I am using asp.net mvc applicaiton and I am new about cross cutting concers. So I need to know where can I use my logger code following example.
I have an interface that logs erros. I am implementing this interface on my code.
public interface ILogger { void Log(Exception exception); }
So I have Controller, ProductService, ProductRepository classes.
public interface ProductController: ApiController{
public IHttpActionResult Get(){
try {
productService.GetProducts();
}catch(Exception e){
logger.Log(e); // 1-Should I use logging in here?
}
}
}
Product service;
public class ProductService{
public IEnumerable<Product> GetProducts(){
try {
productRepository.GetAll();
}catch(Exception e){
logger.Log(e); // 2-Should I use logging in here?
}
}
}
In repository.
public class ProductRepository{
public IEnumerable<Product> GetAll(){
try {
}catch(Exception e){
logger.Log(e); // 3-Should I use logging in here?
}
}
}
I could not determine where can I use logging code. Or add logging in everywhere.
You can implement custom exception filter.
public class LogExceptionAttribute : ExceptionFilterAttribute
{
public ILogger logger { get; set; }
public LogExceptionAttribute(ILogger logger)
{
this.logger = logger;
}
public override void OnException(HttpActionExecutedContext actionExecutedContext)
{
var exception = actionExecutedContext.Exception;
logger.Log(actionExecutedContext.Exception);
// You could also send client a message about exception.
actionExecutedContext.Response =
actionExecutedContext.Request.CreateResponse(HttpStatusCode.InternalServerError, exception.Message);
}
}
Then register it on global level.
GlobalConfiguration.Configuration.Filters.Add(new LogExceptionAttribute(Logger));
This filter would be called for any unhandled exception thrown from controller method.
Related
I tried this answer: [https://stackoverflow.com/questions/18406506/custom-filter-attributes-inject-dependency][1] to implement ActionFilterAttribute (System.Web.Http.Filters) for Web API project (not MVC). But my custom attribute never called in controller. I would be grateful for any advice.
Custom attribute:
public class MyAttribute : FilterAttribute { }
Filter:
public class MyFilter : ActionFilterAttribute
{
private readonly IMyService _myService;
public MyFilter(IMyService myService)
{
_myService = myService;
}
public override async Task OnActionExecutingAsync(HttpActionContext actionContext, CancellationToken cancellationToken)
{
//do some with actionContext
throw new Exception("You can`t go here");
}
}
Controller method:
[My] // Not called
[HttpPost]
[Route("/do-some")]
public async Task DoSome(string myString)
{
//do some
}
Register filter:
public partial class Startup
{
protected void ConfigureApi(IAppBuilder app, IContainer container)
{
var configuration = new HttpConfiguration();
//...
var serviceInstance = container.GetInstance<IMyService>();
configuration.Filters.Add(new MyFilter(serviceInstance));
}
}
Is something wrong here?
Almost everything is fine with the your code, but you should register your filter and service in another way.
In Asp Net Core WebAPI there several ways you can register your filter:
Globally - for all controllers, actions, and Razor Pages. More information in Microsoft documentation
For only one controller/method. More information in Microsoft documentation
Example of global registration:
services.AddControllers(options =>
{
options.Filters.Add(typeof(LoggerFilterAttribute));
});
Example of method registration in Controller:
I want notice - in this case you should use ServiceFilter - this helps DI resolve any dependecines for your filter.
[HttpGet]
[ServiceFilter(typeof(LoggerFilterAttribute))]
public IEnumerable<WeatherForecast> Get()
{
}
This is my simple example for this task:
My SimpleService
public interface ISimpleService
{
void Notify(string text);
}
public class SimpleService : ISimpleService
{
public void Notify(string text)
{
Console.WriteLine($"Notify from {nameof(SimpleService)}. {text}");
}
}
ActionFilterAttribute
public class LoggerFilterAttribute : ActionFilterAttribute
{
private readonly ISimpleService _simpleService;
public LoggerFilterAttribute(ISimpleService simpleService)
{
_simpleService = simpleService;
}
public override void OnActionExecuting(ActionExecutingContext context)
{
_simpleService.Notify($"Method {nameof(OnActionExecuting)}");
}
public override Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
{
_simpleService.Notify($"Method {nameof(OnActionExecutionAsync)}");
return base.OnActionExecutionAsync(context, next);
}
}
The main step - you should choose way of registration, because there is main difference between global registration and per controller/method in code.
If you want use this way of registration - you need only register global filter and this is enough. All magic will be do by WebAPI with DI registration.
services.AddControllers(options =>
{
options.Filters.Add(typeof(LoggerFilterAttribute));
});
If you want use registration per controller/method. You need to register your filter in DI. Because without it you will have Exception.
services.AddScoped<LoggerFilterAttribute>();
[HttpGet]
[ServiceFilter(typeof(LoggerFilterAttribute))]
public IEnumerable<WeatherForecast> Get()
{
}
The last step register my service
services.AddTransient<ISimpleService, SimpleService>();
Results
I am implementing dependency injection using Unity and the Unity.Webforms bootstrapper. I have a DbFactory in my webforms application which initializes my DbContext, and I am wanting to create one instance of this factory per web request, so that my various services will update under the same unit of work.
My question is, does the Unity.Webforms bootstrapper take care of this for me? I believe the answer in this post is suggesting doing the following in order accomplish a single context per request.
container.RegisterType<IDbFactory,DbFactory>(new HierarchicalLifetimeManager());
Is this correct, and is it all I need to do? I'm worried that it is creating a single context per request, but that it is an application wide context (all users sharing the same context).
This probably isn't necessary, but just in case, here is the implementation code for my DbFactory.
public class DbFactory : Disposable, IDbFactory
{
MyDbContext dbContext;
public MyDbContext Init()
{
return dbContext ?? (dbContext = new MyDbContext());
}
protected override void DisposeCore()
{
if(dbContext != null)
{
dbContext.Dispose();
}
}
}
public class Disposable : IDisposable
{
private bool isDisposed;
~Disposable()
{
Dispose(false);
}
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
private void Dispose(bool disposing)
{
if(!isDisposed && disposing)
{
DisposeCore();
}
isDisposed = true;
}
protected virtual void DisposeCore(){}
}
I'm using SpringBoot and I am trying to create a service layer for my web application but i cant make it work.
My classes look like this
ServiceFactory
#Service
public class ServiceFactory {
#Autowired
public static EncuestaService getEncuestaService()
{
return new EncuestaServiceImpl();
}
}
EncuestaService
public interface EncuestaService {
void crearEncuesta(Encuesta encuesta, Map<String,String> parametros);
}
EncuestaServiceImpl
#Service
public class EncuestaServiceImpl implements EncuestaService {
#Override
public void crearEncuesta(Encuesta encuesta, Map<String, String> parametros) {
CrearEncuesta nueva = new CrearEncuesta(encuesta,parametros);
nueva.execute();
}
}
CrearEncuesta
#Service
public class CrearEncuesta {
private Encuesta encuesta;
private Map<String,String> parametros;
#Autowired
private RespuestasRepository respuestasRepository;
#Autowired
private EncuestasRepository encuestasRepository;
public CrearEncuesta(Encuesta encuesta, Map<String,String> parametros) {
super();
this.encuesta = encuesta;
this.parametros = parametros;
}
public void execute()
{
encuestasRepository.save(encuesta);
}
}
Everytime I call ServiceFactory.getEncuestasService().crearEncuesta() from any Controller it returns me a NullPointerException.
From what I have been reading I should not be creating a new EncuestsaServiceImpl() in my ServiceFactory but I don't really know the correct way to do so. I would appreciate if anyone could help me out :P.
Edit:
#SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
Controller
#Controller
public class EncuestaController {
#RequestMapping(value ="registrarEncuesta", method = RequestMethod.POST)
private String formularioEncuesta(#Valid #ModelAttribute("formEncuesta") EncuestaForm formEncuesta, BindingResult bindingResult,#RequestParam Map<String,String> allRequestParams)
{
if (bindingResult.hasErrors()) {
return "nuevaEncuesta";
}
try {
Encuesta nueva = formEncuesta.toEncuesta();
ServiceFactory.getEncuestaService().crearEncuesta(nueva,allRequestParams);
} catch (DataIntegrityViolationException e) {
return "nuevaEncuesta";
}
return "redirect:/encuestas";
}
}
You will have to read a little bit more about dependency injection. The central principle in Spring Framework is dependency injection which should be used to avoid referencing beans (service implementations, repository implementations etc...) statically. Spring container also servers as a bean factory that will instantiate and inject (autowire) implementations to beans that need them.
Because Spring will instantiate service interface implementations for you, you don't need ServiceFactory. In your controller you need to add a reference (a field) to EncuestaService and annotate it as Autowired and Spring will wire in the implementation. And then you can just use it in your controller.
#Controller
public class EncuestaController {
#Autowired
EncuestaService encuestaService;
#RequestMapping(value ="registrarEncuesta", method = RequestMethod.POST)
private String formularioEncuesta(#Valid #ModelAttribute("formEncuesta") EncuestaForm formEncuesta, BindingResult bindingResult,#RequestParam Map<String,String> allRequestParams)
{
if (bindingResult.hasErrors()) {
return "nuevaEncuesta";
}
try {
Encuesta nueva = formEncuesta.toEncuesta();
encuestaService.crearEncuesta(nueva,allRequestParams);
} catch (DataIntegrityViolationException e) {
return "nuevaEncuesta";
}
return "redirect:/encuestas";
}
}
I have WebForms project, and there I have WebApi controller.
How I can inject to controller constructor and to action filter constructor?
I have implemented IDependencyResolver and use it in Global.asax (GlobalConfiguration.Configuration.DependencyResolver), but it doesn't help:
on request controller says that there is no default constructor and filter on application start says that it does not contain a constructor that takes 0 arguments.
Moreover, i need singletone injection to action filter.
Thanks.
UPD
public class ScopeContainer : IDependencyScope
{
protected readonly IUnityContainer _container;
public ScopeContainer(IUnityContainer container)
{
_container = container;
}
public object GetService(Type serviceType)
{
return _container.IsRegistered(serviceType) ? _container.Resolve(serviceType) : null;
}
public IEnumerable<object> GetServices(Type serviceType)
{
return _container.IsRegistered(serviceType) ? _container.ResolveAll(serviceType) : new List<object>();
}
public void Dispose()
{
_container.Dispose();
}
}
public class IoCContainer : ScopeContainer, IDependencyResolver
{
public IoCContainer(IUnityContainer container) : base(container)
{
}
public IDependencyScope BeginScope()
{
var child = _container.CreateChildContainer();
return new ScopeContainer(child);
}
}
public class Global : HttpApplication
{
void Application_Start(object sender, EventArgs e)
{
RegisterRoutes();
ConfigureApi(GlobalConfiguration.Configuration);
}
void ConfigureApi(HttpConfiguration config)
{
var unity = new UnityContainer();
unity.RegisterInstance<ILogger>(new Logger());
unity.RegisterType<IRepository, DbRepository>();
config.DependencyResolver = new IoCContainer(unity);
}
private static void RegisterRoutes()
{
RouteTable.Routes.MapHttpRoute("ServiceApi", "api/{controller}/{action}");
}
}
I think this may be the way you are registering your routes.
WebApi routes are registered in the default project examples via the GlobalConfiguration.Routes rather than the RouteTable.Routes which is used by MVC controllers. If the ApiController is being incorrectly loaded by the MVC routing method it won't find your dependency resolver.
Try modifying your code to this:
public class Global : HttpApplication
{
void Application_Start(object sender, EventArgs e)
{
RegisterRoutes(GlobalConfiguration.Configuration);
ConfigureApi(GlobalConfiguration.Configuration);
}
void ConfigureApi(HttpConfiguration config)
{
var unity = new UnityContainer();
unity.RegisterInstance<ILogger>(new Logger());
unity.RegisterType<IRepository, DbRepository>();
config.DependencyResolver = new IoCContainer(unity);
}
private static void RegisterRoutes(HttpConfiguration config)
{
config.Routes.MapHttpRoute("ServiceApi", "api/{controller}/{action}");
}
}
I was having the same issue, I was working on a project trying to help modernize an old web forms project by converting page by page to Web API / Angular and getting the plumbing just right to use Unity was key.
When I was tracing I noticed unity was trying to resolve the controller classes but not the types to inject into their constructors, so I registered my controllers and it all worked. See my example below
Config setup, register controller and dependency
void ConfigureApi(HttpConfiguration config)
{
var container = UnitySingleton.UnityContainer;
container.RegisterType<IDashboardManager, ExampleStuff>();
container.RegisterType<DashboardController>(new InjectionConstructor(container.Resolve<IDashboardManager>()));
config.DependencyResolver = new UnityIoCContainer(container);
}
And my controller example:
public class DashboardController : ApiController
{
private readonly IDashboardManager _dashboardManager;
public DashboardController(IDashboardManager dashboardManager)
{
_dashboardManager = dashboardManager;
}
public async Task<IEnumerable<string>> Get()
{
return await _dashboardManager.GetDatas();
}
}
This is how I got mine working. It was a little different than the article above.
I have the Global.asax like the code below:
public class MvcApplication : System.Web.HttpApplication
{
public static void RegisterRoutes(RouteCollection routes)
{
// ....
}
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
RegisterRoutes(RouteTable.Routes);
ControllerBuilder.Current.SetControllerFactory(typeof(IOCControllerFactory));
}
}
public class IOCControllerFactory : DefaultControllerFactory
{
private readonly IKernel kernel;
public IOCControllerFactory()
{
kernel = new StandardKernel(new NanocrmContainer());
}
protected override IController GetControllerInstance(RequestContext requestContext, Type controllerType)
{
if (controllerType == null)
return base.GetControllerInstance(requestContext, controllerType);
var controller = kernel.TryGet(controllerType) as IController;
if (controller == null)
return base.GetControllerInstance(requestContext, controllerType);
var standartController = controller as Controller;
if (standartController is IIoCController)
((IIoCController)standartController).SetIoc(kernel);
return standartController;
}
class NanocrmContainer : Ninject.Modules.NinjectModule
{
public override void Load()
{
// ...
Bind<DomainModel.Entities.db>().ToSelf().InRequestScope().WithConstructorArgument("connection", "Data Source=lims;Initial Catalog=nanocrm;Persist Security Info=True;User ID=***;Password=***");
}
}
}
In this case if somewhere it is the class, defined like:
public class UserRepository : IUserRepository
{
private db dataContext;
private IUserGroupRepository userGroupRepository;
public UserRepository(db dataContext, IUserGroupRepository userGroupRepository)
{
this.dataContext = dataContext;
this.userGroupRepository = userGroupRepository;
}
}
then the dataContext instance is created (if no one was created in this request scope) by Ninject.
So the trouble now is - where to invoke dataContext method .Dispose()?
UPD:
so i followed the advice from KeeperOfTheSoul and solved the issue in such way:
public override void ReleaseController(IController controller)
{
base.ReleaseController(controller);
var db = kernel.Get<DomainModel.Entities.db>();
db.Dispose();
}
A good place to handle this is in IControllerFactory.ReleaseController, eg
public override void ReleaseController() {
base.ReleaseController();
//Do whatever you need to clean up the IoC container here
}
In NInject this could be handled by scoping using an activation block, at the start of the request when creating the controller you can store the activation block in the HttpContext's current items, during ReleaseController you can retrieve the previously created activation block and dispose it.
You could also consider using InScope and having the custom scope implement INotifyWhenDisposed. After that the usage is the same as with an activation block, except now you store the scope in the HttpContext's current items.
A pattern that is sometimes used to dispose db connections is to call Dispose from the finaliser.
public class db : IDisposable {
//called by the garbage collector
~db() {
//Call dispose to make sure the resources are cleaned up
Dispose(false);
}
//IDisposable implementation
public void Dispose() {
Dispose(true);
}
//subclasses of db can override Dispose(bool) and clean up their own fields
protected virtual void Dispose (bool disposing) {
if (disposing) {
//Supress finalization as all resources are released by this method
//Calling Dispose on IDisposable members should be done here
GC.SupressFinalize();
}
//Clean up unmanaged resources
//Do not call other objects as they might be already collected if called from the finalizer
}
}
You could hook it into Application_EndRequest.