Restkit 0.20 对象在获取 json 响应后未映射

Posted 2023-03-05

【中文标题】Restkit 0.20 对象在获取 json 响应后未映射

【英文标题】：Restkit 0.20 objects are not mapped after getting json response

【发布时间】：2013-05-14 20:37:08

【问题描述】：

我正在使用 RestKit 0.20。我正在尝试从本地 rails 应用程序下载 json 响应并将其保存到 core-data。我尝试关注https://github.com/RestKit/RKGist/blob/master/TUTORIAL.md，一切正常。 我想多次使用它，所以我将它设为基类（ListController）并将其子类化为 SessionListController 和 EventListController。映射在 AppDelegate.m 中提供。

该应用程序有一个第一个视图控制器，它是根控制器，它始终映射响应并且一切正常。但是一旦我更改视图控制器，我就会得到响应并且操作停止。它甚至没有说映射是否已经开始。我不确定我错过了什么。

这里我正在初始化restkit

AppDelegate.m

#import "AppDelegate.h"
#import <UIKit/UIKit.h>

@implementation AppDelegate   

RKEntityMapping *eventEntityMapping,*sessionEntitiyMapping;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

NSError *error = nil;
NSURL *modelURL = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"event" ofType:@"momd"]];
NSManagedObjectModel *managedObjectModel = [[[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL] mutableCopy];
[self setManagedObjectStore: [[RKManagedObjectStore alloc] initWithManagedObjectModel:managedObjectModel]];

// Initialize the Core Data stack
[self.managedObjectStore createPersistentStoreCoordinator];

NSPersistentStore __unused *persistentStore = [self.managedObjectStore addInMemoryPersistentStore:&error];
NSAssert(persistentStore, @"Failed to add persistent store: %@", error);

[self.managedObjectStore createManagedObjectContexts];

// Set the default store shared instance
[RKManagedObjectStore setDefaultStore:self.managedObjectStore];

NSString *url=@"http://192.168.11.11:3000";

RKObjectManager *objectManager = [RKObjectManager managerWithBaseURL:[NSURL URLWithString:url]];
objectManager.managedObjectStore = self.managedObjectStore;

[RKObjectManager setSharedManager:objectManager];

[self mapEntities];
RKResponseDescriptor *responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:eventEntityMapping pathPattern:@"/api/v1/events" keyPath:nil statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];

[objectManager addResponseDescriptor:responseDescriptor];

RKResponseDescriptor *responseDescriptor2 = [RKResponseDescriptor responseDescriptorWithMapping:sessionEntitiyMapping pathPattern:@"/api/v1/sessions" keyPath:nil statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful)];

[objectManager addResponseDescriptor:responseDescriptor2];


// Override point for customization after application launch.
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard_iPhone" bundle:nil];
UINavigationController *navigationController = [storyboard instantiateViewControllerWithIdentifier:@"mainCenterController"];

IIViewDeckController* secondDeckController =  [[IIViewDeckController alloc] initWithCenterViewController:navigationController
                                                                                      leftViewController:[storyboard instantiateViewControllerWithIdentifier:@"sideBarController"]];
secondDeckController.centerhiddenInteractivity=IIViewDeckCenterHiddenNotUserInteractiveWithTapToClose;
self.window.rootViewController = secondDeckController;
return YES;


-(void)mapEntities
//event
eventEntityMapping = [RKEntityMapping mappingForEntityForName:@"Event" inManagedObjectStore:self.managedObjectStore];
[eventEntityMapping addAttributeMappingsFromDictionary:@
 @"id":             @"event_id",
 @"name":           @"name",
 @"description":    @"desc",
 @"no_of_days":     @"no_of_days",
 @"start_date":     @"start_date",
 ];
eventEntityMapping.identificationAttributes = @[ @"event_id" ];

sessionEntitiyMapping = [RKEntityMapping mappingForEntityForName:@"Session" inManagedObjectStore:self.managedObjectStore];
[sessionEntitiyMapping addAttributeMappingsFromDictionary:@
 @"name":           @"name",
 @"description":    @"desc",
 @"start_time":     @"start_time",
 @"duration":       @"duration",
 @"location_id":    @"location_id",
 @"event_id":       @"event_id",
 @"id":             @"session_id",
 ];
sessionEntitiyMapping.identificationAttributes = @[ @"session_id" ];

我根据基类为 RKManager 调用 getObjectsAtPath 的基类。

ListController.m

@implementation ListController
- (void)viewDidLoad

[super viewDidLoad];
AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
self.managedObjectContext = appDelegate.managedObjectStore.mainQueueManagedObjectContext;
[self loadLocs];
[self.refreshControl beginRefreshing];


-(void)setModel:(Models)model
if(self.model!=model)
    _model=model;
    self.title=[Model displayFor:self.model];
    _fetchedResultsController = nil;
    [self.tableView reloadData];
    [self loadLocs];
    [self.refreshControl beginRefreshing];



- (void)loadLocs

[[RKObjectManager sharedManager] getObjectsAtPath:[Model listApiFor:self.model]
                                       parameters:nil
                                          success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) 
                                              [self.refreshControl endRefreshing];
                                          
                                          failure:^(RKObjectRequestOperation *operation, NSError *error) 
                                              [self.refreshControl endRefreshing];
                                              UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"An Error Has Occurred" message:[error localizedDescription] delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
                                              NSLog(@"error: %@",error);
                                              [alertView show];
                                          ];



#pragma mark - Table View

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView

return [[[self fetchedRCforTableView:tableView] sections] count];


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
id <NSFetchedResultsSectionInfo> sectionInfo = [self.fetchedResultsController sections][section];
return [sectionInfo numberOfObjects];


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];
[self configureCell:cell atIndexPath:indexPath forTableView:tableView];
return cell;


#pragma mark - Fetched results controller
- (NSFetchedResultsController *)fetchedResultsController

if (_fetchedResultsController != nil) 
    return _fetchedResultsController;


NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Edit the entity name as appropriate.
NSEntityDescription *entity = [NSEntityDescription entityForName:[Model entityFor:self.model] inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];

// Set the batch size to a suitable number.
[fetchRequest setFetchBatchSize:20];

// Edit the sort key as appropriate.
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:[Model sortDescriptorFor:self.model] ascending:YES];
NSArray *sortDescriptors = @[sortDescriptor];

[fetchRequest setSortDescriptors:sortDescriptors];

NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:[Model displayFor:self.model]];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;

NSError *error = nil;
if (![self.fetchedResultsController performFetch:&error]) 
    NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
    abort();

NSLog(@"_fetchedResultsController count %d",_fetchedResultsController.fetchedObjects.count);
return _fetchedResultsController;


@end

这是我设置模型名称的基类之一

EventViewController.m

- (void)viewDidLoad

[super viewDidLoad];
self.model=Eventm;
// Do any additional setup after loading the view.

SessionViewController.m

- (void)viewDidLoad

[super viewDidLoad];
self.model=Sessionm;
// Do any additional setup after loading the view.

完整代码在https://github.com/leohemanth/event-app

使用后

RKLogConfigureByName("RestKit", RKLogLevelWarning);
RKLogConfigureByName("RestKit/ObjectMapping", RKLogLevelTrace);
RKLogConfigureByName("RestKit/Network", RKLogLevelTrace);

我可以看到，我得到了正确的 Http 响应，但它没有被映射。我不知道为什么？

【问题讨论】：

日志是不是说有时候找不到响应描述符？或者没有键路径匹配？需要一些日志才能继续或对 JSON 进行采样以进行比较。

没有日志没有任何错误信息。它只是在记录响应文本后停止。事件的示例 json 响应是 gist.github.com/leohemanth/5579457

listApiFor 的代码是什么： - 它返回什么路径？

listApiFor 返回事件的 api 路径 - return @"/api/v1/events" 和会话 return @"/api/v1/sessions"我>

定义响应描述符时，指定不带前导“/”的路径模式。使用跟踪登录时您没有得到任何日志信息似乎很奇怪，通常它会告诉您问题的确切位置。

【参考方案1】：

我刚刚将我的 Restkit 包更新到 0.20.2。我现在没有面临这个问题。它应该在更新中修复。