Question

我想知道是否有人遇到过这个：

我有一个WCF服务，它返回一个Stream（自定义我已创建）。

在下载过程中，可能是发生错误，我希望客户端知道它。

问题是，在下载过程中发生错误时，客户端流从Stream.Read接收“0字节”，并完成（成功）而不是异常/任何其他错误。

有什么解决方案吗？似乎WCF忽略了任何读取错误，然后才关闭流。

代码：

服务器：

public interface IService1
   {

      [OperationContract]
      [WebInvoke(Method = "GET",
         BodyStyle = WebMessageBodyStyle.Bare,
         ResponseFormat = WebMessageFormat.Json,
         UriTemplate = "Data")]
         Stream GetFileStream();
}


public class Service1 : IService1
   {

      public System.IO.Stream GetFileStream()
      {
         return new MyCustomStream();         
      }
}

实现：

 public class MyCustomStream : Stream
   {
      FileStream _Stream;

      private bool wasRead = false;
      public MyCustomStream()
      {
         _Stream = new FileStream(@"someFileOnDisk", FileMode.Open,
                              FileAccess.Read, FileShare.ReadWrite);

      }

~MyCustomStream()
      {
         if (_Stream != null)
         {
            _Stream.Dispose();
         }

      }

public override int Read(byte[] buffer, int offset, int count)
      {
         if (!wasRead)
         {
            wasRead = true;
            return _Stream.Read(buffer, offset, count);
         }
         else
         {
            throw new Exception("ERROR!!!!");
         }         
      }

public override void Close()
      {
         _Stream.Close();
      }

客户端：

internal static HttpWebRequest InitializeRequest(Uri url, string i_RelativeURL, int i_Timeout, string i_MethodType, string i_ContentType)
      {

         System.Net.HttpWebRequest newRequest = (HttpWebRequest)WebRequest.Create(CombineURI(url.AbsoluteUri, i_RelativeURL));
         newRequest.Proxy = null; // We are not using proxy
         newRequest.Timeout = i_Timeout;
         newRequest.Method = i_MethodType;
         newRequest.ContentType = i_ContentType;

         return newRequest;
      }

static void Main(string[] args)
      {
         HttpWebRequest request = InitializeRequest(new Uri(@"http://localhost/WCFTest/Service1.svc"), "data", 999999, "GET", "application/json");

         using (WebResponse response = request.GetResponse())
         {
            using (Stream curStream = response.GetResponseStream())
            {
               byte[] buffer = new byte[2000000]; // ~2MB
               int read = curStream.Read(buffer, 0, buffer.Length);
               int blockToWrite = read;
               while (read > 0)
               {
                  // If we reach to ~1MB of data - write it to the disk
                  if (blockToWrite >= 1000000)
                  {
                     blockToWrite = 0;
                  }

                  read = curStream.Read(buffer, blockToWrite, buffer.Length - blockToWrite); // Returns 0 if exception occurs on server side.
                  blockToWrite += read;
               }
            }
         }
}

通过Stream下载时WCF没有返回任何错误，并且中间发生错误

0 个答案: