Мне нужно обмениваться данными с двух машин с максимально возможной пропускной способностью. У меня есть сервер и клиент.
Клиенту необходимо отправить несколько сообщений на сервер (в реальном приложении 1 сообщение каждые 22 мс). Вместо того чтобы инициализировать сокет каждый раз, когда мне нужно что-то отправить, я хотел бы оставить соединение открытым и написать через сокет несколько сообщений, которые будут инициализированы раз и навсегда.
Вот мой клиент в C #:
using System;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.Text;
using System.Diagnostics;
// State object for receiving data from remote device.
public class StateObject
{
// Client socket.
public Socket workSocket = null;
// Size of receive buffer.
public const int BufferSize = 1024;
// Receive buffer.
public byte[] buffer = new byte[BufferSize];
// Received data string.
public StringBuilder sb = new StringBuilder();
}
public class AsynchronousClient
{
// The port number for the remote device.
private const int port = 11000;
// ManualResetEvent instances signal completion.
private static ManualResetEvent connectDone =
new ManualResetEvent(false);
private static ManualResetEvent sendDone =
new ManualResetEvent(false);
private static ManualResetEvent receiveDone =
new ManualResetEvent(false);
// The response from the remote device.
private static String response = String.Empty;
private static Socket InitClient()
{
// Connect to a remote device.
// Establish the remote endpoint for the socket.
// The name of the
IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName());
IPAddress ipAddress = ipHostInfo.AddressList[1];
IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);
// Create a TCP/IP socket.
Socket client = new Socket(ipAddress.AddressFamily,
SocketType.Stream, ProtocolType.Tcp);
try
{
// Connect to the remote endpoint.
client.BeginConnect(remoteEP,
new AsyncCallback(ConnectCallback), client);
connectDone.WaitOne();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
return client;
}
private static void SendData(Socket client) {
try {
// Send test data to the remote device.
StringBuilder a = new StringBuilder();
Send(client, "This is a test<EOF>");
sendDone.WaitOne();
// Receive the response from the remote device.
Receive(client);
receiveDone.WaitOne();
// Write the response to the console.
Console.WriteLine("Response received : {0}", response);
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
private static void ReleaseClient(Socket client) {
try
{
// Release the socket.
client.Shutdown(SocketShutdown.Both);
client.Close();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
private static void ConnectCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
Socket client = (Socket)ar.AsyncState;
// Complete the connection.
client.EndConnect(ar);
Console.WriteLine("Socket connected to {0}",
client.RemoteEndPoint.ToString());
// Signal that the connection has been made.
connectDone.Set();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
private static void Receive(Socket client)
{
try
{
// Create the state object.
StateObject state = new StateObject();
state.workSocket = client;
// Begin receiving the data from the remote device.
client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReceiveCallback), state);
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
private static void ReceiveCallback(IAsyncResult ar)
{
try
{
// Retrieve the state object and the client socket
// from the asynchronous state object.
StateObject state = (StateObject)ar.AsyncState;
Socket client = state.workSocket;
// Read data from the remote device.
int bytesRead = client.EndReceive(ar);
if (bytesRead > 0)
{
// There might be more data, so store the data received so far.
state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, bytesRead));
// Get the rest of the data.
client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReceiveCallback), state);
}
else
{
// All the data has arrived; put it in response.
if (state.sb.Length >= 1)
{
response = state.sb.ToString();
}
// Signal that all bytes have been received.
receiveDone.Set();
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
private static void Send(Socket client, String data)
{
// Convert the string data to byte data using ASCII encoding.
byte[] byteData = Encoding.ASCII.GetBytes(data);
// Begin sending the data to the remote device.
client.BeginSend(byteData, 0, byteData.Length, 0,
new AsyncCallback(SendCallback), client);
}
private static void SendCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
Socket client = (Socket)ar.AsyncState;
// Complete sending the data to the remote device.
int bytesSent = client.EndSend(ar);
Console.WriteLine("Sent {0} bytes to server.", bytesSent);
// Signal that all bytes have been sent.
sendDone.Set();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
public static int Main(String[] args)
{
Socket client = InitClient();
for (int i = 0; i < 2; i++) {
SendData(client);
}
ReleaseClient(client);
Console.ReadLine();
return 0;
}
А это сервер на Python:
import socketserver
import socket
class MyTCPHandler(socketserver.BaseRequestHandler):
def handle(self):
self.data = self.request.recv(87380).strip()
print("{} wrote:".format(self.client_address[1]))
l = (str(len(self.data)))
print(l)
self.request.sendall(l.encode())
HOST, PORT = socket.gethostname(), 11000
server = socketserver.TCPServer((HOST, PORT), MyTCPHandler)
server.socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
server.serve_forever()
Я могу подключиться к серверу, и если я звоню из C #:
InitClient();
SendData(client);
ReleaseClient(client);
Все отлично работает. Но если, как в моем примере, я пытаюсь перебрать SendData(), я могу отправить только первое сообщение, и при попытке отправить второе, сервер выдаст мне следующую ошибку:
System.Net.Sockets.SocketException (10053): An established connection was aborted by the software in your host machine
at System.Net.Sockets.Socket.BeginReceive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags, AsyncCallback callback, Object state)
at AsynchronousClient.Receive(Socket client) in C:\Users\giuli\source\repos\ApplicationSending\ApplicationSending\Program.cs:line 133 (NdR the lines that corresponds to:
client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReceiveCallback), state);)
Я не могу понять, что происходит. Разве нельзя отправлять несколько сообщений без повторной инициализации сокета?