Linux下使用socket传输文件的C语言简单实现

简单的C语言实现，客户端通过TCP协议向服务器端请求传输的文件，服务器端收到请求后向客户端发送文件。

 

服务器程序和客户端程序应当分别运行在两台计算机上。

在运行服务器端的计算机终端执行：./file_server

在运行客户端的计算终端上执行：./file_client   ipaddr_server

然后根据提示输入要传输的服务器上的文件，该文件必须在服务器的当前运行目录中，否则会提示找不到文件。

 

直接上源码吧：

 

////////////////////////////////////////////////////////////////////////// file_server.c -- socket文件传输服务器端示例代码// /////////////////////////////////////////////////////////////////////#include<netinet/in.h>#include<sys/types.h>#include<sys/socket.h>#include<stdio.h>#include<stdlib.h>#include<string.h>#define HELLO_WORLD_SERVER_PORT    6666#define LENGTH_OF_LISTEN_QUEUE     20#define BUFFER_SIZE                1024#define FILE_NAME_MAX_SIZE         512int main(int argc, char **argv){// set socket's address information// 设置一个socket地址结构server_addr,代表服务器internet的地址和端口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(HELLO_WORLD_SERVER_PORT);// create a stream socket// 创建用于internet的流协议(TCP)socket，用server_socket代表服务器向客户端提供服务的接口int server_socket = socket(PF_INET, SOCK_STREAM, 0);if (server_socket < 0){printf("Create Socket Failed!\n");exit(1);}// 把socket和socket地址结构绑定if (bind(server_socket, (struct sockaddr*)&server_addr, sizeof(server_addr))){printf("Server Bind Port: %d Failed!\n", HELLO_WORLD_SERVER_PORT);exit(1);}// server_socket用于监听if (listen(server_socket, LENGTH_OF_LISTEN_QUEUE)){printf("Server Listen Failed!\n");exit(1);}// 服务器端一直运行用以持续为客户端提供服务while(1){// 定义客户端的socket地址结构client_addr，当收到来自客户端的请求后，调用accept// 接受此请求，同时将client端的地址和端口等信息写入client_addr中struct sockaddr_in client_addr;socklen_t          length = sizeof(client_addr);// 接受一个从client端到达server端的连接请求,将客户端的信息保存在client_addr中// 如果没有连接请求，则一直等待直到有连接请求为止，这是accept函数的特性，可以// 用select()来实现超时检测// accpet返回一个新的socket,这个socket用来与此次连接到server的client进行通信// 这里的new_server_socket代表了这个通信通道int new_server_socket = accept(server_socket, (struct sockaddr*)&client_addr, &length);if (new_server_socket < 0){printf("Server Accept Failed!\n");break;}char buffer[BUFFER_SIZE];bzero(buffer, sizeof(buffer));length = recv(new_server_socket, buffer, BUFFER_SIZE, 0);if (length < 0){printf("Server Recieve Data Failed!\n");break;}char file_name[FILE_NAME_MAX_SIZE + 1];bzero(file_name, sizeof(file_name));strncpy(file_name, buffer,strlen(buffer) > FILE_NAME_MAX_SIZE ? FILE_NAME_MAX_SIZE : strlen(buffer));FILE *fp = fopen(file_name, "r");if (fp == NULL){printf("File:\t%s Not Found!\n", file_name);}else{bzero(buffer, BUFFER_SIZE);int file_block_length = 0;while( (file_block_length = fread(buffer, sizeof(char), BUFFER_SIZE, fp)) > 0){printf("file_block_length = %d\n", file_block_length);// 发送buffer中的字符串到new_server_socket,实际上就是发送给客户端if (send(new_server_socket, buffer, file_block_length, 0) < 0){printf("Send File:\t%s Failed!\n", file_name);break;}bzero(buffer, sizeof(buffer));}fclose(fp);printf("File:\t%s Transfer Finished!\n", file_name);}close(new_server_socket);}close(server_socket);return 0;}

 

//////////////////////////////////////////////////////// file_client.c  socket传输文件的client端示例程序// ///////////////////////////////////////////////////#include<netinet/in.h>                         // for sockaddr_in#include<sys/types.h>                          // for socket#include<sys/socket.h>                         // for socket#include<stdio.h>                              // for printf#include<stdlib.h>                             // for exit#include<string.h>                             // for bzero#define HELLO_WORLD_SERVER_PORT       6666#define BUFFER_SIZE                   1024#define FILE_NAME_MAX_SIZE            512int main(int argc, char **argv){if (argc != 2){printf("Usage: ./%s ServerIPAddress\n", argv[0]);exit(1);}// 设置一个socket地址结构client_addr, 代表客户机的internet地址和端口struct sockaddr_in client_addr;bzero(&client_addr, sizeof(client_addr));client_addr.sin_family = AF_INET; // internet协议族client_addr.sin_addr.s_addr = htons(INADDR_ANY); // INADDR_ANY表示自动获取本机地址client_addr.sin_port = htons(0); // auto allocated, 让系统自动分配一个空闲端口// 创建用于internet的流协议(TCP)类型socket，用client_socket代表客户端socketint client_socket = socket(AF_INET, SOCK_STREAM, 0);if (client_socket < 0){printf("Create Socket Failed!\n");exit(1);}// 把客户端的socket和客户端的socket地址结构绑定if (bind(client_socket, (struct sockaddr*)&client_addr, sizeof(client_addr))){printf("Client Bind Port Failed!\n");exit(1);}// 设置一个socket地址结构server_addr,代表服务器的internet地址和端口struct sockaddr_in  server_addr;bzero(&server_addr, sizeof(server_addr));server_addr.sin_family = AF_INET;// 服务器的IP地址来自程序的参数if (inet_aton(argv[1], &server_addr.sin_addr) == 0){printf("Server IP Address Error!\n");exit(1);}server_addr.sin_port = htons(HELLO_WORLD_SERVER_PORT);socklen_t server_addr_length = sizeof(server_addr);// 向服务器发起连接请求，连接成功后client_socket代表客户端和服务器端的一个socket连接if (connect(client_socket, (struct sockaddr*)&server_addr, server_addr_length) < 0){printf("Can Not Connect To %s!\n", argv[1]);exit(1);}char file_name[FILE_NAME_MAX_SIZE + 1];bzero(file_name, sizeof(file_name));printf("Please Input File Name On Server.\t");scanf("%s", file_name);char buffer[BUFFER_SIZE];bzero(buffer, sizeof(buffer));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，此时buffer中存放的是客户端需要接收的文件的名字send(client_socket, buffer, BUFFER_SIZE, 0);FILE *fp = fopen(file_name, "w");if (fp == NULL){printf("File:\t%s Can Not Open To Write!\n", file_name);exit(1);}// 从服务器端接收数据到buffer中bzero(buffer, sizeof(buffer));int length = 0;while(length = recv(client_socket, buffer, BUFFER_SIZE, 0)){if (length < 0){printf("Recieve Data From Server %s Failed!\n", argv[1]);break;}int write_length = fwrite(buffer, sizeof(char), length, fp);if (write_length < length){printf("File:\t%s Write Failed!\n", file_name);break;}bzero(buffer, BUFFER_SIZE);}printf("Recieve File:\t %s From Server[%s] Finished!\n", file_name, argv[1]);// 传输完毕，关闭socketfclose(fp);close(client_socket);return 0;}