基于libevent实现HttpServer

/********************************************************
Copyright (C),  2016-2018,
FileName:		main
Author:        	红烧肉
Email:         	CoderRoad666@163.com
Created:       	2019/11/26
Description:    使用libevent实现http server功能
********************************************************/
#include <iostream>
#include <string.h>
#include <evhttp.h>
#include <event.h>
#include <string.h>

#include <event2/event.h>
#include <event2/bufferevent.h>
#include <event2/listener.h>
#include <event2/http.h>
#include <event2/bufferevent_compat.h>
#include <event2/http_struct.h>
#include <event2/http_compat.h>
#include <event2/util.h>
#include <event2/buffer.h>

#ifdef _WIN32
#include <windows.h>
#include <time.h>
#include <ws2tcpip.h>
#else
#include <arpa/inet.h>
#endif

#pragma comment(lib, "ws2_32.lib")
#pragma comment(lib, "wsock32.lib")
#pragma comment(lib, "libevent.lib")
#pragma comment(lib, "libevent_core.lib")
#pragma comment(lib, "libevent_extras.lib")

using namespace std;

#define BUF_MAX 1024*16

/************************************
@ Brief:		解析Post请求的数据
@ Author:		woniu201 
@ Created:		2019/11/26
@ Return:            
************************************/
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);
	}
}

/************************************
@ Brief:		解析Get请求uri和请求参数
@ Author:		woniu201 
@ Created:		2019/11/26
@ Return:            
************************************/
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 NULL;
	}

	//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;
}

/************************************
@ Brief:		GET请求处理函数
@ Author:		woniu201 
@ Created:		2019/11/26
@ Return:            
************************************/
void httpHandlerGetMsg(struct evhttp_request *req, void *arg)
{
	if(req == NULL)
	{
		printf("line:%d, %s\n", __LINE__, "Input param req is null.");
		return;
	}

	char *param1 = NULL;
	char *param2 = NULL;

	struct evkeyvalq sign_params = {0};

	//获取url中param1参数
	param1 = find_http_header(req, &sign_params, "param1");
	if(param1 == NULL)
	{
		printf("line:%d, %s\n", __LINE__, "Request uri no param param1.");
	}
	else
	{
		printf("line:%d, Get Request Param: param1=[%s]\n", __LINE__, param1);
	}

	//获取url中param2参数
	param2 = find_http_header(req, &sign_params, "param2");
	if(param2 == NULL)
	{
		printf("line:%d, %s\n", __LINE__, "Request uri no param param2.");
	}
	else
	{
		printf("line:%d, Get Request Param: param1=[%s]\n", __LINE__, param2);
	}
	printf("\n");

	//Http响应请求
	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 SUCC!");
	evhttp_send_reply(req,HTTP_OK,"Client",retbuff);
	evbuffer_free(retbuff);
}

/************************************
@ Brief:		POST请求处理函数
@ Author:		woniu201 
@ Created:		2019/11/26
@ Return:            
************************************/
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 SUCC!");
	evhttp_send_reply(req,HTTP_OK,"Client",retbuff);
	evbuffer_free(retbuff);
}

int main()
{

#ifdef WIN32
	WORD wVersionRequested;
	WSADATA wsaData;
	wVersionRequested = MAKEWORD(2, 2);
	(void)WSAStartup(wVersionRequested, &wsaData);
#endif

	struct evhttp *http_server = NULL;
	short http_port = 8082;
	char *http_addr = "0.0.0.0";

	//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",httpHandlerGetMsg,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;
}