Not supporting proxy mode

[qcastel]

Describe the bug
When trying to proxy requests through Spring cloud gateway:

curl -k --proxy https://local-api.yapily.com:8080  https://httpbin.org/get

the response is:

curl: (56) Received HTTP code 404 from proxy after CONNECT

However:

curl -k  https://local-api.yapily.com:8080/get --header 'host: httpbin.org'

works fine:

{
  "args": {},
  "headers": {
    "Accept": "*/*",
    "Content-Length": "0",
    "Forwarded": "proto=https;host=httpbin.org;for=\"127.0.0.1:56283\"",
    "Host": "httpbin.org",
    "User-Agent": "curl/7.64.1",
    "X-Amzn-Trace-Id": "Root=1-5e4ffd2a-7502421dd2e64f1145125dc3",
    "X-Forwarded-Host": "httpbin.org"
  },
  "origin": "127.0.0.1, 35.189.96.6",
  "url": "https://httpbin.org/get"
}

Sample
I reproduce the issue here:
https://github.com/qcastel/reproduce-spring-cloud-gateway-error

Please note that I use the latest netty snapshot, as they were an NPE on netty that is now solved by reactor/reactor-netty#948

[GuyLewin]

Is it supposed to work to begin with? I believe Spring Cloud Gateway is a reverse proxy that isn't supposed to act as a forward proxy with HTTP CONNECT protocol. Please correct me if I'm wrong.

In order to implement it you can extend WebServerFactoryCustomizer<NettyReactiveWebServerFactory> to change the Netty pipeline, to accept HTTP CONNECT requests.

[spencergibb]

Correct, gateway is a reverse proxy.