interface ICoreWebView2Experimental27

Note

This reference is no longer being maintained. For the latest API reference, see WebView2 API Reference.

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)