Strip headers listed in Connection header per RFC 7230 Section 6.1

[mcollina]

Summary

Per RFC 7230 Section 6.1, a proxy MUST parse the Connection header and remove any headers listed within it before forwarding the request to the upstream server.

Currently, @fastify/reply-from only strips the Connection header itself but does not strip headers named inside it.

Example

Request from client:

GET / HTTP/1.1
Host: localhost
X-Custom-Header: some-value
Connection: X-Custom-Header

Expected behavior: Both Connection and X-Custom-Header should be stripped before forwarding.

Current behavior: Only Connection is stripped; X-Custom-Header is forwarded to upstream.

Reference

• RFC 7230 Section 6.1 - Connection Header Field