强制异步 WebRequest 刷新其缓冲区 c#

Question

我有以下连接代码：

_request = (HttpWebRequest)WebRequest.Create(complianceUrl);
_request.Method = "GET";

var authInfo = string.Format("{0}:{1}", _username, _password);
authInfo = Convert.ToBase64String(Encoding.Default.GetBytes(authInfo));
_request.Headers.Add("Authorization", "Basic " + authInfo);

// set stream parameters
_request.AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip;
_request.Headers.Add("Accept-Encoding", "gzip");
_request.Accept = "application/json";
_request.ContentType = "application/json";
_request.ReadWriteTimeout = 30000;
_request.AllowReadStreamBuffering = false;

_request.Timeout = 30; //seconds, sends 15-second heartbeat.
_asyncCallback = HandleResult;    //Setting handleResult as Callback method...
_request.BeginGetResponse(_asyncCallback, _request);    //Calling BeginGetResponse on

这很好用，缓冲区充满了数据，虽然我有大量数据，但这很好。但是由于数据量小，缓冲区需要一段时间才能填满，如果我有一段时间没有 activity，我想定期刷新缓冲区。

我试过这样做：

_request.GetRequestStream().FlushAsync();

但这是错误的，因为它告诉我我正在引起 ProtocolViolationException 我猜是因为这是一个 GET 动词？

谁能告诉我如何强制连接将缓冲区转储到客户端？

已添加处理响应代码：

private void HandleResult(IAsyncResult result)
{
    using (var response = (HttpWebResponse) _request.EndGetResponse(result))
    using (var stream = response.GetResponseStream())
    using (var memory = new MemoryStream())
    {
        var compressedBuffer = new byte[BlockSize];

        while (stream != null && stream.CanRead)
        {
            var readCount = stream.Read(compressedBuffer, 0, compressedBuffer.Length);

            // if readCount is 0, then the stream must have disconnected.  Process and abort!
            if (readCount == 0)
            {

            }
        }
    }
}

Answer 1

无法使 HTTP 调用的服务器端以特定方式向您发送数据。 HTTP 和 TCP 都没有这方面的规定。你必须拿走你得到的东西，或者与供应商交谈。

Read 在缓冲区满之前不会阻塞。它给你立即到达的东西。这种行为是众所周知的，这不是我的猜测。

The 3rd party service send 15 second heartbeats CRLF which will also eventually fill up the buffer.

这听起来像是服务正在做您想要的。如果是这样，则问题一定出在您的代码中。但不在问题中显示的代码中。试试这个：

    while (true)
    {
        var readCount = stream.Read(compressedBuffer, 0, compressedBuffer.Length);
        Console.WriteLine(readCount);
    }

这应该每 15 秒显示 2 个字节。如果不是，则供应商有过错。如果是，那你就是。

while (stream != null && stream.CanRead) 这很奇怪，因为 none 这些条件可能变为假。即使它们变成假的，你会怎么做？！这应该是 while (true) 加上流耗尽时的 break。

// if readCount is 0, then the stream must have disconnected.

这种情况意味着远程端已经有序地完成了 HTTP 响应的发送。

Answer 2

对于任何感兴趣的人，您可以阅读并手动执行以下操作：

using (var response = (HttpWebResponse) _request.EndGetResponse(result))
using (var stream = response.GetResponseStream())
using (var compressedMemory = new MemoryStream())
using (var uncompressedMemory = new MemoryStream()) // Added new memory stream
using (var gzipStream = new GZipStream(compressedMemory, CompressionMode.Decompress))
{
    var compressedBuffer = new byte[BlockSize];

    while (stream != null && stream.CanRead)
    {
        var readCount = stream.Read(compressedBuffer, 0, compressedBuffer.Length);

        compressedMemory.Write(compressedBuffer.Take(readCount).ToArray(), 0, readCount);
        compressedMemory.Position = 0;

        gzipStream.CopyTo(uncompressedMemory); // use copy to rather than trying to read

        var outputString = Encoding.UTF8.GetString(uncompressedMemory.ToArray());
        Debug.WriteLine(outputString);

        uncompressedMemory.Position = 0;
        uncompressedMemory.SetLength(0);

        compressedMemory.Position = 0;
        compressedMemory.SetLength(0); // reset length
    }
}

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