问题
I'm attempting to configure ELMAH error logging in an ASP.NET 4 application using SQL Server 2008 R2. Is there any way I can tell ELMAH to call our in-house decryption function on the connection string we provide it? Do I need to modify the ELMAH source and rebuild?
<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>
回答1:
You can't just tell ELMAH to do something with your connection string. What you can do, however, is tell ELMAH to call you back when it needs an ErrorLog
, giving you more control at run-time. You can then read the encrypted connection string, decrypt it with your in-house function and return an SqlErrorLog initialized with it.
To do this, you need to provide a method that is compatible with the ServiceProviderQueryHandler delegate. Here's the definition:
public delegate IServiceProvider ServiceProviderQueryHandler(object context);
The implementation of the method must return an instance of an object that implements IServiceProvider
. If you don't feel like writing one yourself to start with, you can get one for free from the .NET Framework. See System.ComponentModel.Design.ServiceContainer. The service provider's GetService
must respond to requests for the ErrorLog
type and you can then, for example, return a SqlErrorLog
object that has been initialized with a connection string manipulated at runtime. Here's a possible implementation:
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;
} ;
This captures the current service point and installs your own instead. The lambda/delegate created pass on service requests to the captured service point when it cannot
satisfy it directly, thus creating a chain. You tell ELMAH about your implementation by setting ServiceCenter.Current
somewhere during the initialization of your application so that's where the above code will need to sit.
Bear in mind that this is a very simple implementation but it should be good enough to get you started and optimize later if needed.
Prior to this addition in 1.2, the only way to do something similar required subclassing and other gymnastics and still yielded partial results. Now you just need to implement a method and hand it over to ELMAH and which simply responds to queries from ELMAH for objects based on their service type.
回答2:
As an addition to the post of Atif Aziz, here the VB.NET version (InitializeElmah_VB9 for the .NET 2.0 version [without lamdda], InitializeElmah for VB.NET for .NET 4.0)
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
来源:https://stackoverflow.com/questions/5981750/configuring-elmah-with-sql-server-logging-with-encrypted-connection-string