c语言实现socket服务端/客户端通过tcp传送文件

服务端启动,客户端通过ip地址连接服务端,然后输入要发送的文件名,发送文件到服务段.

/*client.c*/
#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            512  

int 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socket  
    int 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socket   
    fclose(fp);  
    close(client_socket);  
    return 0;  

}  

/*server.c*/
#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         //端口号
#define LENGTH_OF_LISTEN_QUEUE     20
#define BUFFER_SIZE                1024
#define FILE_NAME_MAX_SIZE         512

int 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;
}

代码摘抄至网络.