一，概述
基于C语言的网络电子词典项目，使用到了tcp协议的并发服务器设计、网络编程、文件I/O、数据库等多方面的知识。可以满足多用户同时登陆，用户登陆后可以查询单词及历史记录，具有查找快速，保密性好等优点。
开发工具: Linux平台GCC交叉编译环境
功能描述：
1、可进行用户注册、登录
2、可对用户查找的单词进行存储，放入SQLite数据库中，对历史记录进行查询。
3、可进行查看和修改用户信息，包括用户名，密码等
4、分为客户端和服务器端，客户端进行用户的注册登录和查找单词等操作，服务器端进行操作数据库，进行存储和查找
项目框架
二，需求分析
1.注册：若用户名已经注册过，可重新注册
2.登录：用户名或密码错误需重新登录
3.查询：输入要查的单词，#键结束查询
4.历史：可以查询当前用户历史查找过的单词
5.退出：退出在线词典
server服务端(流程图)
client客户端
三，项目流程
1.首先搭建一个tcp客户端，一级界面包含组成、登录、退出，二级界面包含单词查询、历史记录、退出。
2.由客户端首先进入注册界面，输入注册的账号和密码，账号和密码就传入到user数据库中保存。再进入登录界面，输入账号和密码，当匹配到user数据库中有相同的账号和密码的时候，就进入二级界面。选择单词查询，输入查询的单词后，匹配dict数据库中的单词，找到该单词后返回单词在数据库中的注释，同时记录进去一条历史记录。选择历史记录，就可调出本次查询的单词、查询时间等信息。选择退出后结束该程序。
四，实战代码：
(1)客服端开发：
主程序
int main(int argc, const char *argv[])
{int sockfd;int n;MSG msg;if(argc != 3){printf("Usage:%s serverip port.\n", argv[0]);return -1;}if((sockfd = socket(AF_INET, SOCK_STREAM,0)) < 0){perror("fail to socket.\n");return -1;}struct sockaddr_in serveraddr;bzero(&serveraddr, sizeof(serveraddr));serveraddr.sin_family = AF_INET;serveraddr.sin_addr.s_addr = inet_addr(argv[1]);serveraddr.sin_port = htons(atoi(argv[2]));if(connect(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) < 0){perror("fail to connect");return -1;}char buf[100];while(1){printf("*****************************************************************\n");printf("* 1.register 2.login 3.quit *\n");printf("*****************************************************************\n");printf("Please choose:");fgets(buf, sizeof(buf), stdin);n = atoi(buf);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);break;default:printf("Invalid data cmd.\n");}}next:while(1){printf("*****************************************************\n");printf("* 1.query_word 2.history_record 3.quit *\n");printf("*****************************************************\n");printf("Please choose:");fgets(buf, sizeof(buf), stdin);n = atoi(buf);switch(n){case 1:do_query(sockfd, &msg);break;case 2:do_history(sockfd, &msg);break;case 3:close(sockfd);exit(0);break;default :printf("Invalid data cmd.\n");}}return 0;
}函数——注册
//注册
int do_register(int sockfd, MSG *msg)
{msg->type = R;printf("Input name:");scanf("%s", msg->name);getchar();printf("Input passwd:");scanf("%s", msg->data);getchar();if(send(sockfd, msg, sizeof(MSG),0) < 0){printf("fail to send.\n");return -1;}if(recv(sockfd, msg, sizeof(MSG), 0) < 0){printf("Fail to recv.\n");return -1;}// ok ! or usr alread exist.printf("%s\n", msg->data);return 0;
}函数——登录
//登陆
int do_login(int sockfd, MSG *msg)
{msg->type = L;printf("Input name:");scanf("%s", msg->name);getchar();printf("Input passwd:");scanf("%s", msg->data);getchar();if(send(sockfd, msg, sizeof(MSG),0) < 0){printf("fail to send.\n");return -1;}if(recv(sockfd, msg, sizeof(MSG), 0) < 0){printf("Fail to recv.\n");return -1;}if(strncmp(msg->data, "OK", 3) == 0){printf("Login ok!\n");return 1;}else {printf("%s\n", msg->data);}return 0;
}
登录——查询
//查询
int do_query(int sockfd, MSG *msg)
{msg->type = Q;puts("--------------");while(1){printf("Input word:");scanf("%s", msg->data);getchar();//客户端，输入#号，返回到上一级菜单if(strncmp(msg->data, "#", 1) == 0)break;//将要查询的单词发送给服务器if(send(sockfd,msg, sizeof(MSG), 0) < 0){printf("Fail to send.\n");return -1;}// 等待接受服务器，传递回来的单词的注释信息if(recv(sockfd, msg,sizeof(MSG), 0) < 0){printf("Fail to recv.\n");return -1;}printf("%s\n", msg->data);}return 0;
}
函数——历史
//历史
int do_history(int sockfd, MSG *msg)
{msg->type = H;send(sockfd, msg, sizeof(MSG), 0);// 接受服务器，传递回来的历史记录信息while(1){recv(sockfd, msg, sizeof(MSG), 0);if(msg->data[0] == '\0')break;//输出历史记录信息printf("%s\n", msg->data);}return 0;
}
服务器开发：
主程序
//0主函数
int main(int argc, const char *argv[])
{int sockfd;struct sockaddr_in serveraddr;int n;MSG msg;sqlite3 *db;int acceptfd;pid_t pid;char *errmsg;if(argc != 3){printf("Usage:%s serverip port.\n", argv[0]);return -1;}
/*************************************************///打开数据库if(sqlite3_open(DATABASE, &db) != SQLITE_OK){printf("%s\n", sqlite3_errmsg(db));return -1;}elseprintf("open DATABASE success.\n");if(sqlite3_exec(db, "create table if not exists usr(name text primary key,pass text);",//primary key主关键字只能有一个NULL, NULL, &errmsg) != SQLITE_OK){printf("%s\n", errmsg);}elseprintf("Create or open usr table success.\n");if(sqlite3_exec(db, "create table if not exists record(name text ,data text,word text);",NULL, NULL, &errmsg) != SQLITE_OK){printf("%s\n", errmsg);}elseprintf("Create or open record table success.\n");
/*************************************************/if((sockfd = socket(AF_INET, SOCK_STREAM,0)) < 0){perror("fail to socket.\n");return -1;}bzero(&serveraddr, sizeof(serveraddr));serveraddr.sin_family = AF_INET;serveraddr.sin_addr.s_addr = inet_addr(argv[1]);serveraddr.sin_port = htons(atoi(argv[2]));if(bind(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) < 0){perror("fail to bind.\n");return -1;}// 将套接字设为监听模式if(listen(sockfd, 5) < 0){printf("fail to listen.\n");return -1;}//处理僵尸进程signal(SIGCHLD,sig_child_handle);while(1){if((acceptfd = accept(sockfd, NULL, NULL)) < 0){perror("fail to accept");return -1;}if((pid = fork()) < 0){perror("fail to fork");return -1;}else if(pid == 0) // 儿子进程{//处理客户端具体的消息close(sockfd);do_client(acceptfd, db);}else // 父亲进程,用来接受客户端的请求的{close(acceptfd);}}return 0;
}函数——登录进入
//1登陆
int do_client(int acceptfd, sqlite3 *db)
{MSG msg;while(recv(acceptfd, &msg, sizeof(msg), 0) > 0){printf("type:%d\n", msg.type);switch(msg.type){case R:do_register(acceptfd, &msg, db);break;case L:do_login(acceptfd, &msg, db);break;case Q:do_query(acceptfd, &msg, db);break;case H:do_history(acceptfd, &msg, db);break;default:printf("Invalid data msg.\n");}}printf("client exit.\n");close(acceptfd);exit(0);return 0;
}
函数——注册
//2注册
void do_register(int acceptfd, MSG *msg, sqlite3 *db)
{char * errmsg;char sql[500];sprintf(sql, "insert into usr values('%s', %s);", msg->name, msg->data);printf("%s\n", sql);if(sqlite3_exec(db,sql, NULL, NULL, &errmsg) != SQLITE_OK){printf("%s\n", errmsg);strcpy(msg->data, "usr name already exist.");}else{printf("client register ok!\n");strcpy(msg->data, "OK!");}if(send(acceptfd, msg, sizeof(MSG), 0) < 0){perror("fail to send");return ;}return ;
}
函数——登录
//3登陆
int do_login(int acceptfd, MSG *msg , sqlite3 *db)
{char sql[500] = {};char *errmsg;int nrow;int ncloumn;char **resultp;sprintf(sql, "select * from usr where name = '%s' and pass = '%s';", msg->name, msg->data);printf("%s\n", sql);if(sqlite3_get_table(db, sql, &resultp, &nrow, &ncloumn, &errmsg)!= SQLITE_OK){printf("%s\n", errmsg);return -1;}elseprintf("get_table ok!\n");// 查询成功，数据库中拥有此用户if(nrow == 1){strcpy(msg->data, "OK");send(acceptfd, msg, sizeof(MSG), 0);return 1;}if(nrow == 0) // 密码或者用户名错误{strcpy(msg->data,"usr/passwd wrong.");send(acceptfd, msg, sizeof(MSG), 0);}return 0;
}函数——查询
//3查询
int do_query(int acceptfd, MSG *msg , sqlite3 *db)
{char word[64];int found = 0;char date[128] = {};char sql[500] = {};char *errmsg;//拿出msg结构体中，要查询的单词strcpy(word, msg->data);found = do_searchword(acceptfd, msg, word);printf("查询一个单词完毕.\n");// 表示找到了单词，那么此时应该将 用户名，时间，单词，插入到历史记录表中去。if(found == 1){//需要获取系统时间get_date(date);sprintf(sql, "insert into record values('%s','%s','%s')",msg->name,date, word);if(sqlite3_exec(db, sql, NULL, NULL, &errmsg) != SQLITE_OK){printf("%s\n", errmsg);return -1;}else{printf("Insert record done.\n");}}else //表示没有找到strcpy(msg->data, "Not found!");// 将查询的结果，发送给客户端send(acceptfd, msg, sizeof(MSG), 0);return 0;
}
函数——打开文件查词
//3.1打开文件查词
int do_searchword(int acceptfd, MSG *msg, char word[])
{FILE * fp;int len = 0;char temp[512] = {};int result;char *p;if((fp = fopen("dict.txt", "r")) == NULL){perror("fail to fopen.\n");strcpy(msg->data, "Failed to open dict.txt");send(acceptfd, msg, sizeof(MSG), 0);return -1;}//打印出，客户端要查询的单词len = strlen(word);printf("%s , len = %d\n", word, len);//读文件，来查询单词while(fgets(temp,512, fp) != NULL){// printf("temp:%s\n", temp);// abandon abresult = strncmp(temp,word,len);if(result < 0)continue;if(result > 0 || ((result == 0) && (temp[len]!=' ')))break;// 表示找到了，查询的单词p = temp + len; // abandon v.akdsf dafsjkj // printf("found word:%s\n", p);while(*p == ' ')p++;strcpy(msg->data, p);printf("found word:%s\n", msg->data);// 注释拷贝完毕之后，应该关闭文件fclose(fp);return 1;}fclose(fp);return 0;
}函数——获得日期
//3.2获得日期
int get_date(char *date)
{time_t t;struct tm *tp;time(&t);//进行时间格式转换tp = localtime(&t);sprintf(date, "%d-%d-%d %d:%d:%d", tp->tm_year + 1900, tp->tm_mon+1, tp->tm_mday, tp->tm_hour, tp->tm_min , tp->tm_sec);printf("get date:%s\n", date);return 0;
}
函数——查询历史
//4.查询历史
int do_history(int acceptfd, MSG *msg, sqlite3 *db)
{char sql[128] = {};char *errmsg;sprintf(sql, "select * from record where name = '%s'", msg->name);//查询数据库if(sqlite3_exec(db, sql, history_callback,(void *)&acceptfd, &errmsg)!= SQLITE_OK)printf("%s\n", errmsg);elseprintf("Query record done.\n");// 所有的记录查询发送完毕之后，给客户端发出一个结束信息msg->data[0] = '\0';send(acceptfd, msg, sizeof(MSG), 0);return 0;
}
函数——历史结果--回调函数 得到查询结果，并且需要将历史记录发送给客户端
//4.1历史结果--回调函数
// 得到查询结果，并且需要将历史记录发送给客户端
int history_callback(void* arg,int f_num,char** f_value,char** f_name)
{// record , name , date , word int acceptfd;MSG msg;acceptfd = *((int *)arg);sprintf(msg.data, "%s , %s", f_value[1], f_value[2]);send(acceptfd, &msg, sizeof(MSG), 0);return 0;
}
