How can I check that an NSData blob is valid as resumeData for an NSURLSessionDownloadTask?

Question

I have an app that\'s using background downloads with the new NSURLSession APIs. When a download cancels or fails in such a way that NSURLSessionDownloadT

Answer 1

I have not found an answer to how to tell if the data is valid ahead of time.

However, I am presently working around the issue like so:

NSData *resumeData = ...;
NSURLRequest *originalURLRequest = ...;
NSURLSessionDownloadTask *downloadTask = nil;

@try {
    downloadTask = [session downloadTaskWithResumeData:resumeData];
}
@catch (NSException *exception) {
    if ([NSInvalidArgumentException isEqualToString:exception.name]) {
        downloadTask = [session downloadTaskWithRequest:originalURLRequest];
    } else {
        @throw exception; // only swallow NSInvalidArgumentException for resumeData
    }
}