ASP.NET Core控制器构造函数：访问请求信息

Question

I have a base controller class with ILog log field, which is set at constructor from custom logger service, passed via dependency injection.

I'd like to access something like request context in controller constructor to get arbitrary HTTP header or HttpContext.Items or something like that to use it when creating my log .

I tried using IHttpContextAccessor . It gives me DefaultHttpContext which does not contain Items added by middleware.

The only thing that i can imagine is to make log property of controller public and write an IActionFilter which sets this property. Because action filters have access to both context and controller instance.

Not having request context in controller constructor looks weird to me, because request information can be useful to avoid boilerplate code in actions. Controllers are created per request anyway, so there's no harm to use some request data in constructor.

Answer 1

For request level logging use an ActionFilter attrbute and inject an ILogger to that. I'm not sure but I think in MVC 5+ the dependency injection is supported in action filter attributes. If not, instead of registering in GlobalFilters , you can implement an IFilterProvider for attaching and instantiating the attribute to the requests you'd like to.

On the other hand, if you need any kind of business level logging (so for example inside an action body), use the injected ILogger in the controller, but then you should not call any logging logic until the process is inside an action. At that point you'll already have a built-up request context.