As a reading system, Bookworm is largely targeted at end-users (i.e., readers) who just want to upload a book. If the ePub has recoverable errors, such as listing the XHTML as ‘text/html’ rather than ‘application/xml+xhtml’, then it ignores them.

What I was proposing was targeted at publishers or developers who use Bookworm as a test bed. It’s a usage I encourage but don’t provide specific tools for. These would be more sophisticated users who need to know what the exact problems were so they can go back and fix their pipeline.

It sounds like you’re thinking of a hybrid group that is producing ePubs as custom books rather than programmatically in batch (for example, tech-savvy self-published authors). That’s similar to what Feedbooks is doing now with their authoring tools, and while it’s a little clunky to use it certainly abstracts away the entire XML underpinning of ePub. I think that’s a better approach than WYSIWYG XML, which I’ve never seen done well.

Also, the feedback process you mention between validation and user corrections is often unnecessary. For example, if I type ‘text/xml’ in a media-type attribute, I don’t want to go through a feedback process to fix that–I just want it to auto-correct. Likewise, if I duplicate something in the manifest, I don’t want to have to go through feedback and confirmation to have it removed, I just want it to go away. Same with spine ordering–if I move or remove something in the toc, I want the changes reflected across manifest, spine and navMap, but I don’t want to have to edit all three elements, much less go through two feedback/validation cycles before realizing that I forgot to duplicate the change across all three.

There are a lot of issues like these that come up with EPUB, and if it’s ever going to appeal to consumers, these things need to become more transparent, not less.

What might be a good first step is a method to inline-edit the source for the various metadata files, if they are found to have simple problems. In the early stages of Bookworm I considered allowing users to edit the human-readable metadata (e.g. title or publisher) and export that back out as an ePub. Something like that could be incorporated not into the Bookworm reader itself, but a separate product that could also perform validation against the specific schemas for OPF and NCX.

So, upload test ePub -> validate -> get opportunity to tweak it -> validate (repeat as necessary) -> output valid ePub.

I think trying to create a full suite for non-technical users is probably best left to the big commercial software firms, though.

If the editor is also made to be informative then users can learn while they work.

A wysiwyg editor on top of epubcheck could provide some friendly messages to the user about things like image format, filetype, etc, while the editing system itself could normalize markup and hide the more confusing aspects of the format.

Is this something that people find interesting?