Trident内核中取验证码图片的几种方法

程序中用了IE的内核，想取出网站中的验证码图片，单独显示出来，调研了以下几路方法

1、枚举所有缓存文件，进行处理，找到想要的，核心代码

if (0)//这段代码可以枚举所有缓存资源，然后对应做处理

{

    LPINTERNET_CACHE_ENTRY_INFO lpCacheEntry = NULL;

    HANDLE hCacheDir = NULL;

    DWORD dwTrySize, dwEntrySize = 4096;

    DWORD dwError = ERROR_INSUFFICIENT_BUFFER;

    BOOL bSuccess, bDone = FALSE; //是否已经处理完，初始设为false

    while(!bDone){

        switch(dwError){

        case ERROR_INSUFFICIENT_BUFFER:     

            if(lpCacheEntry) 

            {

                delete [] lpCacheEntry;

            }

            lpCacheEntry = (LPINTERNET_CACHE_ENTRY_INFO) new char[dwEntrySize];

            lpCacheEntry->dwStructSize = dwEntrySize;

            dwTrySize = dwEntrySize;

            if(!hCacheDir)

            {//为空，说明第一次执行，需要找第一个

                hCacheDir = FindFirstUrlCacheEntry(NULL,lpCacheEntry,&dwTrySize);

                bSuccess = (hCacheDir != NULL);

            }

            else 

            {

                bSuccess = FindNextUrlCacheEntry(hCacheDir,lpCacheEntry,&dwTrySize);

            }

            if(!bSuccess){

                dwError = GetLastError();

                dwEntrySize = dwTrySize; //使用得到的新长度 

            }

            else 

            {

                dwError = ERROR_SUCCESS;

            }

            break; 

            //we are done

        case ERROR_NO_MORE_ITEMS:

            bDone = TRUE;

            break;

            //we have got an entry

        case ERROR_SUCCESS:

            if(bSuccess && (NORMAL_CACHE_ENTRY & lpCacheEntry->CacheEntryType))

            { //

                CString sUrl1 = lpCacheEntry->lpszSourceUrlName;

                if (sUrl1.Compare(s) == 0)

                {

                    //处理

                }

                //     CTime lastModified(lpCacheEntry->LastModifiedTime);

                //     CTime lastAccessed(lpCacheEntry->LastAccessTime);

                //a changed cookie - delete it!

                //     if(lastModified >= m_time || lastAccessed >= m_time){

                //const   CString   name   =   lpCacheEntry->lpszSourceUrlName;  

                //const   CString   result   =   lastModified.Format("%I:%M:%S%p   %d   %b   %Y");  

                //MessageBox   (NULL,   name   +   "   last   modified   "   +   result,   "Deleting cookie",   MB_OK);  

                //DeleteUrlCacheEntry(lpCacheEntry->lpszSourceUrlName);

            }

            //get ready for next entry

            dwTrySize = dwEntrySize;

            if(!FindNextUrlCacheEntry(hCacheDir,lpCacheEntry,&dwTrySize))

            {

                dwError = GetLastError();

                dwEntrySize = dwTrySize;   //使用得到的新长度

            }

            else 

            {

                dwError = ERROR_SUCCESS;

            }

            break;

            //unknown error

        default:

            CString strError; strError.Format(_T("There is an error (%d) when trying deleting temporary internet files.\r\n"),   dwError);  

            TRACE(strError);

            bDone = TRUE;

            break;   

            if(bDone) 

                break;

            Sleep(10);  if(lpCacheEntry){ delete [] lpCacheEntry; lpCacheEntry = NULL;}

            if(hCacheDir){ FindCloseUrlCache(hCacheDir); hCacheDir = NULL;}

            break;

        }

    }

}

2、直接取某个URL对应的缓存资源

if (1)//这段代码可以直接从缓存找到对应URL的图片资源的路径

{

    CString s = dispImg.Get(L"src");

    if (1)

    {

        LPINTERNET_CACHE_ENTRY_INFO lpCacheEntry = NULL;

        DWORD dwEntrySize = 4096;

        lpCacheEntry = (LPINTERNET_CACHE_ENTRY_INFO) new char[dwEntrySize];

        lpCacheEntry->dwStructSize = dwEntrySize;

        BOOL b = GetUrlCacheEntryInfo(s, lpCacheEntry, &dwEntrySize);

        CString sPath = lpCacheEntry->lpszLocalFileName;

    }

}

3、在网页新建一canvas，将图片绘上，然后toDataURL，这样可以得到png格式的，经过base64编码后的字符串，该方法只能在ie9以上使用

if (0)//这段代码只能在IE9以上运行，可以将图片绘到canvas上，再取出png格式经base64编码后的数据

    //然后解码，存到文件中，就得到一个png图片

    //HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION

    //设置对应程序的dword值为10001为强制ie10，9999为强制ie9，8888为强制ie8

{

    CDispatch dispCanvas = disp.InvokePtr(L"createElement", L"canvas");

    dispCanvas.Put(L"width", dispImg.Get(L"naturalWidth"));

    dispCanvas.Put(L"height", dispImg.Get(L"naturalHeight"));

    CDispatch dispCtx = dispCanvas.InvokePtr(L"getContext", L"2d");

    dispCtx.Invoke(L"drawImage", dispImg.p, 0, 0);

    CString sData = dispCanvas.Invoke(L"toDataURL", L"image/png");

    sData = sData.Right(sData.GetLength() - 22);



    int nBuffer = sData.GetLength() + 1;

    byte* buffer = new byte[nBuffer];

    memset(buffer, 0, nBuffer);

    Base64Decode(sData, sData.GetLength(), buffer, &nBuffer);



    CFile f("1.png", CFile::modeCreate|CFile::modeWrite);

    f.Write(buffer, nBuffer);

    delete[] buffer;

}