CKQueryOperation可见性，取消和超时可能性

Question

My application needs to run a CKQueryOperation using a CKDatabase. This requires network access which is not always available.

Once I add a CKQueryOperation to the CKDatabase that's about where my control stops.

Is there a way I can:

1. See of all pending operations specific to a CKDatabase.
2. Cancel an operation once I've added it to the CKDatabase?
3. Set a completion timeout so the operation doesn't stay pending if the network is preventing completion?

I know I can do this with CKDatabase performQuery however I would prefer to use operations if possible, thanks in advance for your help!

Answer 1

For timeout you can set configuration object on the CKQueryOperation:

let config = CKOperation.Configuration()
config.timeoutIntervalForRequest = 5
config.timeoutIntervalForResource = 5

// Config operation
let operation = CKQueryOperation(query: query)
operation.configuration = config
operation.other_stuff..
operation.queryCompletionBlock = { (_, error: Error?) in
        guard error == nil else {
            // Handle timeout error here.
            return
        }
        ...
 }

Default timeout is 60 seconds.