Case insensitive check for host restrictions

[ErikPelli]

Currently the DstHostIs handler is implemented like this:

func DstHostIs(host string) ReqConditionFunc {
	return func(req *http.Request, ctx *ProxyCtx) bool {
		return req.URL.Host == host
	}
}

Suppose we use some handler like this one to block all the requests made to the target host:

proxy.OnRequest(goproxy.DstHostIs("www.reddit.com")).DoFunc(...)

If the user types www.reddit.com, the request would be blocked and an error would be returned.
However, if he types www.ReDDit.com, the request would bypass the restriction and just be accepted because the string is not equal (however the resolved ip from the dns is the reddit server).

@elazarl should we just ignore cases like this? Should we introduce another function where the check is explicit (calling it something like InsensitiveDstHostIs? Or should we directly modify the current one to do a case insensitive check?

[elazarl]

Hmmm... can a dns server elect to be case sensitive? Is there a canonization standard for that?

[ErikPelli]

I've never seen any case sensitive DNS , and I think they don't even exist.
RFC4343 explain explicitly the fact that they should be case insensitive.