RestKit object mapping when the root element is an array, and we use blocks

restkit-rootarray.m

// e.g. server returns [ {name:"foo"}, {name:"bar} ]

_objectManager = [RKObjectManager managerWithBaseURLString:@"http://example.com/api"];

RKObjectMapping *rootMapping = [RKObjectMapping mappingForClass:[MyItem class]];
[rootMapping mapKeyPath:@"name" toAttribute:@"name"];
[_objectManager.mappingProvider addObjectMapping:rootMapping]; // note this just stores our instance..

/// LATER ON

 RKObjectMapping* mapping = [_objectManager.mappingProvider objectMappingForClass:[MyItem class]];
    
    [_objectManager loadObjectsAtResourcePath:path usingBlock:^(RKObjectLoader *loader) {
        loader.objectMapping = mapping; // Here's the key. We're telling RestKit to use the MyItem mapping for the objects in the root.
        
        loader.onDidLoadObjects = ^(NSArray* objects) {
            for (NSObject* ob in objects) {
                if ([ob isKindOfClass:[MyItem class]]) {
                    MyItem* device = (MyItem*)ob;
                    NSLog(@"Found MyItem %@", device.name);
                } else {
                    NSLog(@"hmm.. got a %@", ob);
                }
            }
        };
        
        loader.onDidFailWithError = ^(NSError* error) {
            // do something
        };
        
        loader.onDidFailLoadWithError = ^(NSError* error) {
            // do something
        };
    }];

Starting out with restkit I found it pretty straightforward until I hit a rest command that returned an array. It seems restkit expects there to be a root level object e.g. { data: [ "a", "b", "c"] }. If your server doesn't do this you can't use the automatic mapping system. The solution is simple (manually tell the system which mapping to use) but I took me a while to figure out!