How can you inject a service into an implementation of IClaimsTransformer?

[csaloio]

I need to be able to query a DB in my implementation.

My understanding is that you must add the transform like this in Startup.Configure:

app.UseClaimsTransformation(o => o.Transformer = new MyClaimsTransformer());

But how can it get access to a scoped service from within MyClaimsTransformer ?

[blowdart]

As of right now you can't. @HaoK we did talk about giving claims transformation more love ...

[csaloio]

@blowdart @HaoK I'm not sure how meaningful a transformation you can make without access to your data :(

[HaoK]

Since this is inside of Configure, you can service locate for it to work

var myTransformer = app.Services.GetRequiredService<MyTransformer>();
app.UseClaimsTransformation(o => o.Transformer = myTransformer);

[blowdart]

Kinda ugly though :)

[HaoK]

Also with the new options changes we can just make this work now that options will be a normal service.

[csaloio]

@HaoK I don't understand your example. IApplicationBuilder doesn't seem to have a Services property (at least in RC1). It does have 'ApplicationServices' but my understanding was that this is only appropriate for services that have an application scope. I think it is important that any DB service injected into the transformer have request scope and not be scoped to the application.

[DovydasNavickas]

@HaoK, @blowdart, this really does not make sense, if the request is not exposed to the transformer. Any reasons why you cannot expose that?

[brockallen]

Seems like the IClaimsTransformer really should be pulled from DI, not Options.Transformer.

[DovydasNavickas]

And within current request scope 👏

[lasrol]

@csaloio getting db or usermanager from the ApplicationServices gave me a lot of open data reader errors

[csaloio]

@lasrol I don't suggest using ApplicationServices. What I think could be done (though it is not ideal), is to just new up your context inside of the TransformAsync method in the transformer making sure to wrap it in a using block so it is disposed of. Then use it to read whatever data you need to transform the ClaimsPrincipal.

But as I said, this is far from ideal. Everything about the .Net core design encourages the use of DI but UseClaimsTransformation appears to be a design oversight.

[Eilon]

This would indeed be nice but we are not taking many new features for this release.

[csaloio]

So will this be a breaking change in the future?

[DovydasNavickas]

@Eilon I understand why are you against taking new features into current release, but if you want to follow semver, this change would only go into >=2.0.0 release. And maybe the change needed here is quite simple: a reference to request, which by itself has RequestServices.