interface ICoreWebView2_23

interface ICoreWebView2_23
  : public ICoreWebView2_22

This is the ICoreWebView_23 interface for PostWebMessageAsJsonWithAdditionalObjects.

Summary

Members	Descriptions
PostWebMessageAsJsonWithAdditionalObjects	Same as PostWebMessageAsJson, but also has support for posting DOM objects to page content.

Applies to

Product	Introduced
WebView2 Win32	N/A
WebView2 Win32 Prerelease

Members

PostWebMessageAsJsonWithAdditionalObjects

Same as PostWebMessageAsJson, but also has support for posting DOM objects to page content.

public HRESULT PostWebMessageAsJsonWithAdditionalObjects(LPCWSTR webMessageAsJson, ICoreWebView2ObjectCollectionView * additionalObjects)

The additionalObjects property in the DOM MessageEvent fired on the page content is an array-like list of DOM objects that can be posted to the web content. Currently these can be the following types of objects:

Win32	DOM type
ICoreWebView2FileSystemHandle	FileSystemHandle
nullptr	null

The objects are posted to the web content, following the structured-clone semantics, meaning only objects that can be cloned can be posted. They will also behave as if they had been created by the web content they are posted to. For example, if a FileSystemFileHandle is posted to a web content it can only be re-transferred via postMessage to other web content with the same origin. Warning: An app needs to be mindful when using this API to post DOM objects as this API provides the web content with unusual access to sensitive Web Platform features such as filesystem access! Similar to PostWebMessageAsJson the app should check the Source property of WebView2 right before posting the message to ensure the message and objects will only be sent to the target web content that it expects to receive the DOM objects. Additionally, the order of messages that are posted between PostWebMessageAsJson and PostWebMessageAsJsonWithAdditionalObjects may not be preserved.

ScenarioFileSystemHandleShare::ScenarioFileSystemHandleShare(AppWindow* appWindow)
    : m_appWindow(appWindow)
{
    m_webView = m_appWindow->GetWebView();

    CHECK_FAILURE(m_webView->Navigate(m_appWindow->GetLocalUri(c_samplePath).c_str()));

    CHECK_FAILURE(m_webView->add_NavigationCompleted(
        Callback<ICoreWebView2NavigationCompletedEventHandler>(
            [this, appWindow](
                ICoreWebView2* sender,
                ICoreWebView2NavigationCompletedEventArgs* args) -> HRESULT
            {
                wil::com_ptr<ICoreWebView2_23> webview23 =
                    m_webView.try_query<ICoreWebView2_23>();
                CHECK_FEATURE_RETURN_HRESULT(webview23);
                wil::com_ptr<ICoreWebView2Environment> environment =
                    appWindow->GetWebViewEnvironment();
                wil::com_ptr<ICoreWebView2Environment14>
                    environment14 =
                        environment.try_query<ICoreWebView2Environment14>();
                CHECK_FEATURE_RETURN_HRESULT(environment14);
                wil::com_ptr<ICoreWebView2FileSystemHandle> rootHandle;
                CHECK_FAILURE(environment14->CreateWebFileSystemDirectoryHandle(
                    L"C:\\", COREWEBVIEW2_FILE_SYSTEM_HANDLE_PERMISSION_READ_ONLY,
                    &rootHandle));
                wil::com_ptr<ICoreWebView2ObjectCollection> webObjectCollection;
                IUnknown* webObjects[] = {rootHandle.get()};
                CHECK_FAILURE(environment14->CreateObjectCollection(
                    ARRAYSIZE(webObjects), webObjects, &webObjectCollection));
                wil::unique_cotaskmem_string source;
                CHECK_FAILURE(m_webView->get_Source(&source));

                static const wchar_t* expectedDomain = L"appassets.example";
                wil::unique_bstr sourceDomain = GetDomainOfUri(source.get());

                // Check the source to ensure the message is sent to the correct target content.
                if (std::wstring(expectedDomain) == sourceDomain.get())
                {
                    CHECK_FAILURE(webview23->PostWebMessageAsJsonWithAdditionalObjects(
                        L"{ \"messageType\" : \"RootDirectoryHandle\" }",
                        webObjectCollection.get()));
                }

                return S_OK;
            })
            .Get(),
        &m_navigationCompletedToken));
}