Pass X-Forwarded-Proto in addition to X-Forwarded-Host in reverse-proxy mode

[tbroyer]

I have an application whose behavior changes (generates https:// vs. http:// URLs, set Secure flag on cookies) depending on whether it runs behind a TLS-terminating reverse proxy (production, HAProxy) or not (local dev, plain HTTP). This is done switching on a X-Forwarded-Proto request header (if set to https, we're behind the reverse proxy, otherwise –not set, or other value– we're not).

I'd like to easily test it locally using HTTPS, from time to time, to verify the expected in-production logic.

Looking around for a simple reverse-proxy with TLS support for development, I found devd, but it doesn't add X-Forwarded-Proto.

[cortesi]

I'd merge a patch that implements this, or, alternatively rfc7239.