socket 编程实例

港控/mmm° 2022-08-03 16:33 266阅读 0赞

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;  
\}

`某些注释部分，open,read,write被``fopen``,``fread``,``fwrite``替换。`

`说明一下：`

`fopen``,``fclose``,` `fread``,``fwrite``,``fgetc``,` `fgets``,``fputc``,``fputs``,` `freopen``,``fseek``,``ftell``,` `rewind``等`

`缓冲文件系统`

`缓冲文件系统的特点是：在内存开辟一个“缓冲区”，为程序中的每一个文件使用，当执行读文件的操作时，`

`从磁盘文件将数据先读入内存“缓冲区”， 装满后再从内存“缓冲区”依此读入接收的变量。执行写文件的`

`操作时，先将数据写入内存“缓冲区”，待内存“缓冲区”装满后再写入文件。由此可以看出，内存`

`“缓冲区”的大小，影响着实际操作外存的次数，内存“缓冲区”越大，则操作外存的次数就少，`

`执行速度就快、效率高。一般来说，文件“缓冲区”的大小随机器 而定。`

`open, close, read, write,``getc``,` `getchar``,``putc``,``putchar` `等`

`非缓冲文件系统`

`非缓冲文件系统是借助文件结构体指针来对文件进行管理，通过文件指针来对文件进行访问，既可以读写字符、`