Dr "${FILENAME}.epub" META-INF OEBPS
advzip -z -4 "${FILENAME}.epub"

Given that the mimetype file is not to be compressed, why are you using the advzip with "insane" to compress the epub file? The only option for the mimetype would be 0 to store without compression.

To quote the epub 3.2 OCF ZIP Container specification:

4.3 OCF ZIP Container Media Type Identification

The first file in the OCF ZIP Container MUST be the mimetype file, which meets the following requirements:

The contents of the mimetype file MUST be the MIME media type [RFC2046] string application/epub+zip encoded in US-ASCII [US-ASCII].
The mimetype file MUST NOT contain any leading or trailing padding or white space.
The mimetype file MUST NOT begin with the Unicode byte order mark U+FEFF.
The mimetype file MUST NOT be compressed or encrypted, and there MUST NOT be an extra field in its ZIP header.

[najgori]

i think that advzip does not recompress stored files and mimetype is stored.
for someone advzip could be finishing "touch" to epub before sending it to client or wahtever....

[PenguinCEO]

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[najgori]

I tend not to read documentation. Have you tested it?

[Jellby]

I think I probably missed the fact that advzip could be messing with the mimetype file. So far, I haven't had any problems, either in an actual reader (Kobo) or in calibre (including the "check book" option in the editor), so it could be that advzip is actually not touching the mimetype.

Anyway, the file is so small that even adding it with -X9 results in it being stored without compression.

[DNSB]

Originally Posted by Jellby

I think I probably missed the fact that advzip could be messing with the mimetype file. So far, I haven't had any problems, either in an actual reader (Kobo) or in calibre (including the "check book" option in the editor), so it could be that advzip is actually not touching the mimetype.

Anyway, the file is so small that even adding it with -X9 results in it being stored without compression.

From what I saw in the advzip documentation, 1-4 will check the file and store as uncompressed, with original compression or re-compressed depending on which gives the smaller file size. I suspect the mimetype file is so small that it will not be compressed but you are rolling the dice. Asides, I am not a fan of zopfli -- it is so damned slow.

[Jellby]

but you are rolling the dice.

Yes, I guess you are right. I could always check that the mimetype file remains uncompressed (with e.g. advzip -l).

Asides, I am not a fan of zopfli -- it is so damned slow.

Well, it's not something I have to run thousands of times a day, just once when the ebook is ready. I usually get a reduction to ~98% filesize, so I could also do without it.

[JSWolf]

Originally Posted by PenguinCEO

I am writing a bash script to build an epub from a file folder. The focus of the script are the following lines of code:

zip -X0 ${FILENAME}.epub mimetype
zip -Xr9 ${FILENAME}.epub META-INF/
zip -Xr9 ${FILENAME}.epub oebps/

I would like to compare that code with a possible "standard". Where can I find a document that describes the standard of internal structure and file compression levels within an epub?

You can use ePubPack (Windows) to create your ePub from files. Here's the link to the MR thread.

https://www.mobileread.com/forums/sh...ad.php?t=84675

[PenguinCEO]

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[JSWolf]

Originally Posted by PenguinCEO

I don't use windows. The thread has a standard, not a program, as its argument. In any case: have you read the ePubPack code? Can you guarantee that it fully complies with the standard?

I used to use it. So I know it's fully standards compatible. If it wasn't, someone would have pointed that out in the thread about it.

And as I've said for a long time and will continue to say, Windows is the best OS for eBooks.