Question

我有一个用ASP.NET MVC 2编写的应用程序，它将用户预定事件的日期和时间存储在MSSQL数据库中。我需要应用程序在存储事件发生前72小时向用户发送电子邮件警报，而无需任何手动干预。

实现此并行流程的最佳方式是什么（我已经有电子邮件代码）？

Answer 1

假设您已将事件存储在数据库中，我将创建一个独立于asp.net应用程序运行的Windows服务，该应用程序定期轮询数据库以查找要完成的工作。

Answer 2

如果您可以控制服务器，那么我可能会使用Windows服务（如The Evil Greebo said）。

但假设你没有，我会创建一个类，可能类似于下面的类，你可以使用/继承它。在global.asax中的“Application_start”事件期间实例化此类，并将其副本保存在缓存中。将您的逻辑放在“ExecuteProcess”方法中。你的逻辑可能看起来像（伪代码）：

while(true) 
   check for events that need to have notifications sent

   send any needed notifications

   wait x seconds and repeate

loop

确保MSSQL数据库表中有一个字段，用于跟踪是否已发送通知。

基础基类：

Imports System.Threading

Public MustInherit Class LongRunningProcess
    Public ReadOnly Property Running() As Boolean
        Get
            Return _Running
        End Get
    End Property

    Public ReadOnly Property Success() As Boolean
        Get
            Return _Success
        End Get
    End Property

    Public ReadOnly Property Exception() As Exception
        Get
            Return _Exception
        End Get
    End Property

    Public ReadOnly Property StartTime() As DateTime
        Get
            Return _StartTime
        End Get
    End Property

    Public ReadOnly Property EndTime() As DateTime
        Get
            Return _EndTime
        End Get
    End Property

    Public ReadOnly Property Args() As Object
        Get
            Return _Args
        End Get
    End Property


    Protected _Running As Boolean = False
    Protected _Success As Boolean = False
    Protected _Exception As Exception = Nothing
    Protected _StartTime As DateTime = DateTime.MinValue
    Protected _EndTime As DateTime = DateTime.MinValue
    Protected _Args() As Object = Nothing
    Protected WithEvents _Thread As Thread

    Private _locker As New Object()

    Public Sub Execute(ByVal Arguments As Object)
        SyncLock (_locker)
            'if the process is not running, then...'
            If Not _Running Then
                'Set running to true'
                _Running = True
                'Set start time to now'
                _StartTime = DateTime.Now
                'set arguments'
                _Args = Arguments
                'Prepare to process in a new thread'
                _Thread = New Thread(New ThreadStart(AddressOf ExecuteProcess))

                'Start the thread'
                _Thread.Start()
            End If
        End SyncLock
    End Sub

    Protected MustOverride Sub ExecuteProcess()
End Class

Args属性允许您从“ExecuteProcess”中访问您可能需要的任何参数/变量。

并行处理唤醒并在预定事件发生前72小时发送电子邮件警报

2 个答案: