HttpWebRequest chunked/async POST

Question

嗨,我想将一些动态生成的内容上传到我的网络API.在客户端我使用HttpWebRequest.数据应该上传同步,我想写入流AFTER(!)我执行了HTTP请求.

(从服务器到客户端它确实工作正常,但从客户端到服务器我得到一些例外).

客户端实现如下:

HttpWebRequest httpWebRequest = HttpWebRequest.Create(myUrl) as HttpWebRequest;
httpWebRequest.Method = "POST";
httpWebRequest.Headers["Authorization"] = "Basic " + ... ;
httpWebRequest.PreAuthenticate = true;

httpWebRequest.SendChunked = true;
//httpWebRequest.AllowWriteStreamBuffering = false; //does not help...
httpWebRequest.ContentType = "application/octet-stream";
Stream st = httpWebRequest.GetRequestStream();

Task<WebResponse> response = httpWebRequest.GetResponseAsync();

// NOW: Write after GetResponse()

var b = Encoding.UTF8.GetBytes("Test1");
st.Write(b, 0, b.Length);

b = Encoding.UTF8.GetBytes("Test2");
st.Write(b, 0, b.Length);

b = Encoding.UTF8.GetBytes("Test3");
st.Write(b, 0, b.Length);

st.Close();

var x = response.Result;
Stream resultStream = x.GetResponseStream();
//do some output...

我在stream.write()上得到异常(NotSupportedException:流不支持并发IO读或写操作.).

为什么我这里有例外.有时第一次写入worke而后期写入会抛出异常.在开始时,stream.CanWrite属性为true,但在第一次或第二次或第四次写入后,它变为false ...然后在下一次写入时抛出异常.

编辑:更改AllowWriteStreamBuffering没有帮助

附录: 我发现了我的问题.此问题是由我的代码的顺序引起的.我必须按此顺序调用它:

• GetRequestStream(将异步写入流)(请求在第一次写入后发送到服务器)然后:
• GetResponseAsync()
• 的GetResponseStream()

我认为"GetResponseAsync"会触发客户端发送请求(现在只有标头).但是没有必要,因为在我将第一个比特写入流后,请求已经发送.

我问题的第二个原因:提琴手.(Fiddler目前仅支持响应流而不是请求)

Answer 1

我发现了我的问题.

我的代码顺序导致了问题.

解决方案是按此顺序调用它:

• GetRequestStream(将异步写入流)(请求在第一次写入后发送到服务器)然后:
• GetResponseAsync()
• 的GetResponseStream()

我的理解是"GetResponseAsync"触发客户端发送请求(现在只是头文件),但我发现它是一个不成功的步骤,因为请求已经在最初的几位写入之后发送了流.

我的问题的第二个原因是Fiddler,但Fiddler只支持响应流,而不支持请求.

该代码实现了引用,'HttpWebRequest'类:

HttpWebRequest httpWebRequest = HttpWebRequest.Create("http://xxx") as HttpWebRequest;
httpWebRequest.Method = "POST";
httpWebRequest.Headers["Authorization"] = "Basic " + Convert.ToBase64String(Encoding.ASCII.GetBytes("user:pw"));
httpWebRequest.PreAuthenticate = true;    
httpWebRequest.SendChunked = true;
httpWebRequest.AllowWriteStreamBuffering = false;
httpWebRequest.AllowReadStreamBuffering = false;    
httpWebRequest.ContentType = "application/octet-stream";

Stream st = httpWebRequest.GetRequestStream();

Console.WriteLine("Go");

try
{
    st.Write(buffer, 0, buffer.Length); //with the first write, the request will be send.
    st.Write(buffer, 0, buffer.Length);
    st.Write(buffer, 0, buffer.Length);

    for (int i = 1; i <= 10; i++)
    {        
        st.Write(buffer, 0, buffer.Length); //still writing while I can read on the stream at my ASP.NET web api

    }

}
catch (WebException ex)
{
    var y = ex.Response;

}
finally
{
    st.Close();

}

// Now we can read the response from the server in chunks

Task<WebResponse> response = httpWebRequest.GetResponseAsync();

Stream resultStream = response.Result.GetResponseStream();

byte[] data = new byte[1028];

int bytesRead;

while ((bytesRead = resultStream.Read(data, 0, data.Length)) > 0)
{
    string output = System.Text.Encoding.UTF8.GetString(data, 0, bytesRead);

    Console.WriteLine(output);

}

该代码实现了引用,'HttpClient'类:

HttpClientHandler ch = new HttpClientHandler();

HttpClient c = new HttpClient(ch);    
c.DefaultRequestHeaders.TransferEncodingChunked = true;    
c.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(Encoding.ASCII.GetBytes("user:pw")));

Stream stream = new MemoryStream();

AsyncStream asyncStream = new AsyncStream(); // Custom implementation of the PushStreamContent with the method, "WriteToStream()".

PushStreamContent streamContent = new PushStreamContent(asyncStream.WriteToStream);

HttpRequestMessage requestMessage = new HttpRequestMessage(new HttpMethod("POST"), "http://XXX") { Content = streamContent };

requestMessage.Headers.TransferEncodingChunked = true;

HttpResponseMessage response = await c.SendAsync(requestMessage, HttpCompletionOption.ResponseHeadersRead);

// The request has been sent, since the first write in the "WriteToStream()" method.

response.EnsureSuccessStatusCode();

Task<Stream> result = response.Content.ReadAsStreamAsync();

byte[] data = new byte[1028];

int bytesRead;

while ((bytesRead = await result.Result.ReadAsync(data, 0, data.Length)) > 0)
{
    string output = System.Text.Encoding.UTF8.GetString(data, 0, bytesRead);

    Console.WriteLine(output);

}

Console.ReadKey();