Anyone have a naming strategy that works well for service proxy classes?
For example, if I am given three web services within two projects as follows:
XWs
AService.asmx
YWs
BService.svc
CService.svc
What would use as the Service Reference Name & Namespace for AService, BService and CService ?
In general, I'd like something in the proxy name/namespace to indicate that the thing being used is not a concrete class, but represents a proxy - both so it doesnt clash with usage of concrete classes [and force usage of aliasing or namespace-qualified class names], and so we're not hiding the fact that there's a hop happening (I guess the Wcf Service Proxy generator's default suffix of Client covers that). Also important is that it deals with cases where one is writing a wrapper/shim service that is forwarding a [sub]set of calls to another referenced service.
I've used various styles (Adding Ws, ServiceProxy, Ref or Proxy suffixes? Prefixing with ServiceName.), but have never been fully happy with them.
What's worked well for you? Any style guides make reference to a naming style?
Edit: While Cheeso's answer covers the bulk of my question, I'm still interested in hearing answers on:
A strategy for namespacing proxy classes as in the example above
A style guide that mentions a naming strategy for proxies
I originally used names like ServiceNameProxy and ServiceNameSvcProxy. But, like you, I haven't been particularly satisfied with those names, and as a result I did not stick with them. Now I just resort to ServiceNameService or ServiceNameSvc.
Is the key thing you want to communicate to users of the class that the class is a proxy? The distinction you are making - between a proxy class and a concrete class - seems like applies and alligators. The opposite of concrete is abstract, no? And the proxy class generated by svcutil.exe is, in fact, concrete.
With a naming convention, I think you are trying to indicate that the proxy class communicates to a remote service. (When we call it a "proxy", we mean to indicate it stands in front of something, in this case the remote service. ) If that is the case, then why not ServiceNameService or ServiceNameConnection, or along similar lines? Like System.Data.OleDb.OleDbConnection or System.Data.SqlClient.SqlConnection.
My own chosen naming convention is in line with that. It indicates that the class represents a service, which is assumed to be remote. I don't care so much to accentuate the fact that it is a proxy-to-a-service. For practical purposes the fact that it is a Service is the key thing.
I am also exploring options here. I just read this article by Miguel Castro and he recommends separating out the service, service host, data contract and service contract and I am primarily trying to decide if I should keep all of my service contracts in a separate contract namespace or let those live in each service namespace. Reason for separating them out into their own namespace is that if other services utilized them they are in a more neutral location.
So for example this:
companyname.services.contracts.service1contract
companyname.services.service1
or this:
companyname.services.service1
companyname.services.service1contract
Related
Let's say i do have a service, which is just a REST-API. This rest api provides some data.
As far as i understand, which makes sense, I can encapsulate data, which is sent from and to this service into DTO's. This totaly makes sense, since you'll have some business objects but often you'll need to serialize them in a way. So as far as i understand this would be a generally accepted and know way to abstract it regarding this part.
Then this DTO's are sent trough the REST-API. Regarding the server side it seams pretty straight forward, having some controllers which provide the data or receive them, I'm not seeing any issues there (at least for now).
So regarding my question. On the client side there are objects, which will access this API, this object, in my implementation contains a http client (not sure maybe i decouple them from this objects) and also it contains methods to access the api. So in one way or another, abstracting the use of http client and accessing the API away.
HOW DO YOU NAME THIS OBJECTS ACCESSING THE API?
I'm now naming them XXXManager/XXXHandler/..., but this names feel far to generic and i feel like there has to be some convention or pattern for this? Naming them XXXService also does not feel not completely right, because service for me is like the server side part, this object are accessing the service.
So how would you name this kind of objects and are there some deeper patterns to handle this kind of service/api accessors?
The model/pattern that would work here, is a classical layered architecture, which works like that:
The HttpClient should be wrapped around a class (let's name it ApiClient) that exposes methods for accessing the REST API. In each of those methods, the httpClient is used to execute the HTTP call.
There is a layer of Service/Manager classes that use the ApiClient and also apply their own business logic.
There is a layer of UI components which also inject the Services/Managers to grab the data and render it on the UI.
In this way you decouple the layers, which improves both the scalability and the testability of your code.
The naming somehow depends on the type of the client-side implementation/framework that you have.
If you have a web-frontend client, then the name TransactionService would tell me that this class talks to some external transaction service (Service is not a naming tied to server-side components).
This naming model applies to Angular, for example.
Patterns of Enterprise Application Architecture suggests Gateway, but I'd just go with Client.
As the subject line describes, I am in the process of exposing a C# library into a WCF Service. Eventually we want to expose all the functionality, but at present the scope is limited to a subset of the library API. One of the goals of this exercise is also to make sure that the WCF service uses a Request / Response message exchange pattern. So the interface /API will change as the existing library does not use this pattern
I have started off by implementing the Service Contracts and the Request/Response objects, but when it comes to designing the DataContracts, I am not sure which way to go.
I am split between going back and annotating the existing library classes with DataContract/DataMember attributes VS defining new classes which are like surrogate classes to the existing classes.
Does anyone have any experience with similar task or have any recommendations on which way works best ? I would like to point out that our team owns the existing library so do have the source code for it. Any pointers or best practices will be helpful
My recommendation is to use the Adapter pattern, which in this case basically means create brand new DataContracts and ServiceContracts. This will allow everything to vary independently, and will allow you to optimize the WCF stuff for WCF and the API stuff for the API (if that makes sense). The last thing you want is to go down the modification route and find that something just won't map right once you are almost done.
Starting from .NET 3.5 SP1 you no longer need to decorate objects that you want to expose with [DataContract]/[DataMember] attributes. All public properties will be automatically exposed. This being said personally I prefer to use special DTO objects that I expose and decorate with those attributes. I then use AutoMapper to map between the actual domain models and the objects I want to expose.
If you are going to continue to use the existing library but want to have control over what you expose as the web service API, I would recommend defining new classes as wrapper(s) around the library.
What I mean to say is don't "convert" the existing library even if you think you're not going to continue to use it in other contexts. If it has been tested and proven, then take advantage of that fact and wrap around it.
My understanding is that all contract-implementing code has to be in a single class, that can become very large, obviously. How do I avoid this? I really prefer to have a few small classes doing one part of the communication with clients than a single behemoth class.
The only idea I could think of is using multiple interfaces implemented by a single class split up by partial, but I don't think this is really solving the issue.
You might want to use Inheritance, depending on the structure of yoru code. Usually you can break all code up into smaller pieces, helpers, sub-routines, etc.
It's like with any other API-development, you don't want / don't need everything in the same place in the same package.
First, if your contract is big, can they be refactor into more specific service contracts?
The contract implementation class can be implemented as entry point method. You can always model the implementation and define the appropriate abstraction and have your service contract implementation class calls those internal implementation.
If you could change your code fundamentally, you could expose just a single endpoint that works with request/response messages. This way there could be a single end-point and a single service definition that takes a (possibly derived) request message and returns a response message. Your interface into the service would then just be a single method and in the server side implementation you would route that request object to the actual service implementation (possibly determined by a factory) possibly using metadata on the request message (or even it' type-name) to define what service is being called.
So, your end service interface would just have a method like this:
public interface IServiceRequestor
{
Response ProcessRequest(Request request);
}
This allows you to handle a possibly unlimited number of exposed services without having to know what they will be at compile/dev time, and also avoid a proliferation of Service methods defining the service calls available
That 'single class' usually is a facade, just a communication front-end.
So you should not implement all your logic in the Service implementor.
And your interfaces should be as small as possible (do 1 thing well). But if necessary your facade can call on multiple classes.
We have about 60 partial files called "BeamServer.cs", each in a sub-folder that corresponds to the purpose of the functions in that file. Any helper classes (or other helper files) that are for the same area of our program resides in that folder as well.
Your "one class" represents your "one business need". We found a nice side benefit in that if one of the members of our team is working on the "Accounting" portion of BEAM (our software), then they would check out the file "Accounting\BeamServer.cs" and none of the rest of the team would be effected.
EDIT: Also, the class should only contain the method signatures (and wrapper functions that simply call base.Channel.DoSomething()... Any data structures would of course be their own class files (such as "Person.cs" or "Employee.cs" or whatever).
WCF promotes good design by using interfaces and contracts etc. What baffles me is that, for example in my case if I have 2 sets of business functionality like ICustomerMgmtBIZ
and IProductMgmtBiz. If these two are ServiceContracts, and I have an interface like
IBusinessService:IProductMgmtBIZ,ICustomerMgmtBIZ
and implementation class BusinessService. I see that BusinessService class will be having too much implementation. The workaround I have been using so far is by implementing partial classes.
So bluntly put, can a WCF service have only 1 implementation and 1 service contract ??
No, it is possible to implement more than one Service contract on a WCF Service type (the class that is attributed with the ServiceBehavior attribute), since it is just a matter of having the class implement multiple interfaces. If you are using any of the Visual Studio templates or other kinds of code generators, this may not be immediately clear. However, although you can implement more than one Service Contract interface on a Service type, it does not do you much good if you need the service, presumably a singleton in this case(?), to behave as one service. IBusinessService implies that you need all of the service's functionality to be callable from one client proxy, so that all operations may operate in the same logical session (similar to ASPX web session). If that is not the case, then you are free to define individual proxies for each contract interface, but that will also require that you support one endpoint for each contract.
Is it an absolute requirement that you can only have on WCF ServiceHost instance for your implementation? What factors are influencing your decision?
By the way, partial classes do not trouble me anymore. The idea of splitting out code into multiple files now seems rather natural. For example, storing partial classes in files like ServiceType_IProductMgmtBiz.cs and ServiceType_ICustomerMgmtBIZ.cs seems natural enough, in addition to storing the core logic in ServiceType.cs.
Finally, the following question might be of use...
WCF and Interface Inheritance - Is this a terrible thing to do?
Bluntly put, no - sort of - yes, but. Any workaround is non-optimal and involves using an "IBlank" as a master WCF interface (where your interfaces derive from IBlank), and two endpoints, one implementing IProductMgmtBIZ and the other implementing ICustomerMgmtBIZ. I don't have my dev machine in front of me, this might involve some other overrides. So, at the WCF level you're screwed unless you want to have two WCF ServiceHosts (which is perfectly reasonable).
In short, the workaround is inelegant. Its easier to have two WCF endpoints on the same port with a different extension.
I am developing a WCF web service which has become quite bloated. What techniques do you use to split up the implementation of the contract?
Well you have a couple choices:
First, you could leave it all in one class, but split up into different files using the partial class feature of C#.
Second, you could have the main service class just pass requests off to one of a number of other actual classes that are organized logically.
A third alternative is to consider refactoring to reduce the number of operations you have. Is there actually a use to all of the methods you're exposing?
Finally, you could always split up the service into multiple WCF services.
It's hard to answer your question if you don't give any more information.
Do you mean that your service interface is bloated, or the class implementation? It's hard to answer well, if I don't see the code, or have no other information, anyway, I'll try:
Notice that WCF service is basically just a regular class that implements an interface and has some attributes on its methods. So all the other good OO design rules apply to it. Think about what it does, does it have really single responsibility, if not try to outsource some of that responsibility to other classes that your service depends on. If you need a non-default constructor, use IInstanceProvider to create the service class, and supply it with its dependencies (or if you use Windsor Container use WCF Facility).
If you really want to you can streach your inheritance chain, and move some of the code to a base class. I don't do it, however and always prefer to use composition over inheritance.
Inspect your service contract, and think about how cohesive it really is. Maybe what you should do is to split it, into few smaller, more cohesive services.