interface ICoreWebView2Experimental27

Note

This an experimental API that is shipped with our prerelease SDK. See WebView2 release notes.

interface ICoreWebView2Experimental27
  : public IUnknown

This is the ICoreWebView2Experimental27 interface.

Summary

Members	Descriptions
add_SaveFileSecurityCheckStarting	Adds an event handler for the SaveFileSecurityCheckStarting event.
remove_SaveFileSecurityCheckStarting	Removes an event handler previously added with add_SaveFileSecurityCheckStarting.

Applies to

Product	Introduced
WebView2 Win32	N/A
WebView2 Win32 Prerelease

Members

add_SaveFileSecurityCheckStarting

Adds an event handler for the SaveFileSecurityCheckStarting event.

public HRESULT add_SaveFileSecurityCheckStarting(ICoreWebView2ExperimentalSaveFileSecurityCheckStartingEventHandler * eventHandler, EventRegistrationToken * token)

This event will be raised during system FileTypePolicy checking the dangerous file extension list.

Developers can specify their own logic for determining whether to allow a particular type of file to be saved from the document origin URI. Developers can also determine the save decision based on other criteria.

Here are two properties in ICoreWebView2SaveFileSecurityCheckStartingEventArgs to manage the decision, CancelSave and SuppressDefaultPolicy.

Table of Properties' value and result:

CancelSave	SuppressDefaultPolicy	Result
False	False	Perform the default policy check. It may show the
	security warning UI if the file extension is
	dangerous.
-------—	---—	------------------—
False	True	Skip the default policy check and the possible
	security warning. Start saving or downloading.
-------—	---—	------------------—
True	Any	Skip the default policy check and the possible
	security warning. Abort save or download.

// This example will register the event with two custom rules.
// 1. Suppressing file type policy, security dialog, and allows saving ".eml" files
// directly.
// 2. When the URI is trusted.- Showing customized warning UI when saving ".iso"
// files. It allows to block the saving directly.
bool ScenarioFileTypePolicy::SuppressPolicyForExtension()
{
    if (!m_webView2Experimental27)
        return false;
    m_webView2Experimental27->add_SaveFileSecurityCheckStarting(
        Callback<ICoreWebView2ExperimentalSaveFileSecurityCheckStartingEventHandler>(
            [this](
                ICoreWebView2* sender,
                ICoreWebView2ExperimentalSaveFileSecurityCheckStartingEventArgs* args)
                -> HRESULT
            {
                // Get the file extension for file to be saved.
                // And convert the extension to lower case for a
                // case-insensitive comparasion.
                wil::unique_cotaskmem_string extension;
                CHECK_FAILURE(args->get_FileExtension(&extension));
                std::wstring extension_lower = extension.get();
                std::transform(
                    extension_lower.begin(), extension_lower.end(), extension_lower.begin(),
                    ::towlower);

                // Suppress default policy for ".eml" file.
                if (wcscmp(extension_lower.c_str(), L".eml") == 0)
                {
                    CHECK_FAILURE(args->put_SuppressDefaultPolicy(TRUE));
                }

                // Cancel save/download for ".iso" file.
                if (wcscmp(extension_lower.c_str(), L".iso") == 0)
                {
                    wil::com_ptr<ICoreWebView2Deferral> deferral;
                    CHECK_FAILURE(args->GetDeferral(&deferral));

                    m_appWindow->RunAsync(
                        [this, args = wil::make_com_ptr(args), deferral]()
                        {
                            // With the deferral, the cancel decision and
                            // message box can be replaced with a customized UI.
                            CHECK_FAILURE(args->put_CancelSave(TRUE));
                            MessageBox(
                                m_appWindow->GetMainWindow(), L"The saving has been blocked",
                                L"Info", MB_OK);
                            CHECK_FAILURE(deferral->Complete());
                        });
                }
                return S_OK;
            })
            .Get(),
        &m_saveFileSecurityCheckStartingToken);

    MessageBox(
        m_appWindow->GetMainWindow(),
        (L"Example rules of Dangerous File Security Policy has been applied in this demo page"),
        L"Info", MB_OK);
    return true;
}

remove_SaveFileSecurityCheckStarting

Removes an event handler previously added with add_SaveFileSecurityCheckStarting.

public HRESULT remove_SaveFileSecurityCheckStarting(EventRegistrationToken token)