header middleware

header.go

func (h Headers) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
	for _, rule := range h.Rules {
		if middleware.Path(r.URL.Path).Matches(rule.Path) {
			for _, header := range rule.Headers {
				if strings.HasPrefix(header.Name, "-") {
					w.Header().Del(strings.TrimLeft(header.Name, "-"))
				} else {
					w.Header().Set(header.Name, header.Value)
				}
			}
		}
	}
	return h.Next.ServeHTTP(w, r)
}