Mantle Objective C: mapping nested properties to JSON - ios

Question

I want to use Mantle to serialize some objects to this JSON:
{
"name": "John Smith",
"age": 30,
"department_id":123
}
I have two classes Department Employee:
#import <Mantle/Mantle.h>
#interface Department : MTLModel <MTLJSONSerializing>
#property(nonatomic)int id;
#property(nonatomic)NSString *name;
#end
and the Employee class:
#import <Mantle/Mantle.h>
#import "Department.h"
#interface Employee : MTLModel <MTLJSONSerializing>
#property(nonatomic)NSString *name;
#property(nonatomic)int age;
#property(nonatomic)Department *department;
#end
#implementation Employee
+ (NSDictionary *)JSONKeyPathsByPropertyKey {
return #{
#"name":#"name",
#"age":#"age",
#"department.id":#"department_id"
};
}
#end
when serializing an Employee instance I receive the following
exception: "NSInternalInconsistencyException", "department.id is not a
property of Employee."
What's wrong here? is there a way to serialize the object as as a single dictionary instead of nesting the department object inside the employee object?

Answer 1

first remove this code from your Employee.m file
#implementation Employee
+ (NSDictionary *)JSONKeyPathsByPropertyKey {
return #{
#"name":#"name",
#"age":#"age",
#"department.id":#"department_id"
};
}
and then use the following whenever you want to serialize the Employee object
Employee *objEmployee = [Employee instanceFromDict:responseObject];
I hope it will work for you. All the best!!

Answer 2

OK, I got it from here:
Mantle property class based on another property?
I modified the mapping dictionary to be like this
+ (NSDictionary *)JSONKeyPathsByPropertyKey {
return #{
#"name":#"name",
#"age":#"age",
NSStringFromSelector(#selector(department)) : #[#"department_id"]
};
}
and added:
+ (NSValueTransformer *)departmentJSONTransformer {
return [MTLValueTransformer transformerUsingReversibleBlock:^id(Department *department, BOOL *success, NSError *__autoreleasing *error) {
return [MTLJSONAdapter JSONDictionaryFromModel:department error:nil];
}];
}