I configured decorators as follows
Bind<IEmailService>().To<EmailService>().WhenInjectedInto<LoggerEmailService>();
Bind<IEmailService>().To<LoggerEmailService>().WhenInjectedInto<ExceptionHandlerEmailService>();
Bind<IEmailService>().To<ExceptionHandlerEmailService>();
When I place a break point in the ctor of service implementation, like ExceptionHandlerEmailService or just EmailService, I find that the service is called multiple times. What am I missing?
.InSingletonScope() is what is needed.
Bind<IEmailService>().To<ExceptionHandlerEmailService>().InSingletonScope();
Bind<IEmailService>().To<LoggerEmailService>().WhenInjectedInto<ExceptionHandlerEmailService>();
Bind<IEmailService>().To<EmailService>().WhenInjectedInto<LoggerEmailService>();
Related
Just want to confirm my understanding is correct. If I use Single instance mode for a service:
[ServiceBehavior(InstanceContextMode=InstanceContextMode.Single)]
and this service calls a class from another asssembly which has a static constructor, that constructor is only called the first time ther service is called? The constructor I am talking about sets up a fair number of AutoMapper maps, and I only want this overhead the first time the service is called.
Taking this further, If I have two different services, and they both us the shared class, am I correct that the static constructor is still only called once?
Best
Ray
There is no connection between InstanceContextMode and how many times static constructor is fired. Static constructor is called once per Application Domain. So if your services are hosted within one Application Domain then your constructor will be called once.
As far as I understand you use the contructor to register AutoMapper configuration... To me it is not a good approach. Assuming your services are hosted on IIS you would better create a Global.asax file and then run you mapping registration code in Application_Start method. Of cource you can wrap it in some static method first.
Hope it helps!
I am building a WCF Rest Service using VS2010 .net 4.0 and the Rest service template. I would like to introduce spring.net - IoC but I am not able to get spring initialized when the InstanceContextMode.Single is set. For all other settings I can use IInstanceProvider interface and introduce a custom behaviour.
My question is:
Is there any other way I can get spring initialized?
Sorry I just saw the comments in the main response
If your only problem is the name of the reference, you could create your own and fix the reference parameter, or add a dictionary where you set some aliases in the xml config and do a lookup against that.
As far as I know you can't use Spring when the InstanceContextMode is single; from the doc:
While integrating 'natively' with WCF does seem to be the most natural
approach there is one 'gotya' that needs to be investigated further to
see if there is an acceptable workaround in order for this approach to
be viable. The issue is that if the service is configured to be a
singleton, for example using
[ServiceBehavior(InstanceContextMode=InstanceContextMode.Single)] then
the invocation of the IInstanceProvider is short-circuited.
The documentation suggests this:
One workaround, which is not very appealing, is to use the PerCall instancing mode but set the
singleton attribute in the Spring configuration to true, this way the
same instance is always returned.
More info here: http://www.springframework.net/docs/1.2.0-M1/reference/html/wcf.html
I have a wcf service singleton type, and in the same application an ASP page that uses a service-specific function.
As I can get a reference to the service instance created, not to run twice the manufacturer's service?
My service is published on IIS
I'm guessing you are saying that you have a service that is supposed to be a singleton and because you're in the same AppDomain you can simply create an instance as well.
If you own the service code you can make it a singleton using the Singleton Pattern (there are a number of ways to do that in .NET and Jon Skeet has a list of them here).
Then you need to deal with how does WCF get hold of the instance? In that case there are two options:
Use a ServiceHostFactory and hand the instance to the ServiceHost you create
Implement IInstanceProvider and plumb that in
If you don't control the service class then there is nothing you can do to prevent people creating instances but you can wrap the class in your own singleton and stipulate access must only be via the singleton so it is less likely that someone will create a second instance
within our per-session WCF services hosted in ISS, we would like to use Ninject to IOC different data access component through the interface.
Where would be the best place to declare the binding once? is it in Application_Start of Global.asax?
If it is, how could I obtain the instance through the inferface from Ninject?
I know in StructureMap, we can call something like ObjectFactory.GetInstance()?
What is the equivalent in Ninject?
Thanks
I assume you have looked at the official WCF extension? I usually define my own service factory (referenced in the .SVC file) and reference my Ninject module from there.
As for getting an instance from an interface (i.e. the opposite of having it injected), you do so via the kernel. (You can always have an instance of IKernel injected into any of your classes by adding it to your constructor.) Once you have it, you just use:
kernel.Get<IYourInterface>();
I'm trying to hock up WCF with dependency injection. All the examples that I have found is based on the assumptions that you either uses a .svc (ServiceHostFactory) service or uses app.config to configure the container. Other examples is also based on that the container is passed around to the classes.
I would like a solution where the container is not passed around (not tightly coupled to Unity). Where I don't uses a config file to configure the container and where I use self-hosted services.
The problem is - as I see it - that the ServiceHost is taking the type of the service implementation as a parameter so what different does it do to use the InstanceProvider?
The solution I have come up with at the moment is to register the ServiceHost (or a specialization) an register a Type with a name ( e.g. container.RegisterInstance<Type>("ServiceName", typeof(Service);).
And then container.RegisterType<UnityServiceHost>(new InjectionConstructor(new ResolvedParameter<Type>("ServiceName"))); to register the ServiceHost.
Any better solutions out there? I'm I perhaps way of in my assumptions.
Best regards,
Michael
Use Constructor Injection to wire up your service implementation, just like you would with any other class.
Here's a writeup on how to make WCF understand Constructor Injection.
The example in that answer demonstrates Poor Man's Injection, but you can extrapolate from it and set up your UnityContainer instance in the ServiceHostFactory instead of a hard-coded dependency.
You pass the container instance all the way to the custom IInstanceProvider. Now you can use the container in the GetInstance method:
public object GetInstance(InstanceContext instanceContext)
{
var serviceType = instanceContext.Host.Description.ServiceType;
return this.container.Resolve(serviceType);
}