I am trying to use Nancy as self-hosted in a legacy application, so I am trying to change as little as possible.
My Nancy's modules need to interact with a instance of a object previously constructed that, from the point of view of Nancy is like a singleton. I am guarantee that the same instance will exists during all the lifetime of the Nancy server.
My questions is, how can I use this instance inside my modules? Thanks in advance for any help or reference.
Is this object instance created through a dependency container in the legacy app?
Related
I'm using DotnetCore, WPF and Prism 7 to make a desktop application. I have one service called DbConnectionService that doesn't seem to be created. This service is not injected into any component that is reachable through the View tree(?). Instead, it listens to the IEventAggregator and communicates with the rest of the app through that.
I'm finding that I'm not able to get it to 1. be created, and 2. if it is created it doesn't stick around (GC I assume).
Below is the code I have "shotgunning" anything that will create the DbConnectionService. All to no avail.
containerRegistry.RegisterInstance(typeof(DbConnectionService), "DbConnectionService");
containerRegistry.Register<IDbConnectionService, DbConnectionService>();
containerRegistry.RegisterSingleton(typeof(DbConnectionService));
containerRegistry.GetContainer().RegisterSingleton<DbConnectionService>();
Any help on getting this service to be created and stick around is greatly appreciated.
This service is not injected into any component
That's why it's not created. Either you inject it and rely on the container's magic to create it, or you create it yourself.
You can use the container to keep the object alive (i.e. not garbage collected) through RegisterInstance:
containerRegistry.RegisterInstance( containerRegistry.GetContainer().Resolve<DbConnectionService>() );
Note that Resolve isn't on IContainerRegistry to prevent you from doing this, because you don't want to mix registering and resolving. If you have to, make 110% sure that all dependencies of DbConnectionService are registered beforehand.
I need to create a module that will be used by different applications.
Each application is using its own set of vars (application name, REST urls, ...).
How do I set inner variable, by the hosting application, in module (or in service)?
Need to init these parameters as soon as possible as the application loads.
Thanks.
In your module have a provider. That way the client application can bootstrap configuration.
Read the "Provider Recipe" section on angular's site for an example of this.
You should use the Provider recipe only when you want to expose an API for application-wide configuration that must be made before the application starts. This is usually interesting only for reusable services whose behavior might need to vary slightly between applications.
I am just starting with Angular with a project that seems really suited to it. In this project i must make several instances of a form builder so i have decided to make a service out of the form builder code. All is fine and good up until i take in account the other requirement: Form previews.
I was thinking of something along the lines of what this guy does but then i realised using his approach implies i cannot store/share more than one form (At least with the default injection approach used by Angular) so i gave it some thought and decided that having one instance of the FormBuilder service for each form would cut it. How can i control which instance of my service is injected into my controllers?
Propably you would not inject a specifc FormBuilder instance rather than a InstanceRegistry?
Create a service which returns a function taking the name to resolve and returns the resolved instance. This will be called from your controller.
Optionally, you could create resolves for the route if you are using either ngRoute or ui.router and do the resolving in the resolve block.
.when("...",{
controller:"...",
templateUrl:"...",
resolve:{
form1:["$formFactory", function($formFactory){
return $formFactory("form1")
})
}
})
HTH
I'm trying to dynamically create a service in another service and add it to the inejctor, so that other controllers and services throughout the app can inject it later. I'm not sure if what I'm even trying to do is possible but I've boiled down what I'm trying to do into an example on Plunkr
I'm basically having two modules use each other. One defines how a service should be configured on the fly, and the other module configures the services on the fly. I'm not sure what to do while configuring the new dynamic service though so that it can be found by the injector later and used in other controllers,services etc. Any thoughts?
Ok, so basically I needed to make a provider instead of a service. The provider can create factories, values, constants, etc. See a revised plunker here
I have come across a bit of a problem while using Unity and WPF. The scenario is I have a WPF application which follows the MVVM design pattern. A have a module called ViewKDI. Within this module I have a service called ViewKDIService, the ViewKDIService service utilises another service called UserService.
Every time I load the module ViewKDI I want Unity to return me a new instance of both the ViewKDIService and the UserService.
I have put the below in the shell bootstrapper:
Container.RegisterType<IUserService, UserService>();
In the ViewKDI module I have put the following:
Container.RegisterType<IViewKDIService, ViewKDIService>();
Each time the ViewKDI module loads the ViewKDIService constructor is called. However the UserService constructor is only called the first time, this means that I am not getting a new instance of UserService.
I require unity to give me a new instance of UserService too so that I can manage this session separately from the rest of the application.
Any ideas?
Thanks
Faisal
Unity's default behaviour is to create a new instance of each object each time one is requested, so you shouldn't be seeing this behaviour.
From what I can gather from the source code and MSDN documentation (this is a good read), you can specify a "lifetime manager" object when you register a type to tell Unity how the type should be constructed and cached. Using the TransientLifetimeManager (which essentially does no caching) will cause Unity to re-create the class each time. So try this:
Container.RegisterType<IUserService, UserService>(new TransientLifetimeManager());
... and see if it creates a new UserService each time.