scoket編程，實現文件傳輸

file_server.c

#include<netinet/in.h> // sockaddr_in
#include<sys/types.h>  // socket
#include<sys/socket.h> // socket
#include<stdio.h>    // printf
#include<stdlib.h>   // exit
#include<string.h>   // bzero

#define SERVER_PORT 8000
#define LENGTH_OF_LISTEN_QUEUE 20
#define BUFFER_SIZE 1024
#define FILE_NAME_MAX_SIZE 512

int main(void)
{
  // 聲明並初始化一個服務器端的socket地址結構
  struct sockaddr_in server_addr;
  bzero(&server_addr, sizeof(server_addr));
  server_addr.sin_family = AF_INET;
  server_addr.sin_addr.s_addr = htons(INADDR_ANY);
  server_addr.sin_port = htons(SERVER_PORT);

  // 建立socket，若成功，返回socket描述符
  int server_socket_fd = socket(PF_INET, SOCK_STREAM, 0);
  if(server_socket_fd < 0)
  {
    perror("Create Socket Failed:");
    exit(1);
  }
  int opt = 1;
  setsockopt(server_socket_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));

  // 綁定socket和socket地址結構
  if(-1 == (bind(server_socket_fd, (struct sockaddr*)&server_addr, sizeof(server_addr))))
  {
    perror("Server Bind Failed:");
    exit(1);
  }

  // socket監聽
  if(-1 == (listen(server_socket_fd, LENGTH_OF_LISTEN_QUEUE)))
  {
    perror("Server Listen Failed:");
    exit(1);
  }

  while(1)
  {

// 定義客戶端的socket地址結構
    struct sockaddr_in client_addr;
    socklen_t client_addr_length = sizeof(client_addr);
    // 接受鏈接請求，返回一個新的socket(描述符)，這個新socket用於同鏈接的客戶端通訊
    // accept函數會把鏈接到的客戶端信息寫到client_addr中
    int new_server_socket_fd = accept(server_socket_fd, (struct sockaddr*)&client_addr, &client_addr_length);
    if(new_server_socket_fd < 0)
    {
      perror("Server Accept Failed:");
      break;
    }

    // recv函數接收數據到緩衝區buffer中
    char buffer[BUFFER_SIZE];
    bzero(buffer, BUFFER_SIZE);
    if(recv(new_server_socket_fd, buffer, BUFFER_SIZE, 0) < 0)
    {
      perror("Server Recieve Data Failed:");
      break;
    }

    // 而後從buffer(緩衝區)拷貝到file_name中
    char file_name[FILE_NAME_MAX_SIZE+1];
    bzero(file_name, FILE_NAME_MAX_SIZE+1);
    strncpy(file_name, buffer, strlen(buffer)>FILE_NAME_MAX_SIZE?FILE_NAME_MAX_SIZE:strlen(buffer));
    printf("%s\n", file_name);

    // 打開文件並讀取文件數據
    FILE *fp = fopen(file_name, "r");
    if(NULL == fp)
    {
      printf("File:%s Not Found\n", file_name);
    }
    else
    {
      bzero(buffer, BUFFER_SIZE);
      int length = 0;
      // 每讀取一段數據，便將其發送給客戶端，循環直到文件讀完爲止
      while((length = fread(buffer, sizeof(char), BUFFER_SIZE, fp)) > 0)
      {
        if(send(new_server_socket_fd, buffer, length, 0) < 0)
        {
          printf("Send File:%s Failed./n", file_name);
          break;

         }
        bzero(buffer, BUFFER_SIZE);
      }

      // 關閉文件
      fclose(fp);
      printf("File:%s Transfer Successful!\n", file_name);
    }
    // 關閉與客戶端的鏈接
    close(new_server_socket_fd);
  }
  // 關閉監聽用的socket
  close(server_socket_fd);
  return 0;
}

 

 

file_client.c

#include<netinet/in.h>  // sockaddr_in
#include<sys/types.h>  // socket
#include<sys/socket.h>  // socket
#include<stdio.h>    // printf
#include<stdlib.h>    // exit
#include<string.h>    // bzero

#define SERVER_PORT 8000
#define BUFFER_SIZE 1024
#define FILE_NAME_MAX_SIZE 512

int main()
{
  // 聲明並初始化一個客戶端的socket地址結構
  struct sockaddr_in client_addr;
  bzero(&client_addr, sizeof(client_addr));
  client_addr.sin_family = AF_INET;
  client_addr.sin_addr.s_addr = htons(INADDR_ANY);
  client_addr.sin_port = htons(0);
  // 建立socket，若成功，返回socket描述符
  int client_socket_fd = socket(AF_INET, SOCK_STREAM, 0);
  if(client_socket_fd < 0)
  {
    perror("Create Socket Failed:");
    exit(1);
  }

  // 綁定客戶端的socket和客戶端的socket地址結構 非必需
  if(-1 == (bind(client_socket_fd, (struct sockaddr*)&client_addr, sizeof(client_addr))))
  {
    perror("Client Bind Failed:");
    exit(1);
  }

  // 聲明一個服務器端的socket地址結構，並用服務器那邊的IP地址及端口對其進行初始化，用於後面的鏈接
  struct sockaddr_in server_addr;
  bzero(&server_addr, sizeof(server_addr));
  server_addr.sin_family = AF_INET;
  if(inet_pton(AF_INET, "169.254.12.125", &server_addr.sin_addr) == 0)
  {        

   perror("Server IP Address Error:");
    exit(1);
  }
  server_addr.sin_port = htons(SERVER_PORT);
  socklen_t server_addr_length = sizeof(server_addr);

  // 向服務器發起鏈接，鏈接成功後client_socket_fd表明了客戶端和服務器的一個socket鏈接
  if(connect(client_socket_fd, (struct sockaddr*)&server_addr, server_addr_length) < 0)
  {
    perror("Can Not Connect To Server IP:");
    exit(0);
  }

  // 輸入文件名 並放到緩衝區buffer中等待發送
  char file_name[FILE_NAME_MAX_SIZE+1];
  bzero(file_name, FILE_NAME_MAX_SIZE+1);
  printf("Please Input File Name On Server:\t");
  scanf("%s", file_name);

  char buffer[BUFFER_SIZE];
  bzero(buffer, BUFFER_SIZE);
  strncpy(buffer, file_name, strlen(file_name)>BUFFER_SIZE?BUFFER_SIZE:strlen(file_name));

  // 向服務器發送buffer中的數據
  if(send(client_socket_fd, buffer, BUFFER_SIZE, 0) < 0)
  {
    perror("Send File Name Failed:");
    exit(1);
  }

  // 打開文件，準備寫入
  FILE *fp = fopen(file_name, "w");
  if(NULL == fp)
  {
    printf("File:\t%s Can Not Open To Write\n", file_name);
    exit(1);
  }

  // 從服務器接收數據到buffer中
  // 每接收一段數據，便將其寫入文件中，循環直到文件接收完並寫完爲止
  bzero(buffer, BUFFER_SIZE);
  int length = 0;
  while((length = recv(client_socket_fd, buffer, BUFFER_SIZE, 0)) > 0)
  {
    if(fwrite(buffer, sizeof(char), length, fp) < length)
    {
      printf("File:\t%s Write Failed\n", file_name);
      break;
    }
    bzero(buffer, BUFFER_SIZE);
  }

  // 接收成功後，關閉文件，關閉socket
  printf("Receive File:\t%s From Server IP Successful!\n", file_name);
  close(fp);
  close(client_socket_fd);
  return 0;
}

編譯命令：gcc xxx.c  -o  run

                     ./run