Function httpHostHeader

midway/relay/http.go:33–71

(br *bufio.Reader)

)

func httpHostHeader(br *bufio.Reader) string {
	const maxPeek = 4 << 10
	peekSize := 0
	for {
		peekSize++
		if peekSize > maxPeek {
			b, _ := br.Peek(br.Buffered())
			return httpHostHeaderFromBytes(b)
		}
		b, err := br.Peek(peekSize)
		if n := br.Buffered(); n > peekSize {
			b, _ = br.Peek(n)
			peekSize = n
		}
		if len(b) > 0 {
			if b[0] < 'A' || b[0] > 'Z' {
				// Doesn't look like an HTTP verb
				// (GET, POST, etc).
				return ""
			}
			if bytes.Index(b, crlfcrlf) != -1 || bytes.Index(b, lflf) != -1 {
				req, err := http.ReadRequest(bufio.NewReader(bytes.NewReader(b)))
				if err != nil {
					return ""
				}
				if len(req.Header["Host"]) > 1 {
					// TODO(bradfitz): what does
					// ReadRequest do if there are
					// multiple Host headers?
					return ""
				}
				return req.Host
			}
		}
		if err != nil {
			return httpHostHeaderFromBytes(b)
		}
	}
}

var (
	lfHostColon = []byte("\nHost:")