[置顶] socket 编程实例

服务器部分：

#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

/*

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <unistd.h>

*/

#define HELLO_WORLD_SERVER_PORT    6666

#define LENGTH_OF_LISTEN_QUEUE 20

#define BUFFER_SIZE 1024

#define FILE_NAME_MAX_SIZE 512

 

int main(int argc, char **argv)

{

    //设置一个socket地址结构server_addr,代表服务器internet地址, 端口

    struct sockaddr_in server_addr;

    bzero(&server_addr,sizeof(server_addr)); //把一段内存区的内容全部设置为0

    server_addr.sin_family = AF_INET;

    server_addr.sin_addr.s_addr = htons(INADDR_ANY);

    server_addr.sin_port = htons(HELLO_WORLD_SERVER_PORT);

 

    //创建用于internet的流协议(TCP)socket,用server_socket代表服务器socket

    int server_socket = socket(PF_INET,SOCK_STREAM,0);

    if( server_socket < 0)

    {

        printf("Create Socket Failed!");

        exit(1);

    }

{

   int opt =1;

   setsockopt(server_socket,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt));

}

     

    //把socket和socket地址结构联系起来

    if( bind(server_socket,(struct sockaddr*)&server_addr,sizeof(server_addr)))

    {

        printf("Server Bind Port : %d Failed!", HELLO_WORLD_SERVER_PORT);

        exit(1);

    }

 

    //server_socket用于监听

    if ( listen(server_socket, LENGTH_OF_LISTEN_QUEUE) )

    {

        printf("Server Listen Failed!");

        exit(1);

    }

    while (1) //服务器端要一直运行

    {

        //定义客户端的socket地址结构client_addr

        struct sockaddr_in client_addr;

        socklen_t length = sizeof(client_addr);

 

        //接受一个到server_socket代表的socket的一个连接

        //如果没有连接请求,就等待到有连接请求--这是accept函数的特性

        //accept函数返回一个新的socket,这个socket(new_server_socket)用于同连接到的客户的通信

        //new_server_socket代表了服务器和客户端之间的一个通信通道

        //accept函数把连接到的客户端信息填写到客户端的socket地址结构client_addr中

        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, BUFFER_SIZE);

        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, FILE_NAME_MAX_SIZE+1);

        strncpy(file_name, buffer, strlen(buffer)>FILE_NAME_MAX_SIZE?FILE_NAME_MAX_SIZE:strlen(buffer));

//        int fp = open(file_name, O_RDONLY);

//        if( fp < 0 )

        printf("%s\n",file_name);

        FILE * fp = fopen(file_name,"r");

        if(NULL == fp )

        {

            printf("File:\t%s Not Found\n", file_name);

        }

        else

        {

            bzero(buffer, BUFFER_SIZE);

            int file_block_length = 0;

//            while( (file_block_length = read(fp,buffer,BUFFER_SIZE))>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,实际是给客户端

                if(send(new_server_socket,buffer,file_block_length,0)<0)

                {

                    printf("Send File:\t%s Failed\n", file_name);

                    break;

                }

                bzero(buffer, BUFFER_SIZE);

            }

//            close(fp);

            fclose(fp);

            printf("File:\t%s Transfer Finished\n",file_name);

        }

        //关闭与客户端的连接

        close(new_server_socket);

    }

    //关闭监听用的socket

    close(server_socket);

    return 0;

}

客户端部分：

//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

/*

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <unistd.h>

*/

 

#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internet地址, 端口

    struct sockaddr_in client_addr;

    bzero(&client_addr,sizeof(client_addr)); //把一段内存区的内容全部设置为0

    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);    //0表示让系统自动分配一个空闲端口

    //创建用于internet的流协议(TCP)socket,用client_socket代表客户机socket

    int client_socket = socket(AF_INET,SOCK_STREAM,0);

    if( client_socket < 0)

    {

        printf("Create Socket Failed!\n");

        exit(1);

    }

    //把客户机的socket和客户机的socket地址结构联系起来

    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, 端口

    struct sockaddr_in server_addr;

    bzero(&server_addr,sizeof(server_addr));

    server_addr.sin_family = AF_INET;

    if(inet_aton(argv[1],&server_addr.sin_addr) == 0) //服务器的IP地址来自程序的参数

    {

        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,连接成功后client_socket代表了客户机和服务器的一个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, 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

    send(client_socket,buffer,BUFFER_SIZE,0);

 

//    int fp = open(file_name, O_WRONLY|O_CREAT);

//    if( fp < 0 )

    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

    bzero(buffer,BUFFER_SIZE);

    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 = write(fp, buffer,length);

        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]);

     

    close(fp);

    //关闭socket

    close(client_socket);

    return 0;

}