swift - 使用 URLSession 和 Combine 处理 HTTP 状态代码

Question

我正在尝试处理来自 DataTaskPublisher 的响应读取其响应状态代码。

当状态码大于 299 时，我想返回一个 ServiceError类型为失败。在我见过的每个例子中，我都使用了 .mapError和 .catch ...在这种特定情况下，来自 .flatMap ，我真的不知道如何处理发布者响应以返回错误而不是TResponse ...

    return URLSession.DataTaskPublisher(request: urlRequest, session: .shared)
        .mapError{error in return ServiceError.request}
        .flatMap{ data, response -> AnyPublisher<TResponse, ServiceError> in

            if let httpResponse = response as? HTTPURLResponse,
                (200...299).contains(httpResponse.statusCode){

                return Just(data)
                    .decode(type: TResponse.self, decoder: JSONDecoder())
                    .mapError{error in return ServiceError.decode}
                    .eraseToAnyPublisher()
            }else{
                //???? HOW TO HANDLE THE ERROR?
            }
        }
        .receive(on: RunLoop.main)
        .eraseToAnyPublisher()

Answer 1

enum ServiceErrors: Error { 
    case internalError(_ statusCode: Int)
    case serverError(_ statusCode: Int)
}
    
return URLSession.shared.dataTaskPublisher(for: urlRequest)
            .tryMap { data, response in
                guard let httpResponse = response as? HTTPURLResponse,
                    200..<300 ~= httpResponse.statusCode else {
                        switch (response as! HTTPURLResponse).statusCode {
                        case (400...499):
                            throw ServiceErrors.internalError((response as! HTTPURLResponse).statusCode)
                        default:
                            throw ServiceErrors.serverError((response as! HTTPURLResponse).statusCode)
                        }
                }
                return data
            }
            .mapError { $0 as! ServiceErrors }
            .decode(type: T.self, decoder: JSONDecoder())
            .receive(on: RunLoop.main)
            .eraseToAnyPublisher()

注意:我靠this链接以制作我的错误处理程序。