Custom SessionReplay masks in MAUI Android apps

[jamescrosswell]

Summary

Previously the SessionReplay options for Android supported either Masking everything or masking nothing:

sentry-dotnet/samples/Sentry.Samples.Maui/MauiProgram.cs

Lines 34 to 35 in e8a65cf

	options.Native.ExperimentalOptions.SessionReplay.MaskAllImages = true;
	options.Native.ExperimentalOptions.SessionReplay.MaskAllText = true;

This PR adds the ability to override those "default" masking settings one or more view elements.

Overriding mask settings for specific MAUI components

SDK users would do this first by adding a reference to the Sentry namespace (which gives access to Sentry specific XAML elements):

sentry-dotnet/samples/Sentry.Samples.Maui/MainPage.xaml

Line 4 in e8a65cf

xmlns:sentry="http://schemas.sentry.io/maui"

And then by specifying the sentry:SessionReplay.Mask for any view elements they want to explicitly mask or unmask:

sentry-dotnet/samples/Sentry.Samples.Maui/MainPage.xaml

Lines 13 to 18 in d518620

	<Image
	Source="dotnet_bot.png"
	sentry:SessionReplay.Mask="Unmask"
	SemanticProperties.Description="Cute dot net bot waving hi to you!"
	HeightRequest="200"
	HorizontalOptions="Center" />

Overriding mask settings for types of MAUI components

sentry-dotnet/samples/Sentry.Samples.Maui/MauiProgram.cs

Lines 36 to 38 in d518620

	// Alternatively the masking behaviour for entire classes of VisualElements can be configured here as
	// an exception to the default behaviour.
	options.Native.ExperimentalOptions.SessionReplay.UnmaskControlsOfType<Button>();

Tests

I added a couple of almost inconsequential unit tests. It's very difficult to test these behaviours however since ultimately we're setting properties on native (Android) view elements. Create those view elements requires an IMauiContext which really needs the view element to sit in an actual MAUI application running on Android.

I couldn't think of a practical way to access or leverage the MAUI context that would exist in our Sentry.Maui.Device.TestApp.csproj (I think that's gets created magically by xharness). If anyone who's more experienced with MAUI than me has any ideas about how this could be better tested, maybe we can add better test coverage in the future.

[Flash0ver]

question: Is the term "mask mode" (or "masking mode") established through other SDKs, or is this enum a .NET-only concept to "type-ify" the strings?

[jamescrosswell]

The later - I made it up to limit the number of possibilities presented by the tooling when writing XAML.

[Flash0ver]

I was wondering if we have already established prior art for the enum and it's name.

[jamescrosswell]

Make the event handlers a static method, not an anonymous one.

Thanks @aritchie - new code uses static handlers. To avoid capturing the newvalue variable I had to define two separate handlers and wire up the appropriate handler depending on the mask setting... but the result is static handlers per your recommendation.

[aritchie]

LGTM - ship it!

[bruno-garcia]

can the same API work in iOS once we add there?

[jamescrosswell]

can the same API work in iOS once we add there?

It depends on how masking is done in iOS. I'm not expecting it to work on iOS though. The Java implementation seems quite android specific.