[z]http://blog.csdn.net/luotuo44/article/details/39670221
本文从简单到复杂,展示如何使用libevent。网上的许多例子都是只有服务器端的,本文里面客户端和服务器端都有,以飨读者。
关于libevent编程时的一些疑问可以阅读《libevent编程疑难解答》。假如读者还想了解libevent的具体实现,可以阅读《libevent源码分析》系统文章。
不说这么多了,直接上代码。
初等:
客户端代码:
[cpp] view plain copy
- #include<sys/types.h>
- #include<sys/socket.h>
- #include<netinet/in.h>
- #include<arpa/inet.h>
- #include<errno.h>
- #include<unistd.h>
- #include<stdio.h>
- #include<string.h>
- #include<stdlib.h>
- #include<event.h>
- #include<event2/util.h>
- int tcp_connect_server(const char* server_ip, int port);
- void cmd_msg_cb(int fd, short events, void* arg);
- void socket_read_cb(int fd, short events, void *arg);
- int main(int argc, char** argv)
- {
- if( argc < 3 )
- {
- printf("please input 2 parameter\n");
- return -1;
- }
- //两个参数依次是服务器端的IP地址、端口号
- int sockfd = tcp_connect_server(argv[1], atoi(argv[2]));
- if( sockfd == -1)
- {
- perror("tcp_connect error ");
- return -1;
- }
- printf("connect to server successful\n");
- struct event_base* base = event_base_new();
- struct event *ev_sockfd = event_new(base, sockfd,
- EV_READ | EV_PERSIST,
- socket_read_cb, NULL);
- event_add(ev_sockfd, NULL);
- //监听终端输入事件
- struct event* ev_cmd = event_new(base, STDIN_FILENO,
- EV_READ | EV_PERSIST, cmd_msg_cb,
- (void*)&sockfd);
- event_add(ev_cmd, NULL);
- event_base_dispatch(base);
- printf("finished \n");
- return 0;
- }
- void cmd_msg_cb(int fd, short events, void* arg)
- {
- char msg[1024];
- int ret = read(fd, msg, sizeof(msg));
- if( ret <= 0 )
- {
- perror("read fail ");
- exit(1);
- }
- int sockfd = *((int*)arg);
- //把终端的消息发送给服务器端
- //为了简单起见,不考虑写一半数据的情况
- write(sockfd, msg, ret);
- }
- void socket_read_cb(int fd, short events, void *arg)
- {
- char msg[1024];
- //为了简单起见,不考虑读一半数据的情况
- int len = read(fd, msg, sizeof(msg)-1);
- if( len <= 0 )
- {
- perror("read fail ");
- exit(1);
- }
- msg[len] = ‘\0‘;
- printf("recv %s from server\n", msg);
- }
- typedef struct sockaddr SA;
- int tcp_connect_server(const char* server_ip, int port)
- {
- int sockfd, status, save_errno;
- struct sockaddr_in server_addr;
- memset(&server_addr, 0, sizeof(server_addr) );
- server_addr.sin_family = AF_INET;
- server_addr.sin_port = htons(port);
- status = inet_aton(server_ip, &server_addr.sin_addr);
- if( status == 0 ) //the server_ip is not valid value
- {
- errno = EINVAL;
- return -1;
- }
- sockfd = ::socket(PF_INET, SOCK_STREAM, 0);
- if( sockfd == -1 )
- return sockfd;
- status = ::connect(sockfd, (SA*)&server_addr, sizeof(server_addr) );
- if( status == -1 )
- {
- save_errno = errno;
- ::close(sockfd);
- errno = save_errno; //the close may be error
- return -1;
- }
- evutil_make_socket_nonblocking(sockfd);
- return sockfd;
- }
服务器端代码:
[cpp] view plain copy
- #include<stdio.h>
- #include<string.h>
- #include<errno.h>
- #include<unistd.h>
- #include<event.h>
- void accept_cb(int fd, short events, void* arg);
- void socket_read_cb(int fd, short events, void *arg);
- int tcp_server_init(int port, int listen_num);
- int main(int argc, char** argv)
- {
- int listener = tcp_server_init(9999, 10);
- if( listener == -1 )
- {
- perror(" tcp_server_init error ");
- return -1;
- }
- struct event_base* base = event_base_new();
- //添加监听客户端请求连接事件
- struct event* ev_listen = event_new(base, listener, EV_READ | EV_PERSIST,
- accept_cb, base);
- event_add(ev_listen, NULL);
- event_base_dispatch(base);
- return 0;
- }
- void accept_cb(int fd, short events, void* arg)
- {
- evutil_socket_t sockfd;
- struct sockaddr_in client;
- socklen_t len = sizeof(client);
- sockfd = ::accept(fd, (struct sockaddr*)&client, &len );
- evutil_make_socket_nonblocking(sockfd);
- printf("accept a client %d\n", sockfd);
- struct event_base* base = (event_base*)arg;
- //仅仅是为了动态创建一个event结构体
- struct event *ev = event_new(NULL, -1, 0, NULL, NULL);
- //将动态创建的结构体作为event的回调参数
- event_assign(ev, base, sockfd, EV_READ | EV_PERSIST,
- socket_read_cb, (void*)ev);
- event_add(ev, NULL);
- }
- void socket_read_cb(int fd, short events, void *arg)
- {
- char msg[4096];
- struct event *ev = (struct event*)arg;
- int len = read(fd, msg, sizeof(msg) - 1);
- if( len <= 0 )
- {
- printf("some error happen when read\n");
- event_free(ev);
- close(fd);
- return ;
- }
- msg[len] = ‘\0‘;
- printf("recv the client msg: %s", msg);
- char reply_msg[4096] = "I have recvieced the msg: ";
- strcat(reply_msg + strlen(reply_msg), msg);
- write(fd, reply_msg, strlen(reply_msg) );
- }
- typedef struct sockaddr SA;
- int tcp_server_init(int port, int listen_num)
- {
- int errno_save;
- evutil_socket_t listener;
- listener = ::socket(AF_INET, SOCK_STREAM, 0);
- if( listener == -1 )
- return -1;
- //允许多次绑定同一个地址。要用在socket和bind之间
- evutil_make_listen_socket_reuseable(listener);
- struct sockaddr_in sin;
- sin.sin_family = AF_INET;
- sin.sin_addr.s_addr = 0;
- sin.sin_port = htons(port);
- if( ::bind(listener, (SA*)&sin, sizeof(sin)) < 0 )
- goto error;
- if( ::listen(listener, listen_num) < 0)
- goto error;
- //跨平台统一接口,将套接字设置为非阻塞状态
- evutil_make_socket_nonblocking(listener);
- return listener;
- error:
- errno_save = errno;
- evutil_closesocket(listener);
- errno = errno_save;
- return -1;
- }
中等:
客户端代码:
[cpp] view plain copy
- #include<sys/types.h>
- #include<sys/socket.h>
- #include<netinet/in.h>
- #include<arpa/inet.h>
- #include<errno.h>
- #include<unistd.h>
- #include<stdio.h>
- #include<string.h>
- #include<stdlib.h>
- #include<event.h>
- #include<event2/bufferevent.h>
- #include<event2/buffer.h>
- #include<event2/util.h>
- int tcp_connect_server(const char* server_ip, int port);
- void cmd_msg_cb(int fd, short events, void* arg);
- void server_msg_cb(struct bufferevent* bev, void* arg);
- void event_cb(struct bufferevent *bev, short event, void *arg);
- int main(int argc, char** argv)
- {
- if( argc < 3 )
- {
- printf("please input 2 parameter\n");
- return -1;
- }
- //两个参数依次是服务器端的IP地址、端口号
- int sockfd = tcp_connect_server(argv[1], atoi(argv[2]));
- if( sockfd == -1)
- {
- perror("tcp_connect error ");
- return -1;
- }
- printf("connect to server successful\n");
- struct event_base* base = event_base_new();
- struct bufferevent* bev = bufferevent_socket_new(base, sockfd,
- BEV_OPT_CLOSE_ON_FREE);
- //监听终端输入事件
- struct event* ev_cmd = event_new(base, STDIN_FILENO,
- EV_READ | EV_PERSIST, cmd_msg_cb,
- (void*)bev);
- event_add(ev_cmd, NULL);
- //当socket关闭时会用到回调参数
- bufferevent_setcb(bev, server_msg_cb, NULL, event_cb, (void*)ev_cmd);
- bufferevent_enable(bev, EV_READ | EV_PERSIST);
- event_base_dispatch(base);
- printf("finished \n");
- return 0;
- }
- void cmd_msg_cb(int fd, short events, void* arg)
- {
- char msg[1024];
- int ret = read(fd, msg, sizeof(msg));
- if( ret < 0 )
- {
- perror("read fail ");
- exit(1);
- }
- struct bufferevent* bev = (struct bufferevent*)arg;
- //把终端的消息发送给服务器端
- bufferevent_write(bev, msg, ret);
- }
- void server_msg_cb(struct bufferevent* bev, void* arg)
- {
- char msg[1024];
- size_t len = bufferevent_read(bev, msg, sizeof(msg));
- msg[len] = ‘\0‘;
- printf("recv %s from server\n", msg);
- }
- void event_cb(struct bufferevent *bev, short event, void *arg)
- {
- if (event & BEV_EVENT_EOF)
- printf("connection closed\n");
- else if (event & BEV_EVENT_ERROR)
- printf("some other error\n");
- //这将自动close套接字和free读写缓冲区
- bufferevent_free(bev);
- struct event *ev = (struct event*)arg;
- //因为socket已经没有,所以这个event也没有存在的必要了
- event_free(ev);
- }
- typedef struct sockaddr SA;
- int tcp_connect_server(const char* server_ip, int port)
- {
- int sockfd, status, save_errno;
- struct sockaddr_in server_addr;
- memset(&server_addr, 0, sizeof(server_addr) );
- server_addr.sin_family = AF_INET;
- server_addr.sin_port = htons(port);
- status = inet_aton(server_ip, &server_addr.sin_addr);
- if( status == 0 ) //the server_ip is not valid value
- {
- errno = EINVAL;
- return -1;
- }
- sockfd = ::socket(PF_INET, SOCK_STREAM, 0);
- if( sockfd == -1 )
- return sockfd;
- status = ::connect(sockfd, (SA*)&server_addr, sizeof(server_addr) );
- if( status == -1 )
- {
- save_errno = errno;
- ::close(sockfd);
- errno = save_errno; //the close may be error
- return -1;
- }
- evutil_make_socket_nonblocking(sockfd);
- return sockfd;
- }
服务器端代码:
[cpp] view plain copy
- #include<stdio.h>
- #include<string.h>
- #include<errno.h>
- #include<event.h>
- #include<event2/bufferevent.h>
- void accept_cb(int fd, short events, void* arg);
- void socket_read_cb(bufferevent* bev, void* arg);
- void event_cb(struct bufferevent *bev, short event, void *arg);
- int tcp_server_init(int port, int listen_num);
- int main(int argc, char** argv)
- {
- int listener = tcp_server_init(9999, 10);
- if( listener == -1 )
- {
- perror(" tcp_server_init error ");
- return -1;
- }
- struct event_base* base = event_base_new();
- //添加监听客户端请求连接事件
- struct event* ev_listen = event_new(base, listener, EV_READ | EV_PERSIST,
- accept_cb, base);
- event_add(ev_listen, NULL);
- event_base_dispatch(base);
- event_base_free(base);
- return 0;
- }
- void accept_cb(int fd, short events, void* arg)
- {
- evutil_socket_t sockfd;
- struct sockaddr_in client;
- socklen_t len = sizeof(client);
- sockfd = ::accept(fd, (struct sockaddr*)&client, &len );
- evutil_make_socket_nonblocking(sockfd);
- printf("accept a client %d\n", sockfd);
- struct event_base* base = (event_base*)arg;
- bufferevent* bev = bufferevent_socket_new(base, sockfd, BEV_OPT_CLOSE_ON_FREE);
- bufferevent_setcb(bev, socket_read_cb, NULL, event_cb, arg);
- bufferevent_enable(bev, EV_READ | EV_PERSIST);
- }
- void socket_read_cb(bufferevent* bev, void* arg)
- {
- char msg[4096];
- size_t len = bufferevent_read(bev, msg, sizeof(msg));
- msg[len] = ‘\0‘;
- printf("recv the client msg: %s", msg);
- char reply_msg[4096] = "I have recvieced the msg: ";
- strcat(reply_msg + strlen(reply_msg), msg);
- bufferevent_write(bev, reply_msg, strlen(reply_msg));
- }
- void event_cb(struct bufferevent *bev, short event, void *arg)
- {
- if (event & BEV_EVENT_EOF)
- printf("connection closed\n");
- else if (event & BEV_EVENT_ERROR)
- printf("some other error\n");
- //这将自动close套接字和free读写缓冲区
- bufferevent_free(bev);
- }
- typedef struct sockaddr SA;
- int tcp_server_init(int port, int listen_num)
- {
- int errno_save;
- evutil_socket_t listener;
- listener = ::socket(AF_INET, SOCK_STREAM, 0);
- if( listener == -1 )
- return -1;
- //允许多次绑定同一个地址。要用在socket和bind之间
- evutil_make_listen_socket_reuseable(listener);
- struct sockaddr_in sin;
- sin.sin_family = AF_INET;
- sin.sin_addr.s_addr = 0;
- sin.sin_port = htons(port);
- if( ::bind(listener, (SA*)&sin, sizeof(sin)) < 0 )
- goto error;
- if( ::listen(listener, listen_num) < 0)
- goto error;
- //跨平台统一接口,将套接字设置为非阻塞状态
- evutil_make_socket_nonblocking(listener);
- return listener;
- error:
- errno_save = errno;
- evutil_closesocket(listener);
- errno = errno_save;
- return -1;
- }
高等:
客户端代码:
[cpp] view plain copy
- #include<sys/types.h>
- #include<sys/socket.h>
- #include<netinet/in.h>
- #include<arpa/inet.h>
- #include<errno.h>
- #include<unistd.h>
- #include<stdio.h>
- #include<string.h>
- #include<stdlib.h>
- #include<event.h>
- #include<event2/bufferevent.h>
- #include<event2/buffer.h>
- #include<event2/util.h>
- int tcp_connect_server(const char* server_ip, int port);
- void cmd_msg_cb(int fd, short events, void* arg);
- void server_msg_cb(struct bufferevent* bev, void* arg);
- void event_cb(struct bufferevent *bev, short event, void *arg);
- int main(int argc, char** argv)
- {
- if( argc < 3 )
- {
- //两个参数依次是服务器端的IP地址、端口号
- printf("please input 2 parameter\n");
- return -1;
- }
- struct event_base *base = event_base_new();
- struct bufferevent* bev = bufferevent_socket_new(base, -1,
- BEV_OPT_CLOSE_ON_FREE);
- //监听终端输入事件
- struct event* ev_cmd = event_new(base, STDIN_FILENO,
- EV_READ | EV_PERSIST,
- cmd_msg_cb, (void*)bev);
- event_add(ev_cmd, NULL);
- struct sockaddr_in server_addr;
- memset(&server_addr, 0, sizeof(server_addr) );
- server_addr.sin_family = AF_INET;
- server_addr.sin_port = htons(atoi(argv[2]));
- inet_aton(argv[1], &server_addr.sin_addr);
- bufferevent_socket_connect(bev, (struct sockaddr *)&server_addr,
- sizeof(server_addr));
- bufferevent_setcb(bev, server_msg_cb, NULL, event_cb, (void*)ev_cmd);
- bufferevent_enable(bev, EV_READ | EV_PERSIST);
- event_base_dispatch(base);
- printf("finished \n");
- return 0;
- }
- void cmd_msg_cb(int fd, short events, void* arg)
- {
- char msg[1024];
- int ret = read(fd, msg, sizeof(msg));
- if( ret < 0 )
- {
- perror("read fail ");
- exit(1);
- }
- struct bufferevent* bev = (struct bufferevent*)arg;
- //把终端的消息发送给服务器端
- bufferevent_write(bev, msg, ret);
- }
- void server_msg_cb(struct bufferevent* bev, void* arg)
- {
- char msg[1024];
- size_t len = bufferevent_read(bev, msg, sizeof(msg));
- msg[len] = ‘\0‘;
- printf("recv %s from server\n", msg);
- }
- void event_cb(struct bufferevent *bev, short event, void *arg)
- {
- if (event & BEV_EVENT_EOF)
- printf("connection closed\n");
- else if (event & BEV_EVENT_ERROR)
- printf("some other error\n");
- else if( event & BEV_EVENT_CONNECTED)
- {
- printf("the client has connected to server\n");
- return ;
- }
- //这将自动close套接字和free读写缓冲区
- bufferevent_free(bev);
- struct event *ev = (struct event*)arg;
- event_free(ev);
- }
服务器端代码:
[cpp] view plain copy
- #include<netinet/in.h>
- #include<sys/socket.h>
- #include<unistd.h>
- #include<stdio.h>
- #include<string.h>
- #include<event.h>
- #include<listener.h>
- #include<bufferevent.h>
- #include<thread.h>
- void listener_cb(evconnlistener *listener, evutil_socket_t fd,
- struct sockaddr *sock, int socklen, void *arg);
- void socket_read_cb(bufferevent *bev, void *arg);
- void socket_event_cb(bufferevent *bev, short events, void *arg);
- int main()
- {
- //evthread_use_pthreads();//enable threads
- struct sockaddr_in sin;
- memset(&sin, 0, sizeof(struct sockaddr_in));
- sin.sin_family = AF_INET;
- sin.sin_port = htons(9999);
- event_base *base = event_base_new();
- evconnlistener *listener
- = evconnlistener_new_bind(base, listener_cb, base,
- LEV_OPT_REUSEABLE|LEV_OPT_CLOSE_ON_FREE,
- 10, (struct sockaddr*)&sin,
- sizeof(struct sockaddr_in));
- event_base_dispatch(base);
- evconnlistener_free(listener);
- event_base_free(base);
- return 0;
- }
- //一个新客户端连接上服务器了
- //当此函数被调用时,libevent已经帮我们accept了这个客户端。该客户端的
- //文件描述符为fd
- void listener_cb(evconnlistener *listener, evutil_socket_t fd,
- struct sockaddr *sock, int socklen, void *arg)
- {
- printf("accept a client %d\n", fd);
- event_base *base = (event_base*)arg;
- //为这个客户端分配一个bufferevent
- bufferevent *bev = bufferevent_socket_new(base, fd,
- BEV_OPT_CLOSE_ON_FREE);
- bufferevent_setcb(bev, socket_read_cb, NULL, socket_event_cb, NULL);
- bufferevent_enable(bev, EV_READ | EV_PERSIST);
- }
- void socket_read_cb(bufferevent *bev, void *arg)
- {
- char msg[4096];
- size_t len = bufferevent_read(bev, msg, sizeof(msg)-1 );
- msg[len] = ‘\0‘;
- printf("server read the data %s\n", msg);
- char reply[] = "I has read your data";
- bufferevent_write(bev, reply, strlen(reply) );
- }
- void socket_event_cb(bufferevent *bev, short events, void *arg)
- {
- if (events & BEV_EVENT_EOF)
- printf("connection closed\n");
- else if (events & BEV_EVENT_ERROR)
- printf("some other error\n");
- //这将自动close套接字和free读写缓冲区
- bufferevent_free(bev);
- }
时间: 2024-10-27 12:22:15