Winsockで簡易サーバー

mini_server.hpp

/*
コールバック関数を持つサーバーを作れるサンプル

*/
#pragma comment(lib, "ws2_32.lib")

#include <WinSock2.h>
#include <list>

typedef void (*ONRECV)(const SOCKET socket, const char* data, const int data_length);
typedef void (*ONERROR)(const char* message, const int error_code);

void run_server(const char* ip_address, const unsigned short port, ONRECV on_recv, ONERROR on_error)
{
    // winsock 初期化
    WSADATA d;
    WSAStartup(MAKEWORD(2, 0), &d);

    // サーバー用ソケット作成
    SOCKET server_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    sockaddr_in server_address;
    server_address.sin_family = AF_INET;
    server_address.sin_addr.S_un.S_addr = inet_addr(ip_address);
    server_address.sin_port = htons(port);
    if (bind(server_socket, (sockaddr*)&server_address, sizeof(server_address)) != 0) {
        on_error("socket bind failed", GetLastError());
        return;
    }
    if (listen(server_socket, 5) != 0) {
        on_error("socket listen failed", GetLastError());
    }
    // ノンブロッキングにする
    u_long socket_mode = 1;
    ioctlsocket(server_socket, FIONBIO, &socket_mode);

    // クライアントリスト
    std::list<SOCKET> clients;

    while (true) {
        // 新しいクライアントの受け入れ
        sockaddr_in client_address = {0};
        int client_address_length = sizeof(client_address);
        SOCKET client = accept(server_socket, (sockaddr*)&client_address, &client_address_length);
        if (client != INVALID_SOCKET) {
            clients.push_back(client);
        }

        // 接続済のクライアントからの受信
        for (SOCKET client : clients) {
            char buffer[0xffff] = {0};
            int received_length = recv(client, buffer, 0xffff, 0);
            if (received_length < 1 && GetLastError() != WSAEWOULDBLOCK) {
                clients.remove(client);
                break;
            }
            if (received_length > 0) {
                on_recv(client, buffer, received_length);
            }
        }
        Sleep(10);
    }

    WSACleanup();
}