Re: Send large block of data failed

From: Sami Vaaraniemi (samivawantsnospam_at_jippii.fi)
Date: 02/22/04 

Date: Sun, 22 Feb 2004 02:49:28 -0700

It would help if you told us which exception you get.

Nevertheless, it appears to me that the server expects to read all the data
that was sent in one read. This has a good chance of failing because when
you call stream.Read(body, 0, size) it can return anything from 0 to size
bytes (check out the documentation for NetworkStream.Read). To make sure you
get all the data that was sent, you need to call stream.Read in a loop:

    int size = BytesToInt(length);
    int pos = 0;
    while (size > 0)
    {
        int nread = stream.Read(body, pos, size);
        if (nread == 0) break; // connection was closed
        size -= nread;
        pos += nread;
    }

Sami
www.capehill.net

does not work because
"zhimin" <xiaozhimin1978@163.com> wrote in message
news:Oe44X9O%23DHA.2216@TK2MSFTNGP10.phx.gbl...
> Hi,
> I'm writing a program to send large file(100m) through dotnet using
> TCPListener & TCPClient, I'm sending the file with a ask and response
loop:
>
> 1. Client send a flag 1 to server indicate it has data send to server.
> 2. Client send the buffer block size.
> 3. Client send the actual buffer to the server.
> 4. Server send a flag 1 to client indicating that the buffer has been
> successfully receeived.
> 5. The next loop until all data of the file has been sent.
>
> When the data block is about 5k, the code works very fine, but when I set
> the block size up to about 10k, after some cycles, an exception raised and
> the program failed.
> The most strange is: the cycles number are different every time(with the
> same conditions), such as the first time I failed at the 13th loop, when
I'm
> runing the same pair of applications the next time, I might failed at the
> 17th loop with the same file.
>
> Any help would be appreciated.
>
> Thanks
>
> ps: the main code is listed below, the two cs files are attached.
>
> Client
> ---------------
> TcpClient client = new TcpClient(txtAddress.Text, 8000);
> client.SendBufferSize = 1024*1024;
> client.ReceiveBufferSize = 1024 * 1024;
> client.NoDelay = true;
>
> NetworkStream stream = client.GetStream();
> byte[] length = null;
> byte[] buffer = new byte[1024 *
> Int32.Parse(this.numSize.Value.ToString())];
> byte[] response = new byte[1];
>
> while(true)
> {
> // Read data from file
> size = fStream.Read(buffer, 0, buffer.Length);
> if(size == 0)
> {
> break;
> }
> Console.WriteLine("Time " + time + ", " + size);
> // Send a flag to indicate binary stream will be sent
>
> Console.WriteLine("Send flag ...");
> stream.WriteByte((byte)0);
> stream.Flush();
> length = this.IntToBytes(size);
>
> Console.WriteLine("Send length ..." + size);
> // Send a length message
> stream.Write(length, 0, length.Length);
>
> Console.WriteLine("Send buffer ... size = " + size + "(" +
> buffer.Length + ")");
> // Send data
> stream.Write(buffer, 0, size);
> stream.Flush();
>
> Console.WriteLine("Read response ...");
> // Waite for response
> stream.Read(response, 0, 1);
> Console.WriteLine("Response from server is: " + response[0]);
>
> time++;
> }
> stream.WriteByte((byte)1);
> stream.Flush();
> stream.Close();
> client.Close();
> fStream.Close();
> }
> catch(Exception ex)
> {
> Console.WriteLine("time="+time);
> Console.WriteLine(ex.Message);
> Console.WriteLine(ex.StackTrace);
> }
>
> Server
> ----------------
> int time = 0;
> TcpClient client = listener.AcceptTcpClient();
> client.SendBufferSize = 1024*1024;
> client.ReceiveBufferSize = 1024*1024;
> client.NoDelay = true;
> NetworkStream stream = client.GetStream();
>
> byte[] flag = new byte[1];
> byte[] length = new byte[4];
> byte[] body = new byte[1024 * 1024];
> byte[] response = new byte[]{(byte)1};
>
> string filename = "D:\\file.dat";
>
> if(File.Exists(filename))
> File.Delete(filename);
> FileStream fStream = File.OpenWrite("D:\\file.dat");
> try
> {
> while(true)
> {
> stream.Read(flag, 0, 1);
> Console.WriteLine("Read flag ... " + flag[0]);
> if(flag[0] == (byte)0)
> {
> stream.Read(length, 0, 4);
> int size = BytesToInt(length);
> Console.WriteLine("Read buffer size + " + size);
>
>
> size = stream.Read(body, 0, size);
> Console.WriteLine("Read buffer ...");
>
> Console.Write("Time " + time + ", " + size);
> fStream.Write(body, 0, size);
> fStream.Flush();
> Console.WriteLine(" Send response");
> stream.WriteByte(response[0]);
> stream.Flush();
>
> time++;
> }
> else
> {
> Console.WriteLine("flag = " + flag[0]);
> break;
> }
> }
> }
> catch(Exception e)
> {
> Console.WriteLine(e.Message);
> Console.WriteLine(e.StackTrace);
> }
>
> Console.WriteLine("server time = " + time);
> fStream.Close();
> stream.Close();
> client.Close();
>
>
>

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