RestKit 一对多关系在映射 JSON 响应后没有正确数量的对象

Question

我有一个 NSManagedObject 子类 TAGRemoteObject

TAGRemoteObject.h

extern const struct TAGRemoteObjectAttributes {
    __unsafe_unretained NSString *object_Id;
} TAGRemoteObjectAttributes;

@interface TAGRemoteObject ()

@property (nonatomic, strong) NSString *object_Id;

@end

TAGRemoteObject.m

const struct TAGRemoteObjectAttributes TAGRemoteObjectAttributes = {
    .object_Id = @"object_Id",
};

@implementation TAGRemoteObject

@dynamic object_Id;

+(RKEntityMapping*)entityMappingInManagedObjectStore:(RKManagedObjectStore *)managedObjectStore
{
   RKEntityMapping *entityMapping = [RKEntityMapping mappingForEntityForName:NSStringFromClass([self class]) inManagedObjectStore:managedObjectStore];

    [entityMapping addAttributeMappingsFromDictionary:@{
                                                        @"object_id" : TAGRemoteObjectAttributes.object_Id,
                                                        }];

    [entityMapping setIdentificationAttributes:@[ TAGRemoteObjectAttributes.object_Id ]];

    return entityMapping;
}

@end

然后我有两个TAGRemoteObject的子类。 TAGPost 与 TAGUser 具有一对多 viewedUsers 关系。 TAGUser 与 TAGPost.

也有一对多的 posts 关系

TAGPost.h

extern const struct TAGPostRelationships {
    __unsafe_unretained NSString *viewedUsers;
} TAGPostRelationships;

@interface TAGPost : TAGRemoteObject ()

@property (nonatomic, strong) NSSet *viewedUsers;

@end

TAGPost.m

const struct TAGPostRelationships TAGPostRelationships = {
    .viewedUsers = @"viewedUsers",
};

@implementation TAGPost

@dynamic viewedUsers;

+(RKEntityMapping*)entityMappingInManagedObjectStore:(RKManagedObjectStore *)managedObjectStore
{
    RKEntityMapping *entityMapping = [super entityMappingInManagedObjectStore:managedObjectStore];

    RKEntityMapping *userMapping = [TAGUser entityMappingInManagedObjectStore:managedObjectStore];

    RKRelationshipMapping *viewedUsersMapping = [RKRelationshipMapping relationshipMappingFromKeyPath:@"viewed_users" toKeyPath:TAGJourneyOutgoingPostRelationships.viewedUsers withMapping:userMapping];
    viewedUsersMapping.assignmentPolicy = RKUnionAssignmentPolicy;
    [entityMapping addPropertyMapping:viewedUsersMapping];

    return entityMapping;
}

@end

TAGUser.h

extern const struct TAGUserAttributes {
    __unsafe_unretained NSString *username;
} TAGUserAttributes;

extern const struct TAGUserRelationships {
    __unsafe_unretained NSString *posts;
}

@interface TAGUser : TAGRemoteObject ()

@property (nonatomic, strong) NSString *username;
@property (nonatomic, strong) NSSet *posts;

@end

TAGUser.m

const struct TAGUserAttributes TAGUserAttributes = {
    .username = @"username",
};

const struct TAGUserRelationships TAGUserRelationships = {
    .posts = @"posts",
};

@implementation TAGUser

@dynamic username;
@dynamic posts;

+(RKEntityMapping*)entityMappingInManagedObjectStore:(RKManagedObjectStore *)managedObjectStore
{
    RKEntityMapping *entityMapping = [super entityMappingInManagedObjectStore:managedObjectStore];

    [entityMapping addAttributeMappingsFromDictionary:@{
                                                        @"username" : TAGUserAttributes.username,
                                                        }];

    RKEntityMapping *postEntityMapping = [TAGPost entityMappingInManagedObjectStore:managedObjectStore];

    RKRelationshipMapping *postsRelationshipMapping = [RKRelationshipMapping relationshipMappingFromKeyPath:@"posts" toKeyPath:TAGUserRelationships.posts withMapping:postEntityMapping];
    postsRelationshipMapping.assignmentPolicy = RKUnionAssignmentPolicy;
    [entityMapping addPropertyMapping:postsRelationshipMapping];

    return entityMapping;
}

@end

我遇到的问题是，当我收到这样的 JSON 响应（针对有很多用户的主页）时，我得到的 viewedUsers.count 为 3，这符合预期：

{
    "error": null,
    "result": [
        {
            "object_id": 1,
            "username": "a",
            "posts": [
                {
                    "object_id": 299,
                    "viewed_users": [
                        {
                            "object_id": 3,
                            "username": "b"
                        },
                        {
                            "object_id": 4,
                            "username": "b"
                        },
                        {
                            "object_id": 5,
                            "username": "b"
                        }
                    ]
                }
            ]
        }
    ]
}

但是当我为用户 1 发送所有 post 的请求并得到以下响应时，viewedUsers.count 对每个 [=86= 随机为 0 或 1 ]:

{
    "error": null,
    "result": [
        {
            "object_id": 299,
            "viewed_users": [
                {
                    "object_id": 3,
                    "username": "b"
                },
                {
                    "object_id": 4,
                    "username": "b"
                },
                {
                    "object_id": 5,
                    "username": "b"
                }
            ]
        },
        {
            "object_id": 300,
            "viewed_users": [
                {
                    "object_id": 3,
                    "username": "b"
                },
                {
                    "object_id": 4,
                    "username": "b"
                }
            ]
        },
        {
            "object_id": 301,
            "viewed_users": [
                {
                    "object_id": 3,
                    "username": "b"
                },
                {
                    "object_id": 4,
                    "username": "b"
                },
                {
                    "object_id": 5,
                    "username": "b"
                }
            ]
        }
    ]
}

当我向 homefeed 发送请求时，我映射到 [TAGUser entityMappingInManagedObjectStore:self.objectManager.managedObjectStore];

当我发送请求为用户获取 post 时，我映射到 [TAGPost entityMappingInManagedObjectStore:self.objectManager.managedObjectStore];

我真的不知道为什么映射有时不起作用。当我将 RestKit 的日志记录级别设置为 RKLogLevelTrace 时，它看到长度为 3 的 JSON 数组，但是映射后，关系只有 0 或 1。

编辑： 我怀疑循环关系可能是问题所在，所以我从 TAGUser 映射中删除了 posts 关系。不过我仍然看到这个问题。

Answer 1

原来关系被设置为一对多，而它本应设置为多对多。

RestKit 一对多关系在映射 JSON 响应后没有正确数量的对象

RestKit one-to-many relationship doesn't have the correct number of objects after mapping JSON response

ios

objective-c

restkit