What is a proper way to validate present of mandatory field

[sarunw]

Now I'm using + (id)modelOfClass:(Class)modelClass fromJSONDictionary:(NSDictionary *)JSONDictionary error:(NSError **)error to parse JSON to an object, but if some field is missing it would just assign nil to that property. Is there a way to validate required field and return an error, so I can handle it properly. Didn't see any validation in README.

Another question is when I use + (NSValueTransformer *)mtl_JSONArrayTransformerWithModelClass:(Class)modelClass if the data return isn't array it will failed from the NSAssert([dictionaries isKindOfClass:NSArray.class], @"Expected a array of dictionaries, got: %@", dictionaries); is there a way I can handle this before NSAssert happen, because this will crash the app in production if API is changed.

[robb]

You can implement -validate<Key>:error: so that it considers nil an error and then call -[MTLModel validate:] after deserializing to make sure all fields are in place.

Your second problem will be fixed 2.0 where this will simply be an decoding error. In the mean-time, I guess you can simply copy the current +mtl_JSONArrayTransformerWithModelClass: implementation and make it return something useful for you if its expectations are not met.

Please note that there will be additional changes to the behavior of said method 2.0.

[robb]

Closing this one for lack of activity