Support for URI Template

[m13253]

IETF DoH requires a URI Template while configuring the client.

For example: /query{?dns}

This implementation does not support URI Template yet, and still uses the obsolete ct= parameter to negotiate protocols. We need to eventually switch to URI Template in the future.

But since it does not affect compatibility (either client or server side), and I do not have a clear understanding of it until the next extension of the protocol is published, I plan to leave this issue open and postpone this.

And as always, pull request is welcome.

[m13253]

I plan to solve this problem when IETF proposes any new standards in extension to RFC 8484. At that time it will be clear how we can solve the problem.

Prior to that, it is worth mentioning that we still need to maintain compatibility to Google DoH for the following reason:

• Google DoH is still useful in DNS troubleshooting due to its human-readability.
• Google DoH can be used in pipelines because it is easier to develop programs that processes JSON.
• This project was started way before IETF DoH is released, even before the draft is proposed.

Please discuss if anyone can come up with an idea to maintain compatibility and adapt URI Template.

[gdm85]

Has this changed in the last ~2 years?

[m13253]

It seems that no DoH server really relies on the URI template feature, although it is specified in the RFC.
I think it may not be worth it to implement it — because implementing it requires refactoring some old code.

I would rather leave current code as is.

[m13253]

So this is still an issue, patches are welcome.

But it currently bothers nobody even kept unfixed, and unfortunately my life is getting busy and can't afford allocating efforts to fix this issue.

I prefer to keep it unfixed.