protected override async Task HandleWebResourceRequest(CoreWebView2WebResourceRequestedEventArgs eventArgs)
{
// Unlike server-side code, we get told exactly why the browser is making the request,
// so we can be smarter about fallback. We can ensure that 'fetch' requests never result
// in fallback, for example.
var allowFallbackOnHostPage =
eventArgs.ResourceContext == CoreWebView2WebResourceContext.Document ||
eventArgs.ResourceContext == CoreWebView2WebResourceContext.Other; // e.g., dev tools requesting page source
// Get a deferral object so that WebView2 knows there's some async stuff going on. We call Complete() at the end of this method.
using var deferral = eventArgs.GetDeferral();
var requestUri = QueryStringHelper.RemovePossibleQueryString(eventArgs.Request.Uri);
// First, call into WebViewManager to see if it has a framework file for this request. It will
// fall back to an IFileProvider, but on WinUI it's always a NullFileProvider, so that will never
// return a file.
if (TryGetResponseContent(requestUri, allowFallbackOnHostPage, out var statusCode, out var statusMessage, out var content, out var headers) &&
statusCode != 404)
{
// NOTE: This is stream copying is to work around a hanging bug in WinRT with managed streams.
// See issue https://github.com/microsoft/CsWinRT/issues/670
var memStream = new MemoryStream();
content.CopyTo(memStream);
var ms = new InMemoryRandomAccessStream();
await ms.WriteAsync(memStream.GetWindowsRuntimeBuffer());
var headerString = GetHeaderString(headers);
eventArgs.Response = _coreWebView2Environment !.CreateWebResourceResponse(ms, statusCode, statusMessage, headerString);
}
private void OnRequestInterceptCallback(IntPtr context, IntPtr request, IntPtr userdata)
{
if (request == IntPtr.Zero)
{
return;
}
var url = NativeWebView.GetInterceptRequestUrl(request);
if (url.StartsWith(AppOrigin))
{
var allowFallbackOnHostPage = url.EndsWith("/");
url = QueryStringHelper.RemovePossibleQueryString(url);
if (_webviewManager !.TryGetResponseContentInternal(url, allowFallbackOnHostPage, out var statusCode, out var statusMessage, out var content, out var headers))
{
var header = $"HTTP/1.0 200 OK\r\n";
foreach (var item in headers)
{
header += $"{item.Key}:{item.Value}\r\n";
}
header += "\r\n";
using (MemoryStream memstream = new MemoryStream())
{
content.CopyTo(memstream);
var body = memstream.ToArray();
NativeWebView.SetInterceptRequestResponse(request, header, body, (uint)body.Length);
}
return;
}
}
NativeWebView.IgnoreInterceptRequest(request);
}
protected virtual async Task HandleWebResourceRequest(ICoreWebView2WebResourceRequestedEventArgsWrapper eventArgs)
{
// Unlike server-side code, we get told exactly why the browser is making the request,
// so we can be smarter about fallback. We can ensure that 'fetch' requests never result
// in fallback, for example.
var allowFallbackOnHostPage =
eventArgs.ResourceContext == CoreWebView2WebResourceContextWrapper.Document ||
eventArgs.ResourceContext == CoreWebView2WebResourceContextWrapper.Other; // e.g., dev tools requesting page source
var requestUri = QueryStringHelper.RemovePossibleQueryString(eventArgs.Request.Uri);
// First, call into WebViewManager to see if it has a framework file for this request. It will
// fall back to an IFileProvider, but on WinUI it's always a NullFileProvider, so that will never
// return a file.
if (TryGetResponseContent(requestUri, allowFallbackOnHostPage, out var statusCode, out var statusMessage, out var content, out var headers))
{
// NOTE: This is stream copying is to work around a hanging bug in WinRT with managed streams
var memStream = new MemoryStream();
content.CopyTo(memStream);
var ms = new InMemoryRandomAccessStream();
await ms.WriteAsync(memStream.GetWindowsRuntimeBuffer());
var headerString = GetHeaderString(headers);
eventArgs.SetResponse(ms, statusCode, statusMessage, headerString);
}
}
private byte[] GetResponseBytes(string url, out string contentType, out int statusCode)
{
var allowFallbackOnHostPage = AppOriginUri.IsBaseOfPage(url);
url = QueryStringHelper.RemovePossibleQueryString(url);
if (_webViewHandler._webviewManager !.TryGetResponseContentInternal(url, allowFallbackOnHostPage, out statusCode, out var statusMessage, out var content, out var headers))
{
statusCode = 200;
using var ms = new MemoryStream();
content.CopyTo(ms);
content.Dispose();
contentType = headers["Content-Type"];
return(ms.ToArray());
}
private async Task InitializeWebView2()
{
await _webview.CreateEnvironmentAsync().ConfigureAwait(true);
await _webview.EnsureCoreWebView2Async();
ApplyDefaultWebViewSettings();
_webview.CoreWebView2.AddWebResourceRequestedFilter($"{AppOrigin}*", CoreWebView2WebResourceContextWrapper.All);
var removeResourceCallback = _webview.CoreWebView2.AddWebResourceRequestedHandler((s, eventArgs) =>
{
// Unlike server-side code, we get told exactly why the browser is making the request,
// so we can be smarter about fallback. We can ensure that 'fetch' requests never result
// in fallback, for example.
var allowFallbackOnHostPage =
eventArgs.ResourceContext == CoreWebView2WebResourceContextWrapper.Document ||
eventArgs.ResourceContext == CoreWebView2WebResourceContextWrapper.Other; // e.g., dev tools requesting page source
var requestUri = QueryStringHelper.RemovePossibleQueryString(eventArgs.Request.Uri);
if (TryGetResponseContent(requestUri, allowFallbackOnHostPage, out var statusCode, out var statusMessage, out var content, out var headers))
{
var headerString = GetHeaderString(headers);
eventArgs.SetResponse(content, statusCode, statusMessage, headerString);
}
});
// The code inside blazor.webview.js is meant to be agnostic to specific webview technologies,
// so the following is an adaptor from blazor.webview.js conventions to WebView2 APIs
await _webview.CoreWebView2.AddScriptToExecuteOnDocumentCreatedAsync(@"
window.external = {
sendMessage: message => {
window.chrome.webview.postMessage(message);
},
receiveMessage: callback => {
window.chrome.webview.addEventListener('message', e => callback(e.data));
}
};
").ConfigureAwait(true);
QueueBlazorStart();
var removeMessageCallback = _webview.CoreWebView2.AddWebMessageReceivedHandler(e
=> MessageReceived(new Uri(e.Source), e.WebMessageAsString));
}
protected virtual Task HandleWebResourceRequest(CoreWebView2WebResourceRequestedEventArgs eventArgs)
{
#if WEBVIEW2_WINFORMS || WEBVIEW2_WPF
// Unlike server-side code, we get told exactly why the browser is making the request,
// so we can be smarter about fallback. We can ensure that 'fetch' requests never result
// in fallback, for example.
var allowFallbackOnHostPage =
eventArgs.ResourceContext == CoreWebView2WebResourceContext.Document ||
eventArgs.ResourceContext == CoreWebView2WebResourceContext.Other; // e.g., dev tools requesting page source
var requestUri = QueryStringHelper.RemovePossibleQueryString(eventArgs.Request.Uri);
if (TryGetResponseContent(requestUri, allowFallbackOnHostPage, out var statusCode, out var statusMessage, out var content, out var headers))
{
var headerString = GetHeaderString(headers);
eventArgs.Response = _coreWebView2Environment.CreateWebResourceResponse(content, statusCode, statusMessage, headerString);
}
#elif WEBVIEW2_MAUI
// No-op here because all the work is done in the derived WinUIWebViewManager
#endif
return(Task.CompletedTask);
}
public override WebResourceResponse?ShouldInterceptRequest(AWebView?view, IWebResourceRequest?request)
{
if (request is null)
{
throw new ArgumentNullException(nameof(request));
}
var allowFallbackOnHostPage = false;
var requestUri = request?.Url?.ToString();
var appBaseUri = new Uri(AppOrigin);
var fileUri = requestUri != null ? new Uri(requestUri) : null;
if (fileUri != null && appBaseUri.IsBaseOf(fileUri))
{
var relativePath = appBaseUri.MakeRelativeUri(fileUri).ToString();
if (string.IsNullOrEmpty(relativePath))
{
// For app root, use host page (something like wwwroot/index.html)
allowFallbackOnHostPage = true;
}
}
requestUri = QueryStringHelper.RemovePossibleQueryString(requestUri);
if (requestUri != null &&
_webViewHandler != null &&
_webViewHandler.WebviewManager != null &&
_webViewHandler.WebviewManager.TryGetResponseContentInternal(requestUri, allowFallbackOnHostPage, out var statusCode, out var statusMessage, out var content, out var headers))
{
var contentType = headers["Content-Type"];
return(new WebResourceResponse(contentType, "UTF-8", statusCode, statusMessage, headers, content));
}
return(base.ShouldInterceptRequest(view, request));
}
