backup.cpp

#include <iostream>
#include <cstdlib>
#include <string>
#include <cstring>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netdb.h>

int main(int argc, char **argv) {
  // You can use print statements as follows for debugging, they'll be visible when running tests.
  std::cout << "Logs from your program will appear here!\n";

  // Uncomment this block to pass the first stage
  //
  int server_fd = socket(AF_INET, SOCK_STREAM, 0);
  if (server_fd < 0) {
   std::cerr << "Failed to create server socket\n";
   return 1;
  }
  
  // Since the tester restarts your program quite often, setting SO_REUSEADDR
  // ensures that we don't run into 'Address already in use' errors
  int reuse = 1;
  if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse)) < 0) {
    std::cerr << "setsockopt failed\n";
    return 1;
  }
  
  struct sockaddr_in server_addr;
  server_addr.sin_family = AF_INET;
  server_addr.sin_addr.s_addr = INADDR_ANY;
  server_addr.sin_port = htons(6379);
  
  if (bind(server_fd, (struct sockaddr *) &server_addr, sizeof(server_addr)) != 0) {
    std::cerr << "Failed to bind to port 6379\n";
    return 1;
  }
  
  int connection_backlog = 5;
  if (listen(server_fd, connection_backlog) != 0) {
    std::cerr << "listen failed\n";
    return 1;
  }
  
  struct sockaddr_in client_addr;
  int client_addr_len = sizeof(client_addr);
  
  std::cout << "Waiting for a client to connect...\n";
  
  int client_fd = accept(server_fd, (struct sockaddr *) &client_addr, (socklen_t *) &client_addr_len);
  std::cout << "Client connected\n";
  const char *response ="+PONG\r\n";

  while (true) {
    char buffer[1024];
    int bytes_received = recv(client_fd, buffer, 1024, 0);
    if (bytes_received <= 0) {
      std::cout << "Client disconnected\n";
      break;
    }
    buffer[bytes_received] = '\0';
    std::cout << "Received from client: " << buffer << std::endl;
    send(client_fd, response, strlen(response), 0 );
  
  }
  
  close(server_fd);

  return 0;
}