c# - How to get dependency injection working with IAsyncAuthorizationFilter in ASP.NET Core -

i have implemented iasyncauthorizationfilter interface class; in addition, class derived attribute, can mark controller classes , action methods using it. works far; task onauthorizationasync(authorizationfiltercontext context) method called before action method, , if request not authenticated, http 401 returned response.

[attributeusage(attributetargets.class | attributetargets.method)] public sealed class customauthenticationattribute : attribute, iasyncauthorizationfilter  {     public async task onauthorizationasync(authorizationfiltercontext context)     {         ...     } } 

this attribute used follows...

[customauthenticationattribute] public class somedatacontroller : controller {     [httpget]     public async task getdata()     {         ...     } } 

now, want use application service (which obtains secret private key information required authentication database) , tried use property injection that. injecting dependencies via ctor not choice here since it´s implemented attribute. tried...

[attributeusage(attributetargets.class | attributetargets.method)] public sealed class customauthenticationattribute : attribute, iasyncauthorizationfilter  {     public iprivatekeylookupservice keyservice { get; set; }      public async task onauthorizationasync(authorizationfiltercontext context)     {         string publickey = ...         ...         var privatekey = await this.keyservice.getprivatekeyfrom(publickey);         ...     } } 

...but property injection not seem work here. service registered ioc, properties not wired. asp.net core 1.1 project in use autofac. in startup class configureservices method has that...

public void configureservices(iservicescollection collection) {     ...      var containerbuilder = new containerbuilder();     containerbuilder.registertype<authkeyservice>().as<iprivatekeylookupservice>();      containerbuilder.populate(services);      this.container = containerbuilder.build(); } 

does autofac support auto-wiring iasyncauthorizationfilter types? , if not, how polyfill functionality?

it turned out simple...

in asp.net core there typefilter attribute filter creates filter (specified type) , satisfies constructor arguments involving dependency injection.

i changed implementation of iasyncauthorizationfilter; removed properties , added ctor instead, because typefilter ctor injection work now...

public sealed class customauthenticationattribute : iasyncauthorizationfilter  {     private readonly iprivatekeylookupservice keyservice;     public customauthenticationattribute(         iprivatekeylookupservice keyservice)     {         this.keyservice = keyservice;     }      public async task onauthorizationasync(authorizationfiltercontext context)     {         ...     } } 

i removed inheritance attribute because it´s not needed anymore declaration of attributeusage attribute.

so, can use attribute follows...

[typefilter(typeof(customauthenticationattribute))] public class somedatacontroller : controller {     [httpget]     public async task getdata()     {         ...     } }  

passing additional arguments filter´s ctor possible via object[] arguments property of typefilter class.