带Angularjs的MVC，ASP.NET身份，EmailService和异步调用

Question

查看并尝试解决有关错误消息的许多建议后：

“异步模块或处理程序在异步操作仍处于挂起状态时完成。”

我发现自己处于这样一种情况，即使对MVC accountController的调用实际上已执行了所需的代码（一封电子邮件已发送至具有正确内容的正确位置），并且在controller方法中使用Try / Catch不会“捕获”错误，发起调用的AngularJS工厂将收到服务器错误“页面”。

工厂：（AngularJS）

InitiateResetRequest: function (email) {
                    var deferredObject = $q.defer();

                    $http.post(
                        '/Account/InitiateResetPassword', { email: email }
                    )
                    .success(function (data) {
                            deferredObject.resolve(data);
                    })
                    .error(function (data) {
                        //This is a stop-gap solution that needs to be fixed..!
                        if (data.indexOf("An asynchronous module or handler completed while an asynchronous operation was still pending.") > 0) {
                            deferredObject.resolve(true);
                        } else {
                            deferredObject.resolve(false);
                        }
                    });
                    return deferredObject.promise;
                }

MVC控制器（C＃）：

        [HttpPost]
        [AllowAnonymous]
        public async Task<int> InitiateResetPassword(string email)
        {
            try
            {
                _identityRepository = new IdentityRepository(UserManager);
                string callbackUrl = Request.Url.AbsoluteUri.Replace(Request.Url.AbsolutePath, "/account/reset?id=");
                await _identityRepository.InitiatePasswordReset(email, callbackUrl);
                return 0;
            }
            catch(Exception ex)
            {
                Console.WriteLine(ex.ToString());
                return 1;
            }
        }

身份存储库/ InitiatePasswordReset：

 public async Task InitiatePasswordReset(string email, string callbackUrl)
        {
            try
            {
                var u = await _applicationUserManager.FindByEmailAsync(email);

                string passwordResetToken = await GetResetToken(u);
                callbackUrl = callbackUrl + HttpUtility.UrlEncode(passwordResetToken);
                await _applicationUserManager.SendEmailAsync(u.Id, RESET_SUBJECT, string.Format(RESET_BODY, u.FirstName, u.LastName, callbackUrl));
            }
            catch(Exception ex)
            {      //another vain attempt to catch the exception...
                Console.WriteLine(ex.ToString());
                throw ex;
            }
        }

EmailService已注入ASP.NET标识“ ApplicationUserManager”中

   public class EmailService : IIdentityMessageService
    {
        XYZMailer xyzMailer;
        public EmailService()
        {
            xyzMailer = XYZMailer.getCMRMailer();
        }
        public async Task SendAsync(IdentityMessage message)
        {
            //original code as posted:
            //await Task.FromResult(xyzMailer.SendMailAsync(message));
            //solution from @sirrocco-
            await xyzMailer.SendMailAsync(message);
        }
    }

最后是XYZMailer类

class XYZMailer
    {
        #region"Constants"
        private const string SMTP_SERVER = "XYZEXCHANGE.XYZ.local";
        private const string NO_REPLY = "noReply@XYZCorp.com";
        private const string USER_NAME = "noreply";
        private const string PASSWORD = "theMagicP@55word"; //NO, that is not really the password :) 
        private const int SMTP_PORT = 587;
        private const SmtpDeliveryMethod SMTP_DELIVERY_METHOD = SmtpDeliveryMethod.Network;
        #endregion//Constants

        internal XYZMailer()
        {
            //default c'tor
        }

        private static XYZMailer _XYZMailer = null;
        public static XYZMailer getXYZMailer()
        {
            if (_XYZMailer == null)
            {
                _XYZMailer = new XYZMailer();
            }
            return _XYZMailer;
        }

        public async Task<int> SendMailAsync(IdentityMessage message)
        {
#if DEBUG
                message.Body += "<br/><br/>DEBUG Send To: " + message.Destination;
                message.Destination = "me@XYZCorp.com";
#endif
            // Create the message:
            var mail =
                new MailMessage(NO_REPLY, message.Destination)
                {
                    Subject = message.Subject,
                    Body = message.Body,
                    IsBodyHtml = true
                };

            // Configure the client:
            using (SmtpClient client = new SmtpClient(SMTP_SERVER, SMTP_PORT)
            {
                DeliveryMethod = SMTP_DELIVERY_METHOD,
                UseDefaultCredentials = false,
                Credentials = new System.Net.NetworkCredential(USER_NAME, PASSWORD),
                EnableSsl = true
            })
            {
                // Send:
                await client.SendMailAsync(mail);

            }
            return 0;
        }

    }

（注意：最初，控制器方法只是“公共异步任务InitiateResetPassword，我添加了返回类型，以尝试在服务器上捕获错误。在运行时，返回0；不会命中（断点），catch不会命中，并且在客户端”）

目前，我只是在过滤预期的错误消息，然后告诉javascript将其视为成功。 该解决方案具有“实际工作”的优势……但不是“理想的”。

如何防止服务器上的错误？ 或者， 如何在服务器上捕获错误？

Answer 1

您需要从EmailService删除await Task.FromResult ，因为这样做会导致代码同步执行，而不是异步执行。

至于为什么仍然在try / catch之外引发异常并冒出气泡-我怀疑Task.FromResult也是罪魁祸首-如果现在在SendAsync引发异常（只是为了对其进行测试），则应在控制器中捕获。