Don't remove the `Host` header

[simonzkl]

Hudsucker will always remove the Host header, potentially changing the original request. It should not do that if the Host header was present in the original request. The Host header can be different to the actual host that you're connecting to.

hudsucker/src/proxy/internal.rs

Line 383 in 132acca

// Hyper will automatically add a Host header if needed.

[omjadas]

I agree that it would be better to leave the request as is. However, I recall that leaving the Host header caused issues with hyper and HTTP/2 at the time. I will look into this again and see if this is still the case.

[simonzkl]

Yeah I came to the same conclusion experimenting with this. I think the correct thing might be to leave the header if the HTTP request version is < 2.0.

[omjadas]

I think what would ideally happen is the HOST header would be removed only if the request is going to be made over HTTP/2 between the proxy and the server. However, I don't think this is possible to determine ahead of time (at least when using the client provided by hyper-util).