一个下载Http文件到本地的Demo

最近在做一个项目，需要把一个internet网上的Url文件下载到本地，下面是我使用的一些代码

该代码支持线程.

 

头文件：

#pragma once

#include "afxmt.h"
#include "wininet.h"

#define  WM_HTTP_DOWNLOAD_FINISH WM_USER + 200

 enum e_Down_ErrorCode
{
 e_Down_ErrorCode_Lock   = 1,
 e_Down_ErrorCode_HttpQueryInfo = 2,
 e_Down_ErrorCode_OpenFile = 3,
 e_Down_ErrorCode_Length = 4,
 e_Down_ErrorCode_IO_PENDING = 5
};

class CDownload
{
public:
 CDownload(void);
 ~CDownload(void);

 enum STATUS
 {
  STATUS_IDLE,
  STATUS_OPENING,
  STATUS_DOWNLOADING,
  STATUS_COMPLETE,
  STATUS_ERROR,
 };

 void Start(CString strUrl, CString strFilePath ,int nDowStype , CDialog* pParent);
private:
 static UINT _ThreadEntry(LPVOID lpvParam);
 void Thread();
 
private:
 CString m_strUrl;
 CString m_strFilePath;
 int m_nDownType;
 CDialog* m_pParent;
};

 

 

实现文件:

 

#include "StdAfx.h"
#include "Download.h"
#include <list>

#include "AsiaTrader.h"

using namespace std;

CDownload::CDownload(void)
{
}

CDownload::~CDownload(void)
{
}

void CDownload::Start(CString strUrl, CString strFilePath , int nDowStype ,CDialog* pParent)
{
 m_strUrl = strUrl;
 m_strFilePath = strFilePath;
 m_nDownType = nDowStype;

 m_pParent = pParent ;

 AfxBeginThread(_ThreadEntry, this);
}

UINT CDownload::_ThreadEntry(LPVOID lpvParam)
{
 CDownload *pThis = (CDownload *) lpvParam;

 pThis->Thread();

 return 0;
}

void CDownload::Thread()
{
 char   * pBuf = NULL ;
 int    nBufLen = 0 ;
 TRY
 {
  // connection
  CInternetSession   sess ;
  sess.SetOption (INTERNET_OPTION_CONNECT_TIMEOUT, Query_TimeOut_Time) ;
  sess.SetOption (INTERNET_OPTION_CONNECT_BACKOFF, 1000) ;
  sess.SetOption (INTERNET_OPTION_CONNECT_RETRIES, 1) ;

  DWORD       dwFlag = INTERNET_FLAG_TRANSFER_BINARY|INTERNET_FLAG_DONT_CACHE|INTERNET_FLAG_RELOAD ;

  CHttpFile   * pF = (CHttpFile*)sess.OpenURL(m_strUrl, 1, dwFlag);
  ASSERT(pF);
  if (!pF)
  {
   AfxThrowInternetException(1);
  }

  // connection status
  CString      str ;
  pF->QueryInfo (HTTP_QUERY_STATUS_CODE, str) ;

  // Proxy Authentication Required
  if (str == _T("407"))
  {
   CString   strUsername, strPassword ;   
   pF->SetOption (INTERNET_OPTION_PROXY_USERNAME, (VOID*)(LPCTSTR)strUsername, strUsername.GetLength()) ;
   pF->SetOption (INTERNET_OPTION_PROXY_PASSWORD, (VOID*)(LPCTSTR)strPassword, strPassword.GetLength()) ;
   pF->SendRequest (NULL) ;
  }

  pF->QueryInfo (HTTP_QUERY_STATUS_CODE, str) ;
  if (str != _T("200"))
  {
   pF->Close() ;
   delete pF ;
   AfxThrowInternetException(1);
  }

  // start download
  pF->QueryInfo (HTTP_QUERY_CONTENT_LENGTH, str) ; // file's length

  if (_ttoi(str))
  {
   // know file's size
   int     nLen = (nBufLen = _ttoi(str)) ;
   char    * p = (pBuf = new char[nLen+8]) ;
   ZeroMemory (p, nLen+8) ;

   while ( TRUE)
   {
    // download 8K every
    int   n = pF->Read (p, (nLen < 8192) ? nLen : 8192) ;
    if (n <= 0)
     break ;      // success exit
    p += n ;
    nLen -= n ;    
   }

   // interrupted
   if (nLen != 0)
   {
    delete[] pBuf; pBuf=NULL;
    nBufLen = 0 ;
   }
  }

  pF->Close() ;
  delete pF ;
 }
 CATCH_ALL(e)
 {
 }
 END_CATCH_ALL

 if (pBuf)
 {
  CFile   outFile (m_strFilePath, CFile::modeCreate|CFile::modeReadWrite);
  outFile.Write (pBuf,nBufLen) ; 
  outFile.Close();

  m_pParent->SendMessage(WM_HTTP_DOWNLOAD_FINISH,1,m_nDownType);
  delete[] pBuf ;
 }
 else
 {  
  m_pParent->SendMessage(WM_HTTP_DOWNLOAD_FINISH,0,m_nDownType);
  return  ;
 } 
 return   ;
}