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Using Fault Handling

  • Artigo

During Windows Communication Foundation (WCF) fault handling an exception message is not returned to the client unless a FaultException (or a subtype) is thrown or a FaultContract is implemented. So you can only track data from the fault message itself in these scenarios. An exception in callback implementations automatically comes back as a fault message for both ServerFault and ClientFault track points. However, it will always return a generic fault with a generic message. For more information about WCF fault contracts, see https://go.microsoft.com/fwlink/?LinkId=83132.

You can also track constants and context properties through the fault track points.

If exception details are returned in faults using the IncludeExceptionDetailInFaults attribute, you extract the actual exception message through the XPath.

Fault handling is provided by the fault track points defined in GetServiceContractCallPoint:

  • ServiceFault

  • ClientFault

  • CallbackFault

    When using these fault track points, fault data is always persisted, even when operating in a transaction-based scenario. Transactional integrity is maintained on all non-fault tracked data and non-fault tracked data is rolled back as a response to the fault.

Note

These track points are applied to the reply path and apply only to the ServiceReply, ClientReply and CallbackReply service contract call points provided by GetServiceContractCallPoint.

Fault Configuration Sample

The following sample demonstrates tracking the exception message on a ServiceFault when the service throws a FaultException in the AuthorizationServiceFault event; otherwise it tracks the Boolean expression returned by the operation in the AuthorizationServiceReply event. Either the AuthorizationServiceReply OnEvent or the AuthorizationServiceFault OnEvent is persisted.

Note

The implementation of this sample demonstrates the mutual exclusivity of the ServiceReply and ServiceFault trackpoints.

<ic:OnEvent IsBegin ="true" IsEnd="false" Name="AuthorizationServiceReply" Source="ESCreditCardService">

  <ic:Filter>
    <ic:Expression>
      <wcf:Operation Name="GetServiceContractCallPoint"/>
      <ic:Operation Name ="Constant">
        <ic:Argument>ServiceReply</ic:Argument>
      </ic:Operation>
      <ic:Operation Name ="Equals"/>
      <wcf:Operation Name="GetOperationName" />
      <ic:Operation Name="Constant">
        <ic:Argument>AuthorizeWithDataContract</ic:Argument>
      </ic:Operation>
      <ic:Operation Name ="Equals" />
      <ic:Operation Name ="And" />
    </ic:Expression>
  </ic:Filter>

  <ic:CorrelationID>
    <ic:Expression>
      <wcf:Operation Name="AutoGenerateCorrelationToken"/>
    </ic:Expression>
  </ic:CorrelationID>

  <ic:Update DataItemName="Status" Type="NVARCHAR">
    <ic:Expression>
      <ic:Operation Name="Constant">
        <ic:Argument>Success</ic:Argument>
      </ic:Operation>
    </ic:Expression>
  </ic:Update>

  <ic:Update DataItemName="Result" Type="NVARCHAR">
    <ic:Expression>
      <wcf:Operation Name ="XPath">
        <wcf:Argument>//s:Body/ccservice:*/ccservice:AuthorizeWithDataContractResult</wcf:Argument>
      </wcf:Operation>
    </ic:Expression>
  </ic:Update>

  <ic:Update DataItemName ="Service Call Date" Type ="DATETIME">
    <ic:Expression>
      <wcf:Operation Name ="GetContextProperty">
        <wcf:Argument>EventTime</wcf:Argument>
      </wcf:Operation>
    </ic:Expression>
  </ic:Update>

</ic:OnEvent>

<ic:OnEvent IsBegin ="true" IsEnd="false" Name="AuthorizationServiceFault" Source="ESCreditCardService">

  <ic:Filter>
    <ic:Expression>
      <wcf:Operation Name="GetServiceContractCallPoint"/>
      <ic:Operation Name ="Constant">
        <ic:Argument>ServiceFault</ic:Argument>
      </ic:Operation>
      <ic:Operation Name ="Equals"/>
      <wcf:Operation Name="GetOperationName" />
      <ic:Operation Name="Constant">
        <ic:Argument>AuthorizeWithDataContract</ic:Argument>
      </ic:Operation>
      <ic:Operation Name ="Equals" />
      <ic:Operation Name ="And" />
    </ic:Expression>
  </ic:Filter>

  <ic:CorrelationID>
    <ic:Expression>
      <wcf:Operation Name="AutoGenerateCorrelationToken"/>
    </ic:Expression>
  </ic:CorrelationID>

  <ic:Update DataItemName="Status" Type="NVARCHAR">
    <ic:Expression>
      <ic:Operation Name="Constant">
        <ic:Argument>Fault</ic:Argument>
      </ic:Operation>
    </ic:Expression>
  </ic:Update>

      <ic:Update DataItemName="Source" Type="NVARCHAR">
        <ic:Expression>
          <wcf:Operation Name ="XPath">
            <wcf:Argument>//s:Body/Fault/Reason/Text</wcf:Argument>
          </wcf:Operation>
        </ic:Expression>
      </ic:Update>

  <ic:Update DataItemName ="Service Call Date" Type ="DATETIME">
    <ic:Expression>
      <wcf:Operation Name ="GetContextProperty">
        <wcf:Argument>EventTime</wcf:Argument>
      </wcf:Operation>
    </ic:Expression>
  </ic:Update>

</ic:OnEvent>

See Also

Configuring the WCF Adapter to Intercept BAM Data