利用IHTMLWindow2 的get_document 返回E_ACCESSDENIED 解决方法

冷不防 2022-07-24 10:28 42阅读 0赞

获得iframe标签的元素指针  
CComPtr<IHTMLElement> spAdIframe = ...  
CComQIPtr<IHTMLFrameBase2> spFrameBase2 = spAdIframe;  
CComPtr<IHTMLWindow2> spIframeWindow2 = NULL;  
hr = spFrameBase2->get\_contentWindow(&spIframeWindow2);  
由此可得到iframe元素对应的IHTMLWindow2指针，然而如果直接使用IHTMLWindow2::get\_document来获取IHTMLDocument2指针的话，经常得到的是E\_ACCESSDENIED错误，因为iframe元素经常用于跨域的访问，即iframe内的文档来源src与其parent的src的hostname不同，但可以通过下面的方法绕过webbrowser的安全检查。  
  
CComQIPtr<IHTMLDocument2> HtmlWindowToHtmlDocument(CComQIPtr<IHTMLWindow2> spWindow)  
\{  
ATLASSERT(spWindow != NULL);  
   
CComQIPtr<IHTMLDocument2> spDocument;  
HRESULT hRes = spWindow->get\_document(&spDocument);  
   
if ((S\_OK == hRes) && (spDocument != NULL))  
\{  
// The html document was properly retrieved.  
return spDocument;  
\}  
   
// hRes could be E\_ACCESSDENIED that means a security restriction that  
// prevents scripting across frames that loads documents from different internet domains.  
CComQIPtr<IWebBrowser2> spBrws = HtmlWindowToHtmlWebBrowser(spWindow);  
if (spBrws == NULL)  
\{  
return CComQIPtr<IHTMLDocument2>();  
\}  
   
// Get the document object from the IWebBrowser2 object.  
CComQIPtr<IDispatch> spDisp;  
hRes = spBrws->get\_Document(&spDisp);  
spDocument = spDisp;  
   
return spDocument;  
\}  
   
   
CComQIPtr<IWebBrowser2> HtmlWindowToHtmlWebBrowser(CComQIPtr<IHTMLWindow2> spWindow)  
\{  
    ATLASSERT(spWindow != NULL);  
   
    CComQIPtr<IServiceProvider>   spServiceProvider = spWindow;  
    if (spServiceProvider == NULL)  
    \{  
        return CComQIPtr<IWebBrowser2>();  
    \}  
   
    CComQIPtr<IWebBrowser2> spWebBrws;  
    HRESULT hRes = spServiceProvider->QueryService(IID\_IWebBrowserApp, IID\_IWebBrowser2, (void\*\*)&spWebBrws);  
    if (hRes != S\_OK)  
    \{  
        return CComQIPtr<IWebBrowser2>();  
    \}  
   
    return spWebBrws;  
\}