NuGets with native UWP and .NET core runtimes

[mattleibow]

I am wondering how to create a package that contains native payloads for both UWP and .NET Core clients.

I am building SkiaSharp which supports both UWP apps and .NET Core (Windows 7+). My initial idea was to create a NuGet using a .targets file to include the native payloads:

<file src="output/uwp/SkiaSharp.UWP.targets" target="build\uap10.0\SkiaSharp.Windows.targets" />
<file src="output/uwp/x64/libskia_uwp.dll" target="build\uap10.0\x64\libskia_uwp.dll" />
<file src="output/uwp/x86/libskia_uwp.dll" target="build\uap10.0\x86\libskia_uwp.dll" />
<file src="output/uwp/arm/libskia_uwp.dll" target="build\uap10.0\arm\libskia_uwp.dll" /> 

This worked fine, but then I added .NET Core support (via .NET Standard support). Also, I added the win7 native bits:

<file src="output/windows/x64/libSkiaSharp.dll" target="runtimes/win7-x64/native/libSkiaSharp.dll" /> 
<file src="output/windows/x86/libSkiaSharp.dll" target="runtimes/win7-x86/native/libSkiaSharp.dll" /> 

This worked fine for .NET Core. But, this now had issues for UWP: it installed the win7 dlls into the UWP app. This resulted in both the UWP dlls from the .targets file and the win7 dlls. Not only did this cause issues with the build, but was invalid (win7 dll won't work on UWP). My solution was to add the UWP dlls into the runtimes as well:

<file src="output/uwp/x64/libSkiaSharp.dll" target="runtimes/win10-x64/native/libSkiaSharp.dll" /> 
<file src="output/uwp/x86/libSkiaSharp.dll" target="runtimes/win10-x86/native/libSkiaSharp.dll" /> 
<file src="output/uwp/arm/libSkiaSharp.dll" target="runtimes/win10-arm/native/libSkiaSharp.dll" /> 

This now "worked" for both if I publish .NET Core apps with win7 and install the NuGet into UWP apps. But, this now causes issues if I am building/publishing .NET Core apps on Windows 10. The build system selects the win10 directory for the runtimes (as it should), but these dlls (Windows Universal) are not supported by .NET Core.

Is there some way to let NuGet know that a dll is just for UWP, or am I building my universal dlls wrong?

[eerhardt]

@ericstj @emgarten - Can you select native assets based on a TFM? It sounds like we need a different native asset on netcoreapp than when used on uap.

[emgarten]

Support for runtimes/{rid}/nativeassets/{tfm}/{any?} was added with #2782

Set a min client version of 3.5.0 in your nuspec to ensure that consumers have the correct client version to pick up this nupkg path.

[mattleibow]

Awesome! Thanks!

Just wanted to add that to use NuGet v3.5 in VS 2015, you may have to install the vsix: http://dist.nuget.org/