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
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.
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'm looking at grails (2.2), and it's all beautiful and even magical, how it all works. I'm looking at a Controller class which is created with grails create-controller and out of the box it has many methods and properties available, like render(), redirect(), params, request and I presume it goes on and on.
where does all this get wired in? Where in the code/project/framework do I see that render() is made available as a method? And how is it implemented?
As a java developer I'm used to inheritance and code injection and reflection. And in javascript prototypes can do some black magic. But the XXController.groovy is just a standalone object. Is it the name (XXController) or the location (grails-app/controllers?) or is there some injection happening which the IDE can pick up?
Welcome to the wonderfull world of Grails,
Here you have a couple of links that may help you:
The Section of Controllers in the Web Layer docs.
And the docs of the render method. Check it out the "Quick reference" column at the right for more methods avaliable at the Controllers.
If you are wondering how that magic is done, Grails is an open source project, so as usual, go and serve yourself at Github (warning, it is quite large project).
Grails works on the top of Groovy, which is a Dynamic Language with a powerful support of meta programming. Tha is basically the trick of all the magic of Grails
Finally, Grails is a framework based on CoC (Convection over configuration), So the Controllers will be any class under the directory "grails-app/controllers" and with the suffix "Controller". (In the folder of controllers may be "commandObjects as well).
The integration with well-know ides is quite powerful as well, you should check it out
EDIT
You may also found how the render methods behaves here at github.
And more inyected stuff at the Controllers metaClass package
As of Grails 2.0+ it's implemented using an AST transformation - previously it was done by adding the methods to the Groovy MetaClass. The benefits of the new approach are that things will be a bit faster and use less memory.
GORM domain class methods now use this approach too (except for dynamic methods like findByFooAndBar which have to be added dynamically to the metaclass) and those have the benefit of being callable from Java since the AST adds the methods to the bytecode. This doesn't help controllers though since they're only called from Grails itself as the result of a web request.
For the gory details, ControllersApi is where the methods are, and they're mixed into each controller class by a combination of ControllerTransformer and the code in the doWithDynamicMethods closure in ControllersGrailsPlugin
I have a piece of code that encapsulates functionality that isn't specific to Orchard. However i need to make it available in Orchard via dependency injection. So, I built up an Autofac Module that registers all components (types), but I can't find a way to inform Orchard's Autofac Container about it.
From what i red, there are two ways to add a module to a container:
By supplying the module at to the ContainerBuilder (usually at start-up),
Or by updating the already built Container at runtime with a ContainerBuilder
I can approach the problem in the first way, but I rather do a variant of the second if there is such?
Just add a class deriving from Autofac.Module to your Orchard module and that's it. It will get automatically picked by Orchard during the container construction.
Piotr Szmyd's answer is fundamentally correct, but here's some more detail:
Your Orchard Module is the new .csproj that you've added to the Orchard.sln
Add Autofac as a reference to that csproj (make sure you use the version included with Orchard - not nuget. See here for more details about that problem)
Then add a class that derives from Autofac.Module and which implements Load(ContainerBuilder).
e.g.
using System;
using Autofac;
namespace MyCustom.Module.Namespace
{
public class LoaderModule : Autofac.Module
{
protected override void Load(ContainerBuilder builder)
{
builder.RegisterType<MyClass>().As<IMyInterface>();
}
}
}
As an additional note:
The Autofac registration code only gets invoked at application startup time.
If you are running with the site sitting locally in IIS and the code in VS, then the dynamic compilation nature of Orcahrd means that when you recompile the code, the application doesn't stop.
So in order for this Autofac registration code to be hit (and also for any channges to it to take effect) you have to iisreset to kill the application, so that it reloads the Autofac Registrations.
While developing web project using ASP.NET MVC, I came up against a coupling problem.
When I build custom controller factory (or dependency resolver if using MVC 3), I need this factory to know somehow where to get dependencies from. Here's my code:
//from Global.asax.cs
DependencyResolver.SetResolver(new StructureMapControllerFactory());
class StructureMapControllerFactory: IDependencyResolver {
Container repositories;
public StructureMapControllerFactory()
{
repositories = new RepositoriesContainer();
}
//... rest of the implementation
}
class RepositoriesContainer: Container
{
public RepositoriesContainer()
{
For<IAccountRepository>().Use<SqlAccountRepository>();
//...
}
}
StructureMapControllerFactory class is responsible for injecting dependencies into a controller. As I said, it needs to know where to find these dependencies (I mean concrete classes, like services and repositories implementations).
I have a separate class library called MySite.Data, where all the implementation details live. Contracts, like IAccountRepository, live in library MySite.Contracts. Now, if I reference this MySite.Data library directly from MVC project, there will be a dependency between my site and implementation of its data retrieval. The question is how can I remove it? What are best practices in this situation?
I'm sure it does have a bunch of workarounds, just I haven't found any yet.
Well, as I see it, you can't do exactly that. Your MVC project really really needs to know about concrete classes it is going to use.
You will anyway have to provide those container registrations somewhere and you'll get the dependency on the project/assembly where that type is defined. Shortly, you have to reference MySite.Data from MVC project. Like that:
MySite.Data knows nothing about MVC project
MVC project knows the concrete repositories types to provide correct container registrations.
You can make life simpler with StructureMap Registry objects but you need to include those Registries somewhere as well. Typically those are in the main project or some "StructureMap-adapter" project but you'd need to make reference anyway.
I'd advise that you:
Use MVC3 and drop your custom IControllerFactory if you only use it for DI into your Controllers.
Use StructureMap Registry objects to provide each and every IoC registration ever needed.
Use StructureMap Assembly scanning capabilities to provide components discovery.
Use something much more common as a DependencyResolver, i.e. not a StructureMapControllerFactory but a CommonServiceLocator with StructureMap adapter instead.
Try to abstract from StructureMap itself inside your main app.
And, of course, don't be afraid of making references inside the main project - they have nothing about coupling. It doesn't decrease maintainability. But the wrong architecture does, so be worried about that, not simple reference.