Question

我正在尝试使用SQL Server 2008 R2在ASP.NET 4应用程序中配置ELMAH错误日志记录。有什么办法我可以告诉ELMAH在我们提供的连接字符串上调用我们的内部解密函数吗？我是否需要修改ELMAH源并重建？

<configSections>
  <sectionGroup name="elmah">
    <section name="security" requirePermission="false" type="Elmah.SecuritySectionHandler, Elmah" />
    <section name="errorLog" requirePermission="false" type="Elmah.ErrorLogSectionHandler, Elmah" />
    <section name="errorMail" requirePermission="false" type="Elmah.ErrorMailSectionHandler, Elmah" />
    <section name="errorFilter" requirePermission="false" type="Elmah.ErrorFilterSectionHandler, Elmah" />
  </sectionGroup>
</configSections>

<elmah>
  <security allowRemoteAccess="1" />
  <errorLog type="Elmah.SqlErrorLog, Elmah" connectionStringName="ELMAH" />
</elmah>

<connectionStrings>
  <add name="ELMAH" connectionString="EncryptedConnectionString" providerName="System.Data.SqlClient" />
</connectionStrings>

<system.webServer>
  <handlers>
    <add name="Elmah" verb="POST,GET,HEAD" path="elmah.axd" type="Elmah.ErrorLogPageFactory, Elmah" preCondition="integratedMode" />
  </handlers>
  <modules>
    <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah" />
  </modules>
</system.webServer>

Answer 1

你不能告诉ELMAH对你的连接字符串做些什么。但是，您可以做的是告诉ELMAH在需要ErrorLog时给您回电，让您在运行时获得更多控制权。然后，您可以读取加密的连接字符串，使用内部函数对其进行解密，并返回使用它初始化的SqlErrorLog。

为此，您需要提供与之兼容的方法 ServiceProviderQueryHandler代表。System.ComponentModel.Design.ServiceContainer代表。这是定义：

public delegate IServiceProvider ServiceProviderQueryHandler(object context);

该方法的实现必须返回实现IServiceProvider的对象的实例。如果您不想自己编写一个，可以从.NET Framework免费获得一个。见addition in 1.2。服务提供者的GetService必须响应ErrorLog类型的请求，然后您可以返回已使用在运行时操作的连接字符串初始化的SqlErrorLog对象。这是一个可能的实现：

var parent = ServiceCenter.Current;
ServiceCenter.Current = context => { 
    var container = new ServiceContainer(parent(context)); 
    var connectionSettings = ConfigurationManager.ConnectionStrings["FOOBAR"];
    var connectionString = Decrypt(connectionSettings.ConnectionString);
    var log = new SqlErrorLog(connectionString); 
    container.AddService(typeof(ErrorLog), log); 
    return container; 
  } ;

这会捕获当前的服务点并安装您自己的服务点。 lambda / delegate创建时将服务请求传递给捕获的服务点直接满足它，从而创造一个链。您可以通过在应用程序初始化期间的某处设置ServiceCenter.Current来告诉ELMAH您的实现，以便上述代码需要放置。

请记住，这是一个非常简单的实现，但它应该足以让您在需要时启动并优化。

在此{{3}}之前，做类似事情的唯一方法需要进行子类化和其他体操，但仍然会产生部分结果。现在，您只需要实现一个方法并将其交给ELMAH，它只需根据服务类型响应来自ELMAH的查询对象。

Answer 2

作为Atif Aziz帖子的补充，这里是VB.NET版本（.NET 2.0版本的InitializeElmah_VB9 [没有lamdda]，VB.NET for .NET 4.0的InitializeElmah）

Imports System.Web.SessionState

Public Class Global_asax
    Inherits System.Web.HttpApplication


    Public Overrides Sub Init()
        MyBase.Init()

        InitializeElmah_VB9()
        'InitializeElmah()'
    End Sub

    Public parent As Elmah.ServiceProviderQueryHandler = Nothing

    Sub InitializeElmah_VB9()
        ' TODO: Create Table + Functions '
        parent = Elmah.ServiceCenter.Current
        Elmah.ServiceCenter.Current = AddressOf ElmahCallback
    End Sub

    Function ElmahCallback(objContext As Object) As System.IServiceProvider
        Dim container As New System.ComponentModel.Design.ServiceContainer(parent(objContext))
        Dim connectionSettings As System.Configuration.ConnectionStringSettings = ConfigurationManager.ConnectionStrings("FOOBAR")

        Dim strConnectionString As String = connectionSettings.ConnectionString

        Dim x As New System.Data.SqlClient.SqlConnectionStringBuilder(strConnectionString)
        x.Password = CryptStrings.DeCrypt(x.Password)

        strConnectionString = x.ConnectionString

        Dim log As Elmah.SqlErrorLog = New Elmah.SqlErrorLog(strConnectionString)
        container.AddService(GetType(Elmah.ErrorLog), log)
        Return container
    End Function

    Sub InitializeElmah()
        ' TODO: Create Table + Functions '
        Dim parent As Elmah.ServiceProviderQueryHandler = Elmah.ServiceCenter.Current
        Elmah.ServiceCenter.Current = Function(context)
              Dim container As New System.ComponentModel.Design.ServiceContainer(parent(context))
              Dim connectionSettings As System.Configuration.ConnectionStringSettings = ConfigurationManager.ConnectionStrings("Foobar")
              Dim connectionString As String = connectionSettings.ConnectionString

              Dim x As New System.Data.SqlClient.SqlConnectionStringBuilder(connectionString)

              x.Password = CryptStrings.DeCrypt(x.Password)

              connectionString = x.ConnectionString

              Dim log As Elmah.SqlErrorLog = New Elmah.SqlErrorLog(connectionString)
              container.AddService(GetType(Elmah.ErrorLog), log)

              Return container
          End Function

    End Sub


    Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)
        ' Wird beim Starten der Anwendung ausgelöst
    End Sub


    Sub Session_Start(ByVal sender As Object, ByVal e As EventArgs)
        ' Wird beim Starten der Sitzung ausgelöst
    End Sub


    Sub Application_BeginRequest(ByVal sender As Object, ByVal e As EventArgs)
        ' Wird zu Beginn jeder Anforderung ausgelöst
    End Sub


    Sub Application_AuthenticateRequest(ByVal sender As Object, ByVal e As EventArgs)
        ' Wird beim Versuch der Benutzerauthentifizierung ausgelöst
    End Sub


    Sub Application_Error(ByVal sender As Object, ByVal e As EventArgs)
        ' Wird bei einem Fehler ausgelöst
    End Sub


    Sub Session_End(ByVal sender As Object, ByVal e As EventArgs)
        ' Wird beim Beenden der Sitzung ausgelöst
    End Sub


    Sub Application_End(ByVal sender As Object, ByVal e As EventArgs)
        ' Wird beim Beenden der Anwendung ausgelöst
    End Sub


End Class

使用带有加密连接字符串的SQL Server日志记录配置ELMAH

2 个答案: