marechai/Marechai/Areas/Identity/Pages/Account/Manage/DeletePersonalData.cshtml.cs

using System;
using System.ComponentModel.DataAnnotations;
using System.Threading.Tasks;
using Marechai.Database.Models;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.Extensions.Logging;

namespace Marechai.Areas.Identity.Pages.Account.Manage
{
    public class DeletePersonalDataModel : PageModel
    {
        readonly ILogger<DeletePersonalDataModel> _logger;
        readonly SignInManager<ApplicationUser>   _signInManager;
        readonly UserManager<ApplicationUser>     _userManager;

        public DeletePersonalDataModel(UserManager<ApplicationUser> userManager,
                                       SignInManager<ApplicationUser> signInManager,
                                       ILogger<DeletePersonalDataModel> logger)
        {
            _userManager   = userManager;
            _signInManager = signInManager;
            _logger        = logger;
        }

        [BindProperty]
        public InputModel Input { get; set; }

        public bool RequirePassword { get; set; }

        public async Task<IActionResult> OnGet()
        {
            ApplicationUser user = await _userManager.GetUserAsync(User);

            if(user == null)
            {
                return NotFound($"Unable to load user with ID '{_userManager.GetUserId(User)}'.");
            }

            RequirePassword = await _userManager.HasPasswordAsync(user);

            return Page();
        }

        public async Task<IActionResult> OnPostAsync()
        {
            ApplicationUser user = await _userManager.GetUserAsync(User);

            if(user == null)
            {
                return NotFound($"Unable to load user with ID '{_userManager.GetUserId(User)}'.");
            }

            RequirePassword = await _userManager.HasPasswordAsync(user);

            if(RequirePassword)
            {
                if(!await _userManager.CheckPasswordAsync(user, Input.Password))
                {
                    ModelState.AddModelError(string.Empty, "Incorrect password.");

                    return Page();
                }
            }

            IdentityResult result = await _userManager.DeleteAsync(user);
            string         userId = await _userManager.GetUserIdAsync(user);

            if(!result.Succeeded)
            {
                throw new InvalidOperationException($"Unexpected error occurred deleting user with ID '{userId}'.");
            }

            await _signInManager.SignOutAsync();

            _logger.LogInformation("User with ID '{UserId}' deleted themselves.", userId);

            return Redirect("~/");
        }

        public class InputModel
        {
            [Required, DataType(DataType.Password)]
            public string Password { get; set; }
        }
    }
}