RestKit - Not key value coding-compliant - objective-c

Question

I have a managed object MyEntity that I use without any problem throughout my application.
#interface MyEntity : NSManagedObject
#property (nonatomic, retain) NSString *code;
#property (nonatomic, retain) NSNumber *def_value;
#property (nonatomic, retain) NSString *label;
#property (nonatomic, retain) NSString *link_label;
#property (nonatomic, retain) NSNumber *order;
#end
I have a web service http://my_server/MyEntity which returns me:
[
{
CODE: "TYPE",
LABEL: "Administrative",
ORDER: "3",
DEF_VALUE: "0",
LINK_LABEL: ""
},
{
CODE: "TOPIC",
LABEL: "NDF",
ORDER: "1",
DEF_VALUE: "0",
LINK_LABEL: "Administrative"
},
{
CODE: "TOPIC",
LABEL: "Report",
ORDER: "2",
DEF_VALUE: "1",
LINK_LABEL: "Administrative"
},
{
CODE: "TOPIC",
LABEL: "Other",
ORDER: "3",
DEF_VALUE: "0",
LINK_LABEL: "Administrative"
}, ...
]
I'm trying to map and fetch this list
NSURL *baseUrl = [NSURL URLWithString: #"http://my_server"];
NSString *objName = #"MyEntity";
NSManagedObjectModel *managedObjectModel = [NSManagedObjectModel mergedModelFromBundles:nil];
RKManagedObjectStore *managedObjectStore = [[RKManagedObjectStore alloc] initWithManagedObjectModel:managedObjectModel];
[RKManagedObjectStore setDefaultStore:managedObjectStore];
[managedObjectStore createPersistentStoreCoordinator];
RKObjectManager *objectManager = [RKObjectManager managerWithBaseURL: baseUrl];
RKEntityMapping *objMap = [RKEntityMapping mappingForEntityForName:objName inManagedObjectStore:managedObjectStore];
[objMap addAttributeMappingsFromDictionary: #{
#"CODE": #"code",
#"LABEL": #"label",
#"ORDER": #"order",
#"DEF_VALUE": #"def_value",
#"LINK_LABEL": #"link_label",
}];
RKResponseDescriptor *responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:objMap pathPattern:nil keyPath:nil statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];
[objectManager addResponseDescriptor:responseDescriptor];
[objectManager getObjectsAtPath:objName parameters:nil success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
NSLog(#"ok");
} failure:^(RKObjectRequestOperation *operation, NSError *error) {
NSLog(#"ko");
}];
It's giving me this error
I restkit.network:RKHTTPRequestOperation.m:185 GET'http://my_server/MyEntity'(200 OK)
CoreData: error: Failed to call designated initializer on NSManagedObject class 'MyEntity'
Terminating app due to uncaught exception 'NSUnknownKeyException', reason:
'[ valueForUndefinedKey:]: the entity (null) is not key value coding-compliant for the key "link_label".'
I saw this error on 2 or 3 SO questions but each with a different problem and seem not any of mine.
Can someone help me to debug that ?

Answer 1

You need to fully configure the objectManager:
objectManager.managedObjectStore = managedObjectStore;
You also aren't completing the Core Data stack initialisation:
[managedObjectStore createManagedObjectContexts];