System.Net.Http.HttpRequestException：设备未配置 ---> System.Net.Sockets.SocketException：设备未配置

Question

System.Net.Http.HttpRequestException: Device not configured ---> System.Net.Sockets.SocketException: Device not configured

我在尝试从 aspnet 核心 Web 应用程序的自定义中间件发出 Web 请求时收到上述错误。错误发生在以下代码块的第四行：

var web = new WebClient();
var testing = _configuration.GetSection("IPStack")["AccessKey"];
web.QueryString.Add("access_key", _configuration.GetSection("IPStack")["AccessKey"]);
string ipstackRaw = web.DownloadString($"http://api.ipstack/{ipaddress}");

我在 Mac 上使用 Visual Studio，社区版。是什么导致了这个错误？

更新

自最初的 post 以来，我尝试了一些方法但没有成功。这是我尝试过的：

运行 Visual Studio 中的应用程序，我电脑上的专业版 (Windows 10)
正在使用 HttpClient
在中间件之外尝试请求

Answer 1

我建议你使用 HttpWebRequest

   string apiKey = "YOUR_ACCESS_KEY";
        var request = (HttpWebRequest)WebRequest.Create("https://api.ipstack.com/134.201.250.155?access_key="+ apiKey);
        request.Method = "GET";
        request.UserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36";
        request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8";
        request.Headers.Add("accept-language", "en,hr;q=0.9");
        request.Headers.Add("accept-encoding", "");
        request.Headers.Add("Upgrade-Insecure-Requests", "1");
        WebResponse response = request.GetResponse();
        StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
        string responseFromServer = reader.ReadToEnd();
        reader.Close();
        response.Close();

Answer 2

确保正确键入请求 URI。

改变
string ipstackRaw = web.DownloadString($"http://api.ipstack/{ipaddress}");
到
string ipstackRaw = web.DownloadString($"http://api.ipstack.com/{ipaddress}");

System.Net.Http.HttpRequestException：设备未配置 ---> System.Net.Sockets.SocketException：设备未配置

System.Net.Http.HttpRequestException: Device not configured ---> System.Net.Sockets.SocketException: Device not configured

c#

middleware

httprequest

visual-studio

asp.net-core