RKValueTransformer for NSNumber never called

Question

I am trying to create a custom RKValueTransformer for making a transformation to the data received. An API that I am using returns the latitude without any decimal point. I would like to be able to make some processing and add the decimal point myself. I am able to map the 'lat' field into the actual class:

Found transformable value at keyPath 'lat'. Transforming from class '__NSCFNumber' to 'NSNumber'RKValueTransformer

I created a RKValueTransformer, but it is never called when the data is being mapped.

- (void)setupValueTransformers {

    [[RKValueTransformer defaultValueTransformer] addValueTransformer:[self coordinatesValueTransformer]];

    [[RKValueTransformer defaultValueTransformer] insertValueTransformer:[self coordinatesValueTransformer] atIndex:0];
}

- (RKValueTransformer *)coordinatesValueTransformer {
    return [RKBlockValueTransformer valueTransformerWithValidationBlock:^BOOL(__unsafe_unretained Class inputValueClass, __unsafe_unretained Class outputValueClass) {

        return ([inputValueClass isSubclassOfClass:[NSNumber class]] && [outputValueClass isSubclassOfClass:[NSNumber class]]);
    } transformationBlock:^BOOL(id inputValue, __autoreleasing id *outputValue, __unsafe_unretained Class outputClass, NSError *__autoreleasing *error) {

      //MY PROCESSING here

        return YES;
    }];
}

Answer 1

If the source class matches the destination class then no conversion is required and your transformer will not be called.

KVC validation is the appropriate place for this logic.