在這個段落,我會跟著參考資料的 YoutTube 影片用 C++來實作一個 TCP Server ,那就馬不停蹄的開始吧~

C++ Implementation on TCP Server

  • 首先用 Visula Studio 2022 建立一個空的 C++ 專案,然後在來源檔案的資料夾中新增一個 C++的檔案命名為 main.cpp

    先將一些基本的部分加到 main.cpp ,note: pragma comment 是用來鏈結外部的 Lib 檔案:

    #include <iostream>
    #include <WS2tcpip.h>
    #pragma comment (lib, "ws2_32.lib")
    using namespace std;
    void main()
    
  • 使用註解來先宣告要做的事情<-這個是我在一些外國的程式講師發現的用法
  • 個人覺得對寫程式很有用,能夠整理歸納你的程式邏輯,定義出你程式整體流程(flow),並且能夠再次確認你的程式流程是否符合邏輯

    main.cpp

    void main()
    	// Initialize winsocket
    	// Create a socket
    	// Bind the socket to an ip address and port
    	// Tell winsocket the socket is for listening
    	// Wait for connection
    	// Close listening socket
    	// While loop: accept amd echo message back to client
    	// Close the socket
    	// Shutdown winsocket
    
  • 接下來就接著各個註解的動作開始實作
  • main.cpp

    // Initialize winsocket
    WSADATA wsDaata;
    WORD ver = MAKEWORD(2, 2);
    int wsOk = WSAStartup(ver, &wsDaata);
    if (wsOk != 0)
        cerr << "Can't Initialize winsocket! Quitting" << endl;
        return;
    // Create a socket
    SOCKET listening = socket(AF_INET, SOCK_STREAM, 0);
    if (listening == INVALID_SOCKET)
        cerr << "Can't create a socket! Quitting" << endl;
        return;
    // Bind the ip address and port to a socket
    sockaddr_in hint;
    hint.sin_family = AF_INET;
    hint.sin_port = htons(54000);
    hint.sin_addr.S_un.S_addr = INADDR_ANY;// Could also use inet_pton ...
    bind(listening, (sockaddr*)&hint, sizeof(hint));
    // Tell winsocket the socket is for listening
    listen(listening, SOMAXCONN);
    // Wait for connection
    sockaddr_in client;
    int clientSize = sizeof(client);
    SOCKET clientSocket = accept(listening, (sockaddr*)&client, &clientSize);
    char host[NI_MAXHOST];      // Client's remote name
    char service[NI_MAXHOST];   // Service (i.e. port) the client is connect on
    ZeroMemory(host, NI_MAXHOST);    // Window version, same as memset(host, 0, NI_MAXHOST);
    ZeroMemory(service, NI_MAXHOST);
    if (getnameinfo((sockaddr*)&client, sizeof(client),host,NI_MAXHOST, service, NI_MAXHOST,0) == 0)
        cout << host << " connected on port " << service << endl;
        inet_ntop(AF_INET, &client.sin_addr, host, NI_MAXHOST);
        cout << host << " connected on port " <<
            ntohs(client.sin_port) << endl;
    // Close listening socket
    closesocket(listening);
    // While loop: accept amd echo message back to client
    char buf[4096];
    while (true)
        ZeroMemory(buf, 4096);
        // Wait for client to snd data
        int bytesReceived = recv(clientSocket, buf, 4096, 0);
        if (bytesReceived == SOCKET_ERROR)
            cerr << "Error in recv(). Quitting" << endl;
            break;
        if (bytesReceived == 0)
            cout << "Client disconnected " << endl;
            break;
        // Echo message back to client
        send(clientSocket, buf, bytesReceived + 1, 0);
    // Close the socket
    closesocket(clientSocket);
    // Shutdown winsocket
    WSACleanup();
    

    上面都完成了後,使用CTRL + B來建置我們的程式

    驗證這個 TCP Server,會使用Putty來測試

    a. 在 Visual Studio 2022 按F5,啟動程式
    b. 打開 Putty,Host Name 輸入: 127.0.0.1,Port: 54000,Connection Type: Raw,因為我們的 TCP 只是最簡單的 protocol,所以其他的類別都不支援
    c. 在 Putty 打些內容並按Enter送出,可以收到 Server 的回覆
    https://ithelp.ithome.com.tw/upload/images/20221008/201119967dVNiTw7Ly.png

    那到此為止,就完整的實作了一個 TCP Server 了~

    那 30 天重新認識 C++的部分,就先到這邊啦,在剩餘的 6 天我會再介紹剩下幾個主題~

  • Quick info OpenCV
  • C++ Vector, define, header file
  • Design pattern for Singleton, Template, State
  • More things in C++ concurrency, parallelism
  • Tree algorithm in C++
  • Creating a TCP Server in C++
    What pragma comment actually do

  •