Question

我正在尝试使用嵌套资源网址在相册中获取照片，例如：

GET http://www.myapi.com/albums/:album_id/photos

最难实现的方法是覆盖AFRESTClient子类中的pathForEntity函数。但是，我无法访问相册对象，因此我无法返回包含album_id的URL。我应该如何覆盖/扩展来实现这一目标？请参阅下文，了解我是如何尝试这样做的，请注意我无法提供相册ID的问号：

- (NSString *)pathForEntity:(NSEntityDescription *)entity {

  NSString *path = AFPluralizedString(entity.name);

  if ([entity.name isEqualToString:@"Photo"]) {
    path = [NSString stringWithFormat:@"albums/%d/photos", ??];
  }

  return path;
}

堆叠越高，我在PhotosViewController -viewDidLoad

中有这个

- (void)viewDidLoad
{
  [super viewDidLoad];

  self.title = self.currentAlbum.name;

  NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:@"Photo"];
  fetchRequest.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"createdAt" ascending:NO]];

  NSPredicate *predicate = [NSPredicate predicateWithFormat:@"album == %@", self.currentAlbum];
  fetchRequest.predicate = predicate;

  self.fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:nil];
  self.fetchedResultsController.delegate = self;
  [self.fetchedResultsController performFetch:nil];
}

谢谢！

Answer 1

我们有一个类似的层次结构，最终在我们的AFRESTClient子类中实现了pathForRelationship：forObject：方法。在你的专辑和照片的情况下，我想它会是这样的：

- (NSString *)pathForRelationship:(NSRelationshipDescription *)relationship
                        forObject:(NSManagedObject *)object
{
    if ([object isKindOfClass:[Album class]] && [relationship.name isEqualToString:@"photos"]) {
        Album *album = (Album*)object;
        return [NSString stringWithFormat:@"/albums/%@/photos", album.album_id];
    }
    return [super pathForRelationship:relationship forObject:object];
}

假设您在模型中设置了toMany关系。

具有嵌套资源的AFRESTClient pathForEntity？

1 个答案: