RestKit并将其作为NSManagedObject保存到CoreData

Question

我正在使用RestKit,我想解析并保存元素到核心数据.我有两个json文件:

第一(类别):

[
   {
     "cat_id": 3371,
     "cat_name": "myName",
     "image": 762
   },
   {
     "cat_id": 3367,
     "cat_name": "anotherName",
     "image": 617
   }
]

第二个(元素):

[
  {
    "art_id": "1",
    "node": {
      "author": "name"
    },
    "small_url": 0
  },
  {
    "art_id": "12",
    "node": {
      "author": "anotherName"
    },
    "small_url": 0
  }
]

所以基本的想法是每个类别都有一些元素.所以这是我的CoreData结构:

我下载了restkit示例并使用了TwitterCoreData示例.我的代码是: AppDelegeta.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    NSURL *baseURL = [NSURL URLWithString:@"http://globalURL.com"];
    RKObjectManager *objectManager = [RKObjectManager managerWithBaseURL:baseURL];
    NSManagedObjectModel *managedObjectModel = [NSManagedObjectModel mergedModelFromBundles:nil];
    RKManagedObjectStore *managedObjectStore = [[RKManagedObjectStore alloc] initWithManagedObjectModel:managedObjectModel];
    objectManager.managedObjectStore = managedObjectStore;

    RKEntityMapping *categoryMapping = [RKEntityMapping mappingForEntityForName:@"Category" inManagedObjectStore:managedObjectStore];
    categoryMapping.identificationAttributes = @[ @"catId" ];
    [categoryMapping addAttributeMappingsFromDictionary:@{
     @"cat_id": @"catId",
     @"node.author": @"author",
     }];

    RKEntityMapping *elementsMapping = [RKEntityMapping mappingForEntityForName:@"Elements" inManagedObjectStore:managedObjectStore];
    elementsMapping.identificationAttributes = @[ @"artId" ];
    [elementsMapping addAttributeMappingsFromDictionary:@{
     @"art_id": @"artId",
     @"node.author": @"author",
    }];
    [elementsMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"category" toKeyPath:@"category" withMapping:categoryMapping]];
    RKResponseDescriptor *responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:elementsMapping
                                                                                       pathPattern:nil
                                                                                           keyPath:nil
                                                                                       statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];
    [objectManager addResponseDescriptor:responseDescriptor];


    [managedObjectStore createPersistentStoreCoordinator];
    NSString *storePath = [RKApplicationDataDirectory() stringByAppendingPathComponent:@"MyCoreData.sqlite"];
    NSString *seedPath = [[NSBundle mainBundle] pathForResource:@"MyCoreData" ofType:@"sqlite"];
    NSError *error;
    NSPersistentStore *persistentStore = [managedObjectStore addSQLitePersistentStoreAtPath:storePath fromSeedDatabaseAtPath:seedPath withConfiguration:nil options:nil error:&error];
    NSAssert(persistentStore, @"Failed to add persistent store with error: %@", error);

    // Create the managed object contexts
    [managedObjectStore createManagedObjectContexts];

    // Configure a managed object cache to ensure we do not create duplicate objects
    managedObjectStore.managedObjectCache = [[RKInMemoryManagedObjectCache alloc] initWithManagedObjectContext:managedObjectStore.persistentStoreManagedObjectContext];



    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];
    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];
    return YES;
}

和ViewController.m:

NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"Elements"];
NSSortDescriptor *descriptor = [NSSortDescriptor sortDescriptorWithKey:@"artId" ascending:NO];
fetchRequest.sortDescriptors = @[descriptor];
[[RKObjectManager sharedManager] getObjectsAtPath:@"/detailaddress/:catId" parameters:nil success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
    RKLogInfo(@"Load complete: Table should refresh...");
    NSLog(@"%@",mappingResult);
    [[NSUserDefaults standardUserDefaults] setObject:[NSDate date] forKey:@"LastUpdatedAt"];
    [[NSUserDefaults standardUserDefaults] synchronize];
} failure:^(RKObjectRequestOperation *operation, NSError *error) {
    RKLogError(@"Load failed with error: %@", error);
}];

并且映射日志显示"nil".如何使用restkit将数据从我的第一个json(类别)保存到核心数据中？记得我还没有Elements列表.

当我使用create new file创建NEManagedObject子类时,我有了Elements类.

@interface Elements : NSManagedObject

@property (nonatomic, retain) NSNumber * artId;
@property (nonatomic, retain) NSString * author;
@property (nonatomic, retain) NSString * title;
@property (nonatomic, retain) NSManagedObject *category;

@end

Answer 1

几个月前,我使用RESTKit直到.20发布.老实说,虽然这个图书馆有很好的意图,但根据我的经验,它最终浪费的时间远远超过拯救我的时间.

我已经将它与使用.NET/MVC,PHP,python/Django/TastyPie创建的API一起使用,并且用黑客攻击它来做Twitter的一些事情.这一切都最终成为一项非常有趣的学术活动,但最终只是一点点.RESTKit的旧版本/新版本都假设ALOT关于API响应请求的方式.

随着.10版本的发布,通过使用Obj-C Blocks实现了大量的可定制性.我可以拦截RKRequest的请求/响应,并且几乎覆盖了RESTKit要做的任何事情.这看起来相当棒.现在有了.20版本,一切都变得非常...... 聪明(聪明的代码通常不好).

RK现在为您提供各种"方便"的东西,而不是试图保持通用性和可塑性.这有效地消除了将其插入API所采用的任何(非理想化和逼真)形状的能力.此时,我已经回到使用AFNetworking编写所有代码.我宁愿花些额外的时间来编写自己的解析代码,并且知道当我的单元测试通过时,我已经完成了.不要花费数小时试图让RK注销有意义的错误消息.

RK的另一个真正问题是它没有考虑离线.它的设计假设您的应用程序始终在线,并且只是镜像天空中持久的存储.我的应用程序都在iOS设备上处理内容创建,在创建内容时可能或可能不在线.这是我"定制"RK .10的主要原因.当我看到.20中的变化时,我认为已经足够了,并且回去以旧的方式做事.

也许我只是写我自己的CRUD/REST的架构,因为我开始厌倦使用非常专业图书馆,试图尽一切尽可能少的责任被留给应用程序开发人员尽可能花时间的.像这样的框架往往是瑞士军刀.它们在纸上看起来非常棒,它们可以做任何事情,然后你实际上会尝试切割一些东西而刀片太钝或断裂.好的软件很少做很好的事情,如果它听起来好得令人难以置信,它可能就是这样.