.NET Core Set ClaimsPrincipal from another controller

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In few places in legacy code (more than 100 controllers), we are running action from other controllers.

In .NET Framework it runs OK - ClaimsPrincipal in both controller's action have correct values, but in .NET Core, running SecondController.internalPut() from FirstController gives me NullReferenceException.

FirstController:

[EnableCors]
public class FirstController : BaseApiController
{
    public FirstController(IContextFactory contextFactory) : base(contextFactory)
    {
    }

    [HttpPut]
    [HttpPost]
    [Route("/api/firstcontroller")]
    public IActionResult Put([FromBody] MyDTO data)
    {
        var token = Identity.Token; // <--- correct value

        var secondController = new SecondController(ContextFactory);
        secondController.internalPut(something); <--- NullReferenceException

        return Ok();
    }
}

SecondController:

[EnableCors]
public class SecondController : BaseApiController
{
    public SecondController(IContextFactory contextFactory) : base(contextFactory)
    {
    }

    [HttpPut]
    [HttpPost]
    public async Task<IActionResult> Put(Guid myGuid)
    {
        internalPut(something); // <-- OK
        return Ok();
    }

    internal void internalPut(object something)
    {
        var token = Identity.Token; // <--- NullReferenceException when running from FirstController!!
    }
}

And BaseApiController with TokenIdentity:

[ApiController]
[Route("/api/[controller]")]
[Route("/api/[controller]/[action]")]
public class BaseApiController : ControllerBase
{
    protected readonly IMyContextFactory ContextFactory;

    public BaseApiController(IMyContextFactory contextFactory)
    {
        ContextFactory = contextFactory;
    }

    public TokenIdentity Identity => User?.Identity as TokenIdentity;
}

public class TokenIdentity : GenericIdentity
{
    public Guid Token { get; set; }
    public string User { get; set; }

    public TokenIdentity(Guid token) : base(token.ToString())
    {
        Token = token;
    }
}

How is the easiest fix for this bug? I know that I can change BaseApiController implementation to get ClaimsPrincipal from IHttpContextAccessor, but this means that I need to update constructors for all > 100 controllers in code... It is another way to always have ClaimsPrincipal when we are calling action from another controller?

asp.net-core .net c#
1 Answers

What I recommend as the correct solution

I can't emphasise enough how much I recommend moving shared functionality into its own services, or perhaps look at using the Mediator Pattern (e.g. using the MediatR library) to decouple your controllers from their functionality a little. What I provide below is not a solution, but a band-aid.

What I recommend a QUICK FIX only

Why is this only a quick fix?: because this doesn't instantiate the correct action details and route parameters, so it could potentially cause you some hard-to-find bugs, weird behaviour, URLs maybe not generating correctly (if you use this), etc.

Why am I recommending it?: because I know that sometimes time is not on our side and that perhaps you need a quick fix to get this working while you work on a better solution.

Hacky quick fix

You could add the following method to your base controller class:

private TController CreateController<TController>() where TController: ControllerBase
{
    var actionDescriptor = new ControllerActionDescriptor()
    {
        ControllerTypeInfo = typeof(TController).GetTypeInfo()
    };

    var controllerFactory = this.HttpContext.RequestServices.GetRequiredService<IControllerFactoryProvider>().CreateControllerFactory(actionDescriptor);
    return controllerFactory(this.ControllerContext) as TController;
}

Then instead of var secondController = new SecondController(ContextFactory); you would write:

var secondController = CreateController<SecondController>();
DiplomacyNotWar0
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