add QUERY method support

[rnewson]

Overview

Accept QUERY method wherever POST is allowed when querying the database. Only endpoints that make no state changes are eligible. Send Accept-Query: "application/json" for all requests to such endpoints to aid discovery.

Testing recommendations

TBD

Related Issues or Pull Requests

N/A

Checklist

• This is my own work, I did not use AI, LLM's or similar technology
• Code is written and works correctly
• Changes are covered by tests
• Any new configurable parameters are documented in rel/overlay/etc/default.ini
• Documentation changes were made in the src/docs folder
• Documentation changes were backported (separated PR) to affected branches

[rnewson]

c.f https://datatracker.ietf.org/doc/rfc10008/

[vanshhhhh]

Hey @rnewson, I compiled and tested the draft PR #6051 branch locally on Windows (Python 3.13.7, Erlang OTP 29) at head commit 34c2e9a.

I noticed that:

• Requests to QUERY /db/_find and QUERY /db/_partition/{partition}/_find returned 405 Method Not Allowed with the header Allow: POST.
• Requests to QUERY /db/_explain returned 405 Method Not Allowed with the header Allow: POST.
• Requests to QUERY /db/_index returned 405 Method Not Allowed with the header Allow: GET,POST.

I wanted to coordinate on the planned scope:

1. Is extending QUERY method support to standard and partitioned Mango _find routes intended to be within the scope of this PR effort?
2. Are _explain and _index routes intentionally excluded from QUERY support?
3. If help with adding the Mango subsystem integration is welcome, I would be happy to assist.

[rnewson]

hm, I guess i missed a few spots, but certainly _index is not a query, it creates an index.

[rnewson]

added query method for _find and _explain.

[rnewson]

(noting this is still draft. I haven't written docs or tests, or ensured all QUERY-able endpoints can take all their arguments exclusively from the request body and not the query string).