How to access HttpContext from IRequestHandler using Mediator - Minimal API (C#)

Question

Is there a way to access HttpContext from a request handler? I added a filter to my (minimal API) endpoint to validate the API key, coming from the request headers. Upon successful validation I need the value to Generate JWT for subsequent requests.

Is there a workaround to this? Need a code sample.

Answer 1

Using Carter, it would be something like this (but it is just matter of using equivalent for non-Carter implementation):

public interface ITokenGrabber
{
    void SetToken(string token);
    string GetToken();
}

public class TokenGrabber : ITokenGrabber
{
    private string _token;

    public string GetToken() => _token;

    public void SetToken(string token) => _token = token;
}

public class SampleFilter : IEndpointFilter
{
    public ValueTask<object> InvokeAsync(EndpointFilterInvocationContext context, EndpointFilterDelegate next)
    {
        var grabber = context.HttpContext.RequestServices.GetService<ITokenGrabber>();

        string token = context.HttpContext.Request.Headers["Authorization"];
            
        grabber.SetToken(token);

        return next(context);
    }
}

    public class SomeHandler
        : IRequestHandler<SomeRequest>
    {
        private readonly ITokenGrabber _grabber;

        public GetAllExercisesQueryHandle(ITokenGrabber grabber)
        {
            _grabber = grabber;
        }

        public Task Handle(SomeRequestrequest, CancellationToken cancellationToken)
        {
            Console.WriteLine(_grabber.GetToken());
            
            return ...
        }
    }

Make sure ITokenGrabber is properly configured with scoped lifetime:

builder.Services.AddScoped<ITokenGrabber, TokenGrabber>();