Added avalonia sample app and detailed description

[gentledepp]

Hello!

Me again.

I managed to fix the build.

• The samples do work. (Desktop, iOS and Android)
• the package versions are configured in the Directory.packages.props file.

However, the .\build.cmd fails with the ".Android" and ".iOS" Avalonia projects claiming:

.\build.cmd
Determining projects to restore...
Alle Projekte sind für die Wiederherstellung auf dem neuesten Stand.
Runtime toolset 'aspnetcore/x64 v6.0.32' already installed.
Runtime toolset 'aspnetcore/x64 v7.0.20' already installed.
Determining projects to restore...
C:\Code_gh\openiddict-core_gd.dotnet\sdk\8.0.303\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.TargetFrameworkInference.targets(117,5): error NETSDK1139: The target platform identifier ios was not recognized [C:\Code_gh\openiddict-cor
e_gd\sandbox\OpenIddict.Sandbox.Avalonia.Client\OpenIddict.Sandbox.Avalonia.Client.iOS\OpenIddict.Sandbox.Avalonia.Client.iOS.csproj]
C:\Code_gh\openiddict-core_gd.dotnet\sdk\8.0.303\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.TargetFrameworkInference.targets(117,5): error NETSDK1139: The target platform identifier android was not recognized [C:\Code_gh\openiddict
-core_gd\sandbox\OpenIddict.Sandbox.Avalonia.Client\OpenIddict.Sandbox.Avalonia.Client.Android\OpenIddict.Sandbox.Avalonia.Client.Android.csproj]

Error during the build process.

C:\Code_gh\openiddict-core_gd.dotnet\sdk\8.0.303\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.TargetFrameworkInference.targets(117,5): error NETSDK1139: The target platform identifier ios was not recognized [C:\Code_gh\openiddict-cor
e_gd\sandbox\OpenIddict.Sandbox.Avalonia.Client\OpenIddict.Sandbox.Avalonia.Client.iOS\OpenIddict.Sandbox.Avalonia.Client.iOS.csproj]
C:\Code_gh\openiddict-core_gd.dotnet\sdk\8.0.303\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.TargetFrameworkInference.targets(117,5): error NETSDK1139: The target platform identifier android was not recognized. [C:\Code_gh\openiddict
-core_gd\sandbox\OpenIddict.Sandbox.Avalonia.Client\OpenIddict.Sandbox.Avalonia.Client.Android\OpenIddict.Sandbox.Avalonia.Client.Android.csproj]
0 Warnung(en)
2 Fehler

Build failed with exit code 1. Check errors above.

Interestingly, when I run dotnet build in the openiddict-core root folder, I get a similar error.

However, if I specify the Android sdk explicitly, like the following, then the build succeeds:

dotnet build -p:AndroidSdkDirectory="C:\SDKs\Android\android-sdk" -p:JavaSdkDirectory="C:\SDKs\Android\openjdk\jdk-17.0.8.101-hotspot"

It seems that for whatever reason the .\build.cmd does not pick up the sdks properly.

Any idea why that is the case?
I am terribly sorry for asking this question, but I could not figure out your complex build script until now :-|

Once that is fixed, I am

• planning to re-base on the dev branch and create a new PR
  Before I do that, please let me know if this effort is welcome. Otherwise I'll create a sample in the avalonia repo as an alternative. But for that I'd have to copy your OpenIddict.Sandbox.AspNet.Server and OpenIddict.Sandbox.AspNetCore.Server and I am not sure if that is ok (given your OS license)
• contribute a documentation on the openiddict docs website regarding how to use ms devtunnels with openIddict and how to configure the server (information from my /avalonia/readme.md) in better english. Are you interested in this at all?

[kevinchalet]

Thanks for your PR!

[kevinchalet]

These samples are engineering samples - hence the name, "sandbox" - meant to be used to test OpenIddict features as they are being developed. They are not meant to be used by the general public, so this is likely not the right place for this guidance.

[gentledepp]

Ok, I can add this to the official docs then and reduce this to

How to run the sample on iOS and Android

• set the issuer URI on client and server
• and start the server in dev tunnel with host header forwarding
• for details, please check out the guide on using dev tunnels (that I am going to write)

Would that be ok?

[kevinchalet]

Any idea why that is the case?
I am terribly sorry for asking this question, but I could not figure out your complex build script until now :-|

Honestly, no idea: OpenIddict doesn't do anything fancy and simply uses .NET Arcade.

Before I do that, please let me know if this effort is welcome.

If we can fix the build issues in a way it doesn't prevent the solution from building correctly and eliminate all the tiny extensions/classes - aka "make it minimal" - so it doesn't become a pain to maintain, I don't mind merging it 😄