Come si crea un gestore di eccezioni globale per i servizi WCF?

Question

Voglio registrare tutte le eccezioni lato server.

In ASP.NET scrivo qualcosa di simile in Global.asax.cs, ma funzionerà anche per un servizio WCF?

public class Global : HttpApplication 
{ 
    protected void Application_Error(object sender, EventArgs e) 
    { 
     Exception unhandledException = Server.GetLastError(); 

     //Log exception here 
     ... 
    } 
} 

UPDATE: Io non voglio avere un try ... catch per ogni [OperationContract] nel mio file .svc. Insomma ... Voglio assicurarmi che tutte le eccezioni che i miei servizi generano siano registrate da log4net. Non sto parlando di come il client gestisce l'eccezione.

Answer 1

È possibile creare un registro errori WCF implementando IErrorHandler e associandolo al servizio; in genere (per la registrazione) restituire false da HandleError (consentendo l'esecuzione di altri gestori) e registrare l'errore in HandleError (utilizzando Exception) o in ProvideFault (utilizzando ref Message fault).

applico questo gestore scrivendo un comportamento personalizzato (che eredita da BehaviorBase), che (in ApplyDispatchBehavior) aggiunge l'errore-gestore per endpointDispatcher.ChannelDispatcher.ErrorHandlers se non è già presente.

Il comportamento può essere applicato tramite la configurazione.

Answer 2

Sono stato interessato a questo problema e dopo molte ricerche aperte, inclusi articoli collegati in altre risposte, ecco esattamente ciò di cui qualcuno ha bisogno per questo.

Ecco la classe ErrorHandler avrete bisogno ...

Imports System.ServiceModel.Configuration 
Imports System.ServiceModel.Description 
Imports System.ServiceModel.Dispatcher 

''' <summary> 
''' This class defines a global ErrorHandler, that allows us to control the 
''' fault message returned to the client and perform custom error processing 
''' like logging. 
''' </summary> 
Public Class ErrorHandler 
    Implements IErrorHandler 

    ''' <summary> 
    ''' This method will be called whenever an exception occurs. Therefore, 
    ''' we log it and then return false so the error can continue to propagate up the chain. 
    ''' </summary> 
    ''' <param name="ex">Exception being raised.</param> 
    ''' <returns>False to let the error propagate up the chain, or True to stop the error here.</returns> 
    Public Function HandleError(ByVal ex As Exception) As Boolean Implements IErrorHandler.HandleError 
     'Unknown error occurred at the Service layer, log the event 
     logEvent("Encountered an unknown error at the Service layer.", ex, EventLogEntryType.Error) 

     Return False 
    End Function 

    ''' <summary> 
    ''' This method is optionally used to transform standard exceptions into custom 
    ''' FaultException(Of TDetail) that can be passed back to the service client. 
    ''' </summary> 
    ''' <param name="ex">Exception being raised.</param> 
    ''' <param name="version">SOAP version of the message.</param> 
    ''' <param name="fault">Message object that is returned to the client.</param> 
    Public Sub ProvideFault(ByVal ex As Exception, ByVal version As Channels.MessageVersion, ByRef fault As Channels.Message) Implements IErrorHandler.ProvideFault 
    End Sub 

End Class 

''' <summary> 
''' This class defines a ServiceBehavior, that will allow us to add our 
''' custom ErrorHandler class, defined above, to each channel we have a 
''' service running on. 
''' </summary> 
Public Class ErrorServiceBehavior 
    Implements IServiceBehavior 

    Public Sub AddBindingParameters(serviceDescription As ServiceDescription, serviceHostBase As ServiceHostBase, endpoints As ObjectModel.Collection(Of ServiceEndpoint), bindingParameters As Channels.BindingParameterCollection) Implements IServiceBehavior.AddBindingParameters 
    End Sub 

    Public Sub ApplyDispatchBehavior(serviceDescription As ServiceDescription, serviceHostBase As ServiceHostBase) Implements IServiceBehavior.ApplyDispatchBehavior 
     'Enumerate all channels and add the error handler to the collection 
     Dim handler As New ErrorHandler() 
     For Each dispatcher As ChannelDispatcher In serviceHostBase.ChannelDispatchers 
      dispatcher.ErrorHandlers.Add(handler) 
     Next 
    End Sub 

    Public Sub Validate(serviceDescription As ServiceDescription, serviceHostBase As ServiceHostBase) Implements IServiceBehavior.Validate 
    End Sub 

End Class 

''' <summary> 
''' This class defines a BehaviorExtensionElement, so that we can 
''' use the ErrorServiceBehavior class, defined above, in our App.config. 
''' </summary> 
Public Class ErrorHandlerBehavior 
    Inherits BehaviorExtensionElement 

    Protected Overrides Function CreateBehavior() As Object 
     Return New ErrorServiceBehavior() 
    End Function 

    Public Overrides ReadOnly Property BehaviorType As Type 
     Get 
      Return GetType(ErrorServiceBehavior) 
     End Get 
    End Property 

End Class 

Poi, queste sezioni devono essere aggiunti/aggiornati nel file App.config per il vostro progetto di servizio ...

<system.serviceModel> 
    <extensions> 
    <behaviorExtensions> 
     <!-- Add in our custom error handler --> 
     <add name="ErrorLogging" type="Service.ErrorHandlerBehavior, Service, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" /> 
    </behaviorExtensions> 
    </extensions> 
    <services> 
    <service name="Service.Service" behaviorConfiguration="Service.ServiceBehavior"> 
     <endpoint address="" binding="wsHttpBinding" bindingConfiguration="wsHttp" 
     contract="SentinelService.IService"/> 
     <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" /> 
    </service> 
    </services> 
    <behaviors> 
    <serviceBehaviors> 
     <behavior name="Service.ServiceBehavior"> 
     <serviceMetadata httpGetEnabled="True" /> 
     <serviceDebug includeExceptionDetailInFaults="False" /> 
     <!-- Add in our custom error handler, from behaviorExtensions element --> 
     <ErrorLogging /> 
     </behavior> 
    </serviceBehaviors> 
    </behaviors> 

In particolare, è necessario aggiungere un comportamento Estensione, il suo nome deve essere aggiunto alla sezione comportamento, la sezione comportamento deve essere denominata e quella sezione comportamento deve essere il behaviorConfiguration per il servizio.

Fare attenzione con l'attributo "tipo" sul comportamentoEstensione, tuttavia, deve essere esatto. Se non si è sicuri, è possibile utilizzare quanto segue per determinarlo GetType(ErrorHandlerBehavior).AssemblyQualifiedName.

Se siete interessati, questo è il codice dietro la funzione LogEvent uso ...

''' <summary> 
''' Logs a message and optional exception to the application event log. 
''' </summary> 
''' <param name="message">String message to log.</param> 
''' <param name="ex">Exception to log.</param> 
''' <param name="eventType">EventLogEntryType indicating the message severity.</param> 
Public Sub logEvent(ByVal message As String, Optional ByVal ex As Exception = Nothing, _ 
        Optional ByVal eventType As EventLogEntryType = EventLogEntryType.Information) 
    'Initialize report 
    Dim report As String = message + vbNewLine + vbNewLine 

    'Create eventLogger 
    Dim eventLogger As New EventLog() 

    'Register event source, add any Exception information to the report, and then log it 
    Try 
     'Register the app as an Event Source 
     If Not EventLog.SourceExists("MyAppName") Then 
      EventLog.CreateEventSource("MyAppName", "Application") 
     End If 

     If ex IsNot Nothing Then 
      'Force eventType to error 
      eventType = EventLogEntryType.Error 

      'Add Exception Information to report 
      report += "Exception Information:" + vbNewLine 
      Dim currentException As Exception = ex 
      Dim exCount As Integer = 1 
      While (currentException IsNot Nothing) 
       report += Space(5) + If(exCount = 1, "Message:", "Inner Exception:") + vbNewLine 
       report += Space(10) + currentException.Message + vbNewLine 
       report += Space(5) + "StackTrace:" + vbNewLine 
       report += Space(10) + currentException.StackTrace + vbNewLine 
       report += vbNewLine 

       currentException = currentException.InnerException 
       exCount += 1 
      End While 
     End If 
    Catch reportException As Exception 
     'This catch ensures that no matter what some error report is logged. 
     report += vbNewLine + vbNewLine + "PARTIAL REPORT!!!...AN ERROR WAS ENCOUNTERED GENERATING ERROR REPORT." 
    Finally 
     Try 
      'Log report 
      eventLogger.Source = "MyAppName" 
      eventLogger.WriteEntry(report, eventType) 
     Catch logEventException As Exception 
      'Eat it...nothing can be done at this point and we do 
      'not want the application to crash over an error report 
      'if we can prevent it 
     End Try 
    End Try 
End Sub 

Answer 3

Questa non è una risposta in sé, ma un addendum al grande risposta fornita da SkyBlade002, fornendo il codice data in C#, per convenienza per qualsiasi C# coder:

Ecco il mio codice (in ErrorHandler.cs):

/// <summary> 
///  This class defines a global ErrorHandler, that allows us to control the fault message returned to the client and 
///  perform custom error processing like logging. 
/// </summary> 
public class ErrorHandler : IErrorHandler { 
    private static readonly ILog Log = LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType); 

    /// <summary> 
    ///  Enables the creation of a custom <see cref="T:System.ServiceModel.FaultException`1" /> that is returned from an 
    ///  exception in the course of a service method. 
    /// </summary> 
    /// <remarks> 
    ///  This method is optionally used to transform standard exceptions into custom FaultException(Of TDetail) that 
    ///  can be passed back to the service client. 
    /// </remarks> 
    /// <param name="error">The <see cref="T:System.Exception" /> object thrown in the course of the service operation.</param> 
    /// <param name="version">The SOAP version of the message.</param> 
    /// <param name="fault"> 
    ///  The <see cref="T:System.ServiceModel.Channels.Message" /> object that is returned to the client, or 
    ///  service, in the duplex case. 
    /// </param> 
    public void ProvideFault(Exception error, MessageVersion version, ref Message fault) {} 

    /// <summary> 
    ///  This method will be called whenever an exception occurs. Therefore, 
    ///  we log it and then return false so the error can continue to propagate up the chain. 
    /// </summary> 
    /// <param name="error">Exception being raised.</param> 
    /// <returns>False to let the error propagate up the chain, or True to stop the error here.</returns> 
    public bool HandleError(Exception error) { 
     Log.Error(ex); //TODO your own logging 
     return false; 
    } 

Ecco il mio codice (in ErrorHandlerBehavior.cs):

/// <summary> 
///  This class defines a BehaviorExtensionElement, so that we can use the ErrorServiceBehavior class, defined above, in 
///  our App.config. 
/// </summary> 
public class ErrorHandlerBehavior : BehaviorExtensionElement { 
    /// <summary> 
    ///  Gets the type of behavior. 
    /// </summary> 
    public override Type BehaviorType { 
     get { return typeof (ErrorServiceBehavior); } 
    } 

    /// <summary> 
    ///  Creates a behavior extension based on the current configuration settings. 
    /// </summary> 
    /// <returns> 
    ///  The behavior extension. 
    /// </returns> 
    protected override object CreateBehavior() { 
     return new ErrorServiceBehavior(); 
    } 
} 

Ecco il mio codice (in ErrorServiceBehavior.cs):

/// <summary> 
///  This class defines a ServiceBehavior, that will allow us to add our custom ErrorHandler class, defined above, to 
///  each channel we have a service running on. 
/// </summary> 
public class ErrorServiceBehavior : IServiceBehavior { 
    /// <summary> 
    ///  Provides the ability to inspect the service host and the service description to confirm that the service can run 
    ///  successfully. 
    /// </summary> 
    /// <param name="serviceDescription">The service description.</param> 
    /// <param name="serviceHostBase">The service host that is currently being constructed.</param> 
    public void Validate(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase) {} 

    /// <summary> 
    ///  Provides the ability to pass custom data to binding elements to support the contract implementation. 
    /// </summary> 
    /// <param name="serviceDescription">The service description of the service.</param> 
    /// <param name="serviceHostBase">The host of the service.</param> 
    /// <param name="endpoints">The service endpoints.</param> 
    /// <param name="bindingParameters">Custom objects to which binding elements have access.</param> 
    public void AddBindingParameters(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase, Collection<ServiceEndpoint> endpoints, BindingParameterCollection bindingParameters) {} 

    /// <summary> 
    ///  Provides the ability to change run-time property values or insert custom extension objects such as error handlers, 
    ///  message or parameter interceptors, security extensions, and other custom extension objects. 
    /// </summary> 
    /// <param name="serviceDescription">The service description.</param> 
    /// <param name="serviceHostBase">The host that is currently being built.</param> 
    public void ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase) { 
     //Enumerate all channels and add the error handler to the collection 
     var handler = new ErrorHandler(); 
     foreach (ChannelDispatcher dispatcher in serviceHostBase.ChannelDispatchers) { 
      dispatcher.ErrorHandlers.Add(handler); 
     } 
    } 
}