HostContext.AppSettings always null in self-hosted app

ServiceStack Testing
1

For integration testing, I have created a self-hosted app as shown below, which is the equivalent of the real app.

In the self-hosted app, the HostContext.AppSettings is always null.

public class TestAppHost : AppSelfHostBase
{
  public TestAppHost()
      : base("TESTAPP", typeof(MyService).Assembly)
  {
  }
  
  public override void Configure(Container container)
  {
    var appSettings = HostContext.AppSettings;    // fails: always null
  }
}

The equivalent apphost code works correctly under IIS Express (Rider/VisualStudio) and IIS:

public class AppHost : AppHostBase
{
  public AppHost()
      : base("APP", typeof(MyService).Assembly)
  {
  }
  
  public override void Configure(Container container)
  {
    var appSettings = HostContext.AppSettings;    // success
  }
}

I must not be understanding something, so all help appreciated.

2

Is this a .NET Framework App and do you have an App.config?

3

Sorry, Net Core, using appsettings.json.

Using latest ServiceStack 5.11, under Windows.

4

You should only use the AppHost singleton (i.e. HostContext) after it’s initialized, prior to that (or within your AppHost) you should just access its instance properties instead, e.g:

public override void Configure(Container container)
{
    var appSettings = AppSettings;
}

AppSelfHostBase for .NET Core requires the AppHost is started (i.e. both .Init() and .Start()) before the AppHost is properly initialized.

5

I tried using AppSettings in AppHost’s Configure(), as you showed, but is also not working:

public override void Configure(Container container)
{
    var connStr = AppSettings.GetString("ConnectionString");   // is null
}

The Apphost is being started using:

public class IntegrationTester : IDisposable
{
    private const string BaseUri = "http://localhost:8888";
    private readonly ServiceStackHost _appHost;
    
    public IntegrationTester()
    {
        _appHost = new AppHost()
            .Init()
            .Start(BaseUri);
    }
}

So, should the AppSettings be available in AppHost’s Configure() or is Configure() part of the Start process?

Is this the difference to using “AppHost : AppHostBase” when using IIS/IISExpress?

6

Typically AppSelfHostBase is only used for creating multi-platform (.NET Framework/.NET Core) integration tests as such the default AppSettings looks at the same Web.config/App.config <appSettings/> as .NET Framework integration test projects.

You could override it to look at a custom ASP .NET Configuration provider using their ConfigurationBuilder, e.g:

class AppHost : AppSelfHostBase
{
    public AppHost() : base(nameof(MyTests), typeof(MyTests).Assembly)
    {
        Configuration = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile("appsettings.json")
            .Build();
        AppSettings = new NetCoreAppSettings(Configuration);
    }

    public override void Configure(Container container)
    {
        var stringValue = AppSettings.GetString(stringKey);
        var intValue = AppSettings.Get<int>(intKey);
    }
}

Although if you only need to target .NET Core you may want to consider using the standard Program/Startup.cs for ASP .NET Core projects directly (which AppSelfHostBase is just wrapping), to get full configurability of Kestrel SelfHost Server.

7

Your last suggestion worked perfectly for self-hosting.

Thank you.