Add BlazorWebView skeleton code (#62)

src/BlazorWebView/src/Maui/Tizen/BlazorWebViewHandler.Tizen.cs

@@ -0,0 +1,144 @@
+using System;
+using System.IO;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.FileProviders;
+using Microsoft.Maui.Handlers;
+using TChromium = Tizen.WebView.Chromium;
+using TWebView = Tizen.WebView.WebView;
+
+namespace Microsoft.AspNetCore.Components.WebView.Maui
+{
+	public partial class BlazorWebViewHandler : ViewHandler<IBlazorWebView, WebViewContainer>
+	{
+		private const string AppOrigin = "app://0.0.0.0/";
+		private const string BlazorInitScript = @"
+			window.__receiveMessageCallbacks = [];
+			window.__dispatchMessageCallback = function(message) {
+				window.__receiveMessageCallbacks.forEach(function(callback) { callback(message); });
+			};
+			window.external = {
+				sendMessage: function(message) {
+					window.webkit.messageHandlers.webwindowinterop.postMessage(message);
+				},
+				receiveMessage: function(callback) {
+					window.__receiveMessageCallbacks.push(callback);
+				}
+			};
+
+			Blazor.start();
+
+			(function () {
+				window.onpageshow = function(event) {
+					if (event.persisted) {
+						window.location.reload();
+					}
+				};
+			})();
+		";
+
+		private TizenWebViewManager? _webviewManager;
+		private WebViewExtension.InterceptRequestCallback? _interceptRequestCallback;
+
+		private TWebView NativeWebView => NativeView.WebView;
+
+		private bool RequiredStartupPropertiesSet =>
+			//_webview != null &&
+			HostPage != null &&
+			Services != null;
+
+		protected override WebViewContainer CreateNativeView()
+		{
+			TChromium.Initialize();
+			Context!.CurrentApplication!.Terminated += (s, e) => TChromium.Shutdown();
+			return new WebViewContainer(Context!.NativeParent);
+		}
+
+		protected override void ConnectHandler(WebViewContainer nativeView)
+		{
+			_interceptRequestCallback = OnRequestInterceptCallback;
+			NativeWebView.LoadStarted += OnLoadStarted;
+			NativeWebView.LoadFinished += OnLoadFinished;
+			//NativeWebView.AddJavaScriptMessageHandler("BlazorHandler", PostMessageFromJS);
+			NativeWebView.SetInterceptRequestCallback(_interceptRequestCallback);
+			NativeWebView.GetSettings().JavaScriptEnabled = true;
+
+		}
+
+		protected override void DisconnectHandler(WebViewContainer nativeView)
+		{
+			base.DisconnectHandler(nativeView);
+		}
+
+		private void StartWebViewCoreIfPossible()
+		{
+			if (!RequiredStartupPropertiesSet ||
+				_webviewManager != null)
+			{
+				return;
+			}
+			if (NativeView == null)
+			{
+				throw new InvalidOperationException($"Can't start {nameof(BlazorWebView)} without native web view instance.");
+			}
+
+			var assetConfig = Services!.GetRequiredService<BlazorAssetsAssemblyConfiguration>()!;
+
+			// We assume the host page is always in the root of the content directory, because it's
+			// unclear there's any other use case. We can add more options later if so.
+			var contentRootDir = Path.GetDirectoryName(HostPage!) ?? string.Empty;
+			var hostPageRelativePath = Path.GetRelativePath(contentRootDir, HostPage!);
+
+			var fileProvider = new ManifestEmbeddedFileProvider(assetConfig.AssetsAssembly, root: contentRootDir);
+
+			_webviewManager = new TizenWebViewManager(this, NativeWebView, Services!, MauiDispatcher.Instance, fileProvider, hostPageRelativePath);
+			if (RootComponents != null)
+			{
+				foreach (var rootComponent in RootComponents)
+				{
+					// Since the page isn't loaded yet, this will always complete synchronously
+					_ = rootComponent.AddToWebViewManagerAsync(_webviewManager);
+				}
+			}
+			_webviewManager.Navigate("/");
+		}
+
+		private void OnRequestInterceptCallback(IntPtr context, IntPtr request, IntPtr userdata)
+		{
+			if (request == IntPtr.Zero)
+			{
+				throw new ArgumentNullException(nameof(request));
+			}
+
+			var url = NativeWebView.GetInterceptRequestUrl(request);
+			var urlScheme = url.Substring(0, url.IndexOf(':'));
+
+			if (urlScheme == "app")
+			{
+				var allowFallbackOnHostPage = url.EndsWith("/");
+				if (_webviewManager!.TryGetResponseContentInternal(url, allowFallbackOnHostPage, out var statusCode, out var statusMessage, out var content, out var headers))
+				{
+					var contentType = headers["Content-Type"];
+					var header = $"HTTP/1.0 200 OK\r\nContent-Type:{contentType}; charset=utf-8\r\nCache-Control:no-cache, max-age=0, must-revalidate, no-store\r\n\r\n";
+					var body = new StreamReader(content).ReadToEnd();
+					NativeWebView.SetInterceptRequestResponse(request, header, body, (uint)body.Length);
+					return;
+				}
+			}
+
+			NativeWebView.IgnoreInterceptRequest(request);
+		}
+
+		private void OnLoadStarted(object? sender, EventArgs e)
+		{
+		}
+
+		private void OnLoadFinished(object? sender, EventArgs e)
+		{
+			NativeWebView.SetFocus(true);
+
+			var url = NativeWebView.Url;
+			if (url == AppOrigin)
+				NativeWebView.Eval(BlazorInitScript);
+		}
+	}
+}

src/BlazorWebView/src/Maui/Tizen/TizenWebViewManager.cs

@@ -0,0 +1,37 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using Microsoft.Extensions.FileProviders;
+using TWebView = Tizen.WebView.WebView;
+
+namespace Microsoft.AspNetCore.Components.WebView.Maui
+{
+	public class TizenWebViewManager : WebViewManager
+	{
+		private const string AppOrigin = "app://0.0.0.0/";
+
+		private readonly BlazorWebViewHandler _blazorMauiWebViewHandler;
+		private readonly TWebView _webview;
+
+		public TizenWebViewManager(BlazorWebViewHandler blazorMauiWebViewHandler, TWebView webview, IServiceProvider services, Dispatcher dispatcher, IFileProvider fileProvider, string hostPageRelativePath)
+			: base(services, dispatcher, new Uri(AppOrigin), fileProvider, hostPageRelativePath)
+		{
+			_blazorMauiWebViewHandler = blazorMauiWebViewHandler ?? throw new ArgumentNullException(nameof(blazorMauiWebViewHandler));
+			_webview = webview ?? throw new ArgumentNullException(nameof(webview));
+
+		}
+
+		internal bool TryGetResponseContentInternal(string uri, bool allowFallbackOnHostPage, out int statusCode, out string statusMessage, out Stream content, out IDictionary<string, string> headers) =>
+	TryGetResponseContent(uri, allowFallbackOnHostPage, out statusCode, out statusMessage, out content, out headers);
+
+		/// <inheritdoc />
+		protected override void NavigateCore(Uri absoluteUri)
+		{
+		}
+
+		/// <inheritdoc />
+		protected override void SendMessage(string message)
+		{
+		}
+	}
+}

src/BlazorWebView/src/Maui/Tizen/WebViewContainer.cs

@@ -0,0 +1,31 @@
+using System;
+using Tizen.UIExtensions.ElmSharp;
+using ElmSharp;
+using TWebView = Tizen.WebView.WebView;
+
+namespace Microsoft.AspNetCore.Components.WebView.Maui
+{
+	public class WebViewContainer : WidgetLayout
+	{
+		public TWebView WebView { get; }
+
+		public WebViewContainer(EvasObject parent) : base(parent)
+		{
+			WebView = new TWebView(parent);
+			SetContent(WebView);
+			AllowFocus(true);
+			Focused += OnFocused;
+			Unfocused += OnUnfocused;
+		}
+
+		void OnFocused(object? sender, EventArgs e)
+		{
+			WebView.SetFocus(true);
+		}
+
+		void OnUnfocused(object? sender, EventArgs e)
+		{
+			WebView.SetFocus(false);
+		}
+	}
+}

src/BlazorWebView/src/Maui/Tizen/WebViewExtension.cs

@@ -0,0 +1,69 @@
+using System;
+using System.Runtime.InteropServices;
+using TWebView = Tizen.WebView.WebView;
+
+namespace Microsoft.AspNetCore.Components.WebView.Maui
+{
+    public static class WebViewExtension
+    {
+        public const string ChromiumEwk = "libchromium-ewk.so";
+
+        public static void SetInterceptRequestCallback(this TWebView webView, InterceptRequestCallback callback)
+        {
+			var context = webView.GetContext();
+			var handleField = context.GetType().GetField("_handle", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
+            var contextHandle = (IntPtr?)handleField?.GetValue(context);
+			if (contextHandle != null)
+				ewk_context_intercept_request_callback_set(contextHandle.Value, callback, IntPtr.Zero);
+        }
+
+#pragma warning disable IDE0060 // Remove unused parameter
+        public static bool SetInterceptRequestResponse(this TWebView webView, IntPtr request, string header, string body, uint length)
+#pragma warning restore IDE0060 // Remove unused parameter
+        {
+            return ewk_intercept_request_response_set(request, header, body, length);
+        }
+
+#pragma warning disable IDE0060 // Remove unused parameter
+        public static bool IgnoreInterceptRequest(this TWebView webView, IntPtr request)
+#pragma warning restore IDE0060 // Remove unused parameter
+        {
+            return ewk_intercept_request_ignore(request);
+        }
+
+#pragma warning disable IDE0060 // Remove unused parameter
+		public static string GetInterceptRequestUrl(this TWebView webView, IntPtr request)
+#pragma warning restore IDE0060 // Remove unused parameter
+		{
+			return Marshal.PtrToStringAnsi(_ewk_intercept_request_url_get(request)) ?? string.Empty;
+        }
+
+        [DllImport(ChromiumEwk)]
+		internal static extern IntPtr ewk_view_context_get(IntPtr obj);
+
+		[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+        public delegate void InterceptRequestCallback(IntPtr context, IntPtr request, IntPtr userData);
+
+        [DllImport(ChromiumEwk)]
+		internal static extern void ewk_context_intercept_request_callback_set(IntPtr context, InterceptRequestCallback callback, IntPtr userData);
+
+		[DllImport(ChromiumEwk, EntryPoint = "ewk_intercept_request_url_get")]
+		internal static extern IntPtr _ewk_intercept_request_url_get(IntPtr request);
+
+		[DllImport(ChromiumEwk, EntryPoint = "ewk_intercept_request_http_method_get")]
+		internal static extern IntPtr _ewk_intercept_request_http_method_get(IntPtr request);
+
+		internal static string ewk_intercept_request_http_method_get(IntPtr request)
+		{
+			return Marshal.PtrToStringAnsi(_ewk_intercept_request_http_method_get(request)) ?? string.Empty;
+        }
+
+        [DllImport(ChromiumEwk)]
+		internal static extern bool ewk_intercept_request_ignore(IntPtr request);
+
+#pragma warning disable CA2101 // Specify marshaling for P/Invoke string arguments
+		[DllImport(ChromiumEwk)]
+#pragma warning restore CA2101 // Specify marshaling for P/Invoke string arguments
+		internal static extern bool ewk_intercept_request_response_set(IntPtr request, string header, string body, uint length);
+	}
+}