I have some mvc controllers must instanciate a single logger according the fully qualified controller name.
I try to explain with examples. I have this logger interface:
public interface Ilogger { ... }
and its implementation
public class MyLogger
{
public MyLogger(loggerName)
{
...
}
...
}
Well, I need now different loggers per controllers.
namespace Controllers
{
public class MyFirstController
{
public MyFristController(Ilogger logger) { ... }
...
}
}
namespace Controllers
{
public class MySecondoController
{
public MySecondoController(Ilogger logger) { ... }
...
}
}
I need two different singletons... One per controller, where the constructor parameter loggerName of MyLoggerClass must change according the controller. So, I need two instances:
new MyLogger("Controllers.MyFirstController")
and
new MyLogger("Controllers.MySecondoController")
I am trying something like this:
builder.RegisterControllers(assemblies)
.PropertiesAutowired()
.WithConstructorParameter(typeof(ILoggerProvider));
Where WithConstructorParameter is an extension method:
public static IRegistrationBuilder<TLimit, TReflectionActivatorData, TStyle> WithConstructorParameter<TLimit, TReflectionActivatorData, TStyle>(this IRegistrationBuilder<TLimit, TReflectionActivatorData, TStyle> registration, Type targetType)
where TReflectionActivatorData : ReflectionActivatorData
{
return registration.WithParameter(
(pi, ctx) => pi.ParameterType == targetType,
(pi, ctx) => ...)); // <-- I have been losing here....
}
Is it the correct approach? How can I solvemy problem?
Thank you
I have modified the extension methos as following:
public static IRegistrationBuilder<TLimit, TReflectionActivatorData, TStyle> WithNamedParameter<TLimit, TReflectionActivatorData, TStyle>(this IRegistrationBuilder<TLimit, TReflectionActivatorData, TStyle> registration, Type targetType)
where TReflectionActivatorData : ReflectionActivatorData
{
return registration.WithParameter(
(pi, ctx) => pi.ParameterType == targetType,
(pi, ctx) => ctx.ResolveNamed(pi.Member.DeclaringType.FullName, targetType)
);
}
Related
I am struggling to register with Autofac a hierarchy of classes and interfaces.
I have an interface IMyService defined as below:
public interface IMyService
{
void DoMyService();
}
And I have two abstract classes with implement this interface and called MyServiceA, and MyServiceB:
public abstract class MyServiceA : IMyService
{
public abstract DoMyService();
}
public abstract class MyServiceB : IMyService
{
public abstract DoMyService();
}
Moreover I have a second-level hierarchy for each of the two aforementioned services: MyServiceA1, MyServiceA2, MyServiceB1 and MyServiceB2:
public class MyServiceA1 : MyServiceA
{
public MyServiceA1() : base() {}
public void DoMyService()
{
// Implementation goes here
}
}
public class MyServiceA2 : MyServiceA
{
public MyServiceA2() : base() {}
public void DoMyService()
{
// Implementation goes here
}
}
public class MyServiceB1 : MyServiceB
{
public MyServiceB1() : base() {}
public void DoMyService()
{
// Implementation goes here
}
}
public class MyServiceB2 : MyServiceB
{
public MyServiceB2() : base() {}
public void DoMyService()
{
// Implementation goes here
}
}
I have in input two enums FirstEnum and SecondEnum used to select which of the four concrete types to instantiate:
public enum FirstEnum
{
SvcA,
SvcB
}
public enum SecondEnum
{
Svc1,
Svc2
}
I want to register IMyService and by providing two enums, It will automatically instantiate the good concrete type.
For instance, if I want to resolve an IMyService and I provide FirstEnum.SvcB and SecondEnum.Svc2, it should instantiate the concrete type MyServiceB2 class. Moreover this hierarchy might be updated by adding some other concrete types etc, so I need a generic way of doing it
Does anyone have a clue to help me?
Thanks
If you want to create a specific service dynamically depending on a set of parameters, this is a good use case for an abstract factory:
public interface IMyServiceFactory
{
IMyService Create(FirstEnum e1, SecondEnum e2);
}
public class MyServiceFactory : IMyServiceFactory
{
private readonly ILifetimeScope scope;
public MyServiceFactory(ILifetimeScope scope)
{
if (scope == null)
throw new ArgumentNullException("scope");
this.scope = scope;
}
public IMyService Create(FirstEnum e1, SecondEnum e2)
{
if (e1 == FirstEnum.SvcA)
{
if (e2 == SecondEnum.Svc1)
{
return scope.Resolve<MyServiceA1>();
}
else //svc2
{
return scope.Resolve<MyServiceA2>();
}
}
else //B
{
if (e2 == SecondEnum.Svc1)
{
return scope.Resolve<MyServiceB1>();
}
else //svc2
{
return scope.Resolve<MyServiceB2>();
}
}
}
}
And now your consumer need to get the factory injected instead of the service:
public class MyServiceConsumer
{
private readonly IMyServiceFactory factory;
public MyServiceConsumer(IMyServiceFactory factory)
{
this.factory = factory;
}
public void Do()
{
//var service = this.factory.Create
}
}
Registration :
Autofac.ContainerBuilder builder = new Autofac.ContainerBuilder();
builder.RegisterType<MyServiceA1>().AsSelf().AsImplementedInterfaces();
builder.RegisterType<MyServiceA2>().AsSelf().AsImplementedInterfaces();
builder.RegisterType<MyServiceB1>().AsSelf().AsImplementedInterfaces();
builder.RegisterType<MyServiceB2>().AsSelf().AsImplementedInterfaces();
builder.RegisterType<MyServiceFactory>().As<IMyServiceFactory>();
builder.RegisterType<MyServiceConsumer>();
//and quick test resolve
var container = builder.Build();
var test = container.Resolve<MyServiceConsumer>();
I have a .Net Core 3.1 API controller with a constructor that looks like this:
public class MachineListsController : ControllerBase
{
private readonly jiWeb_ProdContext _context;
private readonly ILogger _logger;
private readonly ILoggingMessageService _loggingMessage;
public MachineListsController(jiWeb_ProdContext context, ILogger<MachineListsController> logger, ILoggingMessageService loggingMessage)
{
_context = context;
_logger = logger;
_loggingMessage = loggingMessage;
}
public string Message { get; set; }
...
}
You can see that I am injecting a .Net Core logging service and the database context into it.
Then I use the logging like this in my controller methods:
[HttpGet("FactoryMachines/{factoryId}")]
public async Task<ActionResult<IEnumerable<MachineList>>> GetMachinesForFactory(Guid factoryId)
{
var machineList = await _context.MachineList.Where(n => n.FactoryId == factoryId).ToListAsync();
Message = _loggingMessage.GetLogSuccess(this.GetType().Name.ToString(), ControllerActions.GetAction, "FactoryMachines", factoryId.ToString());
_logger.LogInformation(Message);
return machineList;
}
The logging is working great, but I'm realizing that I should create a base class that handles logging so I don't have to add or change it inside of every controller I write.
So I started to write this base controller:
[ApiController]
public class MyBaseController : ControllerBase
{
readonly jiWeb_ProdContext _context;
readonly ILogger _logger;
readonly ILoggingMessageService _loggingMessage;
public BaseController(jiWeb_ProdContext context, ILogger<BaseController> logger, ILoggingMessageService loggingMessage)
{
_context = context;
_logger = logger;
_loggingMessage = loggingMessage;
}
}
Then I changed my controller to inherit from it like this:
public class MachineListsController : MyBaseController
{
[HttpGet("FactoryMachines/{factoryId}")]
public async Task<ActionResult<IEnumerable<MachineList>>> GetMachinesForFactory(Guid factoryId)
{
var machineList = await _context.MachineList.Where(n => n.FactoryId == factoryId).ToListAsync();
return machineList;
}
}
But I'm getting error and I'm unsure of what to do on the next step.
Here's the error:
There is no argument given that corresponds to the required formal parameter 'context' of 'BaseController.BaseController(jiWeb_ProdContext, ILogger<BaseController>, ILoggingMessageService)'
Specifically, how do I set up my controllers so that they can just use the base class for logging so I don't have to write logging code for every new controller action I create?
Thanks!
As far as I know, if the base class constructor method contains value, we should pass it in the subclass constructor method and also you should follow Nkosi comment to modify the property to protected.
More details, you could refer to below codes:
[ApiController]
public class MyBaseController : ControllerBase
{
protected readonly ILogger _logger;
public MyBaseController(ILogger<MyBaseController> logger)
{
_logger = logger;
}
}
[Route("api/[controller]")]
public class MachineListsController : MyBaseController
{
public MachineListsController(ILogger<MyBaseController> logger) :base(logger)
{
}
[HttpGet]
public IActionResult Get() {
_logger.Log(Microsoft.Extensions.Logging.LogLevel.Trace,"aaa" );
return Ok();
}
}
I am wondering, would there be a way to do the logging in the base class? Like where you call _logger.Log in the MachineListsController class, could that be moved to base?
As far as I know, we could only add logs before the MachineListsController's action executed or after the MachineListsController's action executed.
If this match your requirement, you could try to use action filter.
You could add iactionfilter interface to the basecontroller and overried the OnActionExecuted and OnActionExecuting method.
More details, you could refer to below codes:
[Route("api/[controller]")]
[ApiController]
public class MyBaseController : ControllerBase, IActionFilter
{
protected readonly ILogger _logger;
public MyBaseController(ILogger<MyBaseController> logger)
{
_logger = logger;
}
public void OnActionExecuted(ActionExecutedContext context)
{
_logger.Log(Microsoft.Extensions.Logging.LogLevel.Trace, "aaa");
int i = 0;
}
public void OnActionExecuting(ActionExecutingContext context)
{
_logger.Log(Microsoft.Extensions.Logging.LogLevel.Trace, "bbb");
int i = 0;
}
}
Result:
Given That
Component.For<IService>().ImplementedBy<SecretService>().Named("secretService")
Component.For<IService>().ImplementedBy<PublicService>().Named("publicService")
And
class Foo{
public Foo(IService publicService){ ...... }
}
And
class Bar{
public Bar(IService secretService){ ...... }
}
Then how can i achieve the following
Foo and Bar should get instances of publicService and secretService respectively, entirely based on name of their constructor parameters.
I have now made it to work using a custom SubDependencyResolver, i added this to the container and now it injects the implementation by name
public class ByParameterNameResolver : ISubDependencyResolver
{
private readonly IKernel kernel;
public ByParameterNameResolver(IKernel kernel)
{
this.kernel = kernel;
}
public virtual bool CanResolve(CreationContext context, ISubDependencyResolver contextHandlerResolver, ComponentModel model, DependencyModel dependency)
{
if (dependency.TargetItemType == null)
return false;
if (string.IsNullOrWhiteSpace(dependency.DependencyKey))
return false;
return kernel.HasComponent(dependency.DependencyKey);
}
public virtual object Resolve(CreationContext context, ISubDependencyResolver contextHandlerResolver, ComponentModel model, DependencyModel dependency)
{
return kernel.Resolve(dependency.DependencyKey, dependency.TargetItemType);
}
}
I've read over several examples that were more complex then I needed and I'm having trouble distilling this down to a simple, concise pattern.
Let's say I have an interface names ICustomService and multiple implementations of ICustomService. I also have a class Consumer that needs to determine at run time which ICustomService to use based upon a parameter.
So I create a classes as follows:
public class Consumer
{
private CustomServiceFactory customServiceFactory;
public Consumer(CustomServiceFactory _customServiceFactory)
{
customServiceFactory = _customServiceFactory;
}
public void Execute(string parameter)
{
ICustomService Service = customServiceFactory.GetService(parameter);
Service.DoSomething();
}
}
public class CustomServiceFactory
{
private IComponentContext context;
public CustomServiceFactory(IComponentContext _context)
{
context = _context;
}
public ICustomService GetService(string p)
{
return context.Resolve<ICustomService>(p); // not correct
}
}
public class ServiceA : ICustomService
{
public void DoSomething()
{
}
}
public class ServiceB : ICustomService
{
public void DoSomething()
{
}
}
Is there an advantage to having my factory implement an interface? How do I fix my factory and register these classes with Autofac so that Consumer.Execute("A") calls DoSomething on WorkerA and Consumer.Execute("B") calls DoSomething on WorkerB?
Thank you
You would register your implementations of ICustomService with keys. For example:
builder.RegisterType<FooService>.Keyed<ICustomService>("someKey");
builder.RegisterType<BarService>.Keyed<ICustomService>("anotherKey");
and then your factory method would be:
public ICustomService GetService(string p)
{
return context.ResolveKeyed<ICustomService>(p);
}
But, you can take this a step further and decouple CustomServiceFactory from IComponentContext:
public class CustomServiceFactory
{
private Func<string, ICustomService> _create;
public CustomServiceFactory(Func<string, ICustomService> create)
{
_create = create;
}
public ICustomService GetService(string p)
{
return _create(p);
}
}
which you would register like so:
builder.Register(c => {
var ctx = c.Resolve<IComponentContext>();
return new CustomServiceFactory(key => ctx.ResolveKeyed<ICustomService>(key));
});
And at that point, assuming CustomServiceFactory doesn't have any other behavior that was omitted for the question, then you as might as well just use and register Func<string, ICustomService> directly.
Here is my setup with Asp.Net Mvc 3:
public abstract class BaseProvider
{
protected ICache Cache;
}
public interface ICache
{
void Add(string key, object data);
void Remove(string key);
...
}
public class MyCache : ICache
{
private static MemoryCache cache = MemoryCache.Default;
void Add(string key, object data)
{
...
}
}
public interface IEmployeeProvider
{
IEnumerable<Employee> GetEmployees(string department);
}
public class EmployeeProvider:BaseProvider,IEmployeeProvider
{
public IEnumerable<Employee> GetEmployees(string department)
{
**if (Cache.Get("employees_"+department)!=null)**
}
}
Starred line throws an error saying that Cache is null.
I tried to register the base class as a type but, I guess it is wrong.
My Autofac setup is like this:
builder.Register(r => new EmployeeProvider()).As<IEmployeeProvider>().InstancePerHttpRequest();
builder.Register(r => new MyCache()).As<ICache>().InstancePerHttpRequest();
builder.RegisterType<BaseProvider>().PropertiesAutowired();
What am I missing?
You should either register EmployeeProvider with PropertiesAutowired() or scan the assembly for every class that inherits from BaseProvider.
The first registration forgets the PropertiesAutowired(), the third line forgets the EmployeeProvider.