How can I pass an instance of LoggerFactory to ActionFilterAttribute

Question

Good day.

I'm trying to use logging by injecting a LoggerFactory in my custom ActionFilterAttribute class but when using the Attribute in one of the controller methods I get an error saying

[CS7036] There is no argument given that corresponds to the required formal parameter 'logger' of 'Tracker.Tracker(ILoggerFactory)' 

Here's the implementation of the class:

using System;
using Microsoft.AspNetCore.Mvc.Filters;
using Microsoft.EntityFrameworkCore;
using Microsoft.AspNetCore.Identity;
using Microsoft.Extensions.Logging;

namespace ImmoSales.Tracking
{
    public class Tracker : ActionFilterAttribute
    {
        public string ActionType { get; set; }
        public string ActionName { get; set; }
        private readonly ILoggerFactory _logger;

        public Tracker(ILoggerFactory logger)
        {
            _logger = logger;
        }

        public override void OnActionExecuting(ActionExecutingContext context)
        {
            base.OnActionExecuting(context);
        }

        public override void OnActionExecuted(ActionExecutedContext context)
        {
            base.OnActionExecuted(context);
        }

        public override void OnResultExecuting(ResultExecutingContext context)
        {
            base.OnResultExecuting(context);
        }

        public override void OnResultExecuted(ResultExecutedContext context)
        {
            base.OnResultExecuted(context);
        }
    }
}

I get the mentioned error when I attempt to use the Tracker in a controller as follows:

[Tracker(ActionType="testType", ActionName="testName")]
public IActionResult Index()
{
    return View();
}

What can be done to fix the error?

Answer 1

Since you are doing constructor injection in your action filter, you may enable it using ServiceFilter attribute where you can pass the type of your filter

[ServiceFilter(typeof(Tracker))]
public IActionResult Index()
{
    // to do : return something
}

Make sure you have registered the filter in the ConfigureServices method

services.AddScoped<Tracker>();

If you want to pass other arguments to the filter, you can update the filter constructor to have those parameters.

public class Tracker : ActionFilterAttribute
{
    private string _actionType { get; set; }
    private string _actionName { get; set; }
    private readonly ILoggerFactory _logger;

    public Tracker(ILoggerFactory logger, string actionType, string actionName)
    {
        this._logger = logger;
        this._actionName = actionName;
        this._actionType = actionType;
    }

    public override void OnActionExecuting(ActionExecutingContext context)
    {
        base.OnActionExecuting(context);
    }

    public override void OnActionExecuted(ActionExecutedContext context)
    {
        base.OnActionExecuted(context);
    }

    public override void OnResultExecuting(ResultExecutingContext context)
    {
        base.OnResultExecuting(context);
    }

    public override void OnResultExecuted(ResultExecutedContext context)
    {
        base.OnResultExecuted(context);
    }
}

and use TypeFilter attribute to enable your filter, where you can explicitly pass the arguments

[TypeFilter(typeof(Tracker), Arguments = new object[] { "Abc", "Xyz" })]
public IActionResult Index()
{
    // to do : return something
}