Web API read header value in controller constructor

Question

Is it possible to get at the header information in the constructor of a web API controller? I want to set variables based off a header value but I don't want to have to do it for each method. I'm particularly interested in a custom header value but I would settle for the Authorization one at this point. I can get it to work in an AuthorizationFilterAttribute but I also need it at the controller level.

[PolicyAuthorize]
public class PoliciesController : ApiController
{
    public PoliciesController()
    {
        var x = HttpContext.Current;  //will be null in constructor
    }

    public HttpResponseMessage Get()
    {
        var x = HttpContext.Current;  //will be available but too late
    }
}

public class PolicyAuthorizeAttribute : AuthorizationFilterAttribute
{
    public override void OnAuthorization(HttpActionContext actionContext)
    {
        var authHeader = actionContext.Request.Headers.Authorization;  //can get at Authorization header here but no HTTPActionContext in controller
    }
}

Answer 1

Following are some options that you can consider...prefer 1. over 2.

1. Store additional data in current request message's properties bag HttpRequestMessage.Properties and have a convenience property in controller which all actions in the controller can access.

   [CustomAuthFilter]
   public class ValuesController : ApiController
   {
       public string Name
       {
           get
           {
               return Request.Properties["Name"].ToString();
           }
       }
   
       public string GetAll()
       {
           return this.Name;
       }
   }
   
   public class CustomAuthFilter : AuthorizationFilterAttribute
   {
       public override void OnAuthorization(HttpActionContext actionContext)
       {
           actionContext.Request.Properties["Name"] = "<your value from header>";
       }
   }
   

2. You could get the current controller's instance and set the property value. Example:

   [CustomAuthFilter]
   public class ValuesController : ApiController
   {
       public string Name { get; set; }
   
       public string GetAll()
       {
           return this.Name;
       }
   }
   
   public class CustomAuthFilter : AuthorizationFilterAttribute
   {
       public override void OnAuthorization(HttpActionContext actionContext)
       {
           ValuesController valuesCntlr = actionContext.ControllerContext.Controller as ValuesController;
   
           if (valuesCntlr != null)
           {
               valuesCntlr.Name = "<your value from header>";
           }
       }
   }