Restkit: Post Json Array and Map response to Managed Objects - objective-c

Question

Here is my setup, Post a list of objects in Json to server and got back with updated results that will be mapped to core data and updated.
-- Post Boday --
{
"memberId": "1000000",
"contacts": [
{
"phoneNumber": "[phone]",
"firstName": "john",
"lastName": "H"
},
{
"phoneNumber": "[phone]",
"firstName": "mary",
"lastName": "K"
}
]
}
-- Post Response --
{
"contacts": [
{
"phoneNumber": "[phone]",
"firstName": "john",
"lastName": "k",
"isMember": "yes"
},
{
"phoneNumber": "[phone]",
"firstName": "mary",
"lastName": "k",
"isMember": "no"
}
]
}
I found another thread which discusses very similar to my case. RestKit: How does one post an array of objects?
This is my setup.
-- SHContact.h --
#interface SHContact : NSManagedObject {}
#property (nonatomic, strong) NSString* phoneNumber;
#property (nonatomic, strong) NSString* firstName;
#property (nonatomic, strong) NSString* lastName;
#property (nonatomic, strong) NSNumber* isMember;
#end
-- SHContactPost.m --
#import "SHContactPost.h"
#implementation SHContactPost
#synthesize contacts;
#synthesize memberId;
- (NSArray*)contacts {
return <list-of-SHContact>;
}
- (NSString *)memberId {
return #"my-member-id";
}
#end
-- RK Mapping --
// Setup our object mappings for SHContact
RKManagedObjectMapping* contactMapping =
[RKManagedObjectMapping mappingForClass:[SHContact class]
inManagedObjectStore:objectManager.objectStore];
contactMapping.primaryKeyAttribute = #"phoneNumber";
[contactMapping mapAttributes:#"phoneNumber",
#"firstName", #"lastName", #"isMember", nil];
[objectManager.mappingProvider setObjectMapping:contactMapping
forKeyPath:#"contacts"];
[[objectManager mappingProvider]
setSerializationMapping:[contactMapping inverseMapping]
forClass:[SHContact class]];
RKObjectMapping *cPostMapping = [RKObjectMapping
mappingForClass:[SHContactPost class]];
[cPostMapping mapKeyPath:#"contacts"
toRelationship:#"contacts"
withMapping:contactMapping];
[cPostMapping mapAttributes:#"memberId", nil];
[objectManager.mappingProvider
setSerializationMapping:[cPostMapping inverseMapping]
forClass:[SHContactPost class]];
[objectManager.router routeClass:[SHContactPost class]
toResourcePath:#"/contacts"
forMethod:RKRequestMethodPOST];
objectManager.serializationMIMEType = RKMIMETypeJSON;
-- Post to server --
SHContactPost *post = [[SHContactPost alloc] init];
RKObjectManager* manager = [RKObjectManager sharedManager];
[manager postObject:post delegate:self];
Server post and response is SUCCESSFUL. However, Reskit was not able to map the result back to the list of SHContact objects. This is the exception. Am I missing something?
restkit.network:RKObjectLoader.m:222 Encountered errors during mapping:
Cannot map a collection of objects onto a non-mutable collection.
Unexpected destination object type 'SHContactPost'
UPDATE: This is what I changed to make it work for me.
-- RK Mapping --
// Setup our object mappings for SHContact
RKManagedObjectMapping* contactMapping =
[RKManagedObjectMapping mappingForClass:[SHContact class]
inManagedObjectStore:objectManager.objectStore];
contactMapping.primaryKeyAttribute = #"phoneNumber";
[contactMapping mapAttributes:#"phoneNumber",
#"firstName", #"lastName", #"isMember", nil];
[objectManager.mappingProvider addObjectMapping:contactMapping];
-- Post to server --
SHContactPost *post = [[SHContactPost alloc] init];
RKObjectManager* manager = [RKObjectManager sharedManager];
RKObjectMapping* responseMapping = [manager.mappingProvider
objectMappingForClass:[SHContact class]];
[manager postObject:post usingBlock:^(RKObjectLoader *loader) {
loader.delegate = self;
loader.targetObject = nil;
responseMapping.rootKeyPath = #"contacts";
loader.objectMapping = responseMapping;
}];
loader.targetObject needs to set it to nil, otherwise, it won't work.