Streamer "asset" URL, path relative to OPF (manifest items), failure with '../' step

[danielweck]

Let's say:

META-INF/container.xml
rootfile@href =>
EPUB/package.opf
manifest>item@href =>
chapter1.xhtml

A typical "fetcher" URL in the current implementations would look like:
https://r2.org/moby-dick.epub/chapter1.xhtml

Now, in my opinion, this is slightly "wrong", because the full path in the EPUB container is actually EPUB/chapter1.xhtml (regardless of its zipped / unzipped status).

Furthermore (and more importantly), we have a problem with relative paths such as:
manifest>item@href => ../cover.jpg
...which would result in URLs such as:

https://r2.org/moby-dick.epub/../cover.jpg
(as you can see, the .. notation interferes because it is not escaped)

So, wouldn't it be better to logically follow the EPUB container file structure?
i.e.:
https://r2.org/moby-dick.epub/cover.jpg
https://r2.org/moby-dick.epub/EPUB/chapter1.xhtml

Note that I implemented support for both syntaxes in the NodeJS streamer, as described here:
https://github.com/edrlab/r2-streamer-js/wiki/Demonstration#epub-resource-urls

[HadrienGardeur]

Well, I can imagine more edge cases.

Let's imagine the following EPUB:

META-INF/encryption.xml
cover.jpg
EPUB/package.opf
EPUB/chapter1.html
EPUB/chapter1.mp3
EPUB/navdoc/toc.html
EPUB/smil/chapter1.smil

Your suggestion should handle two problematic situations:

• accessing META-INF/encryption.xml
• accessing cover.jpg

For EPUB/navdoc/toc.html and EPUB/smil/chapter1.smil do you calculate everything based on the relative path of the Navigation Document, NCX and SMIL?

The Navigation Document would reference ../chapter1.html but with your suggested change, we would have to indicate EPUB/chapter1.html in the manifest.
Same idea for NCX and SMIL.

I can't remember if in EPUB content documents, links can start with a / with for example:

<a href="/EPUB/chapter1.html" />

That specific case would be very problematic because the navigator would attempt to access https://r2.org/EPUB/chapter1.html instead of https://r2.org/moby-dick.epub/EPUB/chapter1.html.

[danielweck]

I think we should close this issue, as this is the active one: #38
(they are cross-referenced, so we won't loose the discussion thread here)