How can i set unique key values to NSOperation in iOS

Question

In my app I'm trying to implement a NSOperationQueue for the web service interaction using AFNetworking. I'm adding a NSOperation one by one into the queue. I want to cancel a particular operation at any time. For that I want to set some unique key to the operation. So, is there any way possible to achieve it?

Answer 1

Create a NSOperation sub class and set one property.

If the app minimum deployment is greater than iOS 8, then you can directly use the .name property.

NSOperationQueue *queue = [NSOperationQueue mainQueue];
if (![[[queue operations] valueForKey:@"name"] containsObject:@"WS"])
{
    NSBlockOperation *op = [NSBlockOperation blockOperationWithBlock:^{
        //your task
    }];
    op.name = @"Unique id";
    [queue addOperation:op];
}
else
{
    NSIndexSet *indexSet = [[queue operations] indexesOfObjectsPassingTest:
                            ^ BOOL(NSBlockOperation *obj, NSUInteger idx, BOOL *stop)
                            {
                                if ([obj.name isEqualToString:@"Unique id"])
                                {
                                    return YES;
                                } else
                                {
                                    return NO;
                                }
                                *stop = YES;
                            } ];

    if (indexSet.firstIndex != NSNotFound)
    {
        NSBlockOperation *queryOpration = [[queue operations] objectAtIndex:indexSet.firstIndex];
        [queryOpration cancel];
    }
}

If the app is not for iOS 8 or greater, then you can create a subclass of the NSOperation and set an identity with the possibility to query with that value:

@interface WSOperation: NSOperation
@property (nonatomic, strong) NSString* operationID;
@end