Update default BlazorWebView host address (#24884)

Update default host address to 0.0.0.1.

Microsoft.Maui-dev.sln

@@ -135,6 +135,7 @@ EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "SharedSource", "SharedSource", "{4F2926C8-43AB-4328-A735-D9EAD699F81D}"
 	ProjectSection(SolutionItems) = preProject
 		src\BlazorWebView\src\SharedSource\AutoCloseOnReadCompleteStream.cs = src\BlazorWebView\src\SharedSource\AutoCloseOnReadCompleteStream.cs
+		src\BlazorWebView\src\SharedSource\HostAddressHelper.cs = src\BlazorWebView\src\SharedSource\HostAddressHelper.cs
 		src\BlazorWebView\src\SharedSource\QueryStringHelper.cs = src\BlazorWebView\src\SharedSource\QueryStringHelper.cs
 		src\BlazorWebView\src\SharedSource\UrlLoadingEventArgs.cs = src\BlazorWebView\src\SharedSource\UrlLoadingEventArgs.cs
 		src\BlazorWebView\src\SharedSource\UrlLoadingStrategy.cs = src\BlazorWebView\src\SharedSource\UrlLoadingStrategy.cs

src/BlazorWebView/src/Maui/BlazorWebView.cs

@@ -11,44 +11,7 @@ namespace Microsoft.AspNetCore.Components.WebView.Maui
 	/// </summary>
 	public partial class BlazorWebView : View, IBlazorWebView
 	{
-		internal static string AppHostAddress { get; } = GetAppHostAddress();
-
-		private const string AppHostAddressAlways0000Switch = "BlazorWebView.AppHostAddressAlways0000";
-
-		private static bool IsAppHostAddressAlways0000Enabled =>
-			AppContext.TryGetSwitch(AppHostAddressAlways0000Switch, out var enabled) && enabled;
-
-		private static string GetAppHostAddress()
-		{
-			if (IsAppHostAddressAlways0000Enabled)
-			{
-				return "0.0.0.0";
-			}
-			else
-			{
-#if IOS || MACCATALYST
-				// On iOS/MacCatalyst 18 and higher the 0.0.0.0 address does not work, so we use localhost instead.
-				// This preserves behavior on older versions of those systems, while defaulting to new behavior on
-				// the new system.
-
-				// Note that pre-release versions of iOS/MacCatalyst have the expected Major/Minor values,
-				// but the Build, MajorRevision, MinorRevision, and Revision values are all -1, so we need
-				// to pass in int.MinValue for those values.
-
-				if (System.OperatingSystem.IsIOSVersionAtLeast(major: 18, minor: int.MinValue, build: int.MinValue) ||
-					System.OperatingSystem.IsMacCatalystVersionAtLeast(major: 18, minor: int.MinValue, build: int.MinValue))
-				{
-					return "localhost";
-				}
-				else
-				{
-					return "0.0.0.0";
-				}
-#else
-				return "0.0.0.0";
-#endif
-			}
-		}
+		internal static string AppHostAddress { get; } = HostAddressHelper.GetAppHostAddress();
 
 		private readonly JSComponentConfigurationStore _jSComponents = new();
 

src/BlazorWebView/src/SharedSource/HostAddressHelper.cs

@@ -0,0 +1,19 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.AspNetCore.Components.WebView;
+
+internal static class HostAddressHelper
+{
+	private const string AppHostAddressAlways0000Switch = "BlazorWebView.AppHostAddressAlways0000";
+
+	private static bool IsAppHostAddressAlways0000Enabled =>
+		AppContext.TryGetSwitch(AppHostAddressAlways0000Switch, out var enabled) && enabled;
+
+	public static string GetAppHostAddress()
+		=> IsAppHostAddressAlways0000Enabled
+			? "0.0.0.0"
+			: "0.0.0.1";
+}

src/BlazorWebView/src/SharedSource/WebView2WebViewManager.cs

@@ -49,10 +49,10 @@ internal class WebView2WebViewManager : WebViewManager
 		// Using an IP address means that WebView2 doesn't wait for any DNS resolution,
 		// making it substantially faster. Note that this isn't real HTTP traffic, since
 		// we intercept all the requests within this origin.
-		internal static readonly string AppHostAddress = "0.0.0.0";
+		internal static readonly string AppHostAddress = HostAddressHelper.GetAppHostAddress();
 
 		/// <summary>
-		/// Gets the application's base URI. Defaults to <c>https://0.0.0.0/</c>
+		/// Gets the application's base URI. Defaults to <c>https://0.0.0.1/</c>.
 		/// </summary>
 		protected static readonly string AppOrigin = $"https://{AppHostAddress}/";