可以通过添加filter对输入或输出数据进行转换和过滤,可以在读取前和写入后对数据进行一系列的预处理操作。
/**
* 事件过滤回调
*/
bufferevent_filter_result filter_in(evbuffer *s, evbuffer *d, ev_ssize_t limit,
bufferevent_flush_mode mode, void *arg )
{
cout << "2、filter_in\n" << endl;
char data[1024] = { 0 };
// 读取并清理原数据
int len = evbuffer_remove(s, data, sizeof(data) - 1);
// 所有字母转成大写
for (int i = 0; i < len; ++i)
{
data[i] = toupper(data[i]);
}
evbuffer_add(d, data, len);
return BEV_OK;
}
bufferevent_filter_result filter_out(evbuffer *s, evbuffer *d, ev_ssize_t limit,
bufferevent_flush_mode mode, void *arg )
{
cout << "4、filter_out\n" << endl;
char data[1024] = { 0 };
// 读取并清理原数据
int len = evbuffer_remove(s, data, sizeof(data) - 1);
string str = "";
str += "================\n";
str += data;
str += "================\n";
evbuffer_add(d, str.c_str(), str.size());
return BEV_OK;
}
void read_cb(bufferevent*bev, void *arg)
{
cout << "3、read_cb\n" << endl;
char data[1024] = { 0 };
int len = bufferevent_read(bev, data, sizeof(data) - 1);
cout << data << endl;
//回复客户消息,经过输出过滤
bufferevent_write(bev, data, len);
}
void write_cb(bufferevent*bev, void *arg)
{
cout << "5、write_cb\n" << endl;
}
void event_cb(bufferevent*bev, short events, void *arg)
{
cout << "6、event_cb\n" << endl;
}
void listen_cb(struct evconnlistener * e, evutil_socket_t s, struct sockaddr *a, int socklen, void *arg)
{
event_base *base = (event_base*)arg;
cout << "1、listen_cb\n" << endl;
// 创建bufferevent
bufferevent *bev = bufferevent_socket_new(base, s, BEV_OPT_CLOSE_ON_FREE);
// 绑定bufferevent filter
bufferevent *bev_filter = bufferevent_filter_new(bev,
filter_in, //输入过滤函数
filter_out, //输出过滤函数
BEV_OPT_CLOSE_ON_FREE, //关闭filter是同时关闭bufferevent
0, //清理的回调函数
0 //传递给回调的参数
);
//设置bufferevent的回调
bufferevent_setcb(bev_filter, read_cb, write_cb, event_cb, NULL);//回调函数的参数
bufferevent_enable(bev_filter, EV_READ | EV_WRITE); // 设置读写权限
}
int main()
{
#ifdef _WIN32
//初始化socket库
WSADATA wsa;
WSAStartup(MAKEWORD(2, 2), &wsa);
#else
// 忽略管道信号,发送数据给已关闭的socket
if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
return 1;
#endif
// 创建libevent的上下文
event_base * base = event_base_new();
// 监听端口
// socket ,bind,listen 绑定事件
sockaddr_in sin;
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_port = htons(SPORT);
evconnlistener *ev = evconnlistener_new_bind(base, // libevent的上下文
listen_cb, // 接收到连接的回调函数
base, // 回调函数获取的参数 arg
LEV_OPT_REUSEABLE | LEV_OPT_CLOSE_ON_FREE, // 地址重用,evconnlistener关闭同时关闭socket
10, // 连接队列大小,对应listen函数
(sockaddr*)&sin, // 绑定的地址和端口
sizeof(sin)
);
// 事件分发处理
if (base)
event_base_dispatch(base);
if (ev)
evconnlistener_free(ev);
if (base)
event_base_free(base);
#ifdef _WIN32
WSACleanup();
#endif
return 0;
}