C＃ReceiveBufferSize显示不正确的值

Question

client.ReceiveBufferSize没有给出正确的接收字节大小。

所以我尝试使用client.Client.SendFile("FileName.png")而仍然给出相同的结果。我还做了一个检查，以确保它发送的图像超过64KB，它确实显示它发送超过64KB（从客户端）。

服务器代码：

TcpListener server = new TcpListener(IPAddress.Any,12345);
TcpClient client = server.AcceptTcpClient();
NetworkStream clientstream = client.GetStream();
                byte[] ImageByte = new byte[client.ReceiveBufferSize];
                int ReceiveCount = await clientstream.ReadAsync(ImageByte,0,ImageByte.Length);
                File.WriteAllBytes("Screenshot.png",ImageByte);

客户代码：

TcpClient client = new TcpClient();
client.Connect(IPAddress.Parse("123.456.789.123"), 12345);
                    byte[] imagebyte = File.ReadAllBytes("ImageCaptured.temp");
                    client.GetStream().Write(imagebyte, 0, imagebyte.Length);
                    File.Delete("ImageCaptured.temp");

client.ReceiveBufferSize假设显示大约128KB，但只显示高达64KB。

Answer 1

TCP不是同一字节[] out“系统中的”byte []。您可以将Write拆分为多个读取，甚至可以将多个写入组合到一个读取中。

您需要做的是在代码中实现Message Framing。这意味着您需要发送您的接收方理解的额外数据，以了解在单个“消息”中发送了多少数据。

这是一个非常简单的例子，其中长度在图片之前发送，然后另一边读取长度然后读取该字节数。

客户代码

using(TcpClient client = new TcpClient())
{
    client.Connect(IPAddress.Parse("123.456.789.123"), 12345);
    using (var clientStream = client.GetStream()) 
    {
        int imageLength = reader.ReadInt32();
        byte[] imagebyte = new byte[imageLength);
        int readBytes = 0;
        while (readBytes < imageLength)
        {
             int nextReadSize = Math.Min(client.Available, imageLength - readBytes);
             readBytes += await clientStream.ReadAsync(imagebyte, readBytes, nextReadSize);
        }
        File.WriteAllBytes("Screenshot.png",imageByte);
    }
}

服务器代码

TcpListener server = new TcpListener(IPAddress.Any,12345);
using(TcpClient client = await server.AcceptTcpClientAsync()) 
{
    byte[] imagebyte = File.ReadAllBytes("ImageCaptured.temp");
    using(BinaryWriter writer = new BinaryWriter(client.GetStream()))
    {
        writer.Write(imagebyte.Length)
        writer.Write(imagebyte, 0, imagebyte.Length);
    }
    File.Delete("ImageCaptured.temp");
}

请注意客户端，如果您没有计划关闭TcpClient并发送更多数据，则需要用using(BinaryWriter writer = new BinaryWriter(client.GetStream()))替换using(BinaryWriter writer = new BinaryWriter(client.GetStream(), Encoding.UTF8, true))