libevent实现的http服务器代码

以下是基于libevent实现的简单HTTP服务器代码，仅供参考：

#include <event2/event.h>
#include <event2/http.h>
#include <event2/buffer.h>
#include <event2/keyvalq_struct.h>

static void http_handler(struct evhttp_request *req, void *arg) {
    struct evbuffer *buf;
    const char *uri = evhttp_request_get_uri(req);

    buf = evbuffer_new();
    if (!buf) {
        perror("failed to create response buffer");
        return;
    }

    evhttp_add_header(evhttp_request_get_output_headers(req), "Content-Type", "text/plain");

    if (evhttp_request_get_command(req) == EVHTTP_REQ_GET) {
        evbuffer_add_printf(buf, "Received a GET request for %s\n", uri);
    } else if (evhttp_request_get_command(req) == EVHTTP_REQ_POST) {
        evbuffer_add_printf(buf, "Received a POST request for %s\n", uri);
    } else {
        evbuffer_add_printf(buf, "Unsupported HTTP method\n");
    }

    evhttp_send_reply(req, HTTP_OK, "OK", buf);
    evbuffer_free(buf);
}

int main(int argc, char **argv) {
    struct event_base *base;
    struct evhttp *http;
    struct evhttp_bound_socket *handle;

    base = event_base_new();
    if (!base) {
        perror("failed to create event base");
        return 1;
    }

    http = evhttp_new(base);
    if (!http) {
        perror("failed to create http server");
        return 1;
    }

    evhttp_set_cb(http, "/", http_handler, NULL);

    handle = evhttp_bind_socket_with_handle(http, "0.0.0.0", 8080);
    if (!handle) {
        perror("failed to bind socket");
        return 1;
    }

    event_base_dispatch(base);

    evhttp_free(http);
    event_base_free(base);

    return 0;
}

以上代码实现了一个简单的HTTP服务器，监听本机的8080端口，当有HTTP请求到来时，根据请求方法（GET或POST）返回相应的响应。其中，libevent提供了evhttp库来实现HTTP协议的处理，evhttp_request_get_uri()获取请求的URI，evhttp_request_get_output_headers()获取请求的响应头，evhttp_add_header()设置响应头，evhttp_request_get_command()获取请求的方法类型（GET或POST），evbuffer_add_printf()将格式化的字符串添加到响应体中，evhttp_send_reply()发送响应，evbuffer_free()释放响应体的内存。