为什么我得到了SerializationException和BinaryFormatter？

Question

我正在开发一个.NET应用程序，在这个应用程序中，服务器通过TCP/IP将JPG压缩图像从摄像头发送到客户端。对于序列化/反序列化，我使用BinaryFormatter类。在我的桌面计算机(client/Windows 10)和我的笔记本电脑(服务器/Windows 10)之间进行测试时，从长远来看，一切正常。当使用LattePanda (server/Windows 7)时，在运行大约3-5分钟(每秒发送/接收30帧)之后，我会得到以下错误：

An unhandled exception of type 'System.Runtime.Serialization.SerializationException' occurred in mscorlib.dll

Additional information: The input stream is not a valid binary format. The starting contents (in bytes) are: 00-00-00-01-00-00-00-FF-FF-FF-FF-01-00-00-00-00-00 ...

下面是服务器代码的一个片段：

    private void distribute(Camera camera, Mat frame) {
        if(clientSockets!=null) {
            if(clientSockets.Count > 0) {
                if(camera.Streaming) {
                    // compress and encapsulate raw image with jpg algorithm
                    CameraImage packet = new CameraImage(camera.Id, frame, camera.CodecInfo, camera.EncoderParams);
                    packet.SystemId = Program.Controller.Identity.Id;
                    packet.SequenceNumber = curSeqNum;
                    byte[] content;
                    using(MemoryStream ms = new MemoryStream()) {
                        BinaryFormatter bf = new BinaryFormatter();
                        bf.Serialize(ms, packet);
                        content = ms.ToArray();
                    }
                    byte[] payload = new byte[content.Length+4];
                    // prefix with packet length
                    Array.Copy(BitConverter.GetBytes(content.Length), 0, payload, 0, 4);
                    // append payload after length header
                    Array.Copy(content, 0, payload, 4, content.Length);
                    // distribute to connected clients
                    this.distribute(payload);
                }
            }
        }
    }

    private void distribute(byte[] bytes) {
        if(Program.Launched) {
            lock(syncobj) {
                // distribute to connected clients
                for(int i=clientSockets.Count-1; i>=0; i--) {
                    try {
                        clientSockets[i].Send(bytes, bytes.Length, SocketFlags.None);
                    } catch(SocketException) {
                        clientSockets.RemoveAt(i);
                    }
                }
            }
        }
    }

下面是客户端代码的一个片段：

    private void receive() {
        try {
            while(running) {
                if((available = clientSocket.Receive(buffer, 4, SocketFlags.None)) > 0) {
                    // receive bytes from tcp stream
                    int offset = 0;
                    int bytesToRead = BitConverter.ToInt32(buffer, 0);
                    byte[] data = new byte[bytesToRead];
                    while(bytesToRead > 0) {
                        int bytesReceived = clientSocket.Receive(data, offset, bytesToRead, SocketFlags.None);
                        offset += bytesReceived;
                        bytesToRead -= bytesReceived;
                    }
                    // deserialize byte array to network packet
                    NetworkPacket packet = null;
                    using(MemoryStream ms = new MemoryStream(data)) {
                        BinaryFormatter bf = new BinaryFormatter();
                        packet = (NetworkPacket)bf.Deserialize(ms);
                    }
                    // deliver network packet to listeners
                    if(packet!=null) {
                        this.onNetworkPacketReceived?.Invoke(packet);
                    }
                    // update network statistics
                    NetworkStatistics.getInstance().TotalBytesRtpIn += data.Length;
                }
            }
        } catch(SocketException ex) {
            onNetworkClientDisconnected?.Invoke(agent.SystemId);
        } catch(ObjectDisposedException ex) {
            onNetworkClientDisconnected?.Invoke(agent.SystemId);
        } catch(ThreadAbortException ex) {
            // allows your thread to terminate gracefully
            if(ex!=null) Thread.ResetAbort();
        }
    }

你知道为什么我只在一台机器上得到SerializationException，而另一台机器没有吗？安装了不同的mscorlib.dll库？如何检查相关版本(?)图书馆？

Answer 1

下面是一个经过调整的your answer版本。现在，如果是clientSocket.Available < 4和running == true，则有一个空的while(true) { }循环。这将占用100%的cpu核心做什么有用的工作。

不要循环直到系统I/O缓冲区中有4个字节，而是使用与消息的有效负载相同的循环，并将其加载到字节数组中作为标题。(我还简化了将有效负载数据读取到异常使用的循环的循环。)

private void receive() {
    try {
        while(running) {
            int offset = 0;
            byte[] header = new byte[4];

            // receive header bytes from tcp stream
            while (offset < header.Length) {
                offset += clientSocket.Receive(header, offset, header.Length - offset, SocketFlags.None);
            }
                int bytesToRead = BitConverter.ToInt32(header, 0);
                // receive body bytes from tcp stream
                offset = 0;
                byte[] data = new byte[bytesToRead];
                while(offset < data.Length) {
                    offset += clientSocket.Receive(data, offset, data.Length - offset, SocketFlags.None);
                }
                // deserialize byte array to network packet
                NetworkPacket packet = null;
                using(MemoryStream ms = new MemoryStream(data)) {
                    BinaryFormatter bf = new BinaryFormatter();
                    packet = (NetworkPacket)bf.Deserialize(ms);
                }
                // deliver network packet to listeners
                if(packet!=null) {
                    this.onNetworkPacketReceived?.Invoke(packet);
                }
                // update network statistics 
                NetworkStatistics.getInstance().TotalBytesRtpIn += data.Length;
            }
        }
    } catch(SocketException ex) {
        onNetworkClientDisconnected?.Invoke(agent.SystemId);
    } catch(ObjectDisposedException ex) {
        onNetworkClientDisconnected?.Invoke(agent.SystemId);
    } catch(ThreadAbortException ex) {
        // allows your thread to terminate gracefully
        if(ex!=null) Thread.ResetAbort();
    }
}

但是，如果从System.Net.Socket类切换到System.Net.TcpClient类，则可以大大简化代码。首先，如果不需要TotalBytesRtpIn进行更新，就可以停止发送标头，因为BinaryFormatter已经将其长度作为有效负载的内部字段存储起来，因此不需要反序列化。然后，您所需要做的就是从NetworkStream获取TcpClient，并在数据包进入时进行处理。

private TcpClient _client; // Set this wherever you had your original Socket set up.

private void receive() {
    try {
        using(var stream = _client.GetStream()) {
            BinaryFormatter bf = new BinaryFormatter();
            while(running) {


#region This part is not needed if you are only going to deserialize the stream and not update TotalBytesRtpIn, make sure the server stops sending the header too!
                    int offset = 0;
                    byte[] header = new byte[4];

                    // receive header bytes from tcp stream
                    while (offset < header.Length) {
                        offset += stream.Read(header, offset, header.Length - offset);
                    }
                    int bytesToRead = BitConverter.ToInt32(header, 0);
#endregion
                    packet = (NetworkPacket)bf.Deserialize(stream);

                    // deliver network packet to listeners
                    if(packet!=null) {
                        this.onNetworkPacketReceived?.Invoke(packet);
                    }
                    // update network statistics
                    NetworkStatistics.getInstance().TotalBytesRtpIn += bytesToRead;
                }
            }
        }
    //These may need to get changed.
    } catch(SocketException ex) {
        onNetworkClientDisconnected?.Invoke(agent.SystemId);
    } catch(ObjectDisposedException ex) {
        onNetworkClientDisconnected?.Invoke(agent.SystemId);
    } catch(ThreadAbortException ex) {
        // allows your thread to terminate gracefully
        if(ex!=null) Thread.ResetAbort();
    }
}

Answer 2

正如Scott建议的那样，我用更安全的方法替换了读取消息头的不安全行：

    private void receive() {
        try {
            while(running) {
                if(clientSocket.Available>=4) {
                    // receive header bytes from tcp stream
                    byte[] header = new byte[4];
                    clientSocket.Receive(header, 4, SocketFlags.None);
                    int bytesToRead = BitConverter.ToInt32(header, 0);
                    // receive body bytes from tcp stream
                    int offset = 0;
                    byte[] data = new byte[bytesToRead];
                    while(bytesToRead > 0) {
                        int bytesReceived = clientSocket.Receive(data, offset, bytesToRead, SocketFlags.None);
                        offset += bytesReceived;
                        bytesToRead -= bytesReceived;
                    }
                    // deserialize byte array to network packet
                    NetworkPacket packet = null;
                    using(MemoryStream ms = new MemoryStream(data)) {
                        BinaryFormatter bf = new BinaryFormatter();
                        packet = (NetworkPacket)bf.Deserialize(ms);
                    }
                    // deliver network packet to listeners
                    if(packet!=null) {
                        this.onNetworkPacketReceived?.Invoke(packet);
                    }
                    // update network statistics
                    NetworkStatistics.getInstance().TotalBytesRtpIn += data.Length;
                }
            }
        } catch(SocketException ex) {
            onNetworkClientDisconnected?.Invoke(agent.SystemId);
        } catch(ObjectDisposedException ex) {
            onNetworkClientDisconnected?.Invoke(agent.SystemId);
        } catch(ThreadAbortException ex) {
            // allows your thread to terminate gracefully
            if(ex!=null) Thread.ResetAbort();
        }
    }

现在它运行得完美无缺:)非常感谢您的帮助！