RestKit one-to-many relationship - ios

Question

I am having a problem with one-to-many relationships in my CoreData-backed entities.
My JSON looks like this:
[
{
"uuid": "0",
"title": "humor",
"providers": [{
"provider": {
"uuid": "1",
"title": "dilbert",
"sections": [{
"section": { "uuid":"1990", "title": "daily"},
"section": { "uuid":"1991", "title": "weekly"},
}],
},
"provider": {
"uuid": "2",
"title": "wizard of id",
},
"provider": {
"uuid": "3",
"title": "bc",
},
},],
},
{
"uuid": "22",
"title": "photo",
},
]
In my case, the top level object is a category, which can have 0..* providers, which can have 0..* sections.
Update: Just to wrap this up, the root of this problem is that the JSON is malformed. There should not be trailing commas in the dictionaries.
My RestKit mappings are:
RKEntityMapping *sectionMapping = [RKEntityMapping mappingForEntityForName:#"DHSection" inManagedObjectStore:managedObjectStore];
[sectionMapping addAttributeMappingsFromDictionary:#{
#"section.uuid" : #"uuid",
#"section.title" : #"title",
}];
sectionMapping.identificationAttributes = #[#"uuid"];
RKEntityMapping *providerMapping = [RKEntityMapping mappingForEntityForName:#"DHProvider" inManagedObjectStore:managedObjectStore];
[providerMapping addAttributeMappingsFromDictionary:#{
#"provider.uuid" : #"uuid",
#"provider.title" : #"title",
}];
providerMapping.identificationAttributes = #[#"uuid"];
RKRelationshipMapping *sectionRelationship = [RKRelationshipMapping relationshipMappingFromKeyPath:#"provider.sections" toKeyPath:#"sections" withMapping:sectionMapping];
[sectionRelationship setAssignmentPolicy:RKUnionAssignmentPolicy];
[providerMapping addPropertyMapping:sectionRelationship];
RKEntityMapping *categoryMapping = [RKEntityMapping mappingForEntityForName:#"DHCategory" inManagedObjectStore:managedObjectStore];
[categoryMapping addAttributeMappingsFromDictionary:#{
#"uuid" : #"uuid",
#"title" : #"title",
}];
categoryMapping.identificationAttributes = #[#"uuid"];
RKRelationshipMapping *providerRelationship = [RKRelationshipMapping relationshipMappingFromKeyPath:#"providers" toKeyPath:#"providers" withMapping:providerMapping];
[providerRelationship setAssignmentPolicy:RKUnionAssignmentPolicy];
[categoryMapping addPropertyMapping:providerRelationship];
RKResponseDescriptor *responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:categoryMapping method:RKRequestMethodGET pathPattern:#"category/list.json" keyPath:nil statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];
[objectManager addResponseDescriptor:responseDescriptor];
[objectManager addFetchRequestBlock:^NSFetchRequest *(NSURL *URL) {
RKPathMatcher *pathMatcher = [RKPathMatcher pathMatcherWithPattern:#"category/list.json"];
NSDictionary *argsDict = nil;
BOOL match = [pathMatcher matchesPath:[URL relativePath] tokenizeQueryStrings:NO parsedArguments:&argsDict];
if (match) {
NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:#"DHCategory"];
fetchRequest.sortDescriptors = #[[NSSortDescriptor sortDescriptorWithKey:#"uuid" ascending:YES]];
return fetchRequest;
}
return nil;
}];
When RestKit parses the response, it correctly parses two categories, but it only loads the first provider and section.
Update 1 Nov 2013: The updated mapping above corrected the relationship mapping for sections to map from key path "provider.sections" vs "sections".
The problem may likely stem from the difference between the response and what is being mapped.
2013-11-01 10:40:06.670 xyz[58006:1003] D restkit.object_mapping:RKMapperOperation.m:377 Executing mapping operation for representation: (
{
providers = (
{
provider = {
sections = (
{
section = {
title = daily;
uuid = 1990;
};
}
);
title = dilbert;
uuid = 1;
};
}
);
title = humor;
uuid = 0;
},
...
while the response was
response.body=[
{
"uuid": "0",
"title": "humor",
"providers": [
{
"provider": {
"uuid": "1",
"title": "dilbert",
"sections": [{
"section": { "uuid":"1990", "title": "daily"},
"section": { "uuid":"1991", "title": "weekly"},
}
],
},
"provider": {
"uuid": "3",
"title": "wizard of id",
},
"provider": {
"uuid": "2",
"title": "bc",
},
},
],
},
...
Any ideas on how to fix or debug this?
Thanks,
Mike