Open Radar

 
[Want to discuss? Get in touch with me @jamesreggio.]

Universal Links have provided a significant improvement to cross-app navigation in iOS 9; however, I encountered one significant pain-point during implementation: it is not possible to remove paths from the `applinks.details.paths` array within the `apple-app-site-association` JSON manifest.

The system permits the use of wildcards, which is convenient for apps that wish to map most URLs into the app; however, the inability to subtract/exclude a path after the wildcard is applied makes this quite difficult for certain URL structures.

I've included an example in the 'Steps to Reproduce' section. My recommendation would be to:

1) Make the ordering of the `paths` array significant.
2) Introduce an prefix operator (ideally `!`) to exclude paths from the manifest.

For inspiration, the `gitignore` pattern format is a good place to start. (The path format in a `gitignore` file is quite simple, and I've never found it impossible to express my needs.) https://git-scm.com/docs/gitignore

Another good example would be the `minimatch` library, though this is less compatible with your existing specification (due to the `**` glob operator). I suggest this because the choice of JSON implies an affinity for JavaScript technologies, of which `minimatch` is the canon for path matching. https://github.com/isaacs/minimatch

Finally, may I kindly recommend that you improve the documentation around the existing wildcard facilities, particularly as they concern leading and trailing slashes. It's not clear whether a leading slash is required (or what happens if it's not and it's omitted), and it's not clear whether an `*` wildcard will match only one or more than one path part.

Steps to Reproduce:
Imagine a website like Twitter, where a user's handle is specified as the first part of a path and there are nested sub-resources under the user's handle. For example:

https://twitter.com/jamesreggio
https://twitter.com/jamesreggio/status/123456

I would like for all of these URLs to launch the Twitter app, but there are a couple of URLs that *should not* load the Twitter app—the OAuth login flow, for instance, which lives at:

https://twitter.com/oauth/new

Now, if I set the `paths` array to the following, I'll capture all of the URLs on the domain, including the `/oauth/new` path:

['/*']

There is no way to include all user profiles, but exclude the `/oauth/new` path.

The ideal facility would allow me to begin with the wildcard, and then subtract paths that should not load the app. For instance:

[
  '*',
  '!/oauth/*'
]

Version:
iOS 9

Configuration:
iPhone