C++通过HTTP请求Get或Post方式请求Json数据

    最近在工作中，由于合作商只提供uRL，我这边需要通过HTTP请求Get或Post方式请求Json数据，然后解析JSON格式，解析json我使用的第三方库jsoncpp，代码如下

#pragma once
#include <iostream>
#include <windows.h>
#include <wininet.h>

using namespace std;

//每次读取的字节数
#define READ_BUFFER_SIZE        4096

enum HttpInterfaceError
{
Hir_Success = 0,        //成功
Hir_InitErr,            //初始化失败
Hir_ConnectErr,            //连接HTTP服务器失败
Hir_SendErr,            //发送请求失败
Hir_QueryErr,            //查询HTTP请求头失败
Hir_404,                //页面不存在
Hir_IllegalUrl,            //无效的URL
Hir_CreateFileErr,        //创建文件失败
Hir_DownloadErr,        //下载失败
Hir_QueryIPErr,            //获取域名对应的地址失败
Hir_SocketErr,            //套接字错误
Hir_UserCancel,            //用户取消下载
Hir_BufferErr,            //文件太大，缓冲区不足
Hir_HeaderErr,            //HTTP请求头错误
Hir_ParamErr,            //参数错误，空指针，空字符
Hir_UnknowErr,
};
enum HttpRequest
{
Hr_Get,
Hr_Post
};
class CWininetHttp
{
public:
CWininetHttp(void);
~CWininetHttp(void);

public:
//  通过HTTP请求：Get或Post方式获取JSON信息 [3/14/2017/shike]
const std::string RequestJsonInfo( const std::string& strUrl,
HttpRequest type = Hr_Get,
std::string lpHeader = "",
std::string lpPostData = "");
protected:
// 解析卡口Json数据 [3/14/2017/shike]
void ParseJsonInfo(const std::string &strJsonInfo);

// 关闭句柄 [3/14/2017/shike]
void Release();

// 释放句柄 [3/14/2017/shike]
void ReleaseHandle( HINTERNET& hInternet );

// 解析URL地址 [3/14/2017/shike]
void ParseURLWeb( std::string strUrl, std::string& strHostName, std::string& strPageName, WORD& sPort);

// UTF-8转为GBK2312 [3/14/2017/shike]
char* UtfToGbk(const char* utf8);

private:
HINTERNET            m_hSession;
HINTERNET            m_hConnect;
HINTERNET            m_hRequest;
HttpInterfaceError    m_error;
};

/*************************************************
File name  :  WininetHttp.cpp
Description:  通过URL访问HTTP请求方式获取JSON
Author     :  shike
Version    :  1.0
Date       :  2016/10/27
Copyright (C) 2016 -  All Rights Reserved
*************************************************/
#include "WininetHttp.h"
//#include "Common.h"
#include <json/json.h>
#include <fstream>
#include "common/CVLog.h"
#pragma comment(lib, "Wininet.lib")
#include <tchar.h>
using namespace std;

extern CCVLog CVLog;

CWininetHttp::CWininetHttp(void):m_hSession(NULL),m_hConnect(NULL),m_hRequest(NULL)
{
}

CWininetHttp::~CWininetHttp(void)
{
Release();
}

//  通过HTTP请求：Get或Post方式获取JSON信息 [3/14/2017/shike]
const std::string CWininetHttp::RequestJsonInfo(const std::string& lpUrl,
HttpRequest type/* = Hr_Get*/,
std::string strHeader/*=""*/,
std::string strPostData/*=""*/)
{
std::string strRet = "";
try
{
if ( lpUrl.empty())
{
throw Hir_ParamErr;
}
Release();
m_hSession = InternetOpen(_T("Http-connect"), INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, NULL);    //局部

if ( NULL == m_hSession )
{
throw Hir_InitErr;
}

INTERNET_PORT port    = INTERNET_DEFAULT_HTTP_PORT;
std::string strHostName = "";
std::string strPageName = "";

ParseURLWeb(lpUrl, strHostName, strPageName, port);
printf("lpUrl:%s,\nstrHostName:%s,\nstrPageName:%s,\nport:%d\n",lpUrl.c_str(),strHostName.c_str(),strPageName.c_str(),(int)port);

m_hConnect = InternetConnectA(m_hSession, strHostName.c_str(), port, NULL, NULL, INTERNET_SERVICE_HTTP, NULL, NULL);

if ( NULL == m_hConnect )
{
throw Hir_ConnectErr;
}

std::string strRequestType;
if ( Hr_Get == type )
{
strRequestType = "GET";
}
else
{
strRequestType = "POST";
}

m_hRequest = HttpOpenRequestA(m_hConnect,strRequestType.c_str(), strPageName.c_str(),"HTTP/1.1", NULL, NULL, INTERNET_FLAG_RELOAD, NULL);
if ( NULL == m_hRequest )
{
throw Hir_InitErr;
}

DWORD dwHeaderSize = (strHeader.empty()) ? 0 : strlen(strHeader.c_str());
BOOL bRet = FALSE;
if ( Hr_Get == type )
{
bRet = HttpSendRequestA(m_hRequest,strHeader.c_str(),dwHeaderSize,NULL, 0);
}
else
{
DWORD dwSize = (strPostData.empty()) ? 0 : strlen(strPostData.c_str());
bRet = HttpSendRequestA(m_hRequest,strHeader.c_str(),dwHeaderSize,(LPVOID)strPostData.c_str(), dwSize);
}
if ( !bRet )
{
throw Hir_SendErr;
}

char szBuffer[READ_BUFFER_SIZE + 1] = {0};
DWORD dwReadSize = READ_BUFFER_SIZE;
if ( !HttpQueryInfoA(m_hRequest, HTTP_QUERY_RAW_HEADERS, szBuffer, &dwReadSize, NULL) )
{
throw Hir_QueryErr;
}
if ( NULL != strstr(szBuffer, "404") )
{
throw Hir_404;
}

while( true )
{
bRet = InternetReadFile(m_hRequest, szBuffer, READ_BUFFER_SIZE, &dwReadSize);
if ( !bRet || (0 == dwReadSize) )
{
break;
}
szBuffer[dwReadSize]='\0';
strRet.append(szBuffer);
}
}
catch(HttpInterfaceError error)
{
m_error = error;
}
return std::move(strRet);
}

// 解析Json数据 [11/8/2016/shike]
void CWininetHttp::ParseJsonInfo(const std::string &strJsonInfo)
{
Json::Reader reader;                                    //解析json用Json::Reader
Json::Value value;                                        //可以代表任意类型
if (!reader.parse(strJsonInfo, value))
{
CVLog.LogMessage(LOG_LEVEL_ERROR,"[CXLDbDataMgr::GetVideoGisData] Video Gis parse data error...");
}
if (!value["result"].isNull())
{
int nSize = value["result"].size();
for(int nPos = 0; nPos < nSize; ++nPos)                //对数据数组进行遍历
{
//PGCARDDEVDATA stru ;
//stru.strCardName        = value["result"][nPos]["tollgateName"].asString();
//stru.strCardCode        = value["result"][nPos]["tollgateCode"].asString();
//std::string strCDNum    = value["result"][nPos]["laneNumber"].asString();    //增加:车道总数
//stru.nLaneNum            = atoi(strCDNum.c_str());
//std::string strLaneDir    = value["result"][nPos]["laneDir"].asString();        //增加:车道方向,进行规则转换
//stru.strLaneDir            = TransformLaneDir(strLaneDir);
//stru.dWgs84_x            = value["result"][nPos]["wgs84_x"].asDouble();
//stru.dWgs84_y            = value["result"][nPos]["wgs84_y"].asDouble();
//stru.dMars_x            = value["result"][nPos]["mars_x"].asDouble();
//stru.dMars_y            = value["result"][nPos]["mars_y"].asDouble();
//lstCardDevData.emplace_back(stru);
}
}
}

// 解析URL地址 [3/14/2017/shike]
void CWininetHttp::ParseURLWeb( std::string strUrl, std::string& strHostName, std::string& strPageName, WORD& sPort)
{
sPort = 80;
string strTemp(strUrl);
std::size_t nPos = strTemp.find("http://");
if (nPos != std::string::npos)
{
strTemp = strTemp.substr(nPos + 7, strTemp.size() - nPos - 7);
}

nPos = strTemp.find('/');
if ( nPos == std::string::npos )    //没有找到
{
strHostName = strTemp;
}
else
{
strHostName = strTemp.substr(0, nPos);
}

std::size_t nPos1 = strHostName.find(':');
if ( nPos1 != std::string::npos )
{
std::string strPort = strTemp.substr(nPos1 + 1, strHostName.size() - nPos1 - 1);
strHostName = strHostName.substr(0, nPos1);
sPort = (WORD)atoi(strPort.c_str());
}
if ( nPos == std::string::npos )
{
return ;
}
strPageName = strTemp.substr(nPos, strTemp.size() - nPos);
}

// 关闭句柄 [3/14/2017/shike]
void CWininetHttp::Release()
{
ReleaseHandle(m_hRequest);
ReleaseHandle(m_hConnect);
ReleaseHandle(m_hSession);
}

// 释放句柄 [3/14/2017/shike]
void CWininetHttp::ReleaseHandle( HINTERNET& hInternet )
{
if (hInternet)
{
InternetCloseHandle(hInternet);
hInternet = NULL;
}
}

// UTF-8转为GBK2312 [3/14/2017/shike]
char* CWininetHttp::UtfToGbk(const char* utf8)
{
int len = MultiByteToWideChar(CP_UTF8, 0, utf8, -1, NULL, 0);
wchar_t* wstr = new wchar_t[len+1];
memset(wstr, 0, len+1);
MultiByteToWideChar(CP_UTF8, 0, utf8, -1, wstr, len);
len = WideCharToMultiByte(CP_ACP, 0, wstr, -1, NULL, 0, NULL, NULL);
char* str = new char[len+1];
memset(str, 0, len+1);
WideCharToMultiByte(CP_ACP, 0, wstr, -1, str, len, NULL, NULL);
if(wstr) delete[] wstr;
return str;
}

WinInet实现的HTTP接口/WinHttp实现的HTTP接口/Socket实现的HTTP接口/下载文件，使用回调接口获取下载进度，这些代码可以在github开源中获取到。