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问为什么我在HttpClient中使用C#时得到“响应过早结束”？
EN

Stack Overflow用户

提问于 2021-10-10 09:03:15

回答 2查看 13.6K关注 0票数 3

我在.Net核心中的第一个代码。服务器也在我的电脑上运行，所以我想把它发送到本地主机。

在有人在这里推荐之后，我增加了内部异常的打印，但是仅仅理解这个问题是不够的。

namespace HTTPClient
{
    // The object I want to send
    public class Msg
    {
        public string ID { get; set; }
        public string Data { get; set; }
        public int RSSIR { get; set; }
        public int RSSIT { get; set; }
        public int Slot { get; set; }
    }

    class Program
    {
        static Msg msg = new Msg
        {
            ID = "00CC",
            Data = "9F4CC",
            RSSIR = 123, 
            RSSIT = 321,
            Slot = 1
        };

        static void Main(string[] args)
        {
            string url = "http://127.0.0.1:5001";
            Console.WriteLine("result = " , callURL(url)); 
            Console.ReadKey();
        }


        public static bool callURL(string url)
        {
            ServicePointManager.ServerCertificateValidationCallback += (sender, cert, chain, sslPolicyErrors) => true;
            bool Result = false;
            HttpClient client = new HttpClient();
            client.BaseAddress = new Uri(url);
            client.DefaultRequestHeaders.Accept.Clear();
            HttpResponseMessage response = null;
            try
            {
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                HttpContent content = new StringContent(JsonConvert.SerializeObject(msg), Encoding.UTF8, "application/json");
                response = client.PostAsync("", content).Result;
            }
            catch (AggregateException err)
            {
                foreach (var errInner in err.InnerExceptions)
                {   // for printing the inner execption
                    Console.WriteLine("ERROR");
                    Console.WriteLine(errInner); 
                }
            }


            if (response.IsSuccessStatusCode)
            {
                Result = true;
            }
            else
            {
                Result = false;
            }
            return Result;
        }
        
    }

}

从捕获内的循环中接收到的错误是：

System.Net.Http.HttpRequestException: An error occurred while sending the request.
 ---> System.IO.IOException: The response ended prematurely.
   at System.Net.Http.HttpConnection.FillAsync()
   at System.Net.Http.HttpConnection.ReadNextResponseHeaderLineAsync(Boolean foldedHeadersAllowed)
   at System.Net.Http.HttpConnection.SendAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at System.Net.Http.HttpConnection.SendAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.SendWithNtConnectionAuthAsync(HttpConnection connection, HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
   at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.FinishSendAsyncBuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)

我如何才能弄明白为什么我不能向服务器发送消息呢？消息的内容会中断连接生成吗？

我用另一个客户端检查了服务器，它正在工作，所以问题必须在我的代码中。

编辑:服务器正在使用https，所以我也将我的URL更改为https，这是我收到的错误：

System.Net.Http.HttpRequestException: The SSL connection could not be established, see inner exception.
 ---> System.Security.Authentication.AuthenticationException: The remote certificate is invalid according to the validation procedure.
   at System.Net.Security.SslStream.StartSendAuthResetSignal(ProtocolToken message, AsyncProtocolRequest asyncRequest, ExceptionDispatchInfo exception)
   at System.Net.Security.SslStream.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.ProcessReceivedBlob(Byte[] buffer, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.ProcessReceivedBlob(Byte[] buffer, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.PartialFrameCallback(AsyncProtocolRequest asyncRequest)
--- End of stack trace from previous location where exception was thrown ---
   at System.Net.Security.SslStream.ThrowIfExceptional()
   at System.Net.Security.SslStream.InternalEndProcessAuthentication(LazyAsyncResult lazyResult)
   at System.Net.Security.SslStream.EndProcessAuthentication(IAsyncResult result)
   at System.Net.Security.SslStream.EndAuthenticateAsClient(IAsyncResult asyncResult)
   at System.Net.Security.SslStream.<>c.<AuthenticateAsClientAsync>b__65_1(IAsyncResult iar)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncCoreLogic(IAsyncResult iar, Func`2 endFunction, Action`1 endAction, Task`1 promise, Boolean requiresSynchronization)
--- End of stack trace from previous location where exception was thrown ---
   at System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore(Stream stream, SslClientAuthenticationOptions sslOptions, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore(Stream stream, SslClientAuthenticationOptions sslOptions, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
   at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.FinishSendAsyncBuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)

我需要添加一些SSL命令才能建立安全连接吗？

Edit2:在callURL()中添加命令后的新错误

---> System.Security.Authentication.AuthenticationException: The remote certificate is invalid according to the validation procedure.
   at System.Net.Security.SslStream.StartSendAuthResetSignal(ProtocolToken message, AsyncProtocolRequest asyncRequest, ExceptionDispatchInfo exception)
   at System.Net.Security.SslStream.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.ProcessReceivedBlob(Byte[] buffer, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.ProcessReceivedBlob(Byte[] buffer, Int32 count, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.PartialFrameCallback(AsyncProtocolRequest asyncRequest)
--- End of stack trace from previous location where exception was thrown ---
   at System.Net.Security.SslStream.ThrowIfExceptional()
   at System.Net.Security.SslStream.InternalEndProcessAuthentication(LazyAsyncResult lazyResult)
   at System.Net.Security.SslStream.EndProcessAuthentication(IAsyncResult result)
   at System.Net.Security.SslStream.EndAuthenticateAsClient(IAsyncResult asyncResult)
   at System.Net.Security.SslStream.<>c.<AuthenticateAsClientAsync>b__65_1(IAsyncResult iar)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncCoreLogic(IAsyncResult iar, Func`2 endFunction, Action`1 endAction, Task`1 promise, Boolean requiresSynchronization)
--- End of stack trace from previous location where exception was thrown ---
   at System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore(Stream stream, SslClientAuthenticationOptions sslOptions, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore(Stream stream, SslClientAuthenticationOptions sslOptions, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
   at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.FinishSendAsyncBuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)

http

.net-core

httpclient

回答 2

Stack Overflow用户

回答已采纳

发布于 2021-10-10 09:16:17

System.IO.IOException: The response ended prematurely意味着您要向其发出HTTP请求的服务器关闭了连接，而没有发送回完整的响应。

它与客户端代码无关，因为它看起来是正确编译和发送内容的。

是的，你应该使用await client.PostAsync，但这与你的问题完全无关。

重复检查http://127.0.0.1:5001 https:// 是否100%正确--也许是https://，或者不是在端口 5001**.**上

如果它是一个使用HTTPS的端点，您可能会得到System.Security.Authentication.AuthenticationException: The remote certificate is invalid according to the validation procedure.，因为它看起来像是在调用一个本地端点。

.NET默认执行SSL证书验证&如果您试图调用没有/无效SSL证书的HTTPS端点，则会引发异常。您可能还没有在计算机上正确设置本地主机证书。

现在，可以通过将ServicePointManager.ServerCertificateValidationCallback设置为始终使用HttpClientHandler.DangerousAcceptAnyServerCertificateValidator返回true来绕过检查。

初始化您的HttpClient如下：

public static bool callURL(string url)
{
  bool Result = false;

  var httpClientHandler = new HttpClientHandler();
  
  #if DEBUG
  httpClientHandler.ServerCertificateCustomValidationCallback = HttpClientHandler.DangerousAcceptAnyServerCertificateValidator;
  #endif

  HttpClient client = new HttpClient(httpClientHandler);
  ...
}

但是，请注意，允许所有SSL证书用于本地开发环境以外的任何内容都是一种安全风险。

读:斯坦福大学的世界上最危险的代码:在非浏览器软件中验证SSL证书。

票数 8

Stack Overflow用户

发布于 2022-04-26 11:35:13

在将.net框架项目移植到.net核心时，我也遇到了类似的问题。我通过像这样使用WinHttpHandler来解决这个问题：

var handler = new WinHttpHandler();
handler.SslProtocols = System.Security.Authentication.SslProtocols.Tls12;
handler.TcpKeepAliveEnabled = true;

using (var hc = new HttpClient(handler))
{
    return wc.GetStringAsync(new Uri(apiUrl)).GetAwaiter().GetResult();
}

票数 1

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/69513783

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