练习：
将 epoll 服务器 客户端拿来用
客户端：写一个界面，里面有注册登录
服务器：处理注册和登录逻辑，注册的话将注册的账号密码写入数据库，登录的话查询数据库中是否存在账号，并验证密码是否正确
额外功能：客户端登录的时候，服务器向客户端发送一个验证码，只有验证码也正确的时候，才能登录成功·
server.c
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/epoll.h>
#include <sqlite3.h>
#include <errno.h>
#include <time.h>
#define MAX_EVENTS 100
typedef struct sockaddr_in addr_in_t;
typedef struct sockaddr addr_t;
enum Type {
TYPE_REGIST,
TYPE_LOGIN,
TYPE_CHAT
};
typedef struct Pack {
enum Type type;
char name[20];
char pswd[20];
char tarname[20];
char text[1024];
} pack_t;
sqlite3 *db; // 数据库指针
// 生成验证码
void generate_code(char *code, int length) {
const char charset[] = "0123456789";
srand(time(NULL));
for (int i = 0; i < length; i++) {
code[i] = charset[rand() % 10];
}
code[length] = '\0';
}
// 设置文件描述符非阻塞模式
void set_nonblocking(int fd) {
int flags = fcntl(fd, F_GETFL, 0);
fcntl(fd, F_SETFL, flags | O_NONBLOCK);
}
// 处理客户端请求
void handle_client(int client) {
pack_t pack = {0};
int res = read(client, &pack, sizeof(pack));
if (res <= 0) {
printf("客户端断开连接\n");
close(client);
return;
}
char sql[256];
char *errmsg = NULL;
switch (pack.type) {
case TYPE_REGIST:
snprintf(sql, sizeof(sql), "INSERT INTO users (name, password) VALUES ('%s', '%s');", pack.name, pack.pswd);
if (sqlite3_exec(db, sql, 0, 0, &errmsg) != SQLITE_OK) {
printf("注册失败: %s\n", errmsg);
strcpy(pack.text, "注册失败，该账号可能已存在！");
sqlite3_free(errmsg);
} else {
strcpy(pack.text, "注册成功！");
}
write(client, &pack, sizeof(pack));
break;
case TYPE_LOGIN: {
snprintf(sql, sizeof(sql), "SELECT password FROM users WHERE name = '%s';", pack.name);
sqlite3_stmt *stmt;
if (sqlite3_prepare_v2(db, sql, -1, &stmt, 0) == SQLITE_OK) {
if (sqlite3_step(stmt) == SQLITE_ROW) {
const char *db_pswd = (const char*)sqlite3_column_text(stmt, 0);
if (strcmp(db_pswd, pack.pswd) == 0) {
char code[6];
generate_code(code, 5);
snprintf(pack.text, sizeof(pack.text), "验证码：%s\n", code);
write(client, &pack, sizeof(pack));
// 等待客户端输入验证码
read(client, &pack, sizeof(pack));
if (strcmp(pack.text, code) == 0) {
strcpy(pack.text, "登录成功！");
} else {
strcpy(pack.text, "验证码错误，登录失败！");
}
} else {
strcpy(pack.text, "密码错误！");
}
} else {
strcpy(pack.text, "账号不存在！");
}
sqlite3_finalize(stmt);
}
write(client, &pack, sizeof(pack));
break;
}
case TYPE_CHAT:
printf("收到消息: %s\n", pack.text);
break;
}
}
int main(int argc, const char *argv[]) {
if (argc != 2) {
printf("请输入端口号\n");
return 1;
}
int port = atoi(argv[1]);
// 初始化数据库
if (sqlite3_open("users.db", &db) != SQLITE_OK) {
printf("无法打开数据库\n");
return 1;
}
const char *create_table_sql = "CREATE TABLE IF NOT EXISTS users (id INTEGER PRIMARY KEY, name TEXT UNIQUE, password TEXT);";
char *errmsg = NULL;
if (sqlite3_exec(db, create_table_sql, 0, 0, &errmsg) != SQLITE_OK) {
printf("创建表失败: %s\n", errmsg);
sqlite3_free(errmsg);
return 1;
}
// 创建服务器 socket
int server = socket(AF_INET, SOCK_STREAM, 0);
addr_in_t addr = {0};
addr.sin_family = AF_INET;
addr.sin_port = htons(port);
addr.sin_addr.s_addr = INADDR_ANY;
bind(server, (addr_t*)&addr, sizeof(addr));
listen(server, 10);
// 设置非阻塞模式
set_nonblocking(server);
// 创建 epoll
int epoll_fd = epoll_create1(0);
struct epoll_event ev, events[MAX_EVENTS];
ev.events = EPOLLIN;
ev.data.fd = server;
epoll_ctl(epoll_fd, EPOLL_CTL_ADD, server, &ev);
printf("服务器启动，监听端口 %d...\n", port);
while (1) {
int n = epoll_wait(epoll_fd, events, MAX_EVENTS, -1);
for (int i = 0; i < n; i++) {
if (events[i].data.fd == server) {
// 处理新连接
int client = accept(server, NULL, NULL);
if (client < 0) {
perror("accept");
continue;
}
set_nonblocking(client);
ev.events = EPOLLIN | EPOLLET;
ev.data.fd = client;
epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client, &ev);
printf("新客户端连接: %d\n", client);
} else {
// 处理客户端请求
handle_client(events[i].data.fd);
}
}
}
sqlite3_close(db);
close(server);
return 0;
}
client.c
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
typedef struct sockaddr_in addr_in_t;
typedef struct sockaddr addr_t;
enum Type {
TYPE_REGIST,
TYPE_LOGIN,
TYPE_CHAT
};
typedef struct Pack {
enum Type type;
char name[20];
char pswd[20];
char tarname[20];
char text[1024];
} pack_t;
void handle_response(int client) {
pack_t pack;
int res = read(client, &pack, sizeof(pack));
if (res > 0) {
printf("服务器: %s\n", pack.text);
}
}
int main(int argc, const char *argv[]) {
if (argc != 2) {
printf("输入端口号\n");
return 1;
}
int port = atoi(argv[1]);
int client = socket(AF_INET, SOCK_STREAM, 0);
addr_in_t addr = {0};
addr.sin_family = AF_INET;
addr.sin_port = htons(port);
addr.sin_addr.s_addr = inet_addr("192.168.126.245");
if (connect(client, (addr_t*)&addr, sizeof(addr)) == -1) {
perror("连接失败");
return 1;
}
printf("连接服务器成功！\n");
while (1) {
int ch;
printf("1: 注册\n2: 登录\n3: 聊天\n0: 退出\n请选择: ");
scanf("%d", &ch);
while (getchar() != '\n');
pack_t pack = {0};
switch (ch) {
case 1:
printf("输入账号: ");
scanf("%s", pack.name);
while (getchar() != '\n');
printf("输入密码: ");
scanf("%s", pack.pswd);
while (getchar() != '\n');
pack.type = TYPE_REGIST;
write(client, &pack, sizeof(pack));
handle_response(client);
break;
case 2:
printf("输入账号: ");
scanf("%s", pack.name);
while (getchar() != '\n');
printf("输入密码: ");
scanf("%s", pack.pswd);
while (getchar() != '\n');
pack.type = TYPE_LOGIN;
write(client, &pack, sizeof(pack));
handle_response(client); // 服务器发送验证码
printf("输入验证码: ");
scanf("%s", pack.text);
while (getchar() != '\n');
write(client, &pack, sizeof(pack));
handle_response(client); // 登录成功 or 失败
break;
case 3:
printf("输入聊天对象: ");
scanf("%s", pack.tarname);
while (getchar() != '\n');
printf("输入消息: ");
fgets(pack.text, sizeof(pack.text), stdin);
pack.text[strcspn(pack.text, "\n")] = '\0'; // 去除换行符
pack.type = TYPE_CHAT;
write(client, &pack, sizeof(pack));
handle_response(client);
break;
case 0:
close(client);
return 0;
default:
printf("无效选项\n");
}
}
return 0;
}
