package gravatarimport ("crypto/sha256""fmt""strings")const baseUrl = "https://www.gravatar.com/avatar"const defaultSize = 80const maxSize = 2048func Url(email string, size int) string {email = strings.ToLower(email)email = strings.TrimSpace(email)hash := sha256.Sum256([]byte(email))if size < 1 {size = defaultSize}size = min(maxSize, size)return fmt.Sprintf("%s/%x?s=%d", baseUrl, hash, size)}