EFCore on Android. Require 'libmod_spatialite' instead of 'mod_spatialite'.

[AndroidEFCoreLover]

Hi,

I cannot use EF Core on Android device, cause I cannot deploy 'mod_spatialite' with APK.
I see Android only allows me to deploy *.so files with the name starting with "lib".

And, in:

efcore/src/EFCore.Sqlite.Core/Infrastructure/SpatialiteLoader.cs

Line 100 in b848377

sqliteConnection.LoadExtension("mod_spatialite");

we specifically require the name, without the 'lib'.

Is it possible to change the name, to allow it to be used on all platforms?

[AndroidEFCoreLover]

Someone describes the restrictions in more detail: https://developercommunity.visualstudio.com/content/problem/841599/androidnativelibrary-so-files-will-not-deploy-to-a.html

[ajcvickers]

/cc @bricelam

[bricelam]

Note for triage: Looks like SQLite only adds the extension (dll, so, dylib, etc.) and not the 'lib' prefix like I initially thought.

A couple of thoughts...

We could expose an option to disable our call to LoadExtension. It's kind of possible today using some lower-level, pubternal APIs:

efcore/src/EFCore.Sqlite.NTS/Extensions/SqliteNetTopologySuiteDbContextOptionsBuilderExtensions.cs

Lines 27 to 36 in 91655d5

	var coreOptionsBuilder = ((IRelationalDbContextOptionsBuilderInfrastructure)optionsBuilder).OptionsBuilder;
	var infrastructure = (IDbContextOptionsBuilderInfrastructure)coreOptionsBuilder;
	#pragma warning disable EF1001 // Internal EF Core API usage.
	// #20566
	var sqliteExtension = coreOptionsBuilder.Options.FindExtension<SqliteOptionsExtension>()
	?? new SqliteOptionsExtension();
	var ntsExtension = coreOptionsBuilder.Options.FindExtension<SqliteNetTopologySuiteOptionsExtension>()
	?? new SqliteNetTopologySuiteOptionsExtension();
	infrastructure.AddOrUpdateExtension(sqliteExtension.WithLoadSpatialite(true));

This would be helpful in this scenario, but also if you're using SpatiaLite directly as your native SQLite library (not as an extension).

We could also try loading libmod_spatialite.so if the just mod_spatialite fails (similar to how .NET probes during P/Invoke).

We could also detect if we're running on Android at runtime and only look for libmod_spatialite...

P.S. I'd love it if you could look through bricelam/mod_spatialite-NuGet#6 and add any additional information you might have.

[AndroidEFCoreLover]

I switched the last to false, and then on creation of each context, I enable loading of extensions, and load the .so we need.
Did a round trip on point geometry on android.