[Android] Encoding webview's source

[kubaflo]

Issues Fixed

Fixes #23767
Fixes #23690

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Screen.Recording.2024-08-04.at.14.06.51.mov	Screen.Recording.2024-08-04.at.14.04.00.mov

[dotnet-policy-service]

Hey there @kubaflo! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[jfversluis]

This just fixes the spaces, there is another issue for square brackets. Should we just use the UriEncode method to catch it all?

[kubaflo]

@jfversluis
The problem with Uri encode: string? encodedUrl = HttpUtility.UrlEncode(url);
https://www.google.com/search?q=test 123 becomes https%3a%2f%2fwww.google.com%2fsearch%3fq%3dtest+123 and Uri.IsWellFormedUriString validates it as a bad URL :/

[jfversluis]

Oh yeah that makes sense. Hmmm I do wonder why this worked in Xamarin.Forms though and not here. Same with #23690

[kubaflo]

@jfversluis
It looks like Xamarin didn't have this logic:

if (url != null && !url.StartsWith('/') && !Uri.IsWellFormedUriString(encodedUrl, UriKind.Absolute))
{
    // URLs like "index.html" can't possibly load, so try "file:///android_asset/index.html"
    url = AssetBaseUrl + url;
} 

void LoadUrl(string url, bool fireNavigatingCanceled)

[mattleibow]

Is there no Uri.EncodeSomething that is safer? What about other "special" characters in the uri?

[kubaflo]

That is a bit problematic: #24002 (comment)

[jfversluis]

Can we only encode whatever comes after the base URL? So only the query string basically?

[kubaflo]

Imo, great idea!

[David-Ernstsson]

Any progress on this? Not sure if I have same problem since a single bracket or space works fine when escaped.

HOWEVER using a space AND a german special character creates error shown above. See sample code:

        var webView = new WebView();
        var text = Uri.EscapeDataString("sehr schön");
        var source = $"https://translate.google.com/?sl=de&tl=en&op=translate&text={text}";

        webView.Source = new UrlWebViewSource { Url = source };