c# - 获取 HttpRequestException : The response ended prematurely

Question

出于某种原因，我收到了 HttpRequestException，其中包含消息“响应提前结束。我正在创建大约 500 个任务，这些任务使用我的 RateLimitedHttpClient 向网站发出请求，以便它可以抓取它。

从 return wait response.Content.ReadAsStringAsync(); 行引发异常。

是否有可能，对于 500 个任务，每个任务需要下载和解析约 20 个页面(总共约 11000 个页面)，我是否超出了 .Net HttpClient 的能力？

public class SECScraper
{
    public event EventHandler<ProgressChangedEventArgs> ProgressChangedEvent;

    public SECScraper(EPSDownloader downloader, FinanceContext financeContext)
    {
        _downloader = downloader;
        _financeContext = financeContext;
    }

    public void Download()
    {
        _numDownloaded = 0;

        var companies = _financeContext.Companies.OrderBy(c => c.Name);
        _interval = companies.Count() / 100;

        var tasks = companies.Select(c => ScrapeSEC(c.CIK) ).ToList();
        Task.WhenAll(tasks);
    }
}

public class RateLimitedHttpClient : IHttpClient
{
    public RateLimitedHttpClient(System.Net.Http.HttpClient client)
    {
        _client = client;
        _client.Timeout = TimeSpan.FromMinutes(30);
        ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;
    }
    public async Task<string> ReadAsync(string url)
    {
        if (!_sw.IsRunning)
            _sw.Start();

        await Delay();

        using var response = await _client.GetAsync(url);

        return await response.Content.ReadAsStringAsync();
    }

    private async Task Delay()
    {
        var totalElapsed = GetTimeElapsedSinceLastRequest();

        while (totalElapsed < MinTimeBetweenRequests)
        {
            await Task.Delay(MinTimeBetweenRequests - totalElapsed);
            totalElapsed = GetTimeElapsedSinceLastRequest();
        };

        _timeElapsedOfLastHttpRequest = (int)_sw.Elapsed.TotalMilliseconds;
    }

    private int GetTimeElapsedSinceLastRequest()
    {
        return (int)_sw.Elapsed.TotalMilliseconds - _timeElapsedOfLastHttpRequest;
    }

    private readonly System.Net.Http.HttpClient _client;
    private readonly Stopwatch _sw = new Stopwatch();
    private int _timeElapsedOfLastHttpRequest;
    private const int MinTimeBetweenRequests = 100;
}

看来我在这里收到了一些 HttpRequestException。

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)
   at POLib.Http.RateLimitedHttpClient.ReadAsync(String url) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\Http\RateLimitedHttpClient.cs:line 23
   at POLib.SECScraper.EPS.EPSDownloader.GetReportLinks(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 65
   at POLib.SECScraper.EPS.EPSDownloader.GetEPSData(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 19
   at POLib.SECScraper.SECScraper.ScrapeSEC(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\SECScraper.cs:line 40
System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.IO.IOException: Unable to read data from the transport connection: An established connection was aborted by the software in your host machine.. ---> System.Net.Sockets.SocketException (10053): An established connection was aborted by the software in your host machine.
   --- End of inner exception stack trace ---
   at System.Net.Security.SslStream.<FillBufferAsync>g__InternalFillBufferAsync|215_0[TReadAdapter](TReadAdapter adap, ValueTask`1 task, Int32 min, Int32 initial)
   at System.Net.Security.SslStream.ReadAsyncInternal[TReadAdapter](TReadAdapter adapter, Memory`1 buffer)
   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)
   at POLib.Http.RateLimitedHttpClient.ReadAsync(String url) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\Http\RateLimitedHttpClient.cs:line 23
   at POLib.SECScraper.EPS.EPSDownloader.GetReportLinks(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 65
   at POLib.SECScraper.EPS.EPSDownloader.GetEPSData(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 19
   at POLib.SECScraper.SECScraper.ScrapeSEC(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\SECScraper.cs:line 40
System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.IO.IOException: Unable to read data from the transport connection: An established connection was aborted by the software in your host machine.. ---> System.Net.Sockets.SocketException (10053): An established connection was aborted by the software in your host machine.
   --- End of inner exception stack trace ---
   at System.Net.Security.SslStream.<WriteSingleChunk>g__CompleteAsync|210_1[TWriteAdapter](ValueTask writeTask, Byte[] bufferToReturn)
   at System.Net.Security.SslStream.WriteAsyncInternal[TWriteAdapter](TWriteAdapter writeAdapter, ReadOnlyMemory`1 buffer)
   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)
   at POLib.Http.RateLimitedHttpClient.ReadAsync(String url) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\Http\RateLimitedHttpClient.cs:line 23
   at POLib.SECScraper.EPS.EPSDownloader.GetReportLinks(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 65
   at POLib.SECScraper.EPS.EPSDownloader.GetEPSData(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 19
   at POLib.SECScraper.SECScraper.ScrapeSEC(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\SECScraper.cs:line 40
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)
   at POLib.Http.RateLimitedHttpClient.ReadAsync(String url) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\Http\RateLimitedHttpClient.cs:line 23
   at POLib.SECScraper.EPS.EPSDownloader.GetReportLinks(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 65
   at POLib.SECScraper.EPS.EPSDownloader.GetEPSData(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 19
   at POLib.SECScraper.SECScraper.ScrapeSEC(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\SECScraper.cs:line 40
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)
>    at POLib.Http.RateLimitedHttpClient.ReadAsync(String url) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\Http\RateLimitedHttpClient.cs:line 23
>    at POLib.SECScraper.EPS.EPSDownloader.GetReportLinks(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 65
>    at POLib.SECScraper.EPS.EPSDownloader.GetEPSData(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 19
>    at POLib.SECScraper.SECScraper.ScrapeSEC(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\SECScraper.cs:line 40
> System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.IO.IOException: Unable to read data from the transport connection: An established connection was aborted by the software in your host machine.. ---> System.Net.Sockets.SocketException (10053): An established connection was aborted by the software in your host machine.
>    --- End of inner exception stack trace ---
>    at System.Net.Security.SslStream.<FillBufferAsync>g__InternalFillBufferAsync|215_0[TReadAdapter](TReadAdapter adap, ValueTask`1 task, Int32 min, Int32 initial)
>    at System.Net.Security.SslStream.ReadAsyncInternal[TReadAdapter](TReadAdapter adapter, Memory`1 buffer)
>    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)
>    at POLib.Http.RateLimitedHttpClient.ReadAsync(String url) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\Http\RateLimitedHttpClient.cs:line 23
>    at POLib.SECScraper.EPS.EPSDownloader.GetReportLinks(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 65
>    at POLib.SECScraper.EPS.EPSDownloader.GetEPSData(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 19
>    at POLib.SECScraper.SECScraper.ScrapeSEC(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\SECScraper.cs:line 40
> System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.IO.IOException: Unable to read data from the transport connection: An established connection was aborted by the software in your host machine.. ---> System.Net.Sockets.SocketException (10053): An established connection was aborted by the software in your host machine.
>    --- End of inner exception stack trace ---
>    at System.Net.Security.SslStream.<WriteSingleChunk>g__CompleteAsync|210_1[TWriteAdapter](ValueTask writeTask, Byte[] bufferToReturn)
>    at System.Net.Security.SslStream.WriteAsyncInternal[TWriteAdapter](TWriteAdapter writeAdapter, ReadOnlyMemory`1 buffer)
System.Net.Http.HttpRequestException: The SSL connection could not be established, see inner exception. ---> System.IO.IOException: Authentication failed because the remote party has closed the transport stream.
   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.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.ProcessAuthentication(LazyAsyncResult lazyResult, CancellationToken cancellationToken)
   at System.Net.Security.SslStream.BeginAuthenticateAsClient(SslClientAuthenticationOptions sslClientAuthenticationOptions, CancellationToken cancellationToken, AsyncCallback asyncCallback, Object asyncState)
   at System.Net.Security.SslStream.<>c.<AuthenticateAsClientAsync>b__65_0(SslClientAuthenticationOptions arg1, CancellationToken arg2, AsyncCallback callback, Object state)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncImpl[TArg1,TArg2](Func`5 beginMethod, Func`2 endFunction, Action`1 endAction, TArg1 arg1, TArg2 arg2, Object state, TaskCreationOptions creationOptions)
   at System.Threading.Tasks.TaskFactory.FromAsync[TArg1,TArg2](Func`5 beginMethod, Action`1 endMethod, TArg1 arg1, TArg2 arg2, Object state, TaskCreationOptions creationOptions)
   at System.Threading.Tasks.TaskFactory.FromAsync[TArg1,TArg2](Func`5 beginMethod, Action`1 endMethod, TArg1 arg1, TArg2 arg2, Object state)
   at System.Net.Security.SslStream.AuthenticateAsClientAsync(SslClientAuthenticationOptions sslClientAuthenticationOptions, CancellationToken cancellationToken)
   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.Threading.Tasks.ValueTask`1.get_Result()
   at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   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)
   at POLib.Http.RateLimitedHttpClient.ReadAsync(String url) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\Http\RateLimitedHttpClient.cs:line 23
   at POLib.SECScraper.EPS.EPSDownloader.GetReportLinks(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 65
   at POLib.SECScraper.EPS.EPSDownloader.GetEPSData(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 19
   at POLib.SECScraper.SECScraper.ScrapeSEC(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\SECScraper.cs:line 40
>    at System.Net.Http.HttpConnection.SendAsyncCore(HttpRequestMessage request, CancellationToken cancellationToken)
System.Net.Http.HttpRequestException: The SSL connection could not be established, see inner exception. ---> System.IO.IOException: Authentication failed because the remote party has closed the transport stream.
   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.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.ProcessAuthentication(LazyAsyncResult lazyResult, CancellationToken cancellationToken)
   at System.Net.Security.SslStream.BeginAuthenticateAsClient(SslClientAuthenticationOptions sslClientAuthenticationOptions, CancellationToken cancellationToken, AsyncCallback asyncCallback, Object asyncState)
   at System.Net.Security.SslStream.<>c.<AuthenticateAsClientAsync>b__65_0(SslClientAuthenticationOptions arg1, CancellationToken arg2, AsyncCallback callback, Object state)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncImpl[TArg1,TArg2](Func`5 beginMethod, Func`2 endFunction, Action`1 endAction, TArg1 arg1, TArg2 arg2, Object state, TaskCreationOptions creationOptions)
   at System.Threading.Tasks.TaskFactory.FromAsync[TArg1,TArg2](Func`5 beginMethod, Action`1 endMethod, TArg1 arg1, TArg2 arg2, Object state, TaskCreationOptions creationOptions)
   at System.Threading.Tasks.TaskFactory.FromAsync[TArg1,TArg2](Func`5 beginMethod, Action`1 endMethod, TArg1 arg1, TArg2 arg2, Object state)
   at System.Net.Security.SslStream.AuthenticateAsClientAsync(SslClientAuthenticationOptions sslClientAuthenticationOptions, CancellationToken cancellationToken)
   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.Threading.Tasks.ValueTask`1.get_Result()
   at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   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)
   at POLib.Http.RateLimitedHttpClient.ReadAsync(String url) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\Http\RateLimitedHttpClient.cs:line 23
   at POLib.SECScraper.EPS.EPSDownloader.GetReportLinks(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 65
   at POLib.SECScraper.EPS.EPSDownloader.GetEPSData(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 19
   at POLib.SECScraper.SECScraper.ScrapeSEC(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\SECScraper.cs:line 40
>    --- End of inner exception stack trace ---
System.Net.Http.HttpRequestException: The SSL connection could not be established, see inner exception. ---> System.IO.IOException: Authentication failed because the remote party has closed the transport stream.
   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.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
   at System.Net.Security.SslStream.ProcessAuthentication(LazyAsyncResult lazyResult, CancellationToken cancellationToken)
   at System.Net.Security.SslStream.BeginAuthenticateAsClient(SslClientAuthenticationOptions sslClientAuthenticationOptions, CancellationToken cancellationToken, AsyncCallback asyncCallback, Object asyncState)
   at System.Net.Security.SslStream.<>c.<AuthenticateAsClientAsync>b__65_0(SslClientAuthenticationOptions arg1, CancellationToken arg2, AsyncCallback callback, Object state)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncImpl[TArg1,TArg2](Func`5 beginMethod, Func`2 endFunction, Action`1 endAction, TArg1 arg1, TArg2 arg2, Object state, TaskCreationOptions creationOptions)
   at System.Threading.Tasks.TaskFactory.FromAsync[TArg1,TArg2](Func`5 beginMethod, Action`1 endMethod, TArg1 arg1, TArg2 arg2, Object state, TaskCreationOptions creationOptions)
   at System.Threading.Tasks.TaskFactory.FromAsync[TArg1,TArg2](Func`5 beginMethod, Action`1 endMethod, TArg1 arg1, TArg2 arg2, Object state)
   at System.Net.Security.SslStream.AuthenticateAsClientAsync(SslClientAuthenticationOptions sslClientAuthenticationOptions, CancellationToken cancellationToken)
   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.Threading.Tasks.ValueTask`1.get_Result()
   at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   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)
   at POLib.Http.RateLimitedHttpClient.ReadAsync(String url) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\Http\RateLimitedHttpClient.cs:line 23
   at POLib.SECScraper.EPS.EPSDownloader.GetReportLinks(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 65
   at POLib.SECScraper.EPS.EPSDownloader.GetEPSData(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\EPS\EPSDownloader.cs:line 19
   at POLib.SECScraper.SECScraper.ScrapeSEC(Int32 cik) in C:\Users\Joshua\source\repos\PortfolioOptimizer\POLib\SECScraper\SECScraper.cs:line 40

Answer 1

你只需要继续挖掘。 “响应提前结束”异常并不是根本原因。继续挖掘内部异常，直到找到最后一个。你会发现这个:

System.IO.IOException: Authentication failed because the remote party has closed the transport stream.

所以这与您的代码无关。您所访问的服务器似乎无法处理负载，或者由于您的访问量太大而故意丢弃您的请求。