Add support for the HTTP QUERY method (RFC 10008)

[psolvy]

Summary

Adds support for the new HTTP QUERY method, standardized in RFC 10008 (Proposed Standard, June 2026).

QUERY is safe and idempotent like GET, but carries a request body like POST — the request content (of any media type) defines the query. Because it is idempotent, a QUERY can be safely retried, unlike POST.

Changes

• Phoenix.Router — add :query to the supported HTTP verbs, generating the query/3 and query/4 route macros (mirroring get, post, etc.). Routing arbitrary verbs already worked via match; this adds the ergonomic, discoverable verb macro.
• Phoenix.ConnTest — add the matching query/3 test helper, for parity with the other verbs.
• guides/routing.md — document QUERY among the supported HTTP verbs.
• mix.exs — raise the minimum Plug requirement to ~> 1.21, the release that parses QUERY request bodies into conn.body_params and treats QUERY as a safe method in Plug.CSRFProtection (Add support for the HTTP QUERY method (RFC 10008) elixir-plug/plug#1319). Because this raises a dependency floor and adds a new public macro, the CHANGELOG targets a 1.9.0 (minor) release.

References

• RFC 10008: The HTTP QUERY Method
• Add support for the HTTP QUERY method (RFC 10008) elixir-plug/plug#1319 — companion Plug support (routing macro, body parsing, CSRF), merged

[SteffenDE]

I assume we need to wait for an updated plug and then bump the minimum plug version?

[psolvy]

@SteffenDE hello!
Yes - you are right. I have already opened a Plug library PR to support a new method
elixir-plug/plug#1319

UPD updated this one with a minimum Plug version and bumped phoenix minor version instead of fix one