Teso_API/Teso API/AuthControllers/LogOutController.cs

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Net.Http.Headers;
using System;
using System.Collections.Generic;
using System.IdentityModel.Tokens.Jwt;
using System.Linq;
using System.Threading.Tasks;
using Teso_API.Models;

namespace Teso_API.AuthControllers
{
    [Route("api/logout")]
    [ApiController]
    public class LogOutController : ControllerBase
    {
        public IConfiguration _configuration;
        private readonly TESOContext _context;
        public LogOutController(TESOContext context, IConfiguration config)
        {
            _context = context;
            _configuration = config;
        }
        [HttpGet]
        public async Task<ActionResult> Post()
        {
            var accessToken = Request.Headers[HeaderNames.Authorization];

            string token = accessToken;
            try
            {
            token = token.Substring(6).Trim();
            var handler = new JwtSecurityTokenHandler();
            var jwtToken = handler.ReadToken(token) as JwtSecurityToken;
            string userGUID = jwtToken.Claims.First(claim => claim.Type == "userGUID").Value;
            
            UserAuth userAuth = await _context.UserAuths.AsQueryable().Where(uid => uid.UserGUID == userGUID).FirstOrDefaultAsync();
            userAuth.DeviceToken = null;

            _context.Entry(userAuth).State = EntityState.Modified;

                await _context.SaveChangesAsync();
                return Ok();
            }
            catch
            {

                return BadRequest();
            }
        }
    }
}