Linux网络编程之socket文件传输示例

本文所述示例程序是基于Linux平台的socket网络编程，实现文件传输功能。该示例是基于TCP流协议实现的socket网络文件传输程序。采用C语言编写。最终能够实现传输任何格式文件的文件传输程序。

代码：

服务器端（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) {   // 声明并初始化一个服务器端的socket地址结构   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);      // 创建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));      // 绑定socket和socket地址结构   if(-1 == (bind(server_socket_fd, (struct sockaddr*)&server_addr, sizeof(server_addr))))   {     perror("Server Bind Failed:");     exit(1);   }        // socket监听   if(-1 == (listen(server_socket_fd, LENGTH_OF_LISTEN_QUEUE)))   {     perror("Server Listen Failed:");     exit(1);   }      while(1)   {     // 定义客户端的socket地址结构     struct sockaddr_in client_addr;     socklen_t client_addr_length = sizeof(client_addr);        // 接受连接请求，返回一个新的socket(描述符)，这个新socket用于同连接的客户端通信     // accept函数会把连接到的客户端信息写到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函数接收数据到缓冲区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;     }        // 然后从buffer(缓冲区)拷贝到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);        // 打开文件并读取文件数据     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;       // 每读取一段数据，便将其发送给客户端，循环直到文件读完为止       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);       }          // 关闭文件       fclose(fp);       printf("File:%s Transfer Successful!\n", file_name);     }     // 关闭与客户端的连接     close(new_server_socket_fd);   }   // 关闭监听用的socket   close(server_socket_fd);   return 0; }

客户端（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() {   // 声明并初始化一个客户端的socket地址结构   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);      // 创建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);   }      // 绑定客户端的socket和客户端的socket地址结构 非必需   if(-1 == (bind(client_socket_fd, (struct sockaddr*)&client_addr, sizeof(client_addr))))   {     perror("Client Bind Failed:");     exit(1);   }      // 声明一个服务器端的socket地址结构，并用服务器那边的IP地址及端口对其进行初始化，用于后面的连接   struct sockaddr_in server_addr;   bzero(&server_addr, sizeof(server_addr));   server_addr.sin_family = AF_INET;   if(inet_pton(AF_INET, "127.0.0.1", &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);      // 向服务器发起连接，连接成功后client_socket_fd代表了客户端和服务器的一个socket连接   if(connect(client_socket_fd, (struct sockaddr*)&server_addr, server_addr_length) < 0)   {     perror("Can Not Connect To Server IP:");     exit(0);   }      // 输入文件名 并放到缓冲区buffer中等待发送   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));        // 向服务器发送buffer中的数据   if(send(client_socket_fd, buffer, BUFFER_SIZE, 0) < 0)   {     perror("Send File Name Failed:");     exit(1);   }      // 打开文件，准备写入   FILE *fp = fopen("/home/yuan/jdk-8u5-linux-x641.tar.gz", "w");   if(NULL == fp)   {     printf("File:\t%s Can Not Open To Write\n", file_name);     exit(1);   }      // 从服务器接收数据到buffer中   // 每接收一段数据，便将其写入文件中，循环直到文件接收完并写完为止   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);   }      // 接收成功后，关闭文件，关闭socket   printf("Receive File:\t%s From Server IP Successful!\n", file_name);   close(fp);   close(client_socket_fd);   return 0; }