LogForgingAsp.cs

using System;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Http.Headers;
using Microsoft.AspNetCore.Mvc;

public class AspController : ControllerBase
{
    public void Action1(string username)
    {
        var logger = new ILogger();
        // BAD: Logged as-is
        logger.Warn(username + " logged in");
    }

    public void Action1(DateTime date)
    {
        var logger = new ILogger();
        // GOOD: DateTime is a sanitizer.
        logger.Warn($"Warning about the date: {date:yyyy-MM-dd}");
    }

    public void Action2(DateTime? date)
    {
        var logger = new ILogger();
        if (date is not null)
        {
            // GOOD: DateTime? is a sanitizer.
            logger.Warn($"Warning about the date: {date:yyyy-MM-dd}");
        }
    }

    public void Action2(bool? b)
    {
        var logger = new ILogger();
        if (b is not null)
        {
            // GOOD: Boolean? is a sanitizer.
            logger.Warn($"Warning about the bool: {b}");
        }
    }
}