server.cpp

#include <cstddef>
#include <cstdlib>
#include <fstream>
#include <iostream>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <string>
#include <unistd.h>
#include <thread>
#include <vector>
#include <mutex>
#include <algorithm>

std::vector<int> clients;
std::mutex clients_mutex;


void broadcast_message(int sender_socket, const char* message, size_t length) {
  std::lock_guard<std::mutex> lock(clients_mutex);

  for(int client_socket : clients) {
    if (client_socket != sender_socket) {
      send(client_socket, message, length, 0);
    }
  }
}


int main() {

  int serverSocket = socket(AF_INET, SOCK_STREAM, 0);

  sockaddr_in serverAddress;
  serverAddress.sin_family = AF_INET;
  serverAddress.sin_port = htons(25575);
  serverAddress.sin_addr.s_addr = INADDR_ANY;

  bind(serverSocket, (struct sockaddr*)&serverAddress, sizeof(serverAddress));
  listen(serverSocket, 5);

  while(true) {
    int clientSocket = accept(serverSocket, nullptr, nullptr);
    std::cout << "Client connected.\n";

    {
      std::lock_guard<std::mutex> lock(clients_mutex);
      clients.push_back(clientSocket);
    }

    std::thread client_thread([clientSocket]() {
      while(true) {
        char buffer[1024] = {0};
        int bytes = recv(clientSocket, buffer, sizeof(buffer), 0);
            

        if (bytes > 0) {
          std::ofstream file("chatlog.txt", std::ios::app);
          
          std::string logMsg(buffer, bytes);
          std::cout << logMsg << std::endl;

          file << logMsg << "\n";
          file.flush();
          
          broadcast_message(clientSocket, buffer, bytes);

        } else if (bytes == 0) {
          std::cout << "Client disconnected.\n";
          break;
        } else {
          break;
        }
      }

      {
        std::lock_guard<std::mutex> lock(clients_mutex);
        clients.erase(std::remove(clients.begin(), clients.end(), clientSocket), clients.end());
      }
      close(clientSocket);
    });
    client_thread.detach();
  }  
  
  return 0;
}