I am unsure where to place my business logic. I have a WCF service which exposes its methods to my client.
Should my business logic go in the service method
public User GetUser(int id)
{
//Retrieve the user from a repository and perform business logic
return user;
}
or should it be in a separate class where each WCF service method will in turn call the business layer methods.
public User GetUser(int id)
{
return _userLogic.GetUser(id);
}
My personal preference is to have WCF as a very thin layer on top of a separate business layer. The WCF layer does nothing more than make calls to the business layer, similar to what you have shown in option 2. This gives you some flexibility in the event that you want to have your business layer consumed by something other than WCF clients (for example, a WPF application calling your business layer directly rather than via WCF).
WCF services are already, by default, designed for reuse. I see no reason not to have some logic in your services, though keep in mind things like the Single Responsibility Principle so you don't end up with a service that does a dozen things.
Even then, if you end up parceling out your functionality into smaller classes, it's not a bad idea at all to host those classes as WCF services. You can then use them in-proc (via pipes) when needed or across machine boundaries (tcp) or even as web services. Create facades as needed to provide access to the functionality of your other, smaller services.
There's no real need to avoid putting any logic in WCF service classes.
I think that the decision depends on your business needs. WCF is a mechanism to transport data (objects) between server and client. If you like your businsess logic runs on server, you should let WCF exposes the object after running your business logic.
It should go in a separate set of classes. Your WCF layer should only contain logic that directly pertains to how the product of the service is delivered.
In your case, I see that you have a WCF method that returns a User (I assume this is a custom class) why have a separate method to return the UserID instead of populating that property as part of returning the User object?
For reuse/testability/maintenance/readability you should always put you BL in a separate layer.
Related
I'm developing a server side application based on DDD.
My application service (wcf layer) has a method which received an XML from the client.
This XML needs to be processed and finally transformed into an object.
In such a case, where's the best place to put the data transformation logic?
Inside the domain model?
Example:
void OnRequestArrived(string xml)
{
ItemRequest request = ItemRequest.New(xml);
}
or in a separate domain service?
void OnRequestArrived(string xml)
{
ItemRequest request = _mappingService.Map(xml);
}
The ItemRequest object is then the main domain model for the business flow..
Thanks
This responsibility belongs to the WCF service. In DDD terms, this is the anti-corruption layer - it maps external models to the domain model at hand. The domain model should be protected from external services as much as possible.
Sometimes it can be convenient to break this single WCF service into two - an application service and a WCF-specific adapter which would adapt the application service to the WCF framework. This is based on the Hexagonal architecture. The application service knows nothing about WCF or serialization formats. The WCF adapter service handles this and other serialization concerns. This can be useful for two reasons. First it keeps your application service clean and focused on its responsibility - the orchestration of domain objects, repositories and other services to implement domain use cases. Second, it allows the same application service to be called from different adapters.
I am using ASP.net MVC3 for my presentation layer and my data access and business logic are exposed through a WCF Service. Should my controllers call the WCF service or should there be a further level of abstraction such as a repository which calls the WCF service.
Repository which calls the service
public ProductController(IProductRepository productRepository)
{
_productRepository = productRepository;
}
public ProductRepository(ProductServiceClient client)
{
_client = client;
}
Service directly in the controllers
public ProductController(ProductServiceClient client)
{
_client = client;
}
The repository classes do nothing apart from call the methods exposed via the service.
Sorry I am well confused about your question, but I am sorry if I have misunderstood. Hope my pointers will clear this up.
Repositories related to persistence and define a way to handle the
infrastructure layer i.e. dealing with data (in memory repository,
sql repository or generic one)
Services if you like use these repositories to perform the
contractual operations such as getting the client in your case.
Services are called by clients or someone that requests services and
service in turn calls the repository which in turn calls the data
operations.
So you may need to change your wcf to work with repositories and let your controller call services..hope that helps
I would start by doing the exact oposite - the WCF should call methods inside the repository.
The data layer should be universal, and should be able to be accessed through any means (wcf should be one, mvc website should be another, etc).
That way you can also unit test your projects, and it's easier to keep track of it. Wcf should be considered as an extra api to your program in this case.
I am more concerned of where the business rules should be stored, but I would vote for mvc controllers for business logic, and wcf services invoking those internally.
I have an class library called ServiceLayer which acts as a repository for a ASP.NET MVC application This service layer has a references to a WCF Service called ProfileService which contains Profile methods to perform CRUD operations on a database etc.
I now need to allow mobile devices to communicate with my application so I have created another WCF Service called ProfileService. This service has a reference to the ServiceLayer class library and makes calls to it to undertake Profile operations.
Now this is quite confusing as I now have 2 ProfileServices. The first communicating with my database etc and exposing itself to my service layer. The second communicating with my service layer and exposing itself to mobile devices.
What is the best way to name your services in a SOA environment to avoid confusion of which type is which? especially when mapping between types.
I may also want to create another service which acts as an API to users of the system. What would I name this service ProfileAPI?? I know each ProfileService is in its own namespace but this doesnt help with readability when creating AutoMapperSettings or performing manual mapping.
So if anybody out there knows of a good way to name services in this environment it would be much appreciated.
You are looking for a Service Facade
You would end up with a Facade, which is just a specialized interface into your real service. You would define the different services as needed (mobile, users, database)
Hi
we have used the WCF service in my project. In our application the following layers are exists,
UI (aspx file), and code behind.
(Customer.aspx)
UI entity Model (CustomerModel.cs)
which is properties of the customer
details.
UI layer calls the Business Façade class with the CustomerModel object.
In Business façade I have referenced the WCF service.
Convert the CustomerModel to CustomerContract.
Call the CustomerService from business façade.
In the service, I have convert CustomerContract into CustomerBO and call the CustomerBO class.
In the CustomerBO class,I have initialized the provider object and call the customer Provider class.
In Provider class, I have access the Database and send data from 8 to 1 layer.
I don't know which design pattern is using in our project. Can anybody help on this to identify design pattern.
Thanks
This is not about design pattern but about architecture. Your architecture itself is not bad but it is really complex so unless you are creating very big project this architecture can be overkill. Moreover your naming of different layers is not correct. What you call BusinessFacade is usually called ServiceAgent. BusinessFacade should be placed on service site and wrapped by WCF service. Usual responsibility of BusinessFacade is to aggregate several business operations into single calls = create less granular API which can be easily and effectively exposed for remote calls.
I have 2 contracts (cA & cB) implemented by a single WCF service with 2 endpoints (epA & epB).
This is not for security purposes, but purely for reasons of clarity/organization, I'd like to only "see" ContractA's operations when I discover the service via endpointA; and likewise, only see ContractB's operations via endpointB.
I don't need to "protect" these operations per se. The scenario is such that any given client only needs one "side" of the service, never both (but, the operations themselves share resources, so it makes sense to have a single service rather than 2 services).
It seems that any given service basically gets 1 WSDL, ergo all operations are exposed to all endpoints. Is that the way it works, or is there a way to "shape" an endpoint by occluding operations not defined by the endpoints contract?
By default, you're right - one service implementation class gets one WSDL which contains all service methods (from all service contracts) that this service class implements.
There are no ways present (as far as I know) to "shape" the WSDL in any (easy) way - WCF does offer ways to get into the process of creating the WSDL (statically or dynamically), but those aren't for the faint of heart. It would be much easier for you to just split the implementation of the service contracts into two separate classes and then you'd have two separate services, separate WSDL's and all.
Marc is absolutelly right. I'm just adding why this happens in WCF. In WCF all metadata related functionality are based around service metadata behavior and mex endpoint. Both these features are defined on service level. So you can't take higher granuality (unless you write a lot of custom code) and specify metadata per endpoint.
WCF service (class) is directly mapped to wsdl:service element which exposes each contract as separate wsdl:port (in WCF known as endpoint). This is the main point in answering your question. If you don't want your second contract in that wsdl:service you can't implement it in the same class.
You have mentioned that your service contracts share resources. In that case your WCF service probably also contains business logic. That is a reason for your problems. The good design for implementing WCF services is to create them only as wrappers around separate business logic classes.