RESTKit：在搜索的关键路径中找不到可映射的对象表示

Posted 2023-02-23

【中文标题】RESTKit：在搜索的关键路径中找不到可映射的对象表示

【英文标题】：RESTKit: No mappable object representations were found at the key paths searched

【发布时间】：2014-04-09 22:20:12

【问题描述】：

日志：

2014-04-09 15:03:10.196 App[49808:60b] request <NSMutableURLRequest: 0xd091170>  URL: http://www.domain.com/meetups?lastrequest=2014-04-09T15%3A03%3A10Z 
2014-04-09 15:03:10.214 App[49808:60b] I restkit.network:RKObjectRequestOperation.m:180 GET 'http://www.domain.com/meetups?lastrequest=2014-04-09T15%3A03%3A10Z'
2014-04-09 15:03:10.300 App[49808:632f] D restkit.object_mapping:RKMapperOperation.m:377 Executing mapping operation for representation: 
    meetups =     (
                
            activities =             (
                                
                    activityId = 37;
                    activityType = "<null>";
                    customData = "<null>";
                    locationAddress = "k2-LocationAddress";
                    locationName = "k2-LocationName";
                    startTime = "0000-00-00 00:00:00";
                ,
                                
                    activityId = 38;
                    activityType = "<null>";
                    customData = "<null>";
                    locationAddress = "k-LocationAddress";
                    locationName = "k-LocationName";
                    startTime = "0000-00-00 00:00:00";
                
            );
            comment = comment;
            gettingBack = "gettingBack Test";
            gettingThere = "gettingBack Test";
            meetingType = 1;
            meetupId = 65;
            modified = "2014-04-09T20:59:29.000Z";
            ownerId = Joe;
            recipientId = "<null>";
        
    );

 and targetObject: (null)
2014-04-09 15:03:10.301 App[49808:632f] D restkit.object_mapping:RKMapperOperation.m:403 Finished performing object mapping. Results: (null)
2014-04-09 15:03:10.302 App[49808:21f] E restkit.network:RKObjectRequestOperation.m:243 GET 'http://www.domain.com/meetups?lastrequest=2014-04-09T15%3A03%3A10Z' (200 OK / 0 objects) [request=0.0849s mapping=0.0000s total=0.1043s]: Error Domain=org.restkit.RestKit.ErrorDomain Code=1001 "No response descriptors match the response loaded." UserInfo=0xd0b5a40 NSErrorFailingURLStringKey=http://www.domain.com/meetups?lastrequest=2014-04-09T15%3A03%3A10Z, NSLocalizedFailureReason=A 200 response was loaded from the URL 'http://www.domain.com/meetups?lastrequest=2014-04-09T15%3A03%3A10Z', which failed to match all (0) response descriptors:, NSLocalizedDescription=No response descriptors match the response loaded., keyPath=null, NSErrorFailingURLKey=http://www.domain.com/meetups?lastrequest=2014-04-09T15%3A03%3A10Z, NSUnderlyingError=0xd08a190 "No mappable object representations were found at the key paths searched."

代码：

@property (strong, nonatomic) RKObjectManager *objectManager;
....

AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
self.objectManager = [self getObjectManager];

self.objectManager.managedObjectStore = [appDelegate setupCoreDataWithRESTKit];

[RKObjectManager sharedManager].requestSerializationMIMEType = RKMIMETypeJSON;

RKEntityMapping *invitationMapping = [RKEntityMapping mappingForEntityForName:@"Invite" inManagedObjectStore:self.objectManager.managedObjectStore];
[invitationMapping addAttributeMappingsFromDictionary:@
                                                        @"recipientId" : @"recipientId",
                                                        @"meetingType" : @"meetingType",
                                                        @"startDate" : @"startDate",
                                                        @"gettingThere" : @"gettingThere",
                                                        @"gettingBack" : @"gettingBack",
                                                        @"comment" : @"comment"
                                                        ];
invitationMapping.identificationAttributes = @[@"meetupId"];

RKEntityMapping *activityMapping = [RKEntityMapping mappingForEntityForName:@"Activity" inManagedObjectStore:self.objectManager.managedObjectStore];
[activityMapping addAttributeMappingsFromDictionary:@
                                                      @"locationName" : @"locationName",
                                                      @"locationAddress" : @"locationAddress",
                                                      @"startTime" : @"startTime",
                                                      @"customData" : @"customData"
                                                      ];
activityMapping.identificationAttributes = @[@"activityId"];
NSIndexSet *statusCodeSet = RKStatusCodeIndexSetForClass(RKStatusCodeClassSuccessful);

[invitationMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"activities" toKeyPath:@"activities" withMapping:activityMapping]];


RKResponseDescriptor *responseDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:invitationMapping
                                                                                        method:RKRequestMethodGET
                                                                                   pathPattern:@"/meetups"
                                                                                       keyPath:@"meetups" statusCodes:statusCodeSet];


NSMutableURLRequest *request = [self.objectManager.HTTPClient requestWithMethod:@"GET"
                                                                           path:@"/meetups"
                                                                     parameters:@@"lastrequest": dateString

                                                                                  ];

 [self.objectManager.HTTPClient  registerHTTPOperationClass:[AFHTTPRequestOperation class]];

RKManagedObjectRequestOperation *operation = [[RKManagedObjectRequestOperation alloc]initWithRequest:request responseDescriptors:@[responseDescriptor]];

operation = [self.objectManager managedObjectRequestOperationWithRequest:request managedObjectContext:self.objectManager.managedObjectStore.mainQueueManagedObjectContext success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) 
    NSArray *array = mappingResult.array;
    NSLog(@"array %@", array);
 failure:^(RKObjectRequestOperation *operation, NSError *error) 

];

[operation start];

Invite 与Activity 有一对多关系，称为activities。

为什么我得到：“在搜索的关键路径中找不到可映射的对象表示。” ?

【问题讨论】：

开启跟踪日志。将响应描述符上的路径模式设置为 nil（仅在直接使用 RKManagedObjectRequestOperation 时）。您不直接使用对象管理器是否有原因？

谢谢。我确实在 AppDelegate 中打开了跟踪日志记录：RKLogConfigureByName("RestKit/ObjectMapping", RKLogLevelTrace);当我将路径模式设置为 nil 时，我得到了同样的错误。我正在使用 RKManagedObjectRequestOperation, b/c 这似乎是基于其他 SO 问题的建议。我应该改用对象管理器吗？

我个人 99% 直接使用RKObjectManager 和 1% 的具体操作。您使用的原始 URL 是什么？

NSURL *baseURL = [NSURL URLWithString:@"rest.domain.com"]; 你需要真实域名吗？

我想知道它最后是否有一个/，但是直接使用RKManagedObjectRequestOperation 时这并不重要。我看不出有什么特别的问题。您可以在某处发布跟踪日志吗？

【参考方案1】：

这是创建操作的正确方法：

RKManagedObjectRequestOperation *operation = [[RKManagedObjectRequestOperation alloc]initWithRequest:request responseDescriptors:@[responseDescriptor]];

但是你用另一个创建的替换那个：

operation = [self.objectManager managedObjectRequestOperationWithRequest:request managedObjectContext:self.objectManager.managedObjectStore.mainQueueManagedObjectContext success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) 

正确使用对象管理器。这个问题是你没有把响应描述符给对象管理器，你只给了刚刚被销毁的操作（因为你替换了它）。

因此，使用您创建的第一个操作并通过调用setCompletionBlockWithSuccess:failure: 在其上设置成功和失败块。

【讨论】：

您需要在执行操作之前设置managedObjectContext（使用对象管理器的另一个好处是这是为您完成的）

操作.managedObjectContext = self.objectManager.managedObjectStore.mainQueueManagedObjectContext;我认为上面的这条线做到了！

最后一个问题：我看到对象返回并被映射。它们是如何保存在 Core Data 中的？

只是一个小问题 :-) RestKit 使用您的responseDescriptor 来了解要创建的实体类型以及如何将传入数据映射到这些新实例中。映射完成后，它会保存 MOC。这就是为什么您需要设置操作的managedObjectContext。因此它可以创建并保存响应。

我目前不使用 Swift，因为它还不够成熟，我的任何客户都无法使用它。目前（据我所知）没有任何将 RestKit 迁移到 Swift 的计划。我还没有打算离开 RestKit