[IOS][WEBVIEW] Unable to run an iframe in a webview

Laodhy commented 1 month ago

Description

Hello,

The aim of my application is to be able, in offline mode, to open an html archive downloaded earlier in an html wrapper consisting of an iframe, or else in online mode to simply display a URL in the webview (no problem with the the online mode).

So, for offline mode, I have an html file defined in MauiAsset, consisting of an iframe in which I'm going to replace the source with the path to my local file

All this works perfectly on Android, and also on iOS simulator. On a physical iPhone, however, it's impossible. All I get is a blank screen.

Here the HTML Wrapper asset :

<!DOCTYPE html>
<html>

<head>
    <meta name="viewport"
          content="width=device-width" />
    <meta http-equiv="Content-Type"
          content="text/html; charset=utf-8" />
    <style>
        body,
        html {
            margin: 0;
            padding: 0;
            border: 0;
            overflow: hidden;
            height: 100%;
            max-height: 100%;
        }

        .center {
            margin: auto;
            width: 50%;
            border: 3px solid green;
            padding: 10px;
            float: right;
        }
    </style>

</head>

<body>
    <script type="text/javascript"> 
         [SOME JAVASCRIPT]
</script>

    <iframe name="mosplayer"
            scrolling="no"
            frameborder="0"
            src="{2}" <!-- I replaced the src by the path of my local file : file://[PATH]-->
            style="width:100%;height:100%;"></iframe>

</body>

</html>

Here's the XAML code :

<ContentView xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:viewmodels="clr-namespace:Mos.ScormComponents.MAUI.Controls.ViewModels"
             x:Name="this"
             x:Class="Mos.ScormComponents.MAUI.Controls.ScormWebviewControl">
    <WebView x:Name="myWebView" Navigating="myWebView_Navigating">
    </WebView>

</ContentView>

Here's the C# code

 private const string BRIDGE_NAME = "jsbridge";

 public static readonly BindableProperty SourceUrlProperty = BindableProperty.Create(
        nameof(SourceUrl),
        typeof(string),
        typeof(ScormWebviewControl), defaultValue: null, propertyChanged: OnSourceUrlPropertyChanged);

 public string SourceUrl
 {
     get => (string)GetValue(SourceUrlProperty);
     set => SetValue(SourceUrlProperty, value);
 }

 public static readonly BindableProperty TrackingDatasProperty = BindableProperty.Create(
        nameof(TrackingDatas),
        typeof(IList<TrackingData>),
        typeof(ScormWebviewControl), defaultValue: new List<TrackingData>(), propertyChanged: OnTrackingDatasPropertyChanged);

 public IReadOnlyCollection<TrackingData> TrackingDatas
 {
     get => (IReadOnlyCollection<TrackingData>)GetValue(TrackingDatasProperty);
     set => SetValue(TrackingDatasProperty, value);
 }

 public static readonly BindableProperty IsTerminatedCommandProperty = BindableProperty.Create(
        nameof(IsTerminatedCommand),
        typeof(ICommand),
        typeof(ScormWebviewControl));

 public ICommand IsTerminatedCommand
 {
     get => (ICommand)GetValue(IsTerminatedCommandProperty);
     set => SetValue(IsTerminatedCommandProperty, value);
 }

    private bool _isLocalFile = false;
    private bool _isFinishing = false;

    internal readonly ScormBusinessLogic scormBusinessLogic;

  public ScormWebviewControl()
    {
        InitializeComponent();
        scormBusinessLogic = new();

    }

    protected override void OnHandlerChanged()
    {
        base.OnHandlerChanged();

#if ANDROID
        Android.Webkit.WebView androidWebview = myWebView.Handler.PlatformView as Android.Webkit.WebView;
        androidWebview.Settings.JavaScriptEnabled = true;
        androidWebview.Settings.AllowFileAccess = true;
        androidWebview.Settings.AllowFileAccessFromFileURLs = true;
        androidWebview.Settings.AllowUniversalAccessFromFileURLs = true;
        androidWebview.ClearCache(true);

#elif MACCATALYST || IOS
        if (myWebView.Handler.PlatformView is WebKit.WKWebView wkWebView)
        {
            wkWebView.Configuration.Preferences.SetValueForKey(Foundation.NSObject.FromObject(true), (Foundation.NSString)"allowFileAccessFromFileURLs");
            wkWebView.Configuration.DefaultWebpagePreferences.AllowsContentJavaScript = true;
            wkWebView.Configuration.Preferences.JavaScriptEnabled = true;
            wkWebView.Configuration.Preferences.JavaScriptCanOpenWindowsAutomatically = true;
        }

#endif

    }

    bool _isTrackingDatasSet = false;
    bool _isSourceSet = false;
    private static async void OnSourceUrlPropertyChanged(BindableObject bindable, object oldValue, object newValue)
    {
        var strValue = newValue?.ToString() ?? string.Empty;

        var control = bindable as ScormWebviewControl;
        control._isSourceSet = strValue != string.Empty;

        if (control._isSourceSet && control._isTrackingDatasSet)
            await control.SetSourceAsync();

    }

    private static async void OnTrackingDatasPropertyChanged(BindableObject bindable, object oldValue, object newValue)
    {
        var control = bindable as ScormWebviewControl;
        control._isTrackingDatasSet = newValue != null;

        if (control._isSourceSet && control._isTrackingDatasSet)
            await control.SetSourceAsync();
    }

    private async Task SetSourceAsync()
    {
        _isLocalFile = IsLocalPath(SourceUrl); //Determine if we should 

        if (_isLocalFile)
        {
            await GetOfflineSourceAsync(SourceUrl);
        }
        else
        {
            myWebView.Source = SourceUrl;
        }
    }

    private async Task GetOfflineSourceAsync(string folderPath)
    {
        if (!Directory.Exists(folderPath))
            throw new DirectoryNotFoundException();

        myWebView.Source = new HtmlWebViewSource()
        {
            BaseUrl = folderPath,
            Html = await scormBusinessLogic.GetHtmlContentAsync(folderPath, TrackingDatas) // Get the html formatted content
        };

    }

My iPhone console displays this error message: WebPageProxy::didFailProvisionalLoadForFrame: frameID=25, isMainFrame=0, domain=<private>, code=-1100, isMainFrame=0

So I decided to test only the iFrame's operation by having it display any web page, and I got exactly the same error Even with :

    <iframe name="mosplayer"
            scrolling="no"
            frameborder="0"
            src="http://www.google.com"
            style="width:100%;height:100%;"></iframe>

And if I set the source of my webview directly on www.google.com, it works.

Here my info.plist file :

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>LSRequiresIPhoneOS</key>
    <true/>
    <key>UIDeviceFamily</key>
    <array>
        <integer>1</integer>
        <integer>2</integer>
    </array>
    <key>UIRequiredDeviceCapabilities</key>
    <array>
        <string>arm64</string>
    </array>
    <key>UISupportedInterfaceOrientations</key>
    <array>
        <string>UIInterfaceOrientationPortrait</string>
        <string>UIInterfaceOrientationLandscapeLeft</string>
        <string>UIInterfaceOrientationLandscapeRight</string>
    </array>
    <key>UISupportedInterfaceOrientations~ipad</key>
    <array>
        <string>UIInterfaceOrientationPortrait</string>
        <string>UIInterfaceOrientationPortraitUpsideDown</string>
        <string>UIInterfaceOrientationLandscapeLeft</string>
        <string>UIInterfaceOrientationLandscapeRight</string>
    </array>
    <key>XSAppIconAssets</key>
    <string>Assets.xcassets/appicon.appiconset</string>
    <key>UILaunchStoryboardName</key>
    <string>MauiSplash</string>
    <key>NSAppTransportSecurity</key>
    <dict>
        <key>NSAllowsArbitraryLoads</key>
        <true/>
        <key>NSExceptionDomains</key>
        <dict>
            <key>google.com</key>
            <dict>
                    <key>NSExceptionAllowsInsecureHTTPLoads</key>
                    <true/>
                    <key>NSExceptionRequiresForwardSecrecy</key>
                    <false/>
            </dict>
        </dict>
    </dict>
</dict>
</plist>

And how I get the html formatted content :

 internal class ScormBusinessLogic
 {
     private const string LOCAL_HTML_FILE = "Assets/HtmlWrapper.html";
     private const string IMS_MANIFEST_FILE_NAME = "imsmanifest.xml";

     private readonly ScormBeanFactory scormBeanFactory;
     private readonly ScoJsParamsFactory scoJsParamsFactory;
     public ScormBusinessLogic() {
         scormBeanFactory = new();
         scoJsParamsFactory = new();
     }

     public async Task<string> GetHtmlContentAsync(string folderScormPath, IReadOnlyCollection<TrackingData> trackingDatas)
     {

         var imsManifestFilepath = Path.Combine(folderScormPath, IMS_MANIFEST_FILE_NAME);  //Irrelevant for the issue
         var dataDictionnary = XmlUtils.DeserializeXmlToDictionnary(imsManifestFilepath);  //Irrelevant for the issue

         string htmlContent = await FileUtils.ReadAssetFile(LOCAL_HTML_FILE); //Read the MauiAssetFile

         var bean = scormBeanFactory.CreateModel(dataDictionnary, folderScormPath); //Irrelevant for the issue
         var jsparams = scoJsParamsFactory.CreateModel(bean, trackingDatas ?? new List<TrackingData>());  //Irrelevant for the issue

         var htmlContentFormatted = htmlContent.Replace("{0}", bean.ScoId)
             .Replace("'{1}'", jsparams.ToJavascriptObject())
             .Replace("{2}", $"file://{bean.IndexFile}"); //bean.IndexFile = the path on the device of the downloaded file

         Console.WriteLine(htmlContentFormatted);
         return htmlContentFormatted;
     }

I'm completely lost and I don't really understand what's going on, I have no other idea but to come and post here.

Steps to Reproduce

1 - Create a new MAUI App 2- Create a MauiAsset which consist of an html file with an iframe 3-Set the iframe src to www.google.com 4-Create a WebView in your XAML Page which load the MauiAsset as source 5- Run your iOS application

Link to public reproduction project repository

No response

Version with bug

8.0.21 SR4.1

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

iOS

Affected platform versions

iOS 15 and more

Did you find any workaround?

No

Relevant log output

No response

github-actions[bot] commented 1 month ago

Hi I'm an AI powered bot that finds similar issues based off the issue title.

Please view the issues below to see if they solve your problem, and if the issue describes your problem please consider closing this one and thumbs upping the other issue to help us prioritize it. Thank you!

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Webview on iOS and Android does not allow local HTML to load additional resources (#20613), similarity score: 0.78

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[iOs] MAUI Blazor Hybrid '//' urls not treated as secure (#19297), similarity score: 0.74

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Laodhy commented 3 weeks ago

Could someone help me or give me some direction? I'm really stuck.

Zhanglirong-Winnie commented 2 weeks ago

Verified this issue with Visual Studio 17.11.0 Preview 2.0 (8.0.21). Can repro on iOS platform.

dotnet / maui