Reading raw EPUB item data in v3

[smoores-dev]

Hello! It's me again, working on the Storyteller iOS app this time.

With v2 (and in v3 on Android), I used an onCreatePublication callback in Publication (now PublicationOpener) to add mediaOverlay properties to all of the links in the readingOrder. Basically, I parsed the OPF manually, and then looked for any media-overlay properties and added those to their respective links.

In the Swift toolkit, I'm not immediately seeing how to do this. Running into two issues:

1. container.readData seems to be internal, and I'm not sure whether there's another way to read the raw file data from the container?
2. Even if container.readData was public, it's now async, but onCreatePublication needs to be sync.

Hoping that there's a way around this that doesn't entail forking... like all of PublicationOpener :/ Any ideas?

Here's the current implementation with Readium v2, in case that's helpful! https://gitlab.com/storyteller-platform/storyteller/-/blob/main/mobile/modules/readium/ios/BookService.swift#L25-67

[smoores-dev]

I actually took a look at container.readData; it's like three lines and the APIs that it uses are public, so that's not actually an issue! Still sort of stuck on needing to make onCreatePublication synchronous

[mickael-menu]

container.readData() is a convenience utility used internally, it's not exposed publicly because we don't want to encourage users to ignore the typed errors returned by Resource.read(). But yeah it's basically just container[href]?.read().get().

Even if container.readData was public, it's now async, but onCreatePublication needs to be sync.

There's no good reason for onCreatePublication to be synchronous (except that async functions were added pretty recently in the toolkit). Feel free to open a PR to make onCreatePublication async 👍

[smoores-dev]

Awesome, will do!