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());
         _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());
       _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。