RESTKIT internal mapping fails if json value == NULL

I am using RESTKIT to map the properties from the server side to the properties in the client side.

I am hitting the [NSNull unsignedIntValue] error when RESTKIT is trying to map a NULL value from the server to a NSUInteger property on the client side.

For example:

//User object property "new_questions_count" defined on client side with NSUInteger property
@interface User : NSObject <NSCoding>
{
    NSUInteger new_questions_count;
}

@property (nonatomic, assign) NSUInteger new_questions_count;

@end

//User Object Mapping - mapping "new_question_count" to server's json value
RKObjectMap开发者_开发技巧ping* userMapping = [RKObjectMapping mappingForClass:[User class]];
[userMapping mapAttributes:@"new_question_count",nil];
[provider setMapping:userMapping forKeyPath:@"user"];

For the above scenario, I will hit the [NSNull unsignedIntValue] error if the json value is "new_questions_count":null.

How can I do a check on the client side and resolve this without having to change the implementation on the server side?

---

Although you have not showed the code where you actually decode the JSON, I am assuming that you are using a third party library that correctly respects the NSNull class. In this case, you can check if the object for key @"x" is null using this:

if ([[dictionary objectForKey:@"x"] isKindOfClass:[NSNull class]]) {
    // it is NULL
} else {
    // it is not NULL, but it still might
    // not be in the dictionary at all.
}