URLSession.shared.dataTaskPublisher接收取消

Question

试图用dataTaskPublisher获取一些数据。然而，不断收到以下日志。它每隔一段时间就会起作用，但不知道有什么区别。更改URL不会产生任何影响。仍然只是偶尔地成功了请求。

Test2:接收订阅：(TryMap)

Test2:请求无限

Test2:接收取消

class DataSource: NSObject, ObservableObject {

  var networker: Networker = Networker()

  func fetch() {
    guard let url = URL(string: "https://jsonplaceholder.typicode.com/posts") else {
      fatalError("Invalid URL")
    }
    networker.fetchUrl(url: url)
  }
}

class Networker: NSObject, ObservableObject {
  var pub: AnyPublisher<Data, Error>? = nil
  var sub: Cancellable? = nil
  
  var data: Data? = nil
  var response: URLResponse? = nil
  
  func fetchUrl(url: URL)  {
    guard let url = URL(string: "https://apple.com") else {
      return
    }
    pub = URLSession.shared.dataTaskPublisher(for: url)
      .receive(on: DispatchQueue.main)
      .tryMap() { data, response in
        guard let httpResponse = response as? HTTPURLResponse,
              httpResponse.statusCode == 200 else {
          throw URLError(.badServerResponse)
        }
        return data
      }
      .print("Test2")

      .eraseToAnyPublisher()
    sub = pub?.sink(
      receiveCompletion: { completion in
        switch completion {
        case .finished:
          break
        case .failure(let error):
          fatalError(error.localizedDescription)
        }
      },
      receiveValue: {
        print($0)
      }
    )
}

Answer 1

添加.store(in：&订阅)