70518

Designing Services and  Method granularityCohesiondefines how methods are grouped into different services. The method within a service are cohesive if they perform similar activities with closely related dataTypes  of CohesionFunctional Cohesionmethods in a service are grouped together because they perform different aspect of single taskSequential cohesionmethods in a service a grouped because they are called during the same phase in a processCommunication cohesionmethod in a service are grouped together because they accept the same data as parametermethod granularityAs a general rule design method that perform an entire transactionAs a general rule if you cannot respond to a request within 5 sec, you should divide the request into multiple methodUsing RESTUnlike SOAP and most other web services implementations, Restful web services do not require the use of XMLMessage and Data Contractswhenever possible  use data contract because it is simpler to define and provide more flexibility by allowing you to use different messaging technique. Choose a message contract only when you need to conform to existing standard, such as when you need to replace an existing SOAP web service or when you need to pass information in the header separate from the data itselfUsing SOAP HeadersSystem related info like custom login credentialuser token, preferences, application or operating system identification and versions, TimeStamps should be communicated through SOAP headers  as opposed to being put in the body of messagesCustom SOAP headers using Generic Classes( create an instance of generic System.ServiceModel.Channels.MessageHeader using the data you need to pass to the header and then adding it to the OperationContext.Current.OutgoingMessageHeaders collection on the client. On the server read the header by calling the generic OperationContext.Current.IncomimhMessageHeaders.GetHeaderAsynchronous: one way operation that does not return response immediately but can return a response using a callback. Client of asyncronous service are not immediately aware of error that might occurSynchronous: A two-way request response operation. The client submits a request and waits until the service returns a response. Synchronous services can return  fault messages which behaves like exception Message Exchange PatternStatefulStateless ( as general rule use stateless where possible)VersioningFollowing this versioning technique ; increment the version number only when an update might cause another application to fail, and have other applications always prefer the version they were compiled and tested in. Updates must provide both backward and forward compatibility (forward compatibly means application compiled with the updates will work on a computer without the update)

New Page