ios - RestKit - 从 RKRequestDescriptor 中排除具有 nil 值的属性映射

Question

问题是，当值为 nil 时，我需要从负载中完全删除属性 @"unitprice"，但如果它在请求中有值，则将其保留在那里。因此 OrderLine 的有效负载相应地如下所示:@{"id":@"orderlineId", @"unitprice":@"unitprice"} 或 @{"id":@"orderlineId"} 请注意映射是一对多的关系。是否有可能做到这一点？非常感谢您的帮助谢谢!/* 请求描述符 */

+(RKObjectMapping*) getSalesOrderMapping:(RKRequestMethod)method {

RKEntityMapping *requestMapping = [RKEntityMapping mappingForEntityForName:@"SalesOrder"
                                                       inManagedObjectStore:[RKManagedObjectStore defaultStore]];
RKEntityMapping *orderLinesMapping = [RKEntityMapping mappingForEntityForName:@"OrderLine"
                                                         inManagedObjectStore:[RKManagedObjectStore defaultStore]];
requestMapping.identificationAttributes = @[ @"salesOrderId" ];
NSMutableDictionary *attributeMappings = [NSMutableDictionary dictionaryWithDictionary:@{
                                                                                         @"id": @"salesOrderId",
                                                                                         }];
NSDictionary *orderLineAttributeMappings = @{
                                             @"id": @"orderlineId",
                                             @"unitprice": @"unitPrice"
                                             };

[orderLinesMapping addAttributeMappingsFromDictionary:orderLineAttributeMappings];
[requestMapping addPropertyMapping:[RKRelationshipMapping relationshipMappingFromKeyPath:@"lines"
                                                                                toKeyPath:@"salesOrderToOrderLines"
                                                                              withMapping:orderLinesMapping]];


return  requestMapping;
}

Answer 1

在映射上将 assignsDefaultValueForMissingAttributes 设置为 NO。您不应该需要 2 个不同的映射(除非您确实希望在 JSON 中为某些属性包含 nil)。