多线程客户端未从服务器接收消息

时间：2013-03-01 02:16:25

标签： c++ sockets client-server client-side

我有一个多客户端服务器程序。客户端控制台将需要等待用户输入要发送到服务器的消息，并且客户端还需要始终可用于从服务器接收消息（这会间歇性地发生）。为了做到这一点，我试图在客户端设置两个线程，一个用于接收，一个用于发送。

最初，客户端程序（我从here下载）旨在向服务器发送消息并立即收到消息。这是初始代码（我没有在这里包含函数，因为我知道它们有效，函数名称不言自明）：

int main()
{
//initialize the winsock library
myTcpSocket::initialize();

//get client's information 
string clientName = clientInfo.getHostName();
string clientIPAddress = clientInfo.getHostIPAddress();

//get server's IP address and name
string serverIPAddress = "";
readServerConfig(serverIPAddress);

myHostInfo serverInfo(serverIPAddress,ADDRESS);
string serverName = serverInfo.getHostName();

//create the socket for client
myTcpSocket myClient(PORTNUM);

// connect to the server.
myClient.connectToServer(serverIPAddress, ADDRESS);

int recvBytes = 0;
while (1)
{
    // send message to server
    char messageToServer[MAX_MSG_LEN+1];
    memset(messageToServer, 0, sizeof(messageToServer));
    cout << "[SEND] ";
    cin.getline(messageToServer,MAX_MSG_LEN);

    winLog << "[SEND] " << messageToServer << endl;
    myClient.sendMessage(string(messageToServer));

    if ( !string(messageToServer).compare("Quit") || !string(messageToServer).compare("quit") ) 
        break;

    //receive message from server
    string messageFromServer = "";
    recvBytes = myClient.receiveMessage(messageFromServer);
    if ( recvBytes == -99 ) break;

    cout   << "[RECV:" << serverName << "]: " << messageFromServer << endl;
    winLog << "[RECV:" << serverName << "]: " << messageFromServer << endl;

}

return 1;
}

此代码有效，但由于服务器在收到消息时并不总是有消息要发送回客户端，这会在客户端保留进程，这就是我使用多线程结构的原因，如下所示（由于上述原因不包括的功能），将接收和发送功能分成不同的线程：

DWORD WINAPI sendHandleThread(LPVOID threadInfo) //sending thread
{
//this structure contains all the data this callback will work on
myThreadArgument* sendArgument = (myThreadArgument*)threadInfo;

//create the socket for client
myTcpSocket myClient(PORTNUM); //PORTNUM = 1200

// connect to the server.
string serverIPAddress = "";
readServerConfig(serverIPAddress);
myClient.connectToServer(serverIPAddress, ADDRESS);

myHostInfo serverInfo(serverIPAddress,ADDRESS);
string serverName = serverInfo.getHostName();

int recvBytes = 0;

while (1)
{
    // send message to server
    char messageToServer[MAX_MSG_LEN+1];
    memset(messageToServer, 0, sizeof(messageToServer));
    cout << "[SEND] ";
    cin.getline(messageToServer,MAX_MSG_LEN);

    winLog << "[SEND] " << messageToServer << endl;
    myClient.sendMessage(string(messageToServer));

    if ( !string(messageToServer).compare("Quit") || !string(messageToServer).compare("quit") ) 
        break;
}
return 1;
}

DWORD WINAPI recHandleThread(LPVOID threadInfo) //receiving thread
{
//this structure contains all the data this callback will work on
myThreadArgument* recArgument = (myThreadArgument*)threadInfo;

//create the socket for client
myTcpSocket myClient(PORTNUM); //PORTNUM = 1200

// connect to the server.
string serverIPAddress = "";
readServerConfig(serverIPAddress);
myClient.connectToServer(serverIPAddress, ADDRESS);

myHostInfo serverInfo(serverIPAddress,ADDRESS);
string serverName = serverInfo.getHostName();

int recvBytes = 0;

while (1)
{
    //receive message from server
    string messageFromServer = "";
    recvBytes = myClient.receiveMessage(messageFromServer);
    if ( recvBytes == -99 ) break;

    cout   << "[RECV:" << serverName << "]: " << messageFromServer << endl;
    winLog << "[RECV:" << serverName << "]: " << messageFromServer << endl;
}
return 1;
}

int main()
{
//semaphore
mySemaphore coutSemaphore(string(""), 1);

//initialize the winsock library
myTcpSocket::initialize();

//get client's information (assume neither the name nor the address is given)
string clientName = clientInfo.getHostName();
string clientIPAddress = clientInfo.getHostIPAddress();

//get server's IP address and name
string serverIPAddress = "";
readServerConfig(serverIPAddress);

myHostInfo serverInfo(serverIPAddress,ADDRESS);
string serverName = serverInfo.getHostName();

//create sending thread
myTcpSocket send;
string sendName = "sendName";
myThreadArgument* sendArgument = new myThreadArgument(&send, &coutSemaphore, sendName);
myThread* sendThread = new myThread(sendHandleThread, (void*)sendArgument);
sendThread->execute();

//create receiving thread
myTcpSocket rec;
string recName = "recName";
myThreadArgument* recArgument = new myThreadArgument(&rec, &coutSemaphore, recName);
myThread* recThread = new myThread(recHandleThread, (void*)recArgument);
recThread->execute();

while (1)
{

    //dummy process
    Sleep(30000);
    cout << "--" << endl;

}

return 1;
}

我已经测试过我已经正确设置了线程 - 但只有我的发送线程工作，即当用户输入消息时，它将被发送到服务器并由服务器接收。但是，我似乎无法从我的服务器收到消息。

我是新手 - 有什么我做错了吗？对不起，如果问题不够明确 - 我不知道还需要什么。

我的服务器代码的相关片段在这里供参考（我不知道是否需要更多，因为服务器部分似乎按照我需要的方式工作） - 目前我已将其设置为测试这样当它从客户端收到消息时，它会立即“回复”（这样我就可以在我的客户端上测试接收线程）。随后它不会立即回复，但只有当它有消息传递给客户端时才会回复。 

DWORD WINAPI clientHandleThread(LPVOID threadInfo)
{
     // this structure will contain all the data this callback will work on
     myThreadArgument* clientArgument = (myThreadArgument*)threadInfo;

   // get the client connection: receiving messages from client and
   // sending messages to the client will all be done by using
   // this client connection
   myTcpSocket* clientConnection = clientArgument->getClientConnect();
   string clientName = clientArgument->getHostName();

   // the server is communicating with this client here
   while(1)
   {
       string messageFromClient = "";

       // receive from the client

       int numBytes = clientConnection->recieveMessage(messageFromClient);
       if ( numBytes == -99 ) break;

       cout   << "[RECV fr " << clientName << "]: " << messageFromClient << endl;

       // if the client wants to disconnect
       if ( messageFromClient.compare("quit") == 0 || messageFromClient.compare("Quit") == 0 )
       {
           break;
       }
       else // send to the client
      {
           clientConnection->sendMessage(string("testing")); //test reply
       }
   }

   // if we reach here, this session with the client is done,
   // so we set the event on this thread to inform the main
  // control that this session is finished
   clientArgument->getExitEvent()->setEvent();
   return 1;
}

1 个答案:

答案 0 :(得分：0)

在您的多线程程序中，您创建了两个客户端，一个在sendHandleThread中，另一个在recHandleThread中，并且有两个连接。当然，服务器通过客户端消息进来的连接发送其回复消息，即。即到sendHandleThread，它不准备接收它，而recHandleThread在它的连接上没有收到任何东西，因为那里没有发送任何东西。 要解决这个问题，您必须只创建一个客户端连接，并让两个线程使用相同的连接。

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