【libevent】http server

[toc]

实现http-server

#include <stdio.h>
#include <stdlib.h>
#include <evhttp.h>
#include <event.h>
#include <string.h>
#include "event2/http.h"
#include "event2/event.h"
#include "event2/buffer.h"
#include "event2/bufferevent.h"
#include "event2/bufferevent_compat.h"
#include "event2/http_struct.h"
#include "event2/http_compat.h"
#include "event2/util.h"
#include "event2/listener.h"

#pragma comment(lib,"ws2_32.lib")
#pragma comment(lib, "Iphlpapi.lib")

#define BUF_MAX 1024*16

//解析post请求数据
void get_post_message(char* buf, struct evhttp_request* req)
{
	size_t post_size = 0;

	post_size = evbuffer_get_length(req->input_buffer);//获取数据长度
	printf("====line:%d,post len:%d\n", __LINE__, post_size);
	if (post_size <= 0)
	{
		printf("====line:%d,post msg is empty!\n", __LINE__);
		return;
	}
	else
	{
		size_t copy_len = post_size > BUF_MAX ? BUF_MAX : post_size;
		printf("====line:%d,post len:%d, copy_len:%d\n", __LINE__, post_size, copy_len);
		memcpy(buf, evbuffer_pullup(req->input_buffer, -1), copy_len);
		buf[post_size] = '\0';
		printf("====line:%d,post msg:%s\n", __LINE__, buf);
	}
}

//解析http头，主要用于get请求时解析uri和请求参数
char* find_http_header(struct evhttp_request* req, struct evkeyvalq* params, const char* query_char)
{
	if (req == NULL || params == NULL || query_char == NULL)
	{
		printf("====line:%d,%s\n", __LINE__, "input params is null.");
		return NULL;
	}

	struct evhttp_uri* decoded = NULL;
	char* query = NULL;
	char* query_result = NULL;
	const char* path;
	const char* uri = evhttp_request_get_uri(req);//获取请求uri

	if (uri == NULL)
	{
		printf("====line:%d,evhttp_request_get_uri return null\n", __LINE__);
		return NULL;
	}
	else
	{
		printf("====line:%d,Got a GET request for <%s>\n", __LINE__, uri);
	}

	//解码uri
	decoded = evhttp_uri_parse(uri);
	if (!decoded)
	{
		printf("====line:%d,It's not a good URI. Sending BADREQUEST\n", __LINE__);
		evhttp_send_error(req, HTTP_BADREQUEST, 0);
		return;
	}

	//获取uri中的path部分
	path = evhttp_uri_get_path(decoded);
	if (path == NULL)
	{
		path = "/";
	}
	else
	{
		printf("====line:%d,path is:%s\n", __LINE__, path);
	}

	//获取uri中的参数部分
	query = (char*)evhttp_uri_get_query(decoded);
	if (query == NULL)
	{
		printf("====line:%d,evhttp_uri_get_query return null\n", __LINE__);
		return NULL;
	}

	//查询指定参数的值
	evhttp_parse_query_str(query, params);
	query_result = (char*)evhttp_find_header(params, query_char);

	return query_result;
}

//处理get请求
void http_handler_testget_msg(struct evhttp_request* req, void* arg)
{
	if (req == NULL)
	{
		printf("====line:%d,%s\n", __LINE__, "input param req is null.");
		return;
	}

	char* sign = NULL;
	char* data = NULL;
	struct evkeyvalq sign_params = { 0 };
	sign = find_http_header(req, &sign_params, "sign");//获取get请求uri中的sign参数
	if (sign == NULL)
	{
		printf("====line:%d,%s\n", __LINE__, "request uri no param sign.");
	}
	else
	{
		printf("====line:%d,get request param: sign=[%s]\n", __LINE__, sign);
	}

	data = find_http_header(req, &sign_params, "data");//获取get请求uri中的data参数
	if (data == NULL)
	{
		printf("====line:%d,%s\n", __LINE__, "request uri no param data.");
	}
	else
	{
		printf("====line:%d,get request param: data=[%s]\n", __LINE__, data);
	}
	printf("\n");

	//回响应
	struct evbuffer* retbuff = NULL;
	retbuff = evbuffer_new();
	if (retbuff == NULL)
	{
		printf("====line:%d,%s\n", __LINE__, "retbuff is null.");
		return;
	}
	evbuffer_add_printf(retbuff, "Receive get request,Thamks for the request!");
	evhttp_send_reply(req, HTTP_OK, "Client", retbuff);
	evbuffer_free(retbuff);
}

//处理post请求
void http_handler_testpost_msg(struct evhttp_request* req, void* arg)
{
	if (req == NULL)
	{
		printf("====line:%d,%s\n", __LINE__, "input param req is null.");
		return;
	}

	char buf[BUF_MAX] = { 0 };
	get_post_message(buf, req);//获取请求数据，一般是json格式的数据
	if (buf == NULL)
	{
		printf("====line:%d,%s\n", __LINE__, "get_post_message return null.");
		return;
	}
	else
	{
		//可以使用json库解析需要的数据
		printf("====line:%d,request data:%s", __LINE__, buf);
	}

	//回响应
	struct evbuffer* retbuff = NULL;
	retbuff = evbuffer_new();
	if (retbuff == NULL)
	{
		printf("====line:%d,%s\n", __LINE__, "retbuff is null.");
		return;
	}
	evbuffer_add_printf(retbuff, "Receive Get request,Thamks for the request!");
	evhttp_send_reply(req, HTTP_OK, "Client", retbuff);
	evbuffer_free(retbuff);
}

int main()
{
	struct evhttp* http_server = NULL;
	short http_port = 8081;
	char* http_addr = "0.0.0.0";

#ifdef _WIN32
	{
		WORD wVersionRequested;
		WSADATA wsaData;
		int err;

		wVersionRequested = MAKEWORD(2, 2);

		err = WSAStartup(wVersionRequested, &wsaData);
		if (err != 0) {
			printf("WSAStartup failed with error: %d\n", err);
			return 0;
		}
	}
#endif // _WIN32

	//初始化
	event_init();
	//启动http服务端
	http_server = evhttp_start(http_addr, http_port);
	if (http_server == NULL)
	{
		printf("====line:%d,%s\n", __LINE__, "http server start failed.");
		return -1;
	}

	//设置请求超时时间(s)
	evhttp_set_timeout(http_server, 5);
	//设置事件处理函数，evhttp_set_cb针对每一个事件(请求)注册一个处理函数，
	//区别于evhttp_set_gencb函数，是对所有请求设置一个统一的处理函数
	evhttp_set_cb(http_server, "/me/testpost", http_handler_testpost_msg, NULL);
	evhttp_set_cb(http_server, "/me/testget", http_handler_testget_msg, NULL);

	//循环监听
	event_dispatch();
	//实际上不会释放，代码不会运行到这一步
	evhttp_free(http_server);

	return 0;
}

使用 postman 请求

Get

// 接口
127.0.0.1:8081/me/testpost

// 请求体
{
    "username": "A",
    "password": "123123Qq",
    "reqtime": "2023年1月28日15:44:58"
}

http-server 控制台输出：

====line:65,Got a GET request for
====line:85,path is:/me/testget
====line:92,evhttp_uri_get_query return null
====line:118,request uri no param sign.
====line:65,Got a GET request for
====line:85,path is:/me/testget
====line:92,evhttp_uri_get_query return null
====line:128,request uri no param data.

Post

# 接口
127.0.0.1:8081/me/testpost

// 请求体
{
    "username": "A",
    "password": "123123Qq",
    "reqtime": "2023年1月28日15:44:58"
}

http-server 控制台输出：

====line:27,post len:98
====line:36,post len:98, copy_len:98
====line:39,post msg:{
"username": "A",
"password": "123123Qq",
"reqtime": "2023骞?鏈?8鏃?5:44:58"
}
====line:168,request data:{
"username": "A",
"password": "123123Qq",
"reqtime": "2023骞?鏈?8鏃?5:44:58"
}

---

B_Code > 网络编程 > libevent

#网络编程 #libevent

【libevent】http server

https://hodlyounger.github.io/B_Code/网络编程/libevent/【Libevent】httpserver/

作者

mingming

发布于

2023年10月27日

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