C# - 为什么 .exe 中的 HttpClient PostAsync 阻塞，但适用于 Visual Studio 2015 -> 调试？

Question

我有一个 C# 控制台应用程序，它必须创建一个 HttpClient 并向我们的“3CX 电话系统管理”门户网站发出一些请求（我必须检索/更改我们员工的电话状态）。为此，我必须登录，将收到的 cookie 保存到 CookieContainer 中，然后继续处理必须使用相同 cookie 的其他请求。代码如下：

public static CookieContainer cookies = null;
public static HttpClientHandler handler = new HttpClientHandler();

static void Main(string[] args) {
    Task.Run(() => ExtListAsync());
    Console.ReadLine();
}

static async Task<bool> LoginAsync() {
    try {
        cookies = new CookieContainer();
        handler = new HttpClientHandler();
        handler.CookieContainer = cookies;

        using (HttpClient client = new HttpClient(handler, disposeHandler: false)) {
            client.BaseAddress = new Uri("https://my.uri.com:5001");
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

            StringContent parameters = new StringContent(@"{""key"":""value"",""key2"":""value2""}", Encoding.UTF8, "application/json");

            // BLOCKS HERE....
            using (HttpResponseMessage response = await client.PostAsync("/api/other", parameters).ConfigureAwait(false)) {
                using (HttpContent content = response.Content) {
                    string responseContent = content.ReadAsStringAsync().Result;

                    var responseCookies = cookies.GetCookies(uri).Cast<Cookie>();

                    if (responseCookies.Count() > 0)
                    {
                        return true;
                    }
                    else
                    {
                        return false;
                    }
                }
            }
        }
    } catch (HttpRequestException ex) {
        Console.WriteLine("\n\r EXCEPTION MESSAGE: " + ex.Message);
        Console.WriteLine("\n\r DATA: " + ex.Data);
        Console.WriteLine("\n\r InnerException: " + ex.InnerException);
        Console.WriteLine("\n\r Source: " + ex.Source);
        Console.WriteLine("\n\r StackTrace: " + ex.StackTrace);
        Console.WriteLine("\n\r TargetSite: " + ex.TargetSite);
        return true;
    }
}

static async Task ExtListAsync() {
    bool loggedIn = await LoginAsync();
    if (loggedIn) { ... }
}

我有这个简单的代码，用 Visual Studio 启动的“开始调试”可以正确执行。 如果我尝试从命令提示符启动 .exe（也尝试使用管理员模式），有时应用程序会在稍有延迟的情况下正确执行，但在大多数情况下，它仍会在“await client.PostAsync(...) "... ，然后抛出一个 HttpRequestException:

EXCEPTION MESSAGE: An error occurred while sending the request.

 DATA: System.Collections.ListDictionaryInternal

 InnerException: System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond xxx.xxx.xxx.xxx:5001
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Exception& exception)
   --- End of inner exception stack trace ---
   at System.Net.HttpWebRequest.EndGetRequestStream(IAsyncResult asyncResult, TransportContext& context)
   at System.Net.Http.HttpClientHandler.GetRequestStreamCallback(IAsyncResult ar)

 Source: mscorlib

 StackTrace:    at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at statusmng3cx.Program.<LoginAsync>d__15.MoveNext() in ...\myPath\Program.cs:line 254

 TargetSite: Void Throw()

有人对此有解释吗？ 提前谢谢你。

更新：

我也尝试添加 SSL 证书：

WebRequestHandler whandler = new WebRequestHandler();
whandler.ClientCertificateOptions = ClientCertificateOption.Manual;

var pem = System.IO.File.ReadAllText("mycert.pem");
byte[] certBuffer = GetBytesFromPEM(pem, "CERTIFICATE");
X509Certificate2 certificate = new X509Certificate2(certBuffer);

whandler.ClientCertificates.Add(certificate);

using (var httpClient = new HttpClient(whandler)) { ... as above ... }

并且发生了同样的事情：通过调试它完美地工作： 状态码 200，ReasonPhrase: 'OK', responseContent: AuthSuccess, ...

通过提示，.exe 不会协作。但是如果我将 3CX 门户 URL 更改为另一个简单的网站，该网站检索静态网页（没有 SSL），.exe 可以完美运行。

Answer 1

最后我用 Java 编写了程序，它可以在控制台上完美运行。

    try {
        TrustStrategy acceptingTrustStrategy = new TrustStrategy() {
            public boolean isTrusted(X509Certificate[] chain, String authType) throws CertificateException {
                return true;
            }
        };

        SSLContextBuilder builder = new SSLContextBuilder();
        builder.loadTrustMaterial(null, acceptingTrustStrategy);
        SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(builder.build());

        HttpClientContext context = HttpClientContext.create();
        CookieStore cookieStore = new BasicCookieStore();
        context.setCookieStore(cookieStore);

        CloseableHttpClient httpClient = HttpClients.custom().setSSLSocketFactory(sslsf).setDefaultRequestConfig(RequestConfig.custom()
                .setCookieSpec(CookieSpecs.STANDARD).build()).setDefaultCookieStore(cookieStore).build();


        HttpPost request = new HttpPost(mainUrl + loginUrl);
        StringEntity params = new StringEntity("myJson");
        request.addHeader("content-type", "application/json");
        request.setEntity(params);
        HttpResponse response = httpClient.execute(request, context);

        System.out.println("Response getStatusLine: " + 

        response.getStatusLine());
    } catch (...) { ... }

然后输出：

Response getStatusLine: HTTP/1.1 200 OK