I'm using Castle Windsor with my WCF service (hosted using console application).
This is my configuration:
container.AddFacility<WcfFacility>().
Register(Component.For<IService>().
ImplementedBy<MyService>().LifeStyle.Transient.
AsWcfService(new DefaultServiceModel().
AddBaseAddresses("someURI").
AddEndpoints(WcfEndpoint.BoundTo(new BasicHttpBinding())).
PublishMetadata(o => o.EnableHttpGet())));
I chose Transient lifestyle for my service and some of this service dependencies are also Transients. As I understand after reading the documentation and some blogs if you have component with lifestyle Transient you should be responsible for releasing it.
Where should I release my transient component? Is this my responsibility or maybe the WcfFacility take care for that somehow?
What is the difference between Transient and PerWcfSession lifestyle
(btw what is the different between PerWcfSession and PerWcfOperation isnt each operation called on WCF service have its own session?)
You have the responsibility to release any component that you resolve directly from the container. So you never release subdependencies of a component that you resolve.
Since in this case the wcf service is resolved for you by the facicility, you don't need to release anything. The facility will take care.
If you register as PerWcfCall you will get one component per wcf call. If you use transient than everytime you have a subdependency of that type you will get a new instance.
Related
I've been running into endless problems attempting to use Windsor with Web API and injecting HttpRequestMessage into downstream dependencies of a controller. Since I've tried all the matching answers on Stackoverflow, I'd like to ask the question in a different way:
In Castle Windsor, how can I resolve a component instance while supplying a value for a downstream dependency? That is, the supplied value is required by a component that is required by the component being resolved.
For context, I'm trying to inject HttpRequestMessage so that I can use it to resolve the request context (primarily to resolve an absolute URL).
Edit I'd also like to point out that I don't currently have a dependency on Web Host / System.Web and I'd rather not change that.
A proper approach is to
Create IMyDesiredRouteParameterProvider
Implement it. Get the current request inside it and get the url
Register it and inject it in the desired dependent class via constructor.
I made myself such an implementation and I can say that this way it works fine. You can make Web.Infrastructure assembly and put the implementation there. Or put both the interface and the implementation there if you are going to reference it from another web module.
using System;
using System.Web;
namespace RouteParameterProvider
{
interface IMyRouteParameterProvider
{
string GetRouteParameter();
}
public class ControllerActionMethodRouteParameterProvider : IMyRouteParameterProvider
{
public string GetRouteParameter()
{
string Parameter = HttpContext.Current.Request.RequestContext.RouteData.Values["controller"] as string;
if (string.IsNullOrEmpty(Parameter))
{
throw new InvalidOperationException();
}
return Parameter;
}
}
}
You can get every possible thing that the Request Context contains from :
HttpContext.Current.Request.RequestContext
And it will be better if you rethink your design decision :
I need HttpRequestMessage to be regstered prior to creating each
instance of SomethingController so that it will be available down at
the LinkGenerator layer.
Containers are to be initialized at runtime and then used to resolve.
I need HttpRequestMessage to be regstered prior to creating each
instance of SomethingController so that it will be available down at
the LinkGenerator layer.
It sounds like you want to register an item with the container at runtime, post-startup. In general, this is not a good practice--registration should be a discrete event that happens when the app is fired up, and the container's state should not be changed during runtime.
Dependency Injection is about resolving service components, not runtime state--state is generally passed via methods (method injection). In this case it sounds like your LinkGenerator component needs access to the ambient state of the request.
I'm not that familiar with HttpRequestMessage, but this answer seems to show that it is possible to retreive it from HttpContext.Current. You could make this a method on your LinkGenerator class, or wrap this call in a separate component that gets injected into LinkGenerator (HttpRequestMessageProvider?). The latter would be my preferred method, as it allows LinkGenerator to be more testable.
Given the lack of a clean way of doing this and Web API not providing information as to the hosted endpoint beyond per-request context objects, I ended up injecting the base url from configuration.
Is this library by Mark Seemann the answer? In the description he writes explicitly :
This approach enables the use of Dependency Injection (DI) because the
request can be injected into the services which require it.
Then gives an example :
// Inside an ApiController
var uri = this.Url.GetLink(a=> a.GetById(1337));
By which you can then pass the URL down the road in the service that you have injected in the controller.
UPDATE :
Mark Seemann wrote about the same exact problem here:
"Because HttpRequestMessage provides the context you may need to
compose dependency graphs, the best extensibility point is the
extensibility point which provides an HttpRequestMessage every time a
graph should be composed. This extensibility point is the
IHttpControllerActivator interface:..."
This way you can pass request context information to a component deep in the object graph by getting from the HttpRequestMessage and passing it to the DI container.
Just take a look at the interface of IHttpControllerActivator.
The WEB API framework gets the IHttpControllerActivator through DependencyResolver. You probably already replaced it by your CastleWindsorDependencyResolver. Now you have to implement and register your HttpControllerActivator and register it.
When the WEB API framework gets IHttpControllerActivator from DependencyResolver (your Castle Windsor DR) and calls IHttpControllerActivator.Create() it will pass you the HttpRequestMessage. You can get your info from there and pass it to the your CastleDR before you call Resolve(typeof(MyController)) which will resolve the whole object graph - that means you will have MyHttpContextInfo to inject in your XYZComponent deep in the resolution stack.
This way tou are passing the arguments in the last possible moment but it is still possible. In Castle Windsor I make such passing of arguments though CreationContext.AdditionalArguments["myArgument"];.
Can someone please help me understand several things?
Do I still have to register PerRequestModule to use
LifeStylePerWebRequest? I use Castle.Windsor 3.2.0.0 and it seems
everything works without this module. I definetly remember that
there was an exception before that tells me "You forget to register
this module".
What "objects tracked by release policy" really
means? I use several Components with LifeStyleTransient but when I
Resolve one I get it in "objects tracked by release policy"
property, when I Resolve others I don't get them there.
How can I check the actual objects stored inside the container (and their
number)?
1) I guess since version 3.x PerRequestModule will be automatically registered by windsor.
2) An object will be tracked by windsor only if needed(for ex if its lifestyle is Transient and it implements IDisposable interface).
3) You can run unit tests checking for handlers or manually set a debug point once you registered all components and navigate with VS viewer container object: it has a property that lists all registered components.
Update: I think is down to a Windsor configuration, does any one have any idea as to what I have not configured correctly with Windsor?
I am currently using Envers within a C# WebApi project. Windsor is used for IoC.
I have a custom RevisionEntity which add a User property to audit the user who has made the data change.
To ensure all configurations were correct I started off with a "simple string here" being added in the NewRevision method;
public class AuditRevisionListener : IRevisionListener
{
public void NewRevision(object revisionEntity)
{
((AuditRevision)revisionEntity).User = "Simple string here";
}
}
and all persisted as expected.
Next step is to achieve a full User object to which I need to obtain the UserService;
public class AuditRevisionListener : IRevisionListener
{
public void NewRevision(object revisionEntity)
{
var userServices = (IUserServices)GlobalConfiguration.Configuration.DependencyResolver.GetService(typeof(IUserServices));
var user = userServices.GetRequestingUser();
((AuditRevision)revisionEntity).User = user;
}
}
However, the DependencyResolver.GetService is throwing the error;
"Cannot access a disposed object. Object name: 'Scope cache was already disposed. This is most likely a bug in the calling code.'. "
UPDATE
I have now created a demo project available at https://github.com/ScottFindlater/WindsorEnversIssue
On first setting up the solution all will run fine because the custom Envers RevisionListener is not performing any dependency resolving.
Run the solution which performs a GET to the HomeController, which simply loads one User and modifies another;
Dependency resolving is shown to be working as there is an ActionFilter called DependencyResolverDoesWork which successfully resolves the UserServices.
Envers is shown to be working as the UserAudit table is populated.
To “turn on” the dependency resolving in the customer RevisionListener navigate to; Domain NHibernate project, Auditing folder, AuditRevisionListener class, NewRevision method and uncomment the 2 lines of code.
Full rebuild and then run the solution again and the project will run time exception in the WindsorDependencyResolver class, GetService method with “Cannot access a disposed object”, and clicking the View Detail Action expands this message to “{"Cannot access a disposed object.\r\nObject name: 'Scope cache was already disposed. This is most likely a bug in the calling code.'."}”.
The comment posted by Roger, thank you so much, which suggests changing the LifeStyle to Singleton does work. However, this demo has been purposefully kept simple and the use of PerWebRequest LifeStyle is needed because the ApplicationServices in the real project has contextual related data injected such as requesting user which is used to enforce security.
I am so stuck now and any pointers/ answers as to what I have setup wrong will be gratefully received. In addition, I know this has been posted at SO and Envers forum, I WILL update an answer on both.
I think is down to a Windsor configuration, does any one have any idea as to what I have not configured correctly with Windsor?
I haven't tried to run your sample, but I think this is down to an interplay between the two http modules defined in your web.config (https://github.com/ScottFindlater/WindsorEnversIssue/blob/master/API%20Endpoints/Web.config)
Castle.MicroKernel.Lifestyle.PerWebRequestLifestyleModule - Controls the lifetime of "per web request" components
APIEndpoints.HttpModules.NHibernateSessionCoordinator - Opens a session and begins a transaction at the beginning of each web request, then commits the transaction and disposes the session at the end of the web request
It is at the point where you commit your transaction - at the end of the request, triggered by NHibernateSessionCoordinator, that any changes you've made to objects within your NHibernate ISession actually get written to the database. This is the point at which Envers does its stuff and, in turn, at which you attempt to resolve IUserService from your Windsor container. The exception is thrown because IUserService is registered with the "per web request" lifestyle and Windsor is treating the current web request as complete and has disposed any objects tied to the request.
Have you tried reversing the order in which the HttpModules are defined, e.g. NHibernateSessionCoordinator before PerWebRequestLifestyleModule? This will result in your NHibernate transaction being committed before per web request components are disposed.
I'm using NServiceBus (3.2.2), RavenDB (1.2.2017-Unstable) and Windsor (3.0.0.4001) in an MVC 4 project.
I have a IHandleMessages class that handles 3 different messages, and that needs an IDocumentSession, and therefore defines a property such as:
public IDocumentSession DocumentSession { get; set; }
I've copied the RavenDbUnitOfWork implementation from NServiceBus' website
I've registered IDocumentStore, IDocumentSession and IManageUnitsOfWork in my Windsor container as follow:
container.Register(
Component
.For<IManageUnitsOfWork>()
.ImplementedBy<RavenUnitOfWork>()
.LifestyleTransient()
);
container.Register(
Component
.For<IDocumentStore>()
.UsingFactoryMethod(k => DocumentStoreHolder.DocumentStore)
.LifestyleSingleton(),
Component
.For<IDocumentSession>()
.UsingFactoryMethod(k => k.Resolve<IDocumentStore>().OpenSession())
.LifestyleTransient()
);
NServiceBus is configured to use my container:
Configure.With()
.CastleWindsorBuilder(container);
I'm encountering the problem that the UnitOfWork and the message handler receive different instances of the DocumentSession. This means that objects stored in the session in the message handler are not saved, since SaveChanges() is called on a different DocumentSession.
Removing the Transient lifestyle causes different kind of problems, that result in concurrency/conflicts when updating objects from RavenDb, since (probably) the message handler keeps getting the same instance of the DocumentSession, which holds a cached version of the updated object.
Update:
As suggested, I've tried changing the registration of the IDocumentSession in Windsor, to the Scope lifestyle, like this:
Component
.For<IDocumentSession>()
.UsingFactoryMethod(k => k.Resolve<IDocumentStore>().OpenSession())
.LifestyleScope()
This causes exceptions when the container tries to resolve the MVC Controller, saying that the scope was not found, and asking if I forgot to call BeginScope().
You need to have a scope of Per Message, not transient or singleton.
I am assuming that your mvc controller has a direct dependency on the IDocumentStore. You need to call container.BeginScope() before each request from the web. You can either do this as an action filter attribute http://msdn.microsoft.com/en-us/library/system.web.mvc.actionfilterattribute.aspx or as an AOP aspect on the controller itself http://cangencer.wordpress.com/2011/06/02/asp-net-mvc-3-aspect-oriented-programming-with-castle-interceptors/.
The issue is you need different lifestyles when using nservicebus in an asp.net mvc website when sharing the IDocumentSession in the same container.
For ASP.NET MVC you need a PerWebRequest lifestyle and for NServiceBus you need the Scoped lifestyle.
To do that i've used the hybrid lifestyle code in the castle contrib project:
https://github.com/castleprojectcontrib/Castle.Windsor.Lifestyles/tree/master/Castle.Windsor.Lifestyles
When calling from an ASP.NET context, it uses the WebRequestScopeAccessor. For NServicebus you need the LifetimeScopeAccessor. This is not in the contrib project, but is easy to add:
public class HybridPerWebRequestLifetimeScopeScopeAccessor : HybridPerWebRequestScopeAccessor
{
public HybridPerWebRequestLifetimeScopeScopeAccessor()
: base(new LifetimeScopeAccessor())
{
}
}
And in your registration code you need something like:
container.Register(Component.For<IDocumentSession>().LifestyleScoped<HybridPerWebRequestLifetimeScopeScopeAccessor>().UsingFactoryMethod(() => RavenDbManager.DocumentStore.OpenSession()));
And here's an implementation for Rhino Service Bus i used before switching to nservicebus:
https://gist.github.com/4655544
In a multilayer application (ASP MVC: UI project, DAL project) i registered in web.config the components.
Now i have this problem: Unit of Work pattern has do be implemented and i need to get the current instance of a particular service. The registration of the services happened in the UI project, but i need to get the current instance of this service in the DAL project. How do i get this reference?
In the UI project i already needed a way to get something resolved:
container = new WindsorContainer(
new XmlInterpreter(new ConfigResource("castle"))
);
personRepository= container.Resolve<IPersonRepository>();
Would it be OK to use the same technique in the DAL project? If yes, should i write the configuration in a separate file, so that it can be accessed by all the layers(projects)?
Sorry for this (i think) naive question but it's my first project using Castle and i think i don't understand the big picture of it!
Code snippet would help a lot.
Thanks in advance!
In a nutshell: one container instance per application, one container configuration that has all the components you need for the application. If you need a service in your DAL, inject the appropriate service interface in your DAL class via constructor (if the dependency is required) or setter (if the dependency is optional).
Try really hard to avoid using a static IoC gateway, it hides the true dependencies of a component and it hampers testability.
See these related questions:
Usage of IoC Containers; specifically Windsor
Is it correct to have many Castle Windsor containers per application if those containers belong to different tiers?
Have a look at this article. It shows you how to write a static class that performs dependency resolution using Castle Windsor. You should consider putting this class in a separate project that can be referenced from both your UI and DAL projects to allow code reuse. As the article explains, your class should provide a bootstrapper facility that initializes your IoC container. In your case, this would look like:
public static class IoC
{
private WindsorContainer _container;
public static void Initialize()
{
_container = new WindsorContainer(
new XmlInterpreter(new ConfigResource("castle"))
);
}
}
The bootstrapper would be invoked from the application startup event in your UI projects Global.asax file.
The other methods for obtaining instances of objects from the container would be as per the article.