Epub validation error

Pixie25 · 04-18-2012, 08:51 PM

I'm getting Epub validation errors

WARNING OEBPS/content.opf 6 24 title element is empty
ERROR OEBPS/content.opf 18 46 character content of element "dc:identifier" invalid; must be a string with length at least 1 (actual length was 0)

Used Indesign CS 5.5 to create.

Any help would be great.

Toxaris · 04-19-2012, 01:55 AM

There must be an unique identifier in the opf file. Most people use the ISBN number when available. More or less the same is valid for the title. The title element in the opf is required in the ePUB specifications.
I assume that in ID this can be done in the metadata.

mmat1 · 04-19-2012, 03:39 AM

Quote:

Originally Posted by Pixie25

WARNING OEBPS/content.opf 6 24 title element is empty
ERROR OEBPS/content.opf 18 46 character content of element "dc:identifier" invalid; must be a string with length at least 1 (actual length was 0)

Used Indesign CS 5.5 to create.

Maybe you missed to fill in some options before creating your epub ?

You may try sigil to correct it, it has a metadata-editor

Pixie25 · 04-19-2012, 08:00 AM

Thank you both.

Issue fixed.

stephentiano · 06-30-2012, 08:15 PM

I know I'm months late to this thread, but I was pleased to find it. Only it leaves me with other questions. For instance, if I'm just trying to put together a sample epub doc from a print book I did design and layout on, what can I use for ID info, since the ISBN is not mine to fool around with? Also, is there generally a "rule book" or operations manual that decodes validator error messages in plain, non-techie English?

Thank you.

AlexBell · 07-01-2012, 02:46 AM

Quote:

Originally Posted by stephentiano

I'm just trying to put together a sample epub doc from a print book I did design and layout on, what can I use for ID info, since the ISBN is not mine to fool around with?

Anything you like as long as it's unique. For example I use afjbnnn where afjb are my intials, and nnn is a three digit number. If I ever get to my thousandth ePub I'll use afjb1000

Jellby · 07-01-2012, 04:09 AM

I use "Jellby:YYYYMMDD", where YYYYMMDD is the date when I create the OPF file. If I create several ones in a single day, I add "b", "c", etc. My identifier looks like this:

Code:

<dc:identifier id="BookId">Jellby:20120701</dc:identifier>

AlPe · 07-01-2012, 04:26 AM

I use UUID, generated by the standard "uuidgen -r" command on any GNU/Linux box.

stacyl276 · 09-11-2012, 01:10 PM

I am getting the error: character content of element "dc:identifier" invalid; must be a string with length at least 1. Sounds like the fix is to open the source code and place the ISB number into the dc: identifier. Can someone post what code and am looking for to add this to? May sound trivial but I am new with code.
Also, the validator is telling me to take the spaces out of my file names. I can't do this since the TOC uses these names. Is this going to be a problem in final validation?

mmat1 · 09-11-2012, 03:42 PM

Quote:

Originally Posted by stacyl276

I am getting the error: character content of element "dc:identifier" invalid; must be a string with length at least 1. Sounds like the fix is to open the source code and place the ISB number into the dc: identifier. Can someone post what code and am looking for to add this to? May sound trivial but I am new with code.
Also, the validator is telling me to take the spaces out of my file names. I can't do this since the TOC uses these names. Is this going to be a problem in final validation?

Jellby has posted a perfect solution 3 messages above. You should replace the whole "<dc:identifier"- line in content.opf with one that matches the sample above.

Btw: Doing this would be easy by using sigil, but which tool do you use ?? Building a toc from filenames is a bit unusual. Spaces and other special character's (such like äöü) in Filenames could cause problems (somewhere in the universe

), but i never heard about a case, where they are a real problem.

stacyl276 · 09-12-2012, 01:25 AM

What program opens the .opf file. I assumed a text editor or Dreamweaver would do this but neither let me. I'm not seeing where I can fix this in the metadata panel (in InDesign) either. I tried to use sigil but I am on OS 10.5.8 and can't seem to find an older download of Sigil anywhere. The newest version needs OS 10.6.

JSWolf · 09-12-2012, 01:45 AM

Quote:

Originally Posted by stacyl276

What program opens the .opf file. I assumed a text editor or Dreamweaver would do this but neither let me. I'm not seeing where I can fix this in the metadata panel (in InDesign) either. I tried to use sigil but I am on OS 10.5.8 and can't seem to find an older download of Sigil anywhere. The newest version needs OS 10.6.

An ePub container is just a ZIP file. Just unZIP the OPF file, make your changes using a text editor and put it back in.

AlexBell · 09-12-2012, 02:12 AM

Quote:

Originally Posted by stacyl276

What program opens the .opf file. I assumed a text editor or Dreamweaver would do this but neither let me. I'm not seeing where I can fix this in the metadata panel (in InDesign) either. I tried to use sigil but I am on OS 10.5.8 and can't seem to find an older download of Sigil anywhere. The newest version needs OS 10.6.

It's just a text file, and my Windows HTML editor opens it without problem. There must be an HTML editor which works on Apples.

Or you could try renaming content.opf to content.txt (or whatever Apple uses for text files) and then rename it back to content.opf when you've edited it.

mzmm · 09-18-2012, 09:39 AM

Quote:

Originally Posted by stacyl276

What program opens the .opf file...

i have a mac and use textwrangler to edit just about all epub content documents (including your opf). also it's free.

Quote:

Originally Posted by stephentiano

what can I use for ID info, since the ISBN

i've also used http://www.famkruithof.net/uuid/uuidgen to generate unique identifiers

04-18-2012, 08:51 PM	#1
Pixie25 Junior Member Posts: 2 Karma: 10 Join Date: Apr 2012 Device: ipad,kindle fire	Epub validation error I'm getting Epub validation errors WARNING OEBPS/content.opf 6 24 title element is empty ERROR OEBPS/content.opf 18 46 character content of element "dc:identifier" invalid; must be a string with length at least 1 (actual length was 0) Used Indesign CS 5.5 to create. Any help would be great.

07-01-2012, 04:09 AM	#7
Jellby frumious Bandersnatch Posts: 7,515 Karma: 18512745 Join Date: Jan 2008 Location: Spaniard in Sweden Device: Cybook Orizon, Kobo Aura	I use "Jellby:YYYYMMDD", where YYYYMMDD is the date when I create the OPF file. If I create several ones in a single day, I add "b", "c", etc. My identifier looks like this: Code: <dc:identifier id="BookId">Jellby:20120701</dc:identifier>

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04-19-2012, 01:55 AM	#2
Toxaris Wizard Posts: 4,520 Karma: 121692313 Join Date: Oct 2009 Location: Heemskerk, NL Device: PRS-T1, Kobo Touch, Kobo Aura	There must be an unique identifier in the opf file. Most people use the ISBN number when available. More or less the same is valid for the title. The title element in the opf is required in the ePUB specifications. I assume that in ID this can be done in the metadata.

04-19-2012, 08:00 AM	#4
Pixie25 Junior Member Posts: 2 Karma: 10 Join Date: Apr 2012 Device: ipad,kindle fire	Thank you both. Issue fixed.

06-30-2012, 08:15 PM	#5
stephentiano Freelance Book Designer Posts: 1 Karma: 10 Join Date: Jun 2012 Device: iPad	I know I'm months late to this thread, but I was pleased to find it. Only it leaves me with other questions. For instance, if I'm just trying to put together a sample epub doc from a print book I did design and layout on, what can I use for ID info, since the ISBN is not mine to fool around with? Also, is there generally a "rule book" or operations manual that decodes validator error messages in plain, non-techie English? Thank you.

07-01-2012, 04:26 AM	#8
AlPe Digital Amanuensis Posts: 727 Karma: 1446357 Join Date: Dec 2011 Location: Turin, Italy Device: Several eReaders and tablets	I use UUID, generated by the standard "uuidgen -r" command on any GNU/Linux box.

09-11-2012, 01:10 PM	#9
stacyl276 Junior Member Posts: 2 Karma: 10 Join Date: Sep 2012 Device: none	I am getting the error: character content of element "dc:identifier" invalid; must be a string with length at least 1. Sounds like the fix is to open the source code and place the ISB number into the dc: identifier. Can someone post what code and am looking for to add this to? May sound trivial but I am new with code. Also, the validator is telling me to take the spaces out of my file names. I can't do this since the TOC uses these names. Is this going to be a problem in final validation?

09-12-2012, 01:25 AM	#11
stacyl276 Junior Member Posts: 2 Karma: 10 Join Date: Sep 2012 Device: none	What program opens the .opf file. I assumed a text editor or Dreamweaver would do this but neither let me. I'm not seeing where I can fix this in the metadata panel (in InDesign) either. I tried to use sigil but I am on OS 10.5.8 and can't seem to find an older download of Sigil anywhere. The newest version needs OS 10.6.