Programming WCF Services - Transactions

1.分布式Transaction地实现需要Two-phase commit protocol 和 负责管理Transaction的第三方的Transaction Manager。

2Transaction 的Reliable和TransactionFlow设置

<netTcpBinding>
   <binding name = "TransactionalTCP"
                                  transactionFlow = "true">
      <reliableSession enabled = "true"/>
   </binding>
</netTcpBinding><netTcpBinding>
   <binding name = "TransactionalTCP"
                                  transactionFlow = "true">
      <reliableSession enabled = "true"/>
   </binding>
</netTcpBinding>

3.允许客户端的Transaction能够进入Service：TransactionFlow(设置在Interface Contract的Function上)，不能够和One-Way一起设置([OperationContract(IsOneWay = true)])

[ServiceContract]interface IMyContract{   [OperationContract]   [TransactionFlow(TransactionFlowOption.Allowed)]   void MyMethod(...);}

4.Ambient Transaction的设置TransactionScopeRequired 

如果客户端已经存在Transaction,则传播到Service，WCF设置Client Transaction 作为 Ambient Transaction.
否则，将在Service端新建一个Transaction
class MyService : IMyContract{   [OperationBehavior(TransactionScopeRequired = true)]   public void MyMethod( )   {      Transaction transaction = Transaction.Current;      Debug.Assert(transaction != null);   }}
5 .Transaction modes as product of binding, contract, and behavior
其中Client/Service是 最decoupled 设置
Binding transaction flow
TransactionFlowOption
TransactionScopeRequired
Transaction mode
False
Allowed
False
None
False
Allowed
True
Service
False
NotAllowed
False
None
False
NotAllowed
True
Service
True
Allowed
False
None
True
Allowed
True
Client/Service
True
Mandatory
False
None
True
Mandatory
True
Client

6，对于Transaction,建议以Per-Call方式，简单，并且生命周期能保持一致。

MyContractClient proxy = new MyContractClient( );using(TransactionScope scope = new TransactionScope( )){   proxy.MyMethod(...);   scope.Complete( );}using(TransactionScope scope = new TransactionScope( )){   proxy.MyMethod(...);   scope.Complete( );}proxy.Close( );