I'm migrating some old ASP.NET MVC 5 code to .NET 6.0 and having some trouble with an AuthorizationFilter that, within its OnAuthorization implementation, accesses the decorated method's controller class instance, like this:
// Get the decorated method's name
string actionName = filterContext.ActionDescriptor.ActionName;
// Get the controller instance and then, its type
Type controllerType = filterContext.Controller.GetType();
I just can´t see how I would get the controller instance (or event the method's name) from the AuthorizationFilterContext available in .NET 6.0. Any help?
create new class
public class LogEntry : IAuthorizationFilter
{
public void OnAuthorization(AuthorizationFilterContext context)
{
var controllerActionDescriptor = context.ActionDescriptor as
ControllerActionDescriptor;
string controllerName =
controllerActionDescriptor?.ControllerName;
string actionName =
controllerActionDescriptor?.ActionName;
}
}
In Program.cs register LogEntry class
builder.Services.AddScoped<LogEntry>();
on controller action method
[ServiceFilter(typeof(LogEntry))]
public IActionResult Index()
{
return View();
}
Related
I am migrating an ASP.NET MVC application to ASP.NET Core 3.1.
And I have a code to check if the session was timed out in my controller, like this:
if (Session.IsNewSession) {
How can I check it in ASP.NET Core?
Thanks
The default implementation of ISession is DistributedSession. This does not expose any property for IsNewSession although its constructor accepts a parameter named isNewSessionKey. So you can use reflection to get that private field of _isNewSessionKey to check it. But that way is not very standard, the name may be changed in future without notifying you any design-time error.
You have several points to intercept and get the info here. The first point is to create a custom ISessionStore (default by DistributedSessionStore) to intercept the call to ISessionStore.Create which gives access to isNewSessionKey. You can capture that value into a request feature just like how the framework set the ISessionFeature after creating the session. Here's the code:
//create the feature interface & class
public interface ISessionExFeature {
bool IsNewSession { get; }
}
public class SessionExFeature : ISessionExFeature {
public SessionExFeature(bool isNewSession){
IsNewSession = isNewSession;
}
public bool IsNewSession { get; }
}
//the custom ISessionStore
public class CustomDistributedSessionStore : DistributedSessionStore, ISessionStore
{
readonly IHttpContextAccessor _httpContextAccessor;
public CustomDistributedSessionStore(IDistributedCache cache,
ILoggerFactory loggerFactory,
IHttpContextAccessor httpContextAccessor) : base(cache, loggerFactory)
{
_httpContextAccessor = httpContextAccessor;
}
ISession ISessionStore.Create(string sessionKey, TimeSpan idleTimeout, TimeSpan ioTimeout, Func<bool> tryEstablishSession, bool isNewSessionKey)
{
var httpContext = _httpContextAccessor.HttpContext;
if(httpContext != null)
{
var sessionExFeature = new SessionExFeature(isNewSessionKey);
httpContext.Features.Set<ISessionExFeature>(sessionExFeature);
}
return Create(sessionKey, idleTimeout, ioTimeout, tryEstablishSession, isNewSessionKey);
}
}
//register the custom ISessionStore inside Startup.ConfigureServices
services.Replace(new ServiceDescriptor(typeof(ISessionStore), typeof(CustomDistributedSessionStore), ServiceLifetime.Transient));
//an extension method to help get the ISessionExFeature conveniently
public static class SessionExFeatureHttpContextExtensions {
public static bool HasNewSession(this HttpContext context){
return context.Features.Get<ISessionExFeature>()?.IsNewSession ?? false;
}
}
To use it in your code:
if (HttpContext.HasNewSession()) {
//...
}
Another point to intercept and get the info is customize both the ISessionStore and ISession. Which means you create a sub class of DistributedSession and expose the property for IsNewSession. That may require more code but it looks more like the old way of getting the info (directly from the Session not kind of via an extension method on HttpContext).
I am trying to inject a service into my action filter but I am not getting the required service injected in the constructor. Here is what I have:
public class EnsureUserLoggedIn : ActionFilterAttribute
{
private readonly ISessionService _sessionService;
public EnsureUserLoggedIn()
{
// I was unable able to remove the default ctor
// because of compilation error while using the
// attribute in my controller
}
public EnsureUserLoggedIn(ISessionService sessionService)
{
_sessionService = sessionService;
}
public override void OnActionExecuting(ActionExecutingContext context)
{
// Problem: _sessionService is null here
if (_sessionService.LoggedInUser == null)
{
context.HttpContext.Response.StatusCode = (int)HttpStatusCode.Unauthorized;
context.Result = new JsonResult("Unauthorized");
}
}
}
And I am decorating my controller like so:
[Route("api/issues"), EnsureUserLoggedIn]
public class IssueController : Controller
{
}
Startup.cs
services.AddScoped<ISessionService, SessionService>();
Using these articles as reference:
ASP.NET Core Action Filters
Action filters, service filters and type filters in ASP.NET 5 and MVC 6
Using the filter as a ServiceFilter
Because the filter will be used as a ServiceType, it needs to be registered with the framework IoC. If the action filters were used directly, this would not be required.
Startup.cs
public void ConfigureServices(IServiceCollection services) {
services.AddMvc();
services.AddScoped<ISessionService, SessionService>();
services.AddScoped<EnsureUserLoggedIn>();
...
}
Custom filters are added to the MVC controller method and the controller class using the ServiceFilter attribute like so:
[ServiceFilter(typeof(EnsureUserLoggedIn))]
[Route("api/issues")]
public class IssueController : Controller {
// GET: api/issues
[HttpGet]
[ServiceFilter(typeof(EnsureUserLoggedIn))]
public IEnumerable<string> Get(){...}
}
There were other examples of
Using the filter as a global filter
Using the filter with base controllers
Using the filter with an order
Take a look, give them a try and see if that resolves your issue.
Hope this helps.
Global filters
You need to implement IFilterFactory:
public class AuthorizationFilterFactory : IFilterFactory
{
public bool IsReusable => false;
public IFilterMetadata CreateInstance(IServiceProvider serviceProvider)
{
// manually find and inject necessary dependencies.
var context = (IMyContext)serviceProvider.GetService(typeof(IMyContext));
return new AuthorizationFilter(context);
}
}
In Startup class instead of registering an actual filter you register your filter factory:
services.AddMvc(options =>
{
options.Filters.Add(new AuthorizationFilterFactory());
});
One more way for resolving this problem. You can get your service via Context as in the following code:
public override void OnActionExecuting(ActionExecutingContext context)
{
_sessionService = context.HttpContext.RequestServices.GetService<ISessionService>();
if (_sessionService.LoggedInUser == null)
{
context.HttpContext.Response.StatusCode = (int)HttpStatusCode.Unauthorized;
context.Result = new JsonResult("Unauthorized");
}
}
Please note that you have to register this service in Startup.cs
services.AddTransient<ISessionService, SessionService>();
Example
private ILoginService _loginService;
public override void OnActionExecuting(ActionExecutingContext context)
{
_loginService = (ILoginService)context.HttpContext.RequestServices.GetService(typeof(ILoginService));
}
Hope it helps.
After reading this article ASP.NET Core - Real-World ASP.NET Core MVC Filters (Aug 2016) I implemented it like this:
In Starup.cs / ConfigureServices:
services.AddScoped<MyService>();
In MyFilterAttribute.cs:
public class MyFilterAttribute : TypeFilterAttribute
{
public MyFilterAttribute() : base(typeof (MyFilterAttributeImpl))
{
}
private class MyFilterAttributeImpl : IActionFilter
{
private readonly MyService _sv;
public MyFilterAttributeImpl(MyService sv)
{
_sv = sv;
}
public void OnActionExecuting(ActionExecutingContext context)
{
_sv.MyServiceMethod1();
}
public void OnActionExecuted(ActionExecutedContext context)
{
_sv.MyServiceMethod2();
}
}
}
In MyFooController.cs :
[MyFilter]
public IActionResult MyAction()
{
}
Edit: Passing arguments like [MyFilter("Something")] can be done using the Arguments property of the TypeFilterAttribute class: How do I add a parameter to an action filter in asp.net? (rboe's code also shows how to inject things (the same way))
While the question implicitly refers to "filters via attributes", it is still worth highlighting that adding filters "globally by type" supports DI out-of-the-box:
[For global filters added by type] any constructor dependencies will be populated by dependency injection (DI). Adding a filter by type is equivalent to filters.Add(new TypeFilterAttribute(typeof(MyFilter))).
https://learn.microsoft.com/en-us/aspnet/core/mvc/controllers/filters?view=aspnetcore-2.2#dependency-injection
With regards to attribute-based filters:
Filters that are implemented as attributes and added directly to controller classes or action methods cannot have constructor dependencies provided by dependency injection (DI). This is because attributes must have their constructor parameters supplied where they're applied. This is a limitation of how attributes work.
https://learn.microsoft.com/en-us/aspnet/core/mvc/controllers/filters?view=aspnetcore-2.2#dependency-injection
However, as mentioned in the previous answers to the OP, there are ways of indirection that can be used to achieve DI. For the sake of completeness, here are the links to the official docs:
ServiceFilterAttribute
TypeFilterAttribute
IFilterFactory implemented on your attribute
I am currently using the Request.Scheme and Request.Host to composite Uri object to get AbsoluteUri for my .net core MVC application.
Uri location = new Uri($"{Request.Scheme}://{Request.Host}");
string applicationRootURL = location.AbsoluteUri;
But this only works in a non-static method.
As I need to re-use this method in another controller, I am thinking to make this action method static. If I do that, the compiler will complaint about the Request.Scheme and Request.Host.
I am wondering what's other options I have to achieve this?
Thank you.
UPDATE:
This is what I have for ControllerA with ActionMethodA
public class ControllerA
{
public bool ActionMethodA()
{
Uri location = new Uri($"{Request.Scheme}://{Request.Host}");
string applicationRootURL = location.AbsoluteUri;
return false;
}
}
And in another ControllerB, I want to ActionMethodB to invoke ActionMethodA from ControllerA:
public class ControllerB
{
public void ActionMethodB()
{
var result = ActionMethodA();
}
}
Is creating an Extension Method to the ControllerA is the most proper way to handle this kind of scenario?
Thank you.
You can also define an extension method directly for the HttpRequest class and use the BuildAbsolute method of the UriHelper class to build the uri.
public static class HttpRequestExtensions
{
public static string GetURI(this HttpRequest request)
{
return UriHelper.BuildAbsolute(request.Scheme, request.Host);
}
}
And use it:
public IActionResult ContollerMethod()
{
var uri = Request.GetURI();
// your code
}
You can write an extension method to a controller or HttpContext object. In the following example I have added an extension method to the controller.
public static class ControllerExtensions
{
public static string GetURI(this Controller controller)
{
Uri location = new Uri($"{ controller.Request.Scheme}://{controller.Request.Host}");
string applicationRootURL = location.AbsoluteUri;
return applicationRootURL;
}
}
Once the extension method is written you can call it in the following manner.
public IActionResult Index()
{
var url = this.GetURI();
return View();
}
Make sure to import namespace of an extension method in your calling code
I create clean APS.NET MVC 4 project and I try make internationalization using this tutorial.
I have problem with using baseController, because when I run project, function from base controller isn't execute. Maybe I forget implement something...
BaseController
public class BaseController : Controller
{
protected override void ExecuteCore()
{
string cultureName = null;
//Attempt to read the culture cookie from Request
HttpCookie cultureCookie = Request.Cookies["_culture"];
if (cultureCookie != null)
cultureName = cultureCookie.Value;
else
cultureName = Request.UserLanguages[0]; //obtain it from HTTP
//Validation culture name
cultureName = CultureHelper.GetImplementedCulture(cultureName); // This is safe
//Modify current thread's cultures
Thread.CurrentThread.CurrentCulture = new System.Globalization.CultureInfo(cultureName);
Thread.CurrentThread.CurrentUICulture = Thread.CurrentThread.CurrentCulture;
base.ExecuteCore();
}
}
HomeController
public class HomeController : BaseController
{
public ActionResult Index()
{
ViewBag.Message = "Modify this template to jump-start your ASP.NET MVC application.";
return View();
}
}
You might want to override the Initialize method instead ExecuteCore.
Here is an explanation and a solution: ExecuteCore() in base class not fired in MVC 4 beta
I am curious why the ApiController handles default parameter values on actions differently than a 'regular' Controller.
This code works just fine, request to /Test means page gets value 1
public class TestController : Controller
{
public ActionResult Index(int page = 1)
{
return View(page);
}
}
This code doesn't work when a request is made to /api/Values. It fails with:
"The parameters dictionary contains a null entry for parameter 'page' of non-nullable type 'System.Int32' for method 'System.Collections.Generic.IEnumerable`1[System.String] Get(Int32)' in 'MvcApplication1.Controllers.Controllers.ValuesController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter."
public class ValuesController : ApiController
{
public IEnumerable<string> Get(int page = 1)
{
return new string[] { page.ToString() };
}
}
Any hints on why this is?
Try adding the [FromUri] or [FromForm] parameter attribute.
public class ValuesController : ApiController
{
public IEnumerable<string> Get([FromUri]int page = 1)
{
return new string[] { page.ToString() };
}
}
Mike Stall has two good posts about parameter binding in Webapi which does not work as it does in ASP MVC. The big problem to get used to is that you can only read the request body once in your pipeline. So if you need to read more than 1 complex object as a parameter, you probably need to resort to ModelBinding by parameter. I had a problem similar to yours when I was reading the content body earlier in the pipeline for logging purposes and did not realize about the read once restriction above and had to solve with my own custom model binder.
Explains model binding at http://blogs.msdn.com/b/jmstall/archive/2012/04/16/how-webapi-does-parameter-binding.aspx and then suggests a way to make WebAPI model binding more like ASP MVC http://blogs.msdn.com/b/jmstall/archive/2012/04/18/mvc-style-parameter-binding-for-webapi.aspx
Try defining as Nullable<T>:
public class ValuesController : ApiController
{
public IEnumerable<string> Get(int? page = 1)
{
return new string[] { page.ToString() };
}
}