I need to implement custom error logging on signalR hubs. This can be done by creating ErrorModule which will inherit from HubPipelineModule and it will be registered on Startup like this
GlobalHost.HubPipeline.AddModule(new ErrorModule());
This is my hub
public class FooHub : Hub
{
public void MethodWithException()
{
throw new Exception();
}
public void FooMethod()
{
}
}
And this is my module
public class ErrorModule : HubPipelineModule
{
protected override void OnIncomingError(ExceptionContext exceptionContext, IHubIncomingInvokerContext invokerContext)
{
//call foo method on foo hub
//log error
}
}
Lets say MethodWithException() is called. It is possible to call FooMethod() on hub which invoked event OnIncomingError ?
With something like this :
protected override void OnIncomingError(ExceptionContext exceptionContext,
IHubIncomingInvokerContext invokerContext)
{
dynamic caller = invokerContext.Hub.Clients.Caller;
caller.ExceptionHandler(exceptionContext.Error.Message);
//log something here
Debug.WriteLine(exceptionContext.Error.Message);
}
EDIT
To call a particular method of the hub you can do :
protected override void OnIncomingError(ExceptionContext exceptionContext,
IHubIncomingInvokerContext invokerContext)
{
var hub = (invokerContext.Hub as HubType); //
hub.MyMethod("myparam","mysecondparam");
//log something here
Debug.WriteLine(exceptionContext.Error.Message);
}
You can find the full code here : How to handle SignalR server exception at client?
Related
Here is my wcfService code -
public class SystemService : ISystemService
{
private IHubContext hubContext;
public SystemService()
{
hubContext = GlobalHost.ConnectionManager.GetHubContext<WebApplication1.MyHub1>();
}
public void SendMessage(string sender, string message)
{
hubContext.Clients.All.SendMessage(sender, message);
}
}
My web application with signalR hub is working fine.
namespace WebApplication1
{
[HubName("myHub1")]
public class MyHub1 : Hub
{
public void SendMessage(string name, string message)
{
// Call the broadcastMessage method to update clients.
Clients.All.broadcastMessage(name, message);
}
}
}
Only the messages from wcf client are not received.
No error messages in tracelog. If possible can anyone advice what I am missing here.
please ask if any other details needed.
Changed the code to generate a proxy. And working now.
public class SystemService : ISystemService
{
private readonly IHubProxy proxy;
// private IHubContext hubContext;
public SystemService()
{
var con = new HubConnection("http://localhost:53098/");
proxy = con.CreateHubProxy("myHub1");
con.Start().Wait();
}
public void SendMessage(string sender, string message)
{
proxy.Invoke("SendMessage", sender, message);
//hubContext.Clients.All.SendMessage(sender, message);
}
}
But shocking, I was first trying with this method only but it didnt worked earlier.. So I tried with IhubContext as above in my question.
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.
Is there anyway to define and add method filters for hub functions (like ActionFilters in mvc)
I mean something like this :
public class MyHub : Hub
{
[Log]
public string RegisterUser(UserModel model){
...
}
}
where I can do some control inside the LogAttribute implementation.
You should be able to achieve similar functionality to action filters in ASP.NET MVC by using SignalR's Hub pipeline:
public class LoggingPipelineModule : HubPipelineModule
{
protected override bool OnBeforeIncoming(IHubIncomingInvokerContext context)
{
Debug.WriteLine("Invoking '{0}.{1}({2})'.",
context.MethodDescriptor.Hub.Name,
context.MethodDescriptor.Name,
string.Join(", ", context.Args));
return base.OnBeforeIncoming(context);
}
protected override object OnAfterIncoming(object result, IHubIncomingInvokerContext context)
{
Debug.WriteLine("Finished Invoking '{0}.{1}'. Returned '{2}'.",
context.MethodDescriptor.Hub.Name,
context.MethodDescriptor.Name,
result);
return base.OnAfterIncoming(result, context);
}
}
If you only want to log for methods with a custom attribute attached, you can check for your custom attribute before logging:
protected override bool OnBeforeIncoming(IHubIncomingInvokerContext context)
{
if (context.MethodDescriptor.Attributes.OfType<MyAttribute>().Any())
{
// Log here.
}
return base.OnBeforeIncoming(context);
}
You can register your module before your call to MapSignalR:
public void Configuration(IAppBuilder app)
{
GlobalHost.HubPipeline.AddModule(new LoggingPipelineModule());
app.MapSignalR();
}
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.