How can I convert my device token (NSData) into an

Question

I am implementing push notifications. I'd like to save my APNS Token as a String.

- (void)application:(UIApplication *)application
didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)newDeviceToken
{
    NSString *tokenString = [NSString stringWithUTF8String:[newDeviceToken bytes]]; //[[NSString alloc]initWithData:newDeviceToken encoding:NSUTF8StringEncoding];
    NSLog(@"%@", tokenString);
    NSLog(@"%@", newDeviceToken);
}

The first line of code prints null. the second prints the token. How can I get my newDeviceToken as an NSString?

Answer 1

I think converting deviceToken to hex byte string has no sense. Why? You will send it to your backend, where it will be transformed back to bytes to be pushed to APNS. So, use NSData's method base64EncodedStringWithOptions, push it to server, and then use reverse base64decoded data :) That is so much easier :)

NSString *tokenString = [tokenData base64EncodedStringWithOptions:NSDataBase64EncodingEndLineWithLineFeed];

Answer 2

Try this one unless the data is null-terminated.

NSString* newStr = [[NSString alloc] initWithData:newDeviceToken encoding:NSUTF8StringEncoding];

Answer 3

Swift

    // make sure that we have token for the devie on the App
    func application(application: UIApplication
        , didRegisterForRemoteNotificationsWithDeviceToken deviceToken: NSData) {

            var tokenStr = deviceToken.description
            tokenStr = tokenStr.stringByReplacingOccurrencesOfString("<", withString: "", options: [], range: nil)
            tokenStr = tokenStr.stringByReplacingOccurrencesOfString(">", withString: "", options: [], range: nil)
            tokenStr = tokenStr.stringByReplacingOccurrencesOfString(" ", withString: "", options: [], range: nil)



            print("my token is: \(tokenStr)")

    }

Answer 4

Throwing my answer on the pile. Avoid using string parsing; It's not guaranteed by the docs that NSData.description will always work that way.

Swift 3 Implementation:

extension Data {
    func hexString() -> String {
        var bytesPointer: UnsafeBufferPointer<UInt8> = UnsafeBufferPointer(start: nil, count: 0)
        self.withUnsafeBytes { (bytes) in
            bytesPointer = UnsafeBufferPointer<UInt8>(start: UnsafePointer(bytes), count:self.count)
        }
        let hexBytes = bytesPointer.map { return String(format: "%02hhx", $0) }
        return hexBytes.joined()
    }
}