[useragent]: Defaults to go-http-client if original request has empty UA

[LaurenceJJones]

Welcome!

• Yes, I've searched similar issues on GitHub and didn't find any.

What did you do?

I currently using whoami to see what requests headers are being proxied by Haproxy to ensure our WAF integration works properly.

However, I found an odd behavior when testing our empty useragent rules, the request from Haproxy to our WAF is correct but the response from whoami shows:

$ curl -A "" http://127.0.0.1:9090/
Hostname: 275a42461af8
IP: 127.0.0.1
IP: ::1
IP: 10.5.5.2
IP: fe80::b48b:e3ff:fe5a:7bef
RemoteAddr: 10.5.5.4:52688
GET / HTTP/1.1
Host: 127.0.0.1:9090
User-Agent: Go-http-client/1.1
Accept: */*
X-Crowdsec-Remediation: allow
X-Unique-Id: 32771e77-2cb0-43c7-83c7-44da150b761a

The reason that this happens is within the code whoami writes the request onto the response writer and the request will default to certain values if some headers are not set.

	if err := r.Write(w); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

What were you expecting?

I expected whoami to actually respond with the requested headers and attempt to stop golang from imposing it "smart" defaults.

What version are you using?

1.11.0

What is your environment & configuration?

  whoami:
    image: traefik/whoami:latest
    networks:
      - crowdsec
    command:
       - --port=2020

Add more configuration information here.

If applicable, please paste the log output in DEBUG level

No response