// This method is invoked when an asynchronous send operation completes.
// The method issues another receive on the socket to read any additional
// data sent from the client
//
// <param name="e"></param>
private void ProcessSend(SocketAsyncEventArgs e)
{
if (e.SocketError == SocketError.Success)
{
// done echoing data back to the client
AsyncUserToken token = (AsyncUserToken)e.UserToken;
// read the next block of data send from the client
bool willRaiseEvent = token.Socket.ReceiveAsync(e);
if (!willRaiseEvent)
{
ProcessReceive(e);
}
}
else
{
CloseClientSocket(e);
}
}
private void ProcessAccept(SocketAsyncEventArgs e)
{
try
{
Interlocked.Increment(ref _clientCount);
// Get the socket for the accepted client connection and put it into the
//ReadEventArg object user token
SocketAsyncEventArgs readEventArgs = _pool.Pop();
AsyncUserToken userToken = (AsyncUserToken)readEventArgs.UserToken;
userToken.Socket = e.AcceptSocket;
userToken.ConnectTime = DateTime.Now;
userToken.Remote = e.AcceptSocket.RemoteEndPoint;
userToken.IPAddress = ((IPEndPoint)(e.AcceptSocket.RemoteEndPoint)).Address;
lock (clients) { clients.Add(userToken); }
if (ClientNumberChange != null)
{
ClientNumberChange(1, userToken);
}
if (!e.AcceptSocket.ReceiveAsync(readEventArgs))
{
ProcessReceive(readEventArgs);
}
}
catch (Exception me)
{
throw;
}
// Accept the next connection request
if (e.SocketError == SocketError.OperationAborted)
{
return;
}
StartAccept(e);
}
//关闭客户端
private void CloseClientSocket(SocketAsyncEventArgs e)
{
AsyncUserToken token = e.UserToken as AsyncUserToken;
lock (clients) { clients.Remove(token); }
//如果有事件,则调用事件,发送客户端数量变化通知
if (ClientNumberChange != null)
{
ClientNumberChange(-1, token);
}
// close the socket associated with the client
try
{
token.Socket.Shutdown(SocketShutdown.Send);
}
catch (Exception) { }
token.Socket.Close();
// decrement the counter keeping track of the total number of clients connected to the server
Interlocked.Decrement(ref _clientCount);
m_maxNumberAcceptedClients.Release();
// Free the SocketAsyncEventArg so they can be reused by another client
e.UserToken = new AsyncUserToken();
_pool.Push(e);
}
// This method is invoked when an asynchronous receive operation completes.
// If the remote host closed the connection, then the socket is closed.
// If data was received then the data is echoed back to the client.
//
/// <summary>
/// 接收数据
/// </summary>
/// <param name="e"></param>
private void ProcessReceive(SocketAsyncEventArgs e)
{
try
{
// check if the remote host closed the connection
AsyncUserToken token = (AsyncUserToken)e.UserToken;
if (e.BytesTransferred > 0 && e.SocketError == SocketError.Success)
{
//读取数据
byte[] data = new byte[e.BytesTransferred];
Array.Copy(e.Buffer, e.Offset, data, 0, e.BytesTransferred);
lock (token.Buffer)
{
token.Buffer.AddRange(data);
}
//注意:你一定会问,这里为什么要用do-while循环?
//如果当客户发送大数据流的时候,e.BytesTransferred的大小就会比客户端发送过来的要小,
//需要分多次接收.所以收到包的时候,先判断包头的大小.够一个完整的包再处理.
//如果客户短时间内发送多个小数据包时, 服务器可能会一次性把他们全收了.
//这样如果没有一个循环来控制,那么只会处理第一个包,
//剩下的包全部留在token.Buffer中了,只有等下一个数据包过来后,才会放出一个来.
do
{
//判断包的长度
byte[] lenBytes = token.Buffer.GetRange(0, 4).ToArray();
int packageLen = BitConverter.ToInt32(lenBytes, 0);
if (packageLen > token.Buffer.Count - 4)
{ //长度不够时,退出循环,让程序继续接收
break;
}
//包够长时,则提取出来,交给后面的程序去处理
byte[] rev = token.Buffer.GetRange(4, packageLen).ToArray();
//从数据池中移除这组数据
lock (token.Buffer)
{
token.Buffer.RemoveRange(0, packageLen + 4);
}
//将数据包交给后台处理,这里你也可以新开个线程来处理.加快速度.
if (ReceiveClientData != null)
{
ReceiveClientData(token, rev);
}
//这里API处理完后,并没有返回结果,当然结果是要返回的,却不是在这里, 这里的代码只管接收.
//若要返回结果,可在API处理中调用此类对象的SendMessage方法,统一打包发送.不要被微软的示例给迷惑了.
} while (token.Buffer.Count > 4);
//继续接收. 为什么要这么写,请看Socket.ReceiveAsync方法的说明
if (!token.Socket.ReceiveAsync(e))
{
this.ProcessReceive(e);
}
}
else
{
CloseClientSocket(e);
}
}
catch (Exception xe)
{
throw;
}
}