Restkit多对多关系导致重复的对象。

Question

对于我的应用程序，我使用的是RestKit application /0.10.0分支。我使用CoreData和RestKit的对象映射特性来加载/同步数据。我正在加载的XML数据看起来如下(简化)：

<iphoneSync>
<time>12-04-03 16:47</time>
<pages>
    <page id="177">
        <title>
            Foo
        </title>
        <meta>
            <tags>
                <tag type="undef" id="16">Lorem</tag>
                <tag type="undef" id="20">Ipsum</tag>
            </tags>
        </meta>         
    </page>
    <page id="580">
        <title>
            Bar
        </title>
        <meta>
            <tags>
                <tag type="undef" id="16">Lorem</tag>
                <tag type="undef" id="20">Ipsum</tag>
                <tag type="" id="46">Abc</tag>
                <tag type="symptom" id="47">Cde</tag>
            </tags>
        </meta>
    </page>
</pages>

​

域类、Page、和标记如下所示：

@interface Page : NSManagedObject
@property (nonatomic, strong) NSNumber * id;
@property (nonatomic, strong) NSString * title;
@property (nonatomic, strong) NSSet *tags;
@end

@interface Tag : NSManagedObject
@property (nonatomic, strong) NSNumber * id;
@property (nonatomic, strong) NSString * name;
@property (nonatomic, strong) NSString * type;
@property (nonatomic, strong) NSSet *pages;
@end

Page实体有许多标记，一个标记可以属于多个页面。所以我把双方的关系设为-很多。从页面到标记的删除规则是层叠的。从标签到页面都是无效的。

​

​

映射设置：

//Tag mapping
RKManagedObjectMapping* tagMapping = [RKManagedObjectMapping mappingForClass:[Tag class] inManagedObjectStore:[RKManagedObjectStore defaultObjectStore]];
tagMapping.setDefaultValueForMissingAttributes = YES;
tagMapping.primaryKeyAttribute = @"id";
[tagMapping mapKeyPathsToAttributes:@"type",@"type",@"text",@"name",@"id",@"id", nil];

//Page mapping
RKManagedObjectMapping* pageMapping = [RKManagedObjectMapping mappingForClass:[Page class] inManagedObjectStore:[RKManagedObjectStore defaultObjectStore]];    
pageMapping.primaryKeyAttribute = @"id";
[pageMapping mapKeyPathsToAttributes:@"id",@"id",@"title",@"title",nil];
[pageMapping mapKeyPath:@"meta.tags.tag" toRelationship:@"tags"  withMapping:tagMapping];
pageMapping.setNilForMissingRelationships = YES;
pageMapping.setDefaultValueForMissingAttributes = YES;

//Root mapping
RKObjectMapping* rootMapping = [RKObjectMapping mappingForClass:[NSMutableDictionary class]];
[rootMapping mapKeyPath:@"iphoneSync.pages.page" toRelationship:@"pages" withMapping:pageMapping];

//RKObjectManager
RKManagedObjectStore* mainManagedObjectStore = [RKManagedObjectStore objectStoreWithStoreFilename:OBJECT_STORE_FILE];
RKObjectManager* objectManager = [RKObjectManager objectManagerWithBaseURL:baseURL];
[RKObjectManager setSharedManager:objectManager];
objectManager.acceptMIMEType = RKMIMETypeXML;
objectManager.serializationMIMEType = RKMIMETypeXML;
objectManager.objectStore = mainManagedObjectStore;
objectManager.objectStore.cacheStrategy = [RKInMemoryManagedObjectCache new];
objectManager.client.cachePolicy = RKRequestCachePolicyNone;

[objectManager.mappingProvider addObjectMapping:rootMapping];    
[objectManager.mappingProvider addObjectMapping:pageMapping];
[objectManager.mappingProvider addObjectMapping:tagMapping];

然后我像这样加载它：

[objectManager loadObjectsAtResourcePath:@"/" usingBlock:^(RKObjectLoader* loader) {
    loader.objectMapping = [[RKObjectManager sharedManager].mappingProvider objectMappingForClass:[NSMutableDictionary class]];
}];

对象被正确地加载和映射，但是ID 16和ID 20的标记被两次存储在数据库中(每个页面实体一个)。但是我希望它们是不同的，这样具有相同ID的标签只能存储一次。我做错了什么？

Answer 1

这个问题已经解决了。这是RestKit中的一个bug。请参阅https://github.com/RestKit/RestKit/issues/661克隆开发分支的最新版本，以获得工作版本。