Mimetype contains wrong type (application/epub+zip expected) error in epub3

[Nautan]

Hi,
I have spent weeks trying to figure out this problem and am hoping you can help me! I am trying to zip my files in the creation of an epub3. I know that the mimetype.txt file must be submitted first (without compression) and then after the OEBPS and META-INF folders - but when I do so (via Winzip, 7zip - I have tried them all!) they all produce the mimetype error. I do not have any additional elements or spaces in the mimetype file - and I am wondering whether extra elements are being added to the mimetupe file in the process of zipping (like timestamp data for example). I have been teaching myself code but am still very much a newbie. If anyone can help me with this I will be SO grateful!!!
Thank you!

[mrmikel]

You might find it easier to use the calibre editor and add files to it and the zipping up will be taken care of when you save it automatically.

[Nautan]

Thanks mrmikel! I am familiar with Calibre and see how you add books, but am not sure how you add files? You mean adding mimetype.txt and the OEBPS folder and the META-INF folder, right? I tried dragging and dropping (as Calibre instructions directed) but this did not work.

[mrmikel]

Open only the calibre editor, or right click on the entry in your library to select edit. You can import just the files you want, use the table of contents editor to create a valid table of contents, etc.

In windows it is accessed by Program Files\calibre2\edit-book.exe.

[Nautan]

Thanks mrmikel, the problem is that I used Calibre about a month ago to create my files and the resultant epub (even though it displayed perfectly in Calibre and in my kindle) still produced the mimetype error in the validation process. After this I went back to scratch, creating all the files and code myself - these files now work perfectly but the problem happens in the zipping process. I tried uploading my files to Calibre as you suggested, but in the process it mixed up all the html files - I corrected the order but still cannot seem to create an epub via Calibre that does not display the mimetype error. Any other ideas?? Thank you so much for your help with this, I am so desperate and just grateful for your time in trying to help me with it.

[Nautan]

Okay I tried it again - and despite my updates in the html code to reflect an epub3 format, and despite my inclusion of an epub nav file (toc.xhtml), the validation detects an epub2 version and generates additional errors

[mrmikel]

Don't try to validate with the tools in calibre. Use epubcheck or a check for whatever publisher you intend to use.

There is no publisher that uses full epub3.

[JSWolf]

One thing you really need to do is make sure your ePub 3 works in ADE 2. If you try to sell a full blown ePub 3 eBook, you won't sell it as hardly anyone will be able to read it.

[DiapDealer]

Originally Posted by JSWolf

One thing you really need to do is make sure your ePub 3 works in ADE 2. If you try to sell a full blown ePub 3 eBook, you won't sell it as hardly anyone will be able to read it.

Not at all relevant to the OP's request for help creating a version 3 ePub that validates.

Originally Posted by Nautan

Hi,
I have spent weeks trying to figure out this problem and am hoping you can help me! I am trying to zip my files in the creation of an epub3. I know that the mimetype.txt file must be submitted first (without compression) and then after the OEBPS and META-INF folders - but when I do so (via Winzip, 7zip - I have tried them all!) they all produce the mimetype error. I do not have any additional elements or spaces in the mimetype file - and I am wondering whether extra elements are being added to the mimetupe file in the process of zipping (like timestamp data for example). I have been teaching myself code but am still very much a newbie. If anyone can help me with this I will be SO grateful!!!
Thank you!

What I've bolded could have been a typo, but please make sure you didn't actually name the mimetype file "mimetype.txt". It should just be " mimetype" with no file extension whatsoever.

I'm not certain Winzip will even allow you to create a proper epub archive. Not without using terminal commands and/or flags anyway. There's a windows program floating around the epub forum here somewhere called ePubPack that claims to be able to create a proper archive from source files. I've not used it however.

As far as calibre goes, I'm not certain if you can edit/save manually created epub3s without compromising/changing the ePub3 OPF file. Never tried it.

[DomesticExtremis]

Originally Posted by DiapDealer

Not at all relevant to the OP's request for help creating a version 3 ePub that validates.


What I've bolded, could have been a typo, but please make sure you didn't actually name the mimetype file "mimetype.txt". It should just be " mimetype" with no file extension whatsoever.

It should be named mimetype, with no extension and contain the text

application/epub+zip

[DiapDealer]

Originally Posted by DomesticExtremis

It should be named mimetype, with no extension and contain the text

Well, yes... though I thought I'd covered fairly clearly what the file name should be, you're absolutely correct about the contents of said file.

Did some testing with calibre's editor by the way:

I was able to open a valid epub3 in calibre's editor; make a few changes to the XHTML; save it; and still end up with an epub3 that passes validation. I'm guessing you won't be able to use any of the automated "fix" or "beautify files" features and maintain its validity as an epub3, but it doesn't seem to break anything when making basic edits. It even seemed to automatically "fix" an epub3 that had a mimetype file that wasn't the first file in the archive without breaking anything else.

[DomesticExtremis]

Originally Posted by DiapDealer

Well, yes... though I thought I'd covered fairly clearly what the file name should be, you're absolutely correct about the contents of said file.

Sorry, one of my eyes was readin gthe Op and the other yours.
They got merged in my brain - pilot error.

[DiapDealer]

Originally Posted by DomesticExtremis

Sorry, one of my eyes was readin gthe Op and the other yours.
They got merged in my brain - pilot error.

No worries. I kind of figured something like that happened.

[skreutzer]

Besides the .txt extension issue (Microsoft Windows may hide extensions of known file types), you want to make sure that the text editor doesn't add a UTF-8 BOM (Byte Order Mark) or a line break at the end of the file (either explicit or implicit, the latter on Unix-like operating systems). The mimetype file has to have the size of exactly 20 bytes.

Calibre doesn't create EPUB3s, it might be usable to edit EPUB3 and keep the result valid, if some buttons aren't pushed.

[skreutzer]

I just found this: http://idpf.org/forum/topic-1694