應該將所有WCF服務代碼包裝在try catch塊中嗎？

Question

try 
{ 
    ///// here is the code that might throw erros. If I discover the user is unauthorized I throw a WebFaultException myself to alert the client 
}  
catch (WebFaultException ex) 
{ 
    throw ex; //but if I wrap all code in try-catch, I have to rethrow the exception o the status code reaches the client 
} 
catch (Exception ex) 
{ 
    throw new WebFaultException(ex.Message, HttpStatusCode.InternalServerError); 
} 

我是否應該將所有內容都包含在try-catch中，或者你推薦什麼？我使用WCF休息-FUL JSON服務

Answer 1

你可以做，但它可能會更好地執行IErrorHandler和add it as a behaviour爲您服務，讓您的未處理的異常在一個地方進行處理，所以你能夠在那裏創建一個故障異常來向用戶返回詳細信息。

ErrorHandler : IErrorHandler 
{ 
... just implement the handling of errors here, however you want to handle them 
} 

然後創建一個使用此行爲：

/// <summary> 
/// Custom WCF Behaviour for Service Level Exception handling. 
/// </summary> 
public class ErrorHandlerBehavior : IServiceBehavior 
    { 
    #region Implementation of IServiceBehavior 


    public void Validate (ServiceDescription serviceDescription, ServiceHostBase serviceHostBase) 
     { 
     } 


    public void AddBindingParameters (ServiceDescription serviceDescription, ServiceHostBase serviceHostBase, 
             Collection<ServiceEndpoint> endpoints, BindingParameterCollection bindingParameters) 
     { 
     } 


    public void ApplyDispatchBehavior (ServiceDescription serviceDescription, ServiceHostBase serviceHostBase) 
     { 
     IErrorHandler errorHandler = new ErrorHandler(); 

     foreach (ChannelDispatcherBase channelDispatcherBase in serviceHostBase.ChannelDispatchers) 
      { 
      var channelDispatcher = channelDispatcherBase as ChannelDispatcher; 

      if (channelDispatcher != null) 
       { 
       channelDispatcher.ErrorHandlers.Add (errorHandler); 
       } 
      } 
     } 

    #endregion 
    } 

然後，如果你是自託管，你可以再補充程序的行爲：

myServiceHost.Description.Behaviors.Add (new ErrorHandlerBehavior()); 

，如果你想添加它通過配置，然後你需要其中的一個：

public class ErrorHandlerElement : BehaviorExtensionElement 
    { 
    public override Type BehaviorType 
     { 
     get { return typeof (ErrorHandlerBehavior); } 
     } 

    protected override object CreateBehavior() 
     { 
     return new ErrorHandlerBehavior(); 
     } 
    } 
} 

，然後配置：

<system.serviceModel> 
<extensions> 
    <behaviorExtensions> 
    <add name="ErrorLogging" type="ErrorHandlerBehavior, ErrorHandling, Version=1.0.0.0, Culture=neutral, PublicKeyToken=<whatever>" /> 
    </behaviorExtensions> 
</extensions> 
<bindings> 
    <basicHttpBinding> 
    <binding name="basicBinding"> 
    </binding> 
    </basicHttpBinding> 
</bindings> 
<services> 
    <service behaviorConfiguration="Service1Behavior" name="Service"> 
    <endpoint address="" binding="basicHttpBinding" bindingConfiguration="basicBinding" contract="Service" /> 
    </service> 
</services> 
<behaviors> 
    <serviceBehaviors> 
    <behavior name="Service1Behavior"> 
     <serviceMetadata httpGetUrl="" httpGetEnabled="true" /> 
     <serviceDebug includeExceptionDetailInFaults="false" /> 
     <ErrorLogging /> <--this adds the behaviour to the service behaviours --> 
    </behavior> 
    </serviceBehaviors> 
</behaviors>