C++连接到 C# 服务器的套接字

Question

我有一个使用 TcpClient 和流用 C# 编写的服务器。当我尝试使用 Winsock 连接到它并使用 C++ 应用程序接收数据时，我可以接收数据，但它有数据，但它还显示一堆其他数据。顺便说一句，我正在使用 cout 打印到缓冲区到控制台。

如果您想查看服务器应发送的内容，请转至 http://onenetworks.us:12345 。服务器将向您发送一个字符串。对我来说，它发送“16READY”，这就是我试图让我的客户只阅读的内容。

这是我的代码，我从 MSDN 页面复制了一个工作代码文件。

    #define WIN32_LEAN_AND_MEAN

#include <winsock2.h>
#include <Ws2tcpip.h>
#include <stdio.h>
#include <iostream>
// Link with ws2_32.lib
#pragma comment(lib, "Ws2_32.lib")

#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "12345"

int main() {

    //----------------------
    // Declare and initialize variables.
    WSADATA wsaData;
    int iResult;

    SOCKET ConnectSocket = INVALID_SOCKET;
    struct sockaddr_in clientService; 

    char *sendbuf = "";
    char recvbuf[DEFAULT_BUFLEN];
    int recvbuflen = DEFAULT_BUFLEN;

    //----------------------
    // Initialize Winsock
    iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
    if (iResult != NO_ERROR) {
        printf("WSAStartup failed: %d\n", iResult);
        return 1;
    }

    //----------------------
    // Create a SOCKET for connecting to server
    ConnectSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (ConnectSocket == INVALID_SOCKET) {
        printf("Error at socket(): %ld\n", WSAGetLastError() );
        WSACleanup();
        return 1;
    }

    //----------------------
    // The sockaddr_in structure specifies the address family,
    // IP address, and port of the server to be connected to.
    clientService.sin_family = AF_INET;
    clientService.sin_addr.s_addr = inet_addr( "199.168.139.14" );
    clientService.sin_port = htons( 12345 );

    //----------------------
    // Connect to server.
    iResult = connect( ConnectSocket, (SOCKADDR*) &clientService, sizeof(clientService) );
    if ( iResult == SOCKET_ERROR) {
        closesocket (ConnectSocket);
        printf("Unable to connect to server: %ld\n", WSAGetLastError());
        WSACleanup();
        return 1;
    }

    // Send an initial buffer
    iResult = send( ConnectSocket, sendbuf, (int)strlen(sendbuf), 0 );
    if (iResult == SOCKET_ERROR) {
        printf("send failed: %d\n", WSAGetLastError());
        closesocket(ConnectSocket);
        WSACleanup();
        return 1;
    }

    printf("Bytes Sent: %ld\n", iResult);

    // shutdown the connection since no more data will be sent
    iResult = shutdown(ConnectSocket, SD_SEND);
    if (iResult == SOCKET_ERROR) {
        printf("shutdown failed: %d\n", WSAGetLastError());
        closesocket(ConnectSocket);
        WSACleanup();
        return 1;
    }

    // Receive until the peer closes the connection
    do {

        iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0);
        std::cout << recvbuf <<std::endl;
        if ( iResult > 0 )
            printf("Bytes received: %d\n", iResult);
        else if ( iResult == 0 )
            printf("Connection closed\n");
        else
            printf("recv failed: %d\n", WSAGetLastError());

    } while(iResult > 0);

    // cleanup
    closesocket(ConnectSocket);
    WSACleanup();
    std::cin.ignore();
    //return 0;
}

Answer 1

仅打印接收到的字符，而不打印发送的整个缓冲区。 iResult 将包含接收到的数据的长度：

    iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0);
    if ( iResult > 0 )
    {
        printf("Bytes received: %d\n", iResult);
        std::cout << std::string(recvbuf, recvbuf+iResult) <<std::endl;

    }
    else if ( iResult == 0 )
        printf("Connection closed\n");
    else
        printf("recv failed: %d\n", WSAGetLastError());

Answer 2

缓冲区的长度设置为 DEFAULT_BUFLEN，因此您通过套接字接收到的任何内容都具有该长度。您可以循环遍历它的每个字符，直到找到值 0（或“\0”）。

Answer 3

你可以这样做：（

...
iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0);
recvbuf[iResult] = 0; // add this to zero terminate the receive buffer
std::cout << recvbuf <<std::endl;
...

当然它假设 iResult 小于 DEFAULT_BUFLEN）