基于TCP流协议的socket网络文件传输Demo：

实现：C语言
功能：文件传输（可以传任何格式的文件）

/*************************************************************************
	> File Name: Server.c
	> Author: SongLee
	> E-mail: lisong.shine@qq.com 
	> Created Time: 2014年03月13日 星期四 22时17分43秒
    > Personal Blog: http://songlee24.github.io/
 ************************************************************************/

#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;
}

/*************************************************************************
	> File Name: Client.c
	> Author: SongLee
	> E-mail: lisong.shine@qq.com 
	> Created Time: 2014年03月14日 星期五 09时41分46秒
    > Personal Blog: http://songlee24.github.io/
 ************************************************************************/

#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(file_name, "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;
}

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