RestKit - GETting a JSON array from a Rails app - ios

Question

I want to get this JSON data with my iOS app: https://sleepy-journey-2871.herokuapp.com/users.json .... RestKit tries to get these users from the url, but it returns 0 objects and says "No mappable representations were found at the key paths searched. No response descriptors match the response loaded."
PLEASE help me figure out what I'm missing or doing wrong! I've been battling this for weeks.
I have Xcode 5.0.2, I successfully installed RestKit with Cocoapods and a Podfile that looks like this:
platform :ios, '6.0'
pod 'RestKit', '~> 0.22.0'
pod 'RestKit/Testing'
pod 'RestKit/Search'
My AppDelegate.m file is below (the didFinishLaunchingWithOptions method):
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
// Override point for customization after application launch.
//Set base url
NSString *baseUrl = #"https://sleepy-journey-2871.herokuapp.com";
//initialize the the http client with baseUrl
AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:[NSURL URLWithString:baseUrl]];
//initialize the RKObjectManager with our http client
RKObjectManager *manager = [[RKObjectManager alloc] initWithHTTPClient:httpClient];
//add text/plain as a JSON content type to properly parse errors
[RKMIMETypeSerialization registerClass:[RKNSJSONSerialization class] forMIMEType:#"text/plain"];
//register JSONRequestOperation to parse JSON in requests
[manager.HTTPClient registerHTTPOperationClass:[AFJSONRequestOperation class]];
//state that we are accepting JSON content type
[manager setAcceptHeaderWithMIMEType:RKMIMETypeJSON];
//configure so that we want the outgoing objects to be serialized into JSON
manager.requestSerializationMIMEType = RKMIMETypeJSON;
//set the shared instance of the object manager, so that we can easily re-use it later
[RKObjectManager setSharedManager:manager];
return YES;
}
I have this code in the viewDidLoad method of the view controller that first loads when the app is launched:
- (void)viewDidLoad
{
[super viewDidLoad];
RKObjectManager *manager = [RKObjectManager sharedManager];
[manager getObjectsAtPath:#"/users"
parameters:nil
success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult)
{
NSLog(#"Loaded databases: %#", [mappingResult array]);
}
failure:^(RKObjectRequestOperation *operation, NSError *error)
{
NSLog(#"Error: %#", [error localizedDescription]);
}];
// Do any additional setup after loading the view, typically from a nib.
}

Answer 1

You have to:
Create a User class.
Create a mapping for User class.
Create a response descriptor.
Pseudocode could look something like:
#interface User : NSObject
#property (nonatomic, copy) NSNumber *userID;
#property (nonatomic, copy) NSString *name;
...
#end
RKObjectMapping *mapping = [RKObjectMapping mappingForClass:[User class]];
[mapping addAttributeMappingsFromDictionary:#{
#"name": #"name",
#"id": #"userID"
...
}];
RKResponseDescriptor *responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:mapping
method:RKRequestMethodAny
pathPattern:nil
keyPath:nil
statusCodes:nil];
...
RKObjectRequestOperation *operation = [[RKObjectRequestOperation alloc] initWithRequest:request
responseDescriptors:#[responseDescriptor]];
[operation setCompletionBlockWithSuccess:^(RKObjectRequestOperation *operation, RKMappingResult *result) {
NSLog(#"The public timeline Tweets: %#", [result array]);
} failure:nil];
[operation start];
Take a look at examples here.