在前面讲完了服务器从建立套接字、绑定、监听和提取，以及客户端的连接，我们已经可以动手实现一个简单的镜像服务器。

错误处理

在那之前，我们先封装一个错误处理函数 errif

可以定义一个uitl.cpp放里面，需要的地方引用即可

util.h

#ifndef UTIL_H
#define UTIL_H
​
void errif(bool, const char*);
​
#endif

util.cpp

#include "util.h"
#include <stdio.h>
#include <stdlib.h>
​
void errif(bool condition, const char *errmsg){if(condition){perror(errmsg);exit(EXIT_FAILURE);}
}

服务端代码

server.cpp

#include<stdio.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<string.h>
#include<unistd.h>
#include "util.h"
​
int main(){int socketfd = socket(AF_INET,SOCK_STREAM,0);errif(sockfd == -1 "socket crete error");struct sockaddr_in serv_addr;bzero(&serv_addr,sizeof(serv_addr));serv_addr.sin_family = AF_INET;serv_addr.sin_addr.s_addr = inet_addr("127.0.0.1");serv_addr.sin_port = htons(8888);errif(bind(sockfd,(sockaddr*)&serv_addr,sizeof(serv_addr)) == -1,"socket bind error");errif(listen(sockfd,SOMAXCONN) == -1,"socket listen error");struct sockaddr_in clnt_addr;socklen_t clnt_addr_len = sizeof(clnt_addr);bzero(&clnt_addr,sizeof(clnt_addr));int clnt_sockfd = accept(sockfd,(sockaddr*)&clnt_addr,&clnt_addr_len);errif(clnt_sockfd == -1,"socket accept error");printf("new client fd %d! IP:%s Port:%d\n",clnt_sockfd,inet_ntoa(clnt_addr.sin_addr),ntohs(clnt_addr.sin_port));//读写while (true) {char buf[1024];bzero(&buf,sizeof(buf));ssize_t read_bytes = read(clnt_sockfd,buf,sizeof(buf));if(read_bytes > 0){printf("message from client fd %d:%s",clnt_sockfd,buf);write(clnt_sockfd,buf,sizeof(buf));}else if(read_bytes == 0){printf("client fd %d disconnected\n",clnt_sockfd);close(clnt_sockfd);break;}else{close(clnt_sockfd);errif(true,"socket read error");}}close(sockfd);return 0;
}

客户端代码

client.cpp

#include <iostream>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <string.h>
#include <unistd.h>
#include "util.h"
​
int main(){int sockfd = socket(AF_INET,SOCK_STREAM,0);errif(sockfd == -1 "socket create error");struct sockaddr_in serv_addr;bzero(&serv_addr,sizeof(serv_addr));serv_addr.sin_family = AF_INET;serv_addr.sin_addr.s_addr = inet_addr("127.0.0.1");serv_addr.sin_port = htons(8888);errif(connect(sockfd,(sockaddr*)&serv_addr,sizeof(serv_addr)) == -1,"socket connect error");while(true){char buf[1024];bzero(&buf,sizeof(buf));scanf("%s",buf);ssize_t write_bytes = write(sockfd,buf,sizeof(buf));if(write_bytes == -1){printf("socket already disconnected, can't write any more!\n");break;}bzero(&buf,sizeof(buf));ssize_t read_bytes = read(sockfd,buf,sizeof(buf));if(read_bytes > 0){printf("message from server:%s",buf);}else if(read_bytes == 0){printf("server socket disconnected\n");break;}else{errif(true, "socket read error");break;}}close(sockfd);return 0;
}