rpc: websocket should respect the "HTTP_PROXY" by default

[oseau]

rpc: the default dialer for websocket should respect the proxy environment variables like "HTTP_PROXY"

By default gorilla/websocket did respect the http_proxy setting, but the newClientTransportWS function explicitly provide a websocket.Dialer without a Proxy which overwrites the default one.

Related code:

• https://github.com/gorilla/websocket/blob/76ecc29eff79f0cedf70c530605e486fc32131d1/client.go#L140-L144

• go-ethereum/rpc/websocket.go

  Lines 221 to 228 in 9ca84e6

  	dialer := cfg.wsDialer
  	if dialer == nil {
  	dialer = &websocket.Dialer{
  	ReadBufferSize: wsReadBuffer,
  	WriteBufferSize: wsWriteBuffer,
  	WriteBufferPool: wsBufferPool,
  	}
  	}

[holiman]

How about the other schemes then? Do they already respect the env proxy settings?

[oseau]

How about the other schemes then? Do they already respect the env proxy settings?

Yes, they already respect the env proxy settings.

The ethclient.Dial in users' codebase goes through => ethclient.DialContext => rpc.DialContext => rpc.DialOptions.

go-ethereum/rpc/client.go

Lines 197 to 212 in 9ca84e6

	switch u.Scheme {
	case "http", "https":
	reconnect = newClientTransportHTTP(rawurl, cfg)
	case "ws", "wss":
	rc, err := newClientTransportWS(rawurl, cfg)
	if err != nil {
	return nil, err
	}
	reconnect = rc
	case "stdio":
	reconnect = newClientTransportIO(os.Stdin, os.Stdout)
	case "":
	reconnect = newClientTransportIPC(rawurl)
	default:
	return nil, fmt.Errorf("no known transport for URL scheme %q", u.Scheme)
	}

In DialOptions we check for the other schemes, for "http(s)" the newClientTransportHTTP function provide a new(http.Client), which according to the doc uses a DefaultTransport with the Proxy: ProxyFromEnvironment enabled. (doc)

https://github.com/ethereum/go-ethereum/blob/9ca84e6b0b8302a0834534f262d4d2dd232640c5/rpc/http.go#L154-L156C3

I found this inconsistence behavior between http(s) and ws(s) because I tried to reach a rpc endpoint behind a proxy, the websocket connection can not be established while the http(s) requests works without problem.

[oseau]

Workaround before the releasing of 1.11.7

replacing ethclient.Dial("wss://***") with

rpc.DialOptions(
	context.Background(),
	"wss://***",
	rpc.WithWebsocketDialer(
		websocket.Dialer{
			Proxy: http.ProxyFromEnvironment,
		}))