libevent 高并发http服务器代码

下面是一个基于libevent的高并发HTTP服务器的代码示例：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <event.h>

#define SERVER_PORT 8080
#define MAX_CLIENTS 64

void on_accept(int fd, short event, void *arg) {
    int client_fd = accept(fd, NULL, NULL);
    if (client_fd < 0) {
        perror("accept");
        return;
    }

    printf("Accepted connection from client %d\n", client_fd);

    struct event_base *base = (struct event_base *)arg;
    struct bufferevent *bev = bufferevent_socket_new(base, client_fd, BEV_OPT_CLOSE_ON_FREE);

    bufferevent_setcb(bev, NULL, NULL, NULL, NULL);
    bufferevent_enable(bev, EV_READ | EV_WRITE);
}

void on_request(struct bufferevent *bev, void *arg) {
    char buffer[1024];
    int n;
    while ((n = bufferevent_read(bev, buffer, sizeof(buffer))) > 0) {
        printf("Received %d bytes from client %d\n", n, bufferevent_getfd(bev));
        bufferevent_write(bev, buffer, n);
    }
}

int main(int argc, char *argv[]) {
    int server_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (server_fd < 0) {
        perror("socket");
        exit(1);
    }

    struct sockaddr_in server_addr = {0};
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    server_addr.sin_port = htons(SERVER_PORT);

    if (bind(server_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        perror("bind");
        exit(1);
    }

    if (listen(server_fd, MAX_CLIENTS) < 0) {
        perror("listen");
        exit(1);
    }

    printf("Server is listening on port %d\n", SERVER_PORT);

    struct event_base *base = event_base_new();
    struct event *server_event = event_new(base, server_fd, EV_READ | EV_PERSIST, on_accept, base);
    event_add(server_event, NULL);

    event_base_dispatch(base);

    return 0;
}

这个程序使用了libevent库来实现一个简单的高并发HTTP服务器，它可以同时处理多个客户端连接。当有新的客户端连接时，服务器会使用bufferevent_socket_new函数创建一个新的bufferevent来处理该连接。当客户端发送数据时，服务器会使用bufferevent_read函数来读取数据，并使用bufferevent_write函数将数据发送回客户端。