Catching NSKeyedUnarchiver exception

Question

In Swift, NSKeyedUnarchiver.unarchiveObjectWithData(data) will throw an exception if data can't be unarchived.

There are some situations where we have no guarantee if that the data is not corrupted, such as when reading from a file.

I am not aware of a try/catch mechanism in Swift, nor that I know of a method like canUnarchive that would help prevent the exception.

Besides implementing the try/catch in Obj-C, is there a pure Swift solution to this problem?

I have the same problem. Have you already found a solution? – return true Oct 21 '14 at 20:09 — return true, Oct 21 '14 at 20:09
Apple should have made a try/catch for swift... – return true Oct 22 '14 at 07:00 — return true, Oct 22 '14 at 07:00
same problem here, and this is crazy.. – Vik Sep 03 '15 at 11:44 — Vik, Sep 03 '15 at 11:44

score 10 · Answer 1 · answered Nov 13 '15 at 18:08

Because unarchiveObjectWithData() doesn't throw its exception, there is currently no way to catch it in Swift (as of writing). The iOS 9 SDK has added a new NSKeyedUnarchiver method decodeTopLevelObject() which now throws an error. You can catch this with the do, try, catch control flow.

do {
    let result = try NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(NSData(...))
} catch {
    print(error)
}

Catching NSKeyedUnarchiver exception

1 Answers1