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TCP/IP通信的客户端实现及服务器响应处理

最新推荐文章于 2022-10-12 15:21:10 发布

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#物联网 #c语言 #tcp/ip

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这是一个C语言实现的TCP/IP通信客户端和服务器的代码示例。客户端可以进行注册、登录、查询和查看历史记录的操作，服务器端处理这些请求并与数据库交互。代码中包含了SQLite数据库操作，用于存储用户信息和历史记录。

client.c

#include<stdio.h>
#include<string.h>
#include<sys/stat.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<linux/in.h>
#include<stdlib.h>

//消息数据包
typedef struct msg
{
   int type;//类型
   char name[128];//用户名
   char data[256];//内容
}MSG;
void do_register(int sockfd,MSG *msg);
int do_login(int sockfd,MSG *msg);
void do_query(int sockfd,MSG *msg);
void do_history(int sockfd,MSG *msg);
int main(int argc, const char *argv[])
{
   if(argc < 3)
   {
       printf("input : %s<ip> <port>\n",argv[0]);
       exit(0);
   }
   MSG msg;
   int login = 0;
   //创建套节字文件
   int sockfd;
   if((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0)
   {
       perror("sockfd err.\n");
       return -1;
   }
   printf("socket yes.\n");
   //填充结构体数组
   struct sockaddr_in serveraddr;
   serveraddr.sin_family = AF_INET;
   serveraddr.sin_port = htons(atoi(argv[2]));
   serveraddr.sin_addr.s_addr = inet_addr(argv[1]);

   //允许重用本地地址和端口号
   int optval = 1;
   socklen_t optval_len = sizeof(optval);
   setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,&optval,optval_len);

   socklen_t addrlen = sizeof(serveraddr);
   //连接服务器
   if(connect(sockfd,(struct sockaddr *)&serveraddr,addrlen) < 0)
   {
       perror("connect err.\n");
       return -1;
   }
   printf("connect yes\n");
   char buf[128] = {0};
   int n = 0;
   while(1)
   { //注册.登录.退出
       printf("*******************************\n");
       printf("* 1:register 2:login 3:quit *\n");
       printf("*******************************\n");
       printf("please choose>>>");
       if(scanf("%d",&n) == 0)
       {
           fgets(buf,sizeof(buf),stdin);
           buf[strlen(buf) -1] = '\0';
           continue;
       }
       switch(n)
       {
       case 1:
           do_register(sockfd,&msg);
           break;
       case 2:
           if(do_login(sockfd,&msg) == 1)
           {
               goto next;
           }
           break;
       case 3:
           close(sockfd);
           exit(0);
       }
   }

void do_register(int sockfd,MSG *msg)
{
   //封装注册msg包
   msg->type = 'R';
   printf("please user name:");
   scanf("%s",msg->name);
   printf("please user code:");
   scanf("%s",msg->data);
   //向服务器发送注册包
   send(sockfd,msg,sizeof(MSG),0);
   //接收服务器反馈
   recv(sockfd,msg,sizeof(MSG),0);
   printf("register: %s\n",msg->data);
   return;
}
int do_login(int sockfd,MSG *msg)
{
   //封装登录包
   msg->type = 'L';
   printf("please user name:");
   scanf("%s",msg->name);
   printf("please user code:");
   scanf("%s",msg->data);
   //发送登录消息
   send(sockfd,msg,sizeof(MSG),0);
   //接收服务器反馈
   recv(sockfd,msg,sizeof(MSG),0);
   //判断是否登录成功
   if(strncmp(msg->data,"OK",3) == 0)
   {
       printf("login OK.\n");
       return 1;
   }
   printf("login:%s\n",msg->data);
   return 0;
}
void do_query(int sockfd,MSG *msg)
{ //封装查询包
   msg->type = 'Q';
   while(1)
   {
       printf("query word:");
       scanf("%s",msg->data);
       if(strcmp(msg->data,"#") == 0)
           break;
//发送查询信号
       send(sockfd,msg,sizeof(MSG),0);
       //接收服务器反馈
       recv(sockfd,msg,sizeof(MSG),0);
       //printf优化解释,打印
   printf("%s\n",msg->data);

   }
   return ;
}
void do_history(int sockfd,MSG *msg)
{
   //封装历史查询包
   msg->type = 'H';
   send(sockfd,msg,sizeof(MSG),0);
   while(1)
   {
       recv(sockfd,msg,sizeof(MSG),0);
   if(   msg->data[0] == '\0')
       break;
       printf("%s\n",msg->data);
   }
   return;
}

Makefile

all:
   gcc server.c -lsqlite3 -o fwq
   gcc client.c -o khd

clean:
   rm fwq khd

Sever.c

#include<stdio.h>
#include<sqlite3.h>
#include<string.h>
#include<sys/stat.h>
#include<sys/types.h>
#include<sys/socket.h>

//消息数据包
typedef struct
{
   int type;//类型
   char name[128];//用户名
   char data[256];//内容
}MSG;
int callback(void *arg,int f_num,char **f_value,char **f_name);
void get_date(char *date);
int do_searchword(int acceptfd, MSG *msg);
void do_register(int acceptfd,MSG *msg,sqlite3 *db);
void do_login(int acceptfd,MSG *msg,sqlite3 *db);
void do_query(int acceptfd,MSG *msg,sqlite3 *db);
void do_history(int acceptfd,MSG *msg,sqlite3 *db);
int main(int argc, const char *argv[])
{
   if(argc < 3)
   {
       printf("input :%s,<ip> <port>\n",argv[0]);
       exit(0);
   }
   sqlite3 *db;
   char *errmsg = NULL;
   int sockfd,acceptfd;
   ssize_t recvaddr;
   MSG msg;
   char buf[128] = {0};
   //创建一个数据库文件
   if(sqlite3_open("str.db",&db) != 0)
   {
       fprintf(stderr,"sqlite3_open failed:%s\n",sqlite3_errmsg(db));
       return -1;
   }
   printf("open yes.\n");
   //添加一个用户信息表，key表明注册的用户名只能唯一
   if(sqlite3_exec(db,"create table str(name char primary key,code char);",NULL,NULL,&errmsg) != 0)
   {
       fprintf(stderr,"create str failed:%s\n",errmsg);
   }
   printf("exec yes.\n");
   //添加一个历史记录的表
   if(sqlite3_exec(db,"create table record(name char,time char,word char);",NULL,NULL,&errmsg) != 0)
   {
       fprintf(stderr,"create record failed:%s\n",errmsg);
   }
   //创建一个套节字文件
   if((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0)
   {
       perror("socket err.\n");
       return -1;
   }
   printf("socket yes.\n");
   //填充结构体数组
   struct sockaddr_in serveraddr,clinentaddr;
   serveraddr.sin_family = AF_INET;
   serveraddr.sin_port = htons(atoi(argv[2]));
   serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);

   //允许重用本地地址和端口号
   int optval = 1;
   socklen_t optval_len = sizeof(optval);
   setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,&optval,optval_len);

   socklen_t serverlen = sizeof(serveraddr);
   socklen_t clinentlen = sizeof(clinentaddr);
   //绑定
   if(bind(sockfd,(struct sockaddr *)&serveraddr,serverlen) < 0)
   {
       perror("bind err.\n");
       return -1;
   }
   printf("bind yes.\n");
   //监听
   if(listen(sockfd,8) < 0)
   {
       perror("listen err.\n");
       return -1;
   }
   printf("listen yes.\n");

   //信号处理函数
   signal(SIGCHLD,SIG_IGN);

   pid_t pid;
   while(1)
   { //阻塞等待连接
       if((acceptfd = accept(sockfd,NULL,NULL)) < 0)
       {
           perror("acceptfd err.\n");
           return -1;
       }
       printf("accept yes.\n");
       //创建进程
       if((pid = fork()) < 0)
       {
           perror("fork err.\n");
           return -1;
       }
       else if(pid == 0)
       {
           //循环接收客户端数据存放到msg包里
           while(recvaddr = recv(acceptfd,&msg,sizeof(msg),0) > 0)
           {
               //根据类型处理
               switch(msg.type)
               {
               case 'R'://.注册
                   do_register(acceptfd,&msg,db);
                   break;
               case 'L'://.登录
                   do_login(acceptfd,&msg,db);
                   break;
               case 'Q'://.查询的单词
                   do_query(acceptfd,&msg,db);
                   break;
               case 'H'://.历史记录
                   do_history(acceptfd,&msg,db);
                   break;
               }
           }
           printf("ip%sclient quit!!!!\n",(char *)inet_ntoa(clinentaddr.sin_addr.s_addr));
           close(acceptfd);
           exit(0);
       }
       else
       {
           printf("** user login. **\n");
       }
   }
   close(sockfd);
   return 0;
}