WCF

1. FaultContract

2. MessageContract

3. Duplex

4. Hosting

5. Transactions

6. Session management

7. Polymorphism

8. tcpbinding

1. FaultContract

• FaultContract helps to do Exception handling in WCF service
• convert .NET exceptions into Fault
• Service client does not have to be built by using .NET framework
• SOAP protocol provides a standard mechanism to report faults within SOAP message.
• So client can recognize it as fault from the SOAP message

• Types of error:
• Domain error: (eg: NoFunds)
• Technical error:  (Expected and                 unexpected technical errors(eg: divide by zero))
• These errors should be mapped to one of the defined faults.
• Structure of SOAP fault is an XML representation of error information.
• SOAP fault contains

§ Code

§ Reason

§ Detail

• Using Fault in service

• Typed and Untyped fault

• Handling service Exceptions at client

2. MessageContract
1. WCF allow you to control SOAP message structure with MessageContract
2. You can modify message by

·   Define custom header

·   Adding elements to SOAP body

·   Altering namespace in SOAP body

3. Message exchange patterns
1. Request response
2. Simplex (one way)
3. Duplex

·         Request  response

o  default message exchange pattern in WCF

o Synchronous remote procedure call(RPC)

·         One way

o Client send message to service, but service does not send message back

o Return type of one-way operation must be void

o Drawback- no way to detect operation failure

o Advantage – performance – as client does not have to wait for response

[OperationContract(IsOneWay = true)]

void MakeDeposit(string account, decimal amount);

·         Duplex

o This pattern consists of 2 separate contracts

o One contract implemented by service, other by client

o 2 one-way messages

4. Polymorphism

·         Operation overloading - Operation with same name, but different parameters

·         Use Name property in OperationContract.

[OperationContract(Name="DepositLocalCurrency")]

void Deposit(string account, decimal amount);

[OperationContract(Name="DepositAnyCurrency")]

void Deposit(string account, Currency amount);

5. Transactions

@server:

1. Select a transaction aware binding

o NetTcpBinding

o NetNamedPipeBinding

o wsHttpBinding

o wsDualHttpBinding

o wsFederationHttpBinding

2. Enable TransactionFlow property of binding in configuration file.

 

   

         transactionProtocol="WSAtomicTransactionOctober2004"/>

 

3. Transactional requirement of operation

@client

1.       Enable transaction flow on binding in configuration file.

2.       Use TransactionScope block at client code