[Wpack] package: URL scheme

[Jeffrey Yasskin <[e-mail]>]

Hi all,

I wanted to raise awareness of a discussion about the URL scheme for
addressing resources within bundles (draft-yasskin-wpack-bundled-exchanges).

We seem to be heading toward a URL of the form
package:<encoded-package-url>$<encoded-resource-uri>, which for a package
URL of https://distributor.example/package.wbn and resource URI of
https://publisher.example/page.html?q=query would lead to a URL of:

*package:https:,,distributor.example,package.wbn;q=query$https:,,publisher.example/page.html?q=query*

This arises from several considerations:
1. A bundle is served from a URL.
2. After a user downloads the bundle, it gets a new URL, often file:///...
3. We can also hash the bundle to get a URI that stays stable across
transfers.
4. Resources inside a bundle are named by URIs (which, since the bundle has
an index, are also URLs even if, like urn:uuid:..., they wouldn't normally
be locators).
5. Once a user downloads a bundle, for web browsers to give its content
storage that's persistent across reloads, as requested in
https://github.com/WICG/webpackage/issues/498, the content needs to be
assigned a non-opaque origin.

I'm updating one of the documents about this in
https://github.com/WICG/webpackage/pull/584 and would welcome comments here
or there.

The URLs are obviously gross, so
https://github.com/WICG/webpackage/pull/560 suggests
that browsers avoid showing them to users in most cases.

We could potentially simplify things if packages named things with just
paths instead of full URIs. We'd then name things based on the bundle's
origin. However, this loses archiving use cases.

This is all further discussed in the following documents and issues, but
you shouldn't feel responsible to read everything here:

*
https://docs.google.com/document/d/1BYQEi8xkXDAg9lxm3PaoMzEutuQAZi1r8Y0pLaFJQoo/edit#
*
https://chromium-review.googlesource.com/c/chromium/src/+/2226248/7#message-0a3efda5aff84770a1729422a5b26aeca3ee4e80
* https://github.com/WICG/webpackage/issues/583
*
https://github.com/WICG/webpackage/blob/master/explainers/navigation-to-unsigned-bundles.md#urls-for-bundle-components
* https://lists.w3.org/Archives/Public/uri/2019Nov/0000.html

Thanks,
Jeffrey