/// <summary>
/// Handle the <see cref="IWebView.DOMContentLoaded" /> event, ensuring the JavaScript bridge is loaded.
/// </summary>
/// <param name="sender">The sender.</param>
/// <param name="e">The <see cref="WebViewControlDOMContentLoadedEventArgs"/> instance containing the event data.</param>
/// <remarks>
/// The bridge can be loaded by
/// - Explicitly using a script tag in the markup of the page, or
/// - Explicitly through handling the navigation or DOM events
///
/// If the JavaScript bridge is already loaded, it will not be loaded again.
/// </remarks>
/// <seealso cref="AllowedScriptNotifyUris"/>
/// <seealso cref="LoadBridge"/>
private void OnWebViewDOMContentLoaded(object sender, WebViewControlDOMContentLoadedEventArgs e)
{
if (e.Uri != null &&
AllowedScriptNotifyUris != null &&
AllowedScriptNotifyUris.Contains(e.Uri) &&
sender is IWebView webView)
{
LoadBridge();
}
}
/// <summary>
/// Handles the <see cref="IWebView.ScriptNotify" /> event.
/// </summary>
/// <param name="sender">The sender.</param>
/// <param name="e">The <see cref="WebViewControlScriptNotifyEventArgs"/> instance containing the event data.</param>
/// <remarks>
/// Since there may be other uses of <code>window.external.notify</code> in use, this method checks to see if the
/// message came from a URI within <see cref="AllowedScriptNotifyUris"/> and the bridge before processing it. If it did,
/// it triggers processing of all queued messages within the bridge asynchronously.
/// </remarks>
/// <seealso cref="AllowedScriptNotifyUris"/>
/// <seealso cref="IsJavaScriptBridgeMessage"/>
/// <seealso cref="FlushAsync"/>
private void OnWebViewScriptNotify(object sender, WebViewControlScriptNotifyEventArgs e)
{
Trace.WriteLine($"Entering {typeof(JavaScriptBridge).FullName}.{nameof(OnWebViewScriptNotify)}", Constants.TraceName);
// White list
// WinForms/WPF do not validate the origins for ScriptNotify like UWP does
// This needs to be done manually for security
if (e.Uri != null && AllowedScriptNotifyUris != null && AllowedScriptNotifyUris.Contains(e.Uri))
{
var message = e.Value;
if (sender is IWebView webView && IsJavaScriptBridgeMessage(message))
{
Trace.WriteLine($"Received command {message}", Constants.TraceName);
// Asynchronously flush the messages from the JavaScript bridge
FlushAsync();
}
}
else
{
Trace.WriteLine($"{nameof(IWebView.ScriptNotify)} received from unknown origin {e.Uri?.Host}", Constants.TraceName);
}
}
