I recently created a WCF service library. I am planning on hosting it in IIS. Since I want to reuse my repository layer I decided to go use Ninject in my WCF service as well (I use it in other projects in the solution).
I installed the Ninject Wcf Extensions. I configured it using the NinjectServiceHostFactory in the svc file. I added a Global.asax file to override the CreateKernel() that inherits from NinjectWcfApplication but I am not sure if I am using the bindings correctly. I first started with:
Bind<IUnitOfWork>().To<UnitOfWork>().InRequestScope();
But I quickly realized that this does not work since no data was saved to my database. It appears that the WCF service does not use the ASP.NET pipeline. I went ahead and tried both of these as well just to see if my data was committed to the database:
Bind<IUnitOfWork>().To<UnitOfWork>().InThreadScope();
Bind<IUnitOfWork>().To<UnitOfWork>().InTransientScope();
No luck. I then decided to try:
Bind<IUnitOfWork>().To<UnitOfWork>().InSingletonScope();
This worked but I don't want my database context to be shared by every single request that comes in to the WCF service. I then did some research and found the following approach:
Bind<IUnitOfWork>().To<UnitOfWork>().InScope(c => OperationContext.Current);
This works but is it correct? I wan t something to resemble the InRequestScope for a MVC application. Each request to the service should get its own Database context.
I suggest to have a look at the latest build from the CI-Server http://teamcity.codebetter.com
You need Ninject, Ninject.Web.Common, Ninject.Extensions.Wcf
With this version you can use InRequestScope for Wcf.
I am new to Ninject, but I can tell you that OperationContext.Current is the equivalent to HttpContext.Current for web application.
So your first thought was to use .InRequestScope(); (which is equivalent to .InScope(c => HttpContext.Current);)
so I guess that using .InScope(c => OperationContext.Current); for WCF is pretty correct.
Related
Looking at an earlier 3.5 based solution, there is an WCF service within the same web project. I thought WCF services generally got their own project.
I usually separate my WCF projects out for maintenance purposes, but they can be within a web project. It is basically the same thing as the old ASMX [WebMethod] process. In fact, any method in a code-behind of a web form can be turned into a web service method by decorating the method accordingly.
I'm a bit new to WCF, so please bear with me. I have a very simple REST Service written up using .NET 3.5, which is exposed through a asp.net web application through a SVC file. Everything is working as expected.
What I would like to know is if it is possible for me to create a plugin structure in WCF, so that I can have third party developers write up expose their functionality through my service. I'm hoping it's possible to dynamically create my endpoints through code, at the moment everything is in my web.config and service.svc files (as far as exposing the contract).
In the end, what I would like to have an active running service that auto checks for new assemblies (if added to the plugins directory), and would automatically add new endpoints, which could have completely different functionalities. One could be a file transfer plugin, another could be a calculator, etc.
But first I need to know if it's even feasible... currently I'm looking into MEF to see if that might help out, as I'm used to just loading DLLs manually (in Desktop apps).
It is possible to use MEF through WCF, I have worked on a similar project in the past. You could expose functions from the plugin DLL's through MEF assume the implementer of the MEF interface is implimenting a function that starts a new WCF service with it's own end points, then call that function from the main service.
See some sample projects below, although none of them are doing what you are asking it is possible that the MEF plugins could have a service host that's starting their very own service with their own end points.
Creating WCF Service Extensibility through MEF
A sample demonstrating how WCF and MEF play together
I've implemented an OData service using ASP.NET WebAPI. I also have some existing web methods in a seperate WCF project which is hosted in an ASP.NET Web Application.
By copying some bits of web config around and copying a couple of code files I've managed to get the WCF methods hosted in the WebAPI project.
Everything seems to be working but I've got a nagging doubt I'm doing something horribly wrong that's going to break when I least expect it.
Is this a good idea?
Depends on your anticipated call volume. The only problem I can think of with this is that incoming WCF requests will be serviced from the same dispatcher thread pool as the OData service. This makes it more likely that you will suffer availability based issues on either endpoint.
I have a server/client application developed in Delphi 2006. The client is Win32 and the Server is a .net 1.1 webservice.
We are in the process of updateing this project, but it has to be done in small steps. I started with the server and created a WCF project in VS2010(C# .net 4.0). The first step is to get the server running in WCF without changing the client. So I used the facade pattern, created a similar interface to the old delphi Webservice added a reference to the old .net 1.1 dll and in my implementation I just called the old .net 1.1 code.
Next step updating the proxy class on the client. This failed. The WSDL importer didn't understand the basicHttpBinding correctly, so the proxy class that was genereated couldn't replace the existing proxy.
After a bit of research I found this blog post.
http://kjellsj.blogspot.com/2006/12/how-to-expose-wcf-service-also-as-asmx.html
This worked, the ASMX WSDL was no different than the old .net 1.1 so everything appered ok.
But it wasn't. When testing the new service I discovered that all my parameters was blank/null on the server. I tried with Fiddler on the client and the parameters is present in the XML that is sent to the server.
So I'm stuck. Any thoughts on how to solve this would be much appreciated. Is there any code that could be interresting to see then let me know.
I ran into a similar problem with a web service asmx... certain data was losing their values. If you are using hierarchical data, you may need to declare the internal or inherited objects using an XmlInclude attribute. For example, if you have a User class that is used in your service and a Customer sub class, you may need to declare the Customer class to the service if it is not used directly in a web method. You would do this as follows.
[XmlInclude(typeof(Customer))]
public class Service : WebService
Of course, it may be nothing to do with this, so good luck if that's the case. :)
Confirm that the parameter names in the new service match the names in the old service. If you have changed the parameter names, they will not map from the XML so will be null in the executing code.
Add KnownType attribute to the sub classes
how can I use ASP.NET session in WCF? or is there any alternative way to use "ASP.NET Session" like structure in WCF such as data storage?
Try having a look as ASPCompatibityMode with WCF and you then turn it on and share the session in the service method
You cannot use the ASP.NET session, since you can easily run a WCF service without having the ASP.NET engine fired up, eg. using a netTcpBinding.
There is however session handling native in WCF, where you can specify this on the service contract using the SessionMode parameter on the ServiceContract attribute.
See http://msdn.microsoft.com/en-us/library/ms733040.aspx for more details
In case anyone is still facing this issue (trying to use a SESSION variable in a .NET Web App consuming a WCF Service). Don't worry about the [AspNetCompatibilityRequirements .......] or adding aspNetCompatibilityEnabled="true" in the web.config.
After playing around with all that for a while I found out all I had to do was change each [WebMethod] within the _______.ASMX.CS to [WebMethod (EnableSession=true)].
So change [WebMethod] to [WebMethod (EnableSession=true)]. That's it.
I found out that from http://weblogs.asp.net/stevewellens/archive/2009/04/05/using-session-state-in-a-web-service.aspx
Thanks!
Bonsai