A API Endpoint with two response

README.md

usage

let route:EndPointsManager.Route<Int,String> = .init(endpoint: <#endpoint#>, info: <#info#>)
let urlManager = EndPointsManager(scheme: <#scheme#>, host: <#host#>, port: <#port#>)

urlManager.fetch(from: route, onConfig: { (url) -> URLRequest in
  return URLRequest(url: url!)
}) { (result) in
     switch result{
       case .success( let model):
         ///get model
       case .apiError(let fail):
         ///get json error
       case .failure(let error):
         ///get other error
       }
}

APIFetching3CaseResult.swift

class EndPointsManager{

  struct Route<Model:Codable,APIError:Codable>{
    let endpoint:String
    let info:[String:String]
  }

  private let urlComponents:URLComponents
  let session = URLSession.shared

  init(scheme:String, host:String, port:Int){
    var urlComponents = URLComponents()
    urlComponents.scheme = scheme
    urlComponents.host = host
    urlComponents.port = port
    self.urlComponents = urlComponents
  }
  enum URLResult<Model:Codable,APIError:Codable,Err:Error>{
    case success(Model)
    case apiError(APIError)
    case failure(Err)
  }

  func fetch<Model: Codable, Fail:Codable> (
    from route: Route<Model,Fail>,
    onConfig: @escaping (URL?) -> URLRequest,
    then: @escaping (URLResult<Model,Fail,Error>) -> Void) {

    var  url  = urlComponents
    url.path = route.endpoint
    let request = onConfig(url.url)

    let task = session.dataTask(with: request) { (data, reponse, error) in
      var result:URLResult<Model,Fail,Error>
      defer {
        DispatchQueue.main.async { then(result)}
      }
      if let error = error {
        result = .failure(error)
        return
      }

      guard let _ = reponse as? HTTPURLResponse else {
        result = .failure(URLError.reponseUnknow)
        return
      }
      guard let data = data else {
        result = .failure(URLError.noData)
        return
      }
      if let model = try? JSONDecoder().decode(Model.self, from: data) {
        result = .success(model)
      } else {
        do {
          let apiFail = try JSONDecoder().decode(Fail.self, from: data)
          result = .apiError(apiFail)
        }catch {
          result = .failure(error)

        }
      }
    }
    DispatchQueue.global().async {
      task.resume()
    }
  }
}

我剛才的狀況是無法確定 data 的結構

@slamdon 這個函式可以將 2 個可能的結構解析, 有想過要使用 onComplete: (Result)->Void 解耦, 可以試試修改看看

@slamdon 我更新了, 看看吧