RestKit Pagination - ios

Question

I'm stuck with a pagination issue.
When I go to /?PageSize=:perPage&Page=:page" I will get a json response like this:
Which I would like to map using the following paginator:
/* BBActivityPaginator */
RKObjectMapping *activityPaginationMapping = [RKObjectMapping mappingForClass:[BBActivityPaginator class]];
[activityPaginationMapping addAttributeMappingsFromDictionary:#{
#"Page" :#"currentPage",
#"PageSize" :#"perPage",
#"TotalResultCount" :#"objectCount"
}];
[activityPaginationMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:#"PagedListItems" toKeyPath:#"activities" withMapping:activityMapping]];
[manager addResponseDescriptor:[RKResponseDescriptor responseDescriptorWithMapping:activityPaginationMapping
pathPattern:#"/?PageSize=:perPage&Page=:page"
keyPath:#"Model.Activities"
statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)]];
which is related to this mapping:
/* BBActivity */
RKObjectMapping *activityMapping = [RKObjectMapping mappingForClass:[BBActivity class]];
[activityMapping addAttributeMappingsFromDictionary:#{
#"Id" :#"identifier",
#"CreatedDateTime" :#"createdOn",
#"Description" :#"description",
#"CreatedDateTimeOrder" :#"order",
#"Type" :#"type",
#"DeletedActivityItem.Message" :#"deleted"
}];
[activityMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:#"User" toKeyPath:#"user" withMapping:userMapping]];
[activityMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:#"ObservationAdded.Observation" toKeyPath:#"observation" withMapping:observationMapping]];
[activityMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:#"SightingNoteAdded.SightingNote" toKeyPath:#"observationNote" withMapping:observationNoteMapping]];
[activityMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:#"SightingNoteAdded.Sighting" toKeyPath:#"observationNoteObservation" withMapping:observationMapping]];
[activityMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:#"IdentificationAdded.Sighting" toKeyPath:#"identificationObservation" withMapping:observationMapping]];
[activityMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:#"IdentificationAdded.Identification" toKeyPath:#"identification" withMapping:identificationMapping]];
[activityMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:#"PostAdded.Post" toKeyPath:#"post" withMapping:postMapping]];
[manager addResponseDescriptor:[RKResponseDescriptor responseDescriptorWithMapping:activityMapping
pathPattern:nil
keyPath:nil
statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)]];
... For brevity I won't add all the mappings...
When I want to make my call to the paginator, I'm wiring up this:
-(void)setPaginatorForStream:(NSString*)streamName {
[BBLog Log:#"BBStreamController.setPaginatorForStream:"];
[BBLog Debug:#"streamName:" withMessage:streamName];
__weak typeof(self) weakSelf = self;
NSString *streamUrl = [NSString stringWithFormat:#"http://api.blahblah.org.au/%#?PageSize=:perPage&Page=:currentPage&X-Requested-With=XMLHttpRequest", streamName];
if (!self.paginator) {
paginationMapping = [RKObjectMapping mappingForClass:[BBActivityPaginator class]];
RKResponseDescriptor *activitiesResponseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:[RKObjectMapping mappingForClass:[BBActivityPaginator class]]
pathPattern:nil
keyPath:nil
statusCodes:[NSIndexSet indexSetWithIndex:200]];
self.paginator = [[BBActivityPaginator alloc]initWithRequest:[NSURLRequest requestWithURL:[[NSURL alloc]initWithString:streamUrl]]
paginationMapping:paginationMapping
responseDescriptors:[[NSArray alloc]initWithObjects:activitiesResponseDescriptor, nil]
andDelegate:weakSelf];
}
self.paginator.perPage = 20;
[self.paginator setCompletionBlockWithSuccess:^(RKPaginator *paginator, NSArray *objects, NSUInteger page) {
[weakSelf.tableItems addObjectsFromArray:objects];
[weakSelf.tableView reloadData];
} failure:^(RKPaginator *paginator, NSError *error) {
NSLog(#"Failure: %#", error);
}];
Which is being activated in this method:
-(void)loadRequest {
[BBLog Log:#"BBStreamController.loadRequest"];
self.fetchBatch++;
[self.paginator loadPage:self.fetchBatch];
//[self.paginator setPaginatorLoading:YES];
self.loading = YES;
}
from the class initialisation:
-(BBStreamController*)initWithGroup:(NSString*)groupIdentifier
andDelegate:(id<BBStreamProtocol>)delegate {
[BBLog Log:#"BBStreamController.initWithGroup:andDelegate:"];
self = [self init];
if(self) {
_controller = delegate;
groupId = groupIdentifier;
[self setPaginatorForStream:groupIdentifier];
[self loadRequest];
}
[self loadView];
return self;
}
And getting nothing but pain...
Output:
E restkit:RKPaginator.m:207 Paginator didn't map info to compute page count. Assuming no pages.
2013-05-06 17:48:09.487 BowerBird[26570:5807] W restkit.object_mapping:RKMapperOperation.m:98 Adding mapping error: No mappable values found for any of the attributes or relationship mappings
Any one familiar with the finer details of RestKit 0.2.x's new pagination?

Answer 1

Your pathPattern and keyPath information needs to be set on the activitiesResponseDescriptor definition, not some paginator response descriptor that isn't actually used for anything.
The response descriptor is for the overall response and describes how to:
Tell that we have a match : pathPattern
Find the data to process : keyPath
Create the response objects : data mapping
The paginator mapping is additional to this and is only used to extract the page data from the response being processed.
Move the path pattern and key path to the response descriptor used for the request. The path pattern should also contain "PagedListItems" by the looks of it.