我正在开发一个.NET应用程序，其中服务器通过TCP / IP将JPG压缩图像从网络摄像头发送到客户端。对于序列化/反序列化，我使用的是BinaryFormatter类。在我的台式计算机（客户端/ 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。使用LattePanda（服务器/ Windows 7）时，运行约3-5分钟后我收到以下错误（我每秒发送/接收30帧）：
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 ...
以下是服务器代码的片段：
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);
}
}
}
}
}
以下是客户端代码的摘录：
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();
}
}
为什么我只在一台机器而不在另一台机器上获得SerializationException的任何想法？安装了不同的mscorlib.dll库？如何检查相关（？）库的版本？
答案 0 :(得分：1)
以下是your answer的调整版本。现在，如果clientSocket.Available < 4和running == true您有一个空的while(true) { }循环。这将占用100％的一个cpu核心，没有任何有用的工作。
在系统I / O缓冲区中有4个字节之前，不要循环执行任何操作，而是使用与消息的有效负载相同的循环，并将其加载到标头的字节数组中。 （我还简化了将有效载荷数据读取到我不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，如果您从System.Net.Socket班级切换到System.Net.TcpClient班级，则可以大大简化您的代码。首先，如果您不需要TotalBytesRtpIn进行更新，则可以停止发送标头，反序列化不需要它，因为BinaryFormatter已将其长度存储为有效负载的内部字段。然后，您需要做的就是从TcpClient获取NetworkStream并在数据包进入时对其进行处理。
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();
}
}
答案 1 :(得分：0)
正如Scott建议的那样，我用更安全的方法替换了读取消息头部的不安全行：
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();
}
}
现在它运行得很完美:)非常感谢你的帮助！