记一次使用MemoryCache不能Get的问题

在.NET Core自带的Angular模板项目中，我想要做一个简单的登录认证。

所以想填写用户名密码，使用guid作为key，存储登录信息，每次页面刷新的时候check它。

思路觉得没有问题，但是一直失效，修改前代码：

public class AuthController : Controller
  {
    private readonly IMemoryCache _cache;
    public AuthController(IMemoryCache cache)
    {
      _cache = cache;
    }
    [HttpPost]
    public IActionResult Post([FromBody]LoginModel model)
    {
      if (model != null && model.UserName == "xxxxx" && model.Password == "yyyyyyy")
      {
        var token = Guid.NewGuid();
        var cacheEntryOptions = new MemoryCacheEntryOptions()
            .SetPriority(CacheItemPriority.NeverRemove)
            .SetSlidingExpiration(TimeSpan.FromDays(7));
        _cache.Set(token, model, cacheEntryOptions);
        return Ok(new { success = true, token = token, model= _cache.Get<LoginModel>(token) });
      }
      return Ok(new { success = false, error = "UserName or Password error." });
    }
    [HttpGet("check/{token}")]
    public IActionResult Check(string token)
    {
      var model = _cache.Get<LoginModel>(token);
      if (model != null && model.UserName == "xxxxx" && model.Password == "yyyyyyy")
      {
        return Ok(new { success = true, model });
      }
      return Ok(new { success = false, model });
    }

    public class LoginModel
    {
      public string UserName { get; set; }
      public string Password { get; set; }
    }
  }

 但是在调用check的api时，就是找不到。

后来发现在set的地方，guid没有ToString，所以导致两次使用过的key不一样。

修改后：

  [Route("api/auth")]
  public class AuthController : Controller
  {
    private readonly IMemoryCache _cache;
    public AuthController(IMemoryCache cache)
    {
      _cache = cache;
    }
    [HttpPost]
    public IActionResult Post([FromBody]LoginModel model)
    {
      if (!model.IsValidUserInfo())
        return Ok(new { success = false, error = "UserName or Password error." });
      var token = Guid.NewGuid().ToString();
      var cacheEntryOptions = new MemoryCacheEntryOptions()
          .SetPriority(CacheItemPriority.NeverRemove)
          .SetSlidingExpiration(TimeSpan.FromDays(7));
      _cache.Set(token, model, cacheEntryOptions);
      return Ok(new { success = true, token = token });
    }
    [HttpGet("check/{token}")]
    public IActionResult Check(string token)
    {
      var model = _cache.Get<LoginModel>(token);
      return Ok(new { success = model.IsValidUserInfo() });
    }

    public class LoginModel
    {
      public string UserName { get; set; }
      public string Password { get; set; }
    }
  }

  public static class extController
  {
    public static bool IsValidUserInfo(this AuthController.LoginModel me)
      => me != null && me.UserName == "xxxx" && me.Password == "yyyy";
  }

注：多加了一个扩展方法，验证登录信息。