Restkit: maps to two responseDescriptor in one request - ios

Question

I have a request gives me two part of data, the json looks like this
{
"banner_content":
[
{
"activi_id":"1",
"activi_pic":
},
{
"activi_id":"2",
"activi_pic":
},
],
"categories":
[
{...},
{...},
]
}
When I write responseDescriptor to map the data, I have found I must define a model which contains banner_content array and categories array (I don't want to )
or else I have to write two responseDescriptors to do, when the request is done, I have to get the two parts of data from (RKMappingResult *)mappingResult
then get array like [mappingResult objectForKey:#"banner_content"] and [mappingResult objectForKey:#"categories"]
it's weird
below is my code
File:RCategory.m
#implementation RCategory
+ (NSDictionary *)_mapping {
return #{#"title" : #"title"};
}
+ (RKObjectMapping *)mapping {
// Setup our object mappings
RKObjectMapping *categoryMapping = [RKObjectMapping mappingForClass:[self class]];
[categoryMapping addAttributeMappingsFromDictionary:[[self class] _mapping]];
RKObjectMapping *itemMapping = [RCategoryItem mapping];
RKRelationshipMapping* relationShipMapping = [RKRelationshipMapping relationshipMappingFromKeyPath:#"content"
toKeyPath:#"items"
withMapping:itemMapping];
[categoryMapping addPropertyMapping:relationShipMapping];
return categoryMapping;
}
#end
File:RAd.m ignored
File:viewController.m
- (void)loadCategory {
// Load the object model via RestKit
RKObjectManager *objectManager = [RKObjectManager sharedManager];
RKObjectMapping *categoryMapping = [RCategory mapping];
RKResponseDescriptor *categoryResponseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:categoryMapping
method:RKRequestMethodGET
pathPattern:nil
keyPath:#"category"
statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];
RKObjectMapping *adsMapping = [RAd mapping];
RKResponseDescriptor *adResponseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:adsMapping
method:RKRequestMethodGET
pathPattern:nil
keyPath:#"banner_content"
statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];
//** DO I MUST ADD TWO RESPONSE_DESCRIPTOR FOR ONE REQUEST??**
[objectManager addResponseDescriptor:categoryResponseDescriptor];
[objectManager addResponseDescriptor:adResponseDescriptor];
[objectManager getObjectsAtPath:RPATH(CATEGORY_PATH)
parameters:nil
success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
NSArray* statuses = [mappingResult array];
[self.categories addObjectsFromArray:statuses];
if ([self isViewLoaded]) {
[self.tableView reloadData];
}
}
failure:^(RKObjectRequestOperation *operation, NSError *error) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Error"
message:[error localizedDescription]
delegate:nil
cancelButtonTitle:#"OK"
otherButtonTitles:nil];
[alert show];
NSLog(#"Hit error: %#", error);
}];
}
Does anybody have a better way to solve my problem?
BTW I write -mapping in the Model Class, It's the easiest and best way I can think out
I would like to know how do you write the mapping.

Answer 1

You need 2 response descriptors because the response has 2 logically separate parts. This is fine. If you were using Core Data then you wouldn't be concerned as all your objects would simply be saved to the context and you can fetch them as required. With object mapping, if you don't care about the grouping then you can get an array of all objects from the mapping result.
Creating your mappings from data returned by the model objects is fine - but it does limit you because you can only have one source key per destination key. What happens when you have a different response for the same object with a different key that means the same as some other key (hopefully you don't, but it all depends on the server API).