Doesn't work with http2

[SPAHI4]

I'm using this server https://github.com/molnarg/node-http2

(node:1640) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): Error: Cannot set deprecated header: connection

I tried to remove this string https://github.com/glenjamin/webpack-hot-middleware/blob/e0a0c469fb72651ca022328fa45b788c6901845d/middleware.js#L58
works fine, but I'm not sure that it's a nice solution.

upd. after deleting this I get other error

(node:2003) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 2): Error: Sending illegal frame (DATA) in CLOSED state.

[glenjamin]

Any idea how to detect if it's an http connection? If so we could skip that header in those scenarios.

[SPAHI4]

@glenjamin this condition should work
(req.socket.alpnProtocol || req.socket.npnProtocol) === 'h2'
h2 is a protocol version, we can get it from here https://github.com/molnarg/node-http2/blob/master/lib/protocol/index.js#L39

[glenjamin]

Any idea if that's an implementation details or something the http2 projects officially supports for detection?

If there's some confirmation that it's the latter, I'll happily merge a PR which makes this header conditional

[cainrus]

Documentations says request.httpVersion
https://nodejs.org/api/http2.html#http2_request_httpversion

PR: #322