I am facing an issue with Autofac WCF Integration when I configure the service to be Singleton. If I remove the InstanceContextMode and Singletion autofac configuration, then service works fine. I have also configured Autofac Interceptors, and they also work fine without Singleton configuration.
Also, point to note that if I remove the interceptor from autofac component registration, then also WCF works fine with InstanceContextMode set as Single.
But I need to have the WCF working with Interceptors and InstanceContextMode as Single both, and this combination isn't working.
Any help is appreciated.
Attached image shows the error I am getting and also link to github repo is provided below with the sample application.
https://github.com/devlic1/AutofacWCFTest
Related
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.
We have a windows service that is self-hosting a WCF Data Service, using the DataServiceHost class. Everything is working just fine, but we would like to hook up some HTTPModules to the service, if possible. One of the HTTP Modules would be for custom basic authentication, the other for auditing (including responses, which is why an HTTP Module works so well for this).
Keep in mind that we are running as a regular windows service, so we have no web.config, the service is not hosted by IIS, and it is not an ASP.Net application.
So, my questions are:
Is it possible to have an HTTP Module listen on a self-hosted WCF data service?
If this is not possible, what options would I have that are similiar to the power of an HTTP Module?
WCF doesn't operate on the same request pipeline as standard ASP.NET applications, although you can take advantage of a number of ASP.NET features (like session) if you configure your service for ASP.NET compatibility.
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Required)]
However, it looks like you just need something that will let you jump into the pipeline the way that HTTPModules do for an ASP.NET Application. That being the case, there are plenty of options. You can check out this page for a lot of samples.
You mentioned authentication, and there are plenty of options built into WCF that can save you from rolling your own solution. Check it out here.
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.
where should I put the code for configuring AutoMapper mapping between DTO and EntityFramework Entities for WCF PerSession services?
If in the default constructor, does that mean every session will create an individual mapping and causes lots of overhead on the server side?
Thanks
Configuration of AutoMapper is global for the whole application so your service should not do any configuration itself. AutoMapper should be configured in your application bootstraper (when the application starts). For example in WCF service hosted in IIS (over HTTP) you can use standard Global.asax and Application_Start.
I have a dependency injection container setup in my application and I'm thinking that composing the container every time a WCF service request comes in is going to be inefficient.
Can somebody explain to me, for an http/IIS hosted WCF service, what the lifecycle of the service is? If I can figure this out, I can make an educated decision on where the container is to be stored, instantiated, destroyed, etc.
If your InstanceContextMode is PerCall, the service class will be created from scratch for every incoming request, and then disposed of when it's done.
If your InstanceContextMode is PerSession, the service class will be created and used to service one given client for the duration of the session (or until an "InactivityTimeout" is encountered, or an error occurs).
If your InstanceContextMode is Single (singleton), the service class will be created when the first request comes in and will stay in memory as long as requests keep coming in, as long as no error occurs and no inactivityTimeout is reached.
So, there you have it! Of course, the concurrency mode (for PerSession and Single services) will also come into play to make things just a tad more "interesting"
As you mention that you were trying to integrate WCF service instantiation with a dependency injection container, I'd just like to say that I've had a very positive experience using the Castle WCF Integration Facility to do just that.
It's specific to the Castle Windsor dependency injection container but with it being open source you can look inside and understand some of the challenges and solutions provided.
It depends on your ServiceBehavour.
Specifically this and this.