Without `wt-available-protocols`, moq-relay (`web-transport-quinn`) falls
back to the legacy in-band SETUP exchange (moq-lite-02) instead of
selecting the moq-lite-03 sub-protocol from the ALPN-style negotiation
header. Then the relay tries to decode our first post-CONNECT bytes as a
SETUP_CLIENT message, hits an unknown control type, and closes the QUIC
connection with `connection closed err=invalid value` — surfaced
client-side as a stuck SUBSCRIBE that ends with
`subscribe stream FIN before reply for id=0` (the bidi gets FIN'd because
the whole connection is being torn down).
Pass `wt-available-protocols: "moq-lite-03"` on the Extended CONNECT
request, encoded as an RFC 8941 Structured Field List of strings (the
header format mandated by draft-ietf-webtrans-http3-14 §3.3). With this,
moq-relay logs `negotiated version=moq-lite-03 transport="quic"` and the
SUBSCRIBE makes it into the relay's actual moq-lite session pump.
Mechanism: web-transport-proto's `ConnectRequest::encode` reads
`self.protocols` and writes them as a comma-separated list of bare
strings under `wt-available-protocols`. The server side (web-transport-
quinn) reads the same header into `request.protocols`, and moq-native's
`QuinnRequest::ok()` picks the first match against its supported ALPN
list (`moq-lite-04`, `moq-lite-03`, `moq-00`, `moqt-15`, etc.). On
match, version selection happens via the WT sub-protocol response and
the in-band SETUP is skipped — which is what moq-lite-03 expects.
Default the factory list to `["moq-lite-03"]`. Callers that want a
different version (or to disable sub-protocol negotiation entirely
to talk to a SETUP-based server) override the constructor parameter.
Bare-metal harness: NostrNestsHarness.startExternal() now skips the
TCP probe of the moq-relay port. moq-relay binds UDP only; the Docker
forwarder happens to also open TCP, but a directly-launched binary
doesn't, so the previous `Socket(host, 4443)` probe failed with
ConnectException. The QUIC handshake from the test surfaces a real
transport problem if any.
Claude
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