file-server/hasher.go
func (s MD5Hasher) IsHash(h string) bool {
	if len(h) != s.HashLength {
		return false
	}
	var found bool
	for _, c := range h {
		found = false
		for _, m := range hexChars {
			if c == m {
				found = true
				break
			}
		}
		if !found {
			return false
		}
	}
	return true
}
func (s MD5Hasher) IsHash(h string) bool {
	if len(h) != s.HashLength {
		return false
	}
	var found bool
	for _, c := range h {
		found = false
		for _, m := range hexChars {
			if c == m {
				found = true
				break
			}
		}
		if !found {
			return false
		}
	}
	return true
}
// IsHash checks is provided string a valid hash.