如何通过代理服务器进行HTTP文件下载？立即结帐，谢谢！

Question

下面是我写的一个实现HTTP文件下载的函数，采用直连方式。如何让它支持HTTP代理？是修改修改某些参数？还是干脆采用别的方式？
BOOL HeslNetOper::HttpFileDown(CString& strDownURL,CString& strLocalSavePath)
{
CInternetSession lInternetSession(NULL,1,INTERNET_OPEN_TYPE_DIRECT,NULL,NULL,0);
//1、打开下载文件
CHttpFile* pHttpFile=NULL;
try
{
pHttpFile=(CHttpFile*)lInternetSession.OpenURL(strDownURL); DWORD dwRet;
pHttpFile->QueryInfoStatusCode(dwRet);
}
catch(CInternetException* e)
{
char szCause[255];
e->GetErrorMessage(szCause, 255);
AfxMessageBox(szCause);
e->Delete();
pHttpFile=NULL; return FALSE;
}
//2、保存下载文件
if(pHttpFile)
{
//打开本地文件
CStdioFile lStdioFile;
lStdioFile.Open(strLocalSavePath,CFile::modeCreate|CFile::modeWrite|CFile::typeBinary);
//向本地文件中写入数据
char chrBuffer[2048];
DWORD dwBytesRead;
while((dwBytesRead=pHttpFile->Read(chrBuffer,2048))>0)
{
lStdioFile.Write(chrBuffer,dwBytesRead);
} //资源回收
lStdioFile.Close();
pHttpFile->Close();
delete pHttpFile;
pHttpFile=NULL;
}
}

Answer 1

DWORD GetHttpFileByUrl(CString& strUrl,CString& strFileText)
{
char szTextBuffer[1024];
memset(szTextBuffer,0,sizeof(szTextBuffer));    CInternetSession NetSession;
CHttpFile *pFile = NULL; 

DWORD dwReadBytes = 0;

TRY
{
CString strServer;
CString strObject;
DWORD dwServiceType;
INTERNET_PORT nServerPort;

if(!AfxParseURL(strUrl,dwServiceType,strServer,strObject,nServerPort))
{
return 1;
//URL address is invalid.
}

CHttpConnection *pHttpConnection = NetSession.GetHttpConnection(strServer,nServerPort,NULL,NULL);
if(pHttpConnection == NULL) //Network net connection.
{
return 5;
}

RE_SEND_HTTP_REQUEST: pFile = pHttpConnection->OpenRequest(
NULL, strObject, NULL, 1, NULL, NULL,
INTERNET_FLAG_RELOAD | INTERNET_FLAG_DONT_CACHE | INTERNET_FLAG_KEEP_CONNECTION
);
if(pFile==NULL)
{
NetSession.Close();
return 10;
}

//AfxMessageBox("SendRequest");
if(!pFile->SendRequest(NULL))
{
NetSession.Close();
return 15;
}
DWORD dwStatusCode;
if(!pFile->QueryInfoStatusCode(dwStatusCode))
{
NetSession.Close();
return 20;
} if (dwStatusCode == HTTP_STATUS_PROXY_AUTH_REQ || dwStatusCode == HTTP_STATUS_DENIED)
{
char szData[51];
DWORD dwSize;
//may read error info of the file to szData
do
{
//::InternetReadFile(m_hHttpFile, (LPVOID)szData, 50, &dwSize);
dwSize = pFile->Read(&szData,50);
}
while (dwSize != 0);

if(!pFile->ErrorDlg(
NULL,ERROR_INTERNET_INCORRECT_PASSWORD,
FLAGS_ERROR_UI_FILTER_FOR_ERRORS |
FLAGS_ERROR_UI_FLAGS_GENERATE_DATA|
FLAGS_ERROR_UI_FLAGS_CHANGE_OPTIONS,
NULL)
)
{
NetSession.Close();
return 25;
} //until dwStatusCode==HTTP_STATUS_OK we can do next
goto RE_SEND_HTTP_REQUEST;

}
else
{
if(dwStatusCode!=HTTP_STATUS_OK)
{
//NetSession.Close();
//return 30;
}
} //?áè?êy?Yμ?szTextBuffer
DWORD dwLength = pFile->GetLength();
if(dwLength < sizeof(szTextBuffer))
{
dwReadBytes = pFile->Read(szTextBuffer, dwLength);
}
else
{
dwReadBytes = pFile->Read(szTextBuffer, sizeof(szTextBuffer)-1);   //?á·μ??μ??á1?
}
        
strFileText = szTextBuffer;
pFile->Close();
NetSession.Close();
}
CATCH(CInternetException , pEr)
{
//pEr->ReportError();
return 2;
}
    CATCH(CFileException , pEr)
{
//pEr->ReportError();
return 3;
}
END_CATCH return 0;
}