Add uri typed headers

[keithamus]

PR Type

Feature

PR Checklist

• Tests for the changes have been added / updated.
• Documentation comments have been added / updated.
• A changelog entry has been made for the appropriate packages.
• Format code with the latest stable rustfmt.
• (Team) Label with affected crates and semver status.

Overview

This adds the Location, Content-Location and Referer typed headers. It also adds the TryIntoHeaderValue trait for Uri which allows Uri to be a typed value for these headers.

While Location technically is a different type than Content-Location and Referer (Location allows for protocol relative URIs) I think it's not a large enough distinction to warrant a separate type, as using protocol relative urls is quite rare. However we could use url::Url instead of Uri for Location if we wanted to allow for that distinction.

The motivation for this PR is to allow for using Referer as an Extractor, and the other two were easy enough to also add, and complete the trifecta of URI related headers (to the best of my knowledge).

[keithamus]

@robjtede those changes have been made. Let me know if you have any more feedback.

[keithamus]

I'm still interested in this patch, if you think it's worth merging in.

[robjtede]

Just come back to this and I still like it, but I'm going to make the Location (and possibly ContentLocation after some more research) use url::Url instead of http::Uri so that fragments (/path?query#fragment) are supported.

I'll cut a release with what's been merged already and get to this one afterwards. Should be easy to fixup and get out this weekend.

[robjtede]

Run into a hurdle with that idea, that url::Url doesn't support relative references, e.g.: /new-path. So both types seem incapable of expressing what we actually want from Location/Content-Location.