多线程客户端未从服务器接收消息

Multi-threaded client not receiving messages from server

本文关键字:消息 服务器 客户端 多线程      更新时间:2023-10-16

我有一个多客户端服务器程序。客户端控制台需要等待用户输入消息以发送到服务器,并且客户端还需要始终可用于从服务器接收消息(这种情况间歇性地发生(。为此,我尝试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(我从这里下载(旨在向服务器发送消息并立即接收消息。这是初始代码(我在这里没有包含函数,因为我知道它们有效,并且函数名称是不言自明的(:

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;
}

这段代码有效,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,这会阻碍客户端的进程,这就是为什么我使用如下多线程结构(由于上述原因不包括函数(,将接收和发送函数分成不同的线程:

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;
}

我已经测试了我已经正确设置了线程 - 但只有我的发送线程有效,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 - 我做错了什么吗?抱歉,如果问题不够清楚 - 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( - 目前我已经设置了它进行测试,以便当它收到来自客户端的消息时,它会立即"回复"(以便我可以在我的客户端上测试接收线程(。随后,它不会立即回复,但只有在有消息要传递给客户端时才回复。

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;
}

在多线程程序中,您正在创建两个客户端,一个在sendHandleThread中,另一个在recHandleThread中,并因此具有两个连接。当然,服务器通过客户端消息进入的连接发送其回复消息,即发送到sendHandleThread,后者不准备接收它,而recHandleThread通过其连接不接收任何内容,因为没有发送任何内容。若要纠正此问题,必须仅创建一个客户端连接,并让两个线程使用相同的连接。