In the aspnetboilerplate documentation is a tutorial on how to use the Abp.AspNetCore.OData module. I study this module as a reference for creating my own GraphQL module. However, I am somewhat confused on why after declaring a dependency on the OData module it is still required to explicitly configure the services with
services.AddOData();
inside the Startup class from the actual Asp.NET Core project?
Sure, it is required because the Abp.AspNetCore.OData module does not do it. But isn't a big part of the idea of ABP's module system to automatically register all dependencies when declaring a dependency on a specific module with the DependsOn attribute? This way the encapsulation in a ABP module seems somewhat useless.
services.AddOData() is called in Startup.cs; it would require hacking around to be called in an ABP module.
Often, services.AddXxx() calls depend on the earlier adding of other services.
Not all of those services are going to be ABP modules so it's not possible to make sure that they are called in the order that the service needs and the developer wants.
Related
If I in my AppHostBase descendant (web api project ) use container.AutoWire(this), it will result in a NullReferenceException in the ServiceStack code, if I am using a web project, thus starting it with the CreateHostBuilder(args).Build().Run(); in the main method.
The error is reproduced in this Github project: https://github.com/tedekeroth/ServiceStackAutoWireTest
The error occurs in AppHostBase.Netcore.Cs, line 158:
If I remove the container.AutoWire(this); in TestAppHost.cs, the error goes away, but then the dependency injection does not work, meaning the Logger in TestAppHostproperty is not assigned:
I am not sure why this happens or what I can do about it. I'd appreciate some input, thanks.
Setup
Visual Studio 2019
Target framework: .NET 5.0 (Console Application)
Project SDK: Microsoft.NET.Sdk.Web
ServiceStack 5.11.0
The IOC AutoWire API attempts to autowire all public property dependencies of an object which is definitely something you should never attempt to do with the AppHost which encapsulates the configuration and behavior of your ServiceStack App where indiscriminatingly overriding every public property is going to leave it in a corrupted state.
Registering your AppHost in the IOC shouldn't be necessary as it's available everywhere via the HostContext.AppHost singleton. It's also a bad idea trying to reference any type defined in your Host Project, (the AppHost being the canonical example) since it creates a circular reference to your Host project in your App logic dependencies which shouldn't have any references back to its Host project, your Host project is supposed to reference all your projects .dll's, configure your App's and all its dependencies, not the other way around.
Should you need access to any Plugins it's recommended to use the GetPlugin<T>() API in your Service for optional plugins or AssertPlugin<T>() for required plugins. If you need to resolve any deps manually you can use TryResolve<T>() API in your Service class. For any of your App's custom config I'd recommend registering them in a custom AppConfig class for your Services to access like any other dependencies.
Otherwise if you really need access to the AppHost you can use the HostContext.AppHost singleton. If you absolutely need to have the AppHost in the IOC, just register it as a normal singleton, i.e. don't try to autowire it:
container.Register<IAppHost>(c => this);
However as mentioned earlier I'd strongly advise against it, have everything your App needs in a custom class (e.g. AppConfig) that is accessed like a normal dependency.
I'm creating a web API using ASP.NET Core, and I'm using SimpleInjector as my DI framework. I understand the basics of how to use SI with ASP.NET Core; my problem is more an architectural one.
I have a project with integration tests for the API project, in order to test the raw API endpoints and responses. Naturally, the test server (set up using Microsoft.AspNetCore.TestHost) should use the API project's real Startup class.
The problem lies in where to register mocks for the controllers' dependencies, because I don't want to have all the production implementations being registered when testing: Firstly, most of them are, of course, dependencies used by the production implementations of the controller dependencies I'll be mocking in the first place; and secondly, in case I update my controllers and forget to register mocks of the new dependencies, I want my code to fail (container verification) instead of silently using production dependencies that are present in the container.
Thus, the dependencies can't be registered in the Startup class. That's fine by me – I think I'd rather keep the composition root in a separate assembly referencing all other assemblies, anyway. AFAICS the ASP.NET Core project would need to reference this project, which exposes a single method that returns a pre-registered container that can be used in the Startup class, where it's needed to register e.g. the controller activator (and will undergo final validation).
But this begs the question: How to get the container – being already registered with all my application components (whether production implementations from the composition root project, or mocks from the integration test project) – into my Startup class?
My initial solution is to simply have a static property on the Startup class called e.g. Container, and assign that before using WebHostBuilder. This seems "pragmatically robust": The application will fail fast (NullReferenceException) if it's not set before the Startup class is run, and the property is only used during setup, so I don't really need to guard against it being set multiple times or being set to null or any such thing – if it's assigned before startup, it works, if not, it won't start.
Does this seem like a solid solution, or am I oblivious to any obvious ways this will will come back to bite me later on? Are there any better solutions?
In the new ASP.NET 5.0 (vNext), the startup code relies on the IApplicationBuilder interface. The Use method is used to add a handler to the builder, while Build is used to construct the final delegate. But I can't figure out what is the purpose of New. I've been digging in GitHub, but can't find any place where that's used.
Anyone understand what is the purpose of that method?
New() creates a second ApplicationBuilder, sharing all the ApplicationServices and ServerFeatures of the first one, but none of the middleware. It is used internally by the branching extensions (Map, MapWhen, UseWhen) to create the new 'branch'.
You can find the implementation here: ApplicationBuilder.cs.
In some cases, it is also useful in higher-level frameworks.
For exemple, the [MiddlewareFilter] attribute in MVC Core uses New() internally to execute a piece of ASP.NET Core middleware inside the MVC framework (i.e. as a filter). MVC Core creates a small pipeline around the middleware, builds it into a RequestDelegate, then runs the HttpContext through it. Just like ASP.NET Core does with your 'main' pipeline built in Startup.cs.
Thanks to this feature, we can reuse a piece of general-purpose ASP.NET Core middleware, from inside MVC.
For more information, see MiddlewareFilterBuilder.cs in ASP.NET MVC Core.
It appears to be there to branch [clone] the original instance (as can be demonstrated in src/Microsoft.AspNet.Http/Extensions/MapExtensions.cs). There was also a previous MapWhenExtensions.cs, but it appears to have been removed from the dev branch.)
I suspect it's an artifact of a previous design that would provide the ability to bind middleware based on circumstances without affecting the root's configuration. The fact that it's been there since before IBuilder was refactored to IApplicationBuilder and that most dependencies were in files that have since been removed from the dev branch, I would venture a guess that it's old news.
Of course it's hard to tell given neither the interface nor the base implementation are commented.
I've an ASP.NET MVC application using Ninject3 (NuGet install). The solution contains:
an MVC project (composition root);
a Domain Model project;
a Data Layer project;
a scheduler project (running scheduled jobs within a windows service and holding an alternative composition root);
some other projects.
I'm following the approach to have many small modules spread across the projects defining the bindings. The two composition roots use exactly the same bindings.
I cannot figure out how to configure scope for the modules within the class libraries. For example, given these bindings:
Bind<IDomainService1>()
.To<Service1Impl>()
.InSingletonScope(); //This should always be a singleton
Bind<IDomainService2>()
.To<Service2Impl>(); //No scope specified
I would always want a single instance of Service1Impl, whereas scope for Service2Impl should depend on the composition root used. MVC project should have InRequestScope() for Service2Impl (and for all other bindings with unspecified scope). Scheduler project, which does not run within an http context, should use InThreadScope().
Is this approach correct? If yes, what is the right way of configuring this behaviour?
In Ninject, not specifying the scope means InTransientScope().
Your choices are to either duplicate the bindings or create a custom InScope() scoping rule for the binding.
The cleanest solution (especially given that MVC is already in play) is for you to create a plugin that slots into the InRequestScope() mechanism.
There is a CreateScope() method which currently has minimal documentation in the ninject.extensions.namedscope README, which is used like this. It requires you to select 'Include Prerelease' in NuGet. (And I should be writing a wiki article on it but I have too many other things on my plate...)
I am trying to properly use Ninject to inject log4net logging into my MVC3 application. I am using the Ninject.MVC3 package, so I have the NinjectMVC3 class that automatically extends the App_Start method and contains the RegisterServices method that binds all dependencies. I also have the Ninject.Extensions.Logging.Log4Net package, but I don't know how to use it. I already know how to configure log4net in my web.config, but don't know how to use this extension for DI.
I have read all the following articles/posts, but none of them seem to define how to properly setup a project for DI logging.
At http://dotnetdarren.wordpress.com/2010/07/29/logging-in-mvc-part-4-log4net/, Darren
provides a great article, but doesn't seem to deal with DI (at least I don't see it).
At Using Ninject to fill Log4Net Dependency,
Remo Gloor states here that the extensions should provide all that's needed for implementation, but it doesn't show the code of how to instantiate it.
The documentation for ninject.extensions.logging at https://github.com/ninject/ninject.extensions.logging/wiki/Using is very limited at best. I have re-read it many times, and still don't see how to use bind the injection in the NinjectMVC3 class, or concrete examples of how to call the logger from my controller class for example.
At the most promising article, Moosaka provides some great code at Ninject.Extensions.Logging.Log4net unexpected behavior, but when I try it, I get a compile error in the LoggerFactory at ILogger logger = new Logger(type); stating "Cannot access protected constructor 'Logger' here". Also, he states to "Tuck this whole mess away into a separate class library". Does that mean as a whole separate project?
I'm just getting lost in all the differing options and dated posts and would like any input on how to use Dependancy Injection with Ninject and Log4Net in my MVC3 project. Also, if it matters, all of my Ninject code is in my domain project, but the logging needs done from both the domain and web project (and mocked in my unit tests). Any help is appreciated.
You shouldn't have to configure anything except the normal log4net config.
All you have to do is to inject a ILogger wherever you want to log.
https://github.com/ninject/ninject.extensions.logging/wiki/Using