在已部署的Appengine应用中，用户ID可以超过64位吗？

Question

I am working on an appengine app in Go and when I tried to get an appengine User's ID and convert it to a 64-bit int with this code:

id, err := strconv.ParseInt(user.ID, 10, 64)

I got this error:

ERROR: error executing inner: strconv.ParseInt: parsing "185804764220139124118": value out of range

Does this error occur on appengine IDs in deployed code as well?

Answer 1

The ID field of the User type is defined with type string. Just because it contains digits, there is no guarantee that it fits into an int64.

The Go AppengineSDK uses values that fit into int64, but this is not true in production environment. They are usually longer than the max value of int64. They are handed to you as strings, so treat them like that: strings. Nothing forces you to convert them to a number. I don't know where you got the idea to convert them to numbers, but don't do that. They are strings.

Note: User.ID is not to be mistaken with Key.IntID() which is defined to be of type int64.