socket服务端代码

【实例简介】socket服务端代码

    简单的服务端代码

【核心代码】

#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;  
}