Maui iOS failing to load local resources in using WebView Source

[Telavian]

Description

I would like to load local html content in a WebView. Assuming the file was named data.html and was packaged correctly then
<WebView Source="data.html" />
works on windows and android however it fails on iOS with a uri format exception.

This appears to be because the windows and android versions handle relative uri paths while the iOS one does not.
Windows:

maui/src/Core/src/Platform/Windows/MauiWebView.cs

Line 122 in 0a07dab

uri = new Uri(LocalScheme + url, UriKind.RelativeOrAbsolute);

Android:

maui/src/Core/src/Platform/Android/MauiWebView.cs

Line 38 in 0a07dab

url = AssetBaseUrl + url;

The iOS one does a new Uri() directly which will fail if the uri is not an absolute path.

maui/src/Core/src/Platform/iOS/MauiWKWebView.cs

Line 93 in 0a07dab

var uri = new Uri(url ?? string.Empty);

Thus that line throws an exceptions which kills the application.

 	0x88 in System.Uri.CreateThis	C#
 	0x21 in System.Uri..ctor	C#
 	0x62 in Microsoft.Maui.Platform.MauiWKWebView.LoadUrl	C#
 	0x7 in Microsoft.Maui.Controls.UrlWebViewSource.Load	C#
 	0x10 in Microsoft.Maui.Platform.WebViewExtensions.UpdateSource	C#
 	0x19 in Microsoft.Maui.Handlers.WebViewHandler.MapSource	C#
 	0x21 in Microsoft.Maui.PropertyMapper<Microsoft.Maui.IWebView,Microsoft.Maui.Handlers.IWebViewHandler>.	C#
 	0x18 in Microsoft.Maui.PropertyMapper.UpdatePropertyCore	C#
 	0x1D in Microsoft.Maui.PropertyMapper.UpdateProperties	C#
 	0xCB in Microsoft.Maui.Handlers.ElementHandler.SetVirtualView	C#
 	0x2 in Microsoft.Maui.Handlers.ViewHandler<Microsoft.Maui.IWebView,WebKit.WKWebView>.SetVirtualView	C#
 	0x7 in Microsoft.Maui.Handlers.ViewHandler<Microsoft.Maui.IWebView,WebKit.WKWebView>.SetVirtualView	C#
 	0x65 in Microsoft.Maui.Controls.Element.SetHandler	C#
 	0x2 in Microsoft.Maui.Controls.Element.set_Handler	C#
 	0x18 in Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler	C#
 	0xB0 in Microsoft.Maui.Platform.ElementExtensions.ToHandler	C#
 	0x2 in Microsoft.Maui.Platform.ElementExtensions.ToPlatform	C#
 	0xB2 in Microsoft.Maui.Handlers.LayoutHandler.SetVirtualView	C#
 	0x7 in Microsoft.Maui.Handlers.ViewHandler<Microsoft.Maui.ILayout,Microsoft.Maui.Platform.LayoutView>.SetVirtualView	C#
 	0x65 in Microsoft.Maui.Controls.Element.SetHandler	C#
 	0x2 in Microsoft.Maui.Controls.Element.set_Handler	C#
 	0x18 in Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler	C#
 	0xB0 in Microsoft.Maui.Platform.ElementExtensions.ToHandler	C#
 	0x2 in Microsoft.Maui.Platform.ElementExtensions.ToPlatform	C#
 	0x13 in Telerik.Maui.RadSideDrawerExtensions.UpdateMainContent	C#
 	0xC in Telerik.Maui.Handlers.RadSideDrawerHandler.MapMainContent	C#
 	0x21 in Microsoft.Maui.PropertyMapper<Telerik.Maui.IRadSideDrawer,Telerik.Maui.Handlers.RadSideDrawerHandler>.	C#
 	0x18 in Microsoft.Maui.PropertyMapper.UpdatePropertyCore	C#
 	0x1D in Microsoft.Maui.PropertyMapper.UpdateProperties	C#
 	0xCB in Microsoft.Maui.Handlers.ElementHandler.SetVirtualView	C#
 	0x2 in Microsoft.Maui.Handlers.ViewHandler<Telerik.Maui.IRadSideDrawer,TelerikUI.TKSideDrawerView>.SetVirtualView	C#
 	0x7 in Microsoft.Maui.Handlers.ViewHandler<Telerik.Maui.IRadSideDrawer,TelerikUI.TKSideDrawerView>.SetVirtualView	C#
 	0x65 in Microsoft.Maui.Controls.Element.SetHandler	C#
 	0x2 in Microsoft.Maui.Controls.Element.set_Handler	C#
 	0x18 in Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler	C#
 	0xB0 in Microsoft.Maui.Platform.ElementExtensions.ToHandler	C#
 	0x2 in Microsoft.Maui.Platform.ElementExtensions.ToPlatform	C#
 	0xB2 in Microsoft.Maui.Handlers.LayoutHandler.SetVirtualView	C#
 	0x7 in Microsoft.Maui.Handlers.ViewHandler<Microsoft.Maui.ILayout,Microsoft.Maui.Platform.LayoutView>.SetVirtualView	C#
 	0x65 in Microsoft.Maui.Controls.Element.SetHandler	C#
 	0x2 in Microsoft.Maui.Controls.Element.set_Handler	C#
 	0x18 in Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler	C#
 	0xB0 in Microsoft.Maui.Platform.ElementExtensions.ToHandler	C#
 	0x2 in Microsoft.Maui.Platform.ElementExtensions.ToPlatform	C#
 	0xB2 in Microsoft.Maui.Handlers.LayoutHandler.SetVirtualView	C#
 	0x7 in Microsoft.Maui.Handlers.ViewHandler<Microsoft.Maui.ILayout,Microsoft.Maui.Platform.LayoutView>.SetVirtualView	C#
 	0x65 in Microsoft.Maui.Controls.Element.SetHandler	C#
 	0x2 in Microsoft.Maui.Controls.Element.set_Handler	C#
 	0x18 in Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler	C#
 	0xB0 in Microsoft.Maui.Platform.ElementExtensions.ToHandler	C#
 	0x2 in Microsoft.Maui.Platform.ElementExtensions.ToPlatform	C#
 	0x60 in Microsoft.Maui.Handlers.ContentViewHandler.UpdateContent	C#
 	0x1 in Microsoft.Maui.Handlers.ContentViewHandler.MapContent	C#
 	0x21 in Microsoft.Maui.PropertyMapper<Microsoft.Maui.IContentView,Microsoft.Maui.Handlers.IContentViewHandler>.	C#
 	0x18 in Microsoft.Maui.PropertyMapper.UpdatePropertyCore	C#
 	0x1D in Microsoft.Maui.PropertyMapper.UpdateProperties	C#
 	0xCB in Microsoft.Maui.Handlers.ElementHandler.SetVirtualView	C#
 	0x2 in Microsoft.Maui.Handlers.ViewHandler<Microsoft.Maui.IContentView,Microsoft.Maui.Platform.ContentView>.SetVirtualView	C#
 	0x2 in Microsoft.Maui.Handlers.ContentViewHandler.SetVirtualView	C#
 	0x7 in Microsoft.Maui.Handlers.ViewHandler<Microsoft.Maui.IContentView,Microsoft.Maui.Platform.ContentView>.SetVirtualView	C#
 	0x65 in Microsoft.Maui.Controls.Element.SetHandler	C#
 	0x2 in Microsoft.Maui.Controls.Element.set_Handler	C#
 	0x18 in Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler	C#
 	0xB0 in Microsoft.Maui.Platform.ElementExtensions.ToHandler	C#
 	0x2 in Microsoft.Maui.Platform.ViewExtensions.ToHandler	C#
 	0x19 in Microsoft.Maui.Controls.Platform.Compatibility.ShellSectionRootRenderer.SetPageRenderer	C#
 	0xA1 in Microsoft.Maui.Controls.Platform.Compatibility.ShellSectionRootRenderer.LoadRenderers	C#
 	0xD3 in Microsoft.Maui.Controls.Platform.Compatibility.ShellSectionRootRenderer.ViewDidLoad	C#
 	0x88 in UIKit.UIApplication.xamarin_UIApplicationMain	C#
 	0x6 in UIKit.UIApplication.UIApplicationMain	C#
 	0x51 in UIKit.UIApplication.Main	C#

Steps to Reproduce

1. Create a new Maui project
2. Add an html asset file data.html
3. Update view XAML to include <WebView Source="data.html" />
4. Verify working on windows/android
5. Verify not working on iOS

Link to public reproduction project repository

https://github.com/Telavian/iosError

Version with bug

6.0.486 (current)

Last version that worked well

Unknown/Other

Affected platforms

iOS

Affected platform versions

iOS 16

Did you find any workaround?

It appears using the current app directory works.

                url = Path.Combine(Directory.GetCurrentDirectory(), url);
                return $"file://{url}";

Relevant log output

No response

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[jsuarezruiz]

The issue will be fixed by #10804