Routing WebView2 REST calls to local .NET 5 Controllers - asp.net

Question

I'm currently designing an Angular SPA web client, backed with .NET5 REST. It's all in the same Visual Studio project, and it builds / runs fine.
I'm now investigating the possibility of distributing this as a windows desktop application. I was able to get Electron.NET to work, but it seems like a round-about solution (Node?!). I also didn't particularly like that the resources were visible/changeable in the distributed app.
This led me to investigate using WebView2 within WPF (Microsoft seems to be making a similar transition with MSTeams.) I've found some examples, but they only use:
solely remote content ("www.bing.com")
local content, but only img / html / etc
postmessage, etc to communicate using custom objects.
None of these is what I want. Well, that's not entirely true. I need #2 to load the Angular SPA, but when the WebView2-hosted Angular invokes HttpClient, I'd like to intercept that request in the host application and Route it to my REST Controllers. This would allow me to keep nearly all of my code intact, and presumably ship a smaller, more obfuscated exe.
Is this possible? obvious? Is my desire fundamentally flawed? (wouldn't be the first time)

Answer 1

Chromium.AspNetCore.Bridge offers a solution to the problem. It uses owin to host the server-side code in memory, and provides a RequestInterceptor to cleanly relay all requests to the "server" code.
The link above has working examples, but briefly:
App.xaml.cs:
private IWebHost _host;
private AppFunc _appFunc;
public AppFunc AppFunc
{
get { return _appFunc; }
}
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
Environment.SetEnvironmentVariable("ASPNETCORE_ENVIRONMENT", "Development");
_ = Task.Run(async () =>
{
var builder = new WebHostBuilder();
builder.ConfigureServices(services =>
{
var server = new OwinServer();
server.UseOwin(appFunc =>
{
_appFunc = appFunc;
});
services.AddSingleton<IServer>(server);
});
_host = builder
.UseStartup<Startup>()
.UseContentRoot(Directory.GetCurrentDirectory())
.Build();
await _host.RunAsync();
});
}
MainWindow.xaml.cs
private AppFunc _appFunc;
public MainWindow()
{
InitializeComponent();
Browser.CoreWebView2InitializationCompleted += Browser_CoreWebView2InitializationCompleted;
}
private void Browser_CoreWebView2InitializationCompleted(object sender, CoreWebView2InitializationCompletedEventArgs e)
{
if (e.IsSuccess)
{
_appFunc = ((App)Application.Current).AppFunc;
Browser.CoreWebView2.WebResourceRequested += BrowserWebResourceRequestedAsync;
Browser.CoreWebView2.AddWebResourceRequestedFilter("*", CoreWebView2WebResourceContext.All);
}
}
private async void BrowserWebResourceRequestedAsync(object sender, CoreWebView2WebResourceRequestedEventArgs e)
{
var deferral = e.GetDeferral();
var request = new ResourceRequest(e.Request.Uri, e.Request.Method, e.Request.Headers, e.Request.Content);
var response = await RequestInterceptor.ProcessRequest(_appFunc, request);
var coreWebView2 = (CoreWebView2)sender;
e.Response = coreWebView2.Environment.CreateWebResourceResponse(response.Stream, response.StatusCode, response.ReasonPhrase, response.GetHeaderString());
deferral.Complete();
}