Function trimURL

command/certificate/remote.go:79–95

trimURL returns the host[:port] if the input is a URL, otherwise returns an empty string (and 'isURL:false'). If the URL is valid and no port is specified, the default port determined by the URL prefix is used. Examples: trimURL("https://smallstep.com/onboarding") -> "smallstep.com:443", true, nil

(ref string)

// trimURL("hTtPs://sMaLlStEp.cOm") -> "sMaLlStEp.cOm:443", true, nil
// trimURL("hTtPs://sMaLlStEp.cOm hello") -> "", false, err{"invalid url"}
func trimURL(ref string) (string, bool, error) {
	tmp := strings.ToLower(ref)
	for prefix := range urlPrefixes {
		if strings.HasPrefix(tmp, prefix) {
			u, err := url.Parse(ref)
			if err != nil {
				return "", false, errors.Wrapf(err, "error parsing URL '%s'", ref)
			}
			if _, _, err := net.SplitHostPort(u.Host); err != nil {
				port := strconv.FormatUint(uint64(urlPrefixes[prefix]), 10)
				u.Host = net.JoinHostPort(u.Host, port)
			}
			return u.Host, true, nil
		}
	}
	return "", false, nil
}