http2 demo not working as expected

[mcollina]

Consider the following:

import { request, fetch, Agent, Client, setGlobalDispatcher } from './index.js'

setGlobalDispatcher(new Agent({
  allowH2: true
}))

// Not working as expected
// the request is done using HTTP/1.1
const res1 = await fetch(`https://http2.pro/api/v1`)
console.log(await res1.json())

// Not working as expected, the response is never received
const client = new Client('https://http2.pro', {
  allowH2: true
})

const res2 = await request(`https://http2.pro/api/v1`, { dispatcher: client })
console.log(await res2.body.json())

[mcollina]

@metcoder95

[KhafraDev]

maybe a "forceH2" option is needed?

[mcollina]

technically it should use http2 if alpn says it's available

[metcoder95]

I need to dig deeper into it, but the bug is quite peculiar.

The ALPN negotiation was successful, and the socket has been connected through h2. A request has been successfully triggered to the server, but the server basically has not replied at all, meaning that no body is being received, not even the response headers static the stream has been made.

[metcoder95]

I also find smaller improvements that I'll push soon. I'll try to dig deeper soon into this to see if I can find the root cause

[metcoder95]

nvm, find the issue 😓
Opening PR now

[ShenHongFei]

setGlobalDispatcher(new Agent({
  allowH2: true
}))

// Not working as expected
// the request is done using HTTP/1.1
const res1 = await fetch(`https://http2.pro/api/v1`)
console.log(await res1.json())

This part does not work properly because Agent uses lib/pool.js, and allowH2 is not passed here. The relevant logic is in

undici/lib/pool.js

Lines 53 to 62 in 9fa8224

	if (typeof connect !== 'function') {
	connect = buildConnector({
	...tls,
	maxCachedSessions,
	socketPath,
	timeout: connectTimeout == null ? 10e3 : connectTimeout,
	...(util.nodeHasAutoSelectFamily && autoSelectFamily ? { autoSelectFamily, autoSelectFamilyAttemptTimeout } : undefined),
	...connect
	})
	}

And

undici/lib/agent.js

Lines 21 to 25 in 9fa8224

	function defaultFactory (origin, opts) {
	return opts && opts.connections === 1
	? new Client(origin, opts)
	: new Pool(origin, opts)
	}

Client will be used only if connections is set to 1, otherwise Pool will be used, so you need to set connections: 1 (I don’t know if it is reasonable)

setGlobalDispatcher(new Agent({
  allowH2: true,
  connections: 1
}))