package guestbook import ( "errors" "time" ) type Reply struct { ID int64 `json:"-"` Created time.Time `json:"created,omitempty"` Message string `json:"message"` } func NewReply(entryID int64, message string) (*Reply, error) { if message == "" { return nil, errors.New("empty reply field") } return &Reply{ ID: entryID, Created: time.Now().UTC(), Message: message}, nil }