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how can I validate this invalid property in web api?

I have a user search request object which looks like this:
UserSearchRequest
{
FirstName:"John",
LastName:"Smith",
Expand:["groups","devices"]
}
Expand is an optional parameter. I have validation which checks that the provided Expand parameters are within thin expected set of parameters. The problem is that if a client submits a request like this:
{
FirstName:"John",
LastName:"Smith",
Expand:1
}
By default Web API 2 will pass this request to the controller method with an Expand value of null. So the user won't know that he submitted a bad request and the controller won't be able to identify it as a bad request b/c null is a valid value for this property. Is there a way to override this default behavior?

Action filters are triggered before controller executes its logic. I will give a general idea of what you need to do to get you on the right track.
First requirement for ActionFilter is to create your own filter class by extending ActionFilterAttribute class.
The following is a sample for this
public class ValidateCustomModel : ActionFilterAttribute
{
public override void OnActionExecuting(HttpActionContext actionContext)
{
//Write your logic to check that all attributes are not null
}
}
Now onto the second step. This step will register your filter in WebApiConfig class so that the application will know that it has to pass requests to this filter wherever the attribute is used
config.Filters.Add(new ValidateModelAttribute());
Now the third step is to call the custom class as an attribute on the controller method that is being executed when user makes a request.
[ValidateModel]
Hope this helps you to customise it for your own logic. Happy coding.

Authorization in ASP.net5

I am trying to see if there is something "out of the box" in ASP.net5 for authorization for my application needs. I am using a group/permission based approach for authorization. Using Identity3 I am using Role as Group and then I have created permissions from this. Each permission has a resource that it links to and 1 or more values, like:
Resource = Page, Permissions = Add, Update, View, Delete
Another complication is that the groups have dynamic names, and dynamic permissions!!
I have started to read about authorization in ASP.net5 and it seems that I have found something called Policies, which sound good. It seems to force you to use Claims, which is possible if I use a ClaimsTransformer to get all my permissions and add them as claims from the Db. But am I right in thinking that I would have to create a policy for each Permission, on each resource? That seems like a lot of setup.
Is there anything that I do not know about is already built in ASP.net5 that I could use? Like an attribute like this
[Authorize("Page", "Delete")]
Which I could add to the PageController Delete method.
If I have to use some sort of service and DI that into the controller to implement this, then that would be fine as well.

There is a ClaimsPrincipalPermissionAttribute that can fit to your requirements.
Or you can implement your own AuthorizeAttribute.

I use AspNet.Security.OpenIdConnect.Server for authorization. But you can also have a look at OpenIddict
In any case you can add the Authorize attribute to any method you want like this
[Authorize(Roles = "Administrator,SimpleUser,AnOtherRole")]
public void MyMethod() {}

Resource based authorization might fulfill your needs, but I am a little confused with the page being the resource, rather than what the page acts upon.
Taking your Page/Delete combination, I would imagine that rather than the resource being Page, your Page Delete action takes a parameter, indicating the page that is to be deleted? (If this is not the case then this approach isn't going to work of course)
In this case you'd do something like
[Authorize]
public class PageController : Controller
{
IAuthorizationService _authorizationService;
public PageController(IAuthorizationService authorizationService)
{
_authorizationService = authorizationService;
}
public Delete(int pageId)
{
var page = pageRepo.GetPage(pageId);
if (await authorizationService.AuthorizeAsync(User, page, Operations.Delete))
{
return View(page);
}
else
{
return new ChallengeResult();
}
}
}
In order to enable this you're write a handler based on page and an Operations requirement (or any old requirement, but a parameterized operations requirement means you can write a single handler and branch accordingly).
We tried very hard to move away from putting data in the attribute, and move it into requirements, because data in attributes is, to be frank, a maintenance nightmare.
One other thing to note; as handlers are resolved through DI you could inject your user to permissions resolver into the handler, which would avoid using claims transformation.

ASP.NET provides authentication mechanism out of the box which is easy to use, example:
public class HomeController : Controller
{
[Authorize]
public ActionResult Index()
{
ViewBag.Message = "This can be viewed only by authenticated users only";
return View();
}
[Authorize(Roles="admin")]
public ActionResult AdminIndex()
{
ViewBag.Message = "This can be viewed only by users in Admin role only";
return View();
}
}
Check this tutorial
Or if you want more sophisticated mechanism you can implement your own memberhsip provider based on the ASP.NET Membership Provider

Dealing with Session timeout in ASP.NET MVC

I am working on a MVC application and I have a requirement of dealing with errors and session timeouts by redirecting the user to different error pages based on few parameters in the query string.
The issue I am facing is that i tried to implement this by saving the required parameters from querystring into a session and then redirecting to error pages. But before every HttpGet and Post action in my controllers I am checking if session is active.
So in case of a situation where session values are lost and not able to read them.
How can I implement this thing in any other way?

You need to check whether the session exists, has the fields you expect and is active. If the session does not exist or does not have a fields you expect, then handle the case when the session does not exist yet/expired. If it is not active, then handle the case when the session is no longer active. If everything is ok, then handle the request normally. If the session expired, then handle it as expired.

to check about session, you can use an ActionFilter like this:
public class SessionActiveFilterAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
var activeSession = Session["user"];
if (activeSession == null)
//Here, do a redirect
base.OnActionExecuting(filterContext);
}
}
Also, you can use a third option to save the session, like Redis Cache http://blogs.msdn.com/b/webdev/archive/2014/05/12/announcing-asp-net-session-state-provider-for-redis-preview-release.aspx

I know this is a dead story now. But I post this answer for the new comers. Please see the nice tutorial in codeproject about how to check session values in Action Filters.
In a dynamic web application, the session is crucial to hold the information of current logged in user identity/data. So someone without authentication cannot have access to some Page or any ActionResult, to implement this kind of functionality, we need to check session exists (is not null) in every action which required authentication.So, the general method is as follows:
[HttpGet]
public ActionResult Home()
{
if(Session["ID"] == null)
return RedirectToAction("Login","Home");
}
We have to check the above 2 statements each time and in each ActionResult, but it may cause 2 problems.
Repeat Things: As per the good programming stranded, we don't have to repeat the things. Create a module of common code and access it multiple times/repeatedly
Code missing: We have to write code multiple times so it might happen some time we forget to write code in some method or we missed it.
How To Avoid?
The ASP.NET MVC provides a very great mechanism i.e., Action Filters. An action filter is an attribute. You can apply most action filters to either an individual controller action or an entire controller.
If you want to know more about action filter, please click here.
So we will create a custom Action Filter that handles session expiration and if session is null, redirect to Login Action.
Create a new class in your project and copy the following code:
namespace YourNameSpace
{
public class SessionTimeoutAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
HttpContext ctx = HttpContext.Current;
if (HttpContext.Current.Session["ID"] == null)
{
filterContext.Result = new RedirectResult("~/Home/Login");
return;
}
base.OnActionExecuting(filterContext);
}
}
}
Now our Action Filter is created and we are ready to use it. The following code will show you how we can apply attribute to Action or to complete controller.
Apply to Action
[HttpGet]
[SessionTimeout]
public ActionResult MyProfile()
{
return View();
}
Apply to Controller
[SessionTimeout]
public class HomeController : Controller
{
}
Now all actions of Home Controller will check for session when hit with the help of Action Filter. So we have reduced the code and repetitive things. This is the benefits of Action Filters.

Intercepting Request in Global.asax

I have an ASP.NET MVC Application using MVC 4.5. I have been instructed to put a query string authorization to the application. The application serves as a data processor for another application at the front.
We decided to append a querystring in the requesting URLs containing a hash code for instance http://dr.appbox.us/DataReport/?passcode=HASHCODE.
The HASHCODE can be checked and if it matches the request is permitted further.
Now I have about 20 controllers in the application, is there a way that I can check if the HASHCODE is valid in global.asax and redirect the user to error page from there?
Also please tell me if there is a way to check if I can bypass this hashcode for Ajax requests in the application.
Thanks

You can use a custom action filter for this. If you create a new class that inherits from ActionFilterAttribute and override the OnActionExecuting method. Here you can validate the passcode and redirect if required.
public class HashCodeCheckFilterAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
var passcode = filterContext.HttpContext.Request.QueryString["passcode"];
// Validate passcode
var valid = false;
// If invalid then do some error processing
if (!valid)
{
// Redirect to errro page....
filterContext.Result = new RedirectToRouteResult("NameOfErrorRoute");
return;
}
base.OnActionExecuting(filterContext);
}
}
You can then either use this on specific controllers / actions as an attribute:
[HashCodeCheckFilter]
public class HomeController : Controller
{
// GET: Home
[HashCodeCheckFilter]
public ActionResult Index()
{
return View();
}
}
Or you can register it in Application_Start (Or App_Start/FilterConfig) as a global filter that applies to all requests:
GlobalFilters.Filters.Add(new HashCodeCheckFilterAttribute());
If you want to not check if the request is an ajax request you can check the HTTP_X_REQUESTED_WITH header on the request to see if it equals xmlhttprequest.

is there a way that I can check if the HASHCODE is valid in global.asax and redirect the user to error page from there
I would use a HttpHandler which is better suitable for this. (See documentation here and here and step-by-step tutorial here)
Also please tell me if there is a way to check if I can bypass this hashcode for Ajax requests in the application.
You could check if the HttpContext.Current.Request.Headers["x-requested-with"] is XMLHttpRequest. Then it is an AJAX call and you could skip the authentication step. Additionally, you could set a session variable when receiving the hashcode for the first time and check if that hashcode is still valid when the AJAX request is done. Then you will have a better security then just not checking it.

It sounds to me like you should be looking at implementing an IAuthorizationFilter rather than trying to use Global.asax. An implementation of IAuthorizationFilter will run before any request and you can choose what to do if the hashcode in invalid.

Since you're using asp.net MVC I would look at global action filters within your application. You can register an action filter as a global action filter through your global.asax.
GlobalFilters.Filters.Add(new MyActionFilterAttribute());
Within your action filter you can put the code to check for your hash, this will get executed each time any of your actions are called on the controllers.
public class MyActionFilterAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
if(!filterContext.RequestContext.HttpContext.Request.IsAjaxRequest())
{
// CHECK HASH HERE
}
base.OnActionExecuting(filterContext);
}
}
Check out these resources for more information
http://weblogs.asp.net/gunnarpeipman/asp-net-mvc-3-global-action-filters
https://msdn.microsoft.com/en-us/library/system.web.mvc.globalfiltercollection(v=vs.98).aspx

User (IPrincipal) not available on ApiController's constructor using Web Api 2.1 and Owin

I am Using Web Api 2.1 with Asp.Net Identity 2. I am trying to get the authenticated User on my ApiController's constructor (I am using AutoFac to inject my dependencies), but the User shows as not authenticated when the constructor is called.
I am trying to get the User so I can generate Audit information for any DB write-operations.
A few things I'm doing that can help on the diagnosis:
I am using only app.UseOAuthBearerTokens as authentication with Asp.Net Identity 2. This means that I removed the app.UseCookieAuthentication(new CookieAuthenticationOptions()) that comes enabled by default when you are creating a new Web Api 2.1 project with Asp.Net Identity 2.
Inside WebApiConfig I'm injecting my repository:
builder.RegisterType<ValueRepository>().As<IValueRepository>().InstancePerRequest();
Here's my controller:
[RoutePrefix("api/values")]
public class ValuesController : ApiController
{
private IValueRepository valueRepository;
public ValuesController(IValueRepository repo)
{
valueRepository = repo;
// I would need the User information here to pass it to my repository
// something like this:
valueRepository.SetUser(User);
}
protected override void Initialize(System.Web.Http.Controllers.HttpControllerContext controllerContext)
{
base.Initialize(controllerContext);
// User is not avaliable here either...
}
}
But if I inspect the User object on the constructor, this is what I get:
The authentication is working, if I don't pass my token, it will respond with Unauthorized. If I pass the token and I try to access the user from any of the methods, it is authenticated and populated correctly. It just doesn't show up on the constructor when it is called.
In my WebApiConfig I am using:
public static void Register(HttpConfiguration config)
{
config.SuppressDefaultHostAuthentication();
config.Filters.Add(new HostAuthenticationFilter(OAuthDefaults.AuthenticationType));
// Web API routes
config.MapHttpAttributeRoutes();
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = RouteParameter.Optional }
);
// ... other unrelated injections using AutoFac
}
I noticed that if I remove this line: config.SuppressDefaultHostAuthentication() the User is populated on the constructor.
Is this expected? How can I get the authenticated user on the constructor?
EDIT:
As Rikard suggested I tried to get the user in the Initialize method, but it is still not available, giving me the same thing described in the image.

The problem lies indeed with config.SuppressDefaultHostAuthentication().
This article by Brock Allen nicely explains why that is. The method sets the principal intentionally to null so that default authentication like cookies do not work. Instead, the Web API Authentication filter then takes care of the authentication part.
Removing this configuration when you do not have cookie authentication could be an option.
A neat solution as mentioned here, is to scope the Web API parts of the application, so that you can separate out this configuration to a specific path only:
public void Configuration(IAppBuilder app)
{
var configuration = WebApiConfiguration.HttpConfiguration;
app.Map("/api", inner =>
{
inner.SuppressDefaultHostAuthentication();
// ...
inner.UseWebApi(configuration);
});
}

Don't know if this is still relevant, but I've had exactly the same problems, as you've described above. I've managed to solve it using custom OWIN middleware component.
Some info about my application structure:
Using MVC WebApp and WebAPI in same project (probably not the best option, but I have no time to change it, since deadline is approaching ;))
Using AutoFac as IoC container
Implemented custom ICurrentContext to hold information about currently logged on user (with CookieAuth in MVC and Bearer Token Auth in WebAPI), which is injected where needed (controllers, BAL objects, etc.)
Using EntityFramework 6 for Db access
Converted ASP.NET Identity to use int keys rather than string (http://www.asp.net/identity/overview/extensibility/change-primary-key-for-users-in-aspnet-identity)
So on to the code. This is my ICurrentContext interface:
public interface ICurrentContext
{
User CurrentUser { get; set; } // User is my User class which holds some user properties
int? CurrentUserId { get; }
}
and implementation of it:
public class DefaultCurrentContext : ICurrentContext
{
public User CurrentUser { get; set; }
public int? CurrentUserId { get { return User != null ? CurrentUser.Id : (int?)null; } }
}
I've also created an OWIN middleware component:
using System.Threading.Tasks;
using Microsoft.AspNet.Identity;
using Microsoft.Owin;
namespace MyWebApp.Web.AppCode.MiddlewareOwin
{
public class WebApiAuthInfoMiddleware : OwinMiddleware
{
public WebApiAuthInfoMiddleware(OwinMiddleware next)
: base(next)
{
}
public override Task Invoke(IOwinContext context)
{
var userId = context.Request.User.Identity.GetUserId<int>();
context.Environment[MyWebApp.Constants.Constant.WebApiCurrentUserId] = userId;
return Next.Invoke(context);
}
}
}
Some information about this component: MyWebApp.Constants.Constant.WebApiCurrentUserId is some string constant (you can use your own) that I've used to avoid typos since its used in more than one place. Basicly what this middleware does, is that it adds current UserId to the OWIN environment dictionary and then Invokes the next action in pipeline.
Then I've created Use* extension statement to include OMC (OWIN Middleware Component) into OWIN pipeline:
using System;
using Owin;
namespace MyWebApp.Web.AppCode.MiddlewareOwin
{
public static class OwinAppBuilderExtensions
{
public static IAppBuilder UseWebApiAuthInfo(this IAppBuilder #this)
{
if (#this == null)
{
throw new ArgumentNullException("app");
}
#this.Use(typeof(WebApiAuthInfoMiddleware));
return #this;
}
}
}
To use this OMC, I've put the Use* statement right after Use* statement for Bearer token inside my Startup.Auth.cs:
// Enable the application to use bearer tokens to authenticate users
app.UseOAuthBearerTokens(OAuthOptions); // This was here before
// Register AuthInfo to retrieve UserId before executing of Api controllers
app.UseWebApiAuthInfo(); // Use newly created OMC
Now the actual usage of this principle was inside AutoFac's Register method (called on some bootstrap code at the start of web application; in my case this was inside Startup class (Startup.cs), Configuration method) for my ICurrentContext implementation which is:
private static void RegisterCurrentContext(ContainerBuilder builder)
{
// Register current context
builder.Register(c =>
{
// Try to get User's Id first from Identity of HttpContext.Current
var appUserId = HttpContext.Current.User.Identity.GetUserId<int>();
// If appUserId is still zero, try to get it from Owin.Enviroment where WebApiAuthInfo middleware components puts it.
if (appUserId <= 0)
{
object appUserIdObj;
var env = HttpContext.Current.GetOwinContext().Environment;
if (env.TryGetValue(MyWebApp.Constants.Constant.WebApiCurrentUserId, out appUserIdObj))
{
appUserId = (int)appUserIdObj;
}
}
// WORK: Read user from database based on appUserId and create appUser object.
return new DefaultCurrentContext
{
CurrentUser = appUser,
};
}).As<ICurrentContext>().InstancePerLifetimeScope();
}
This method is called where I build AutoFac's container (hence the input parameter of type ContainerBuilder).
This way I got single implementation of CurrentContext, no matter how user was authenticated (via MVC Web Application or Web API). Web API calls in my case were made from some desktop application, but database and most of codebase were the same for MVC App and Web API.
Don't know if its the right way to go, but it has worked for me. Although I am still a little concerned how would this behave thread-wise, since I don't know exactly how using HttpContext.Current inside API calls would behave. I've read somewhere that OWIN Dictionary is used per-request basis, so I think this is safe approach. And I also think that this isn't so neat code, but rather a little nasty hack to read UserId. ;) If there's anything wrong with using this approcah, I'd appreciate any comment regarding it. I've been strugling with this for two weeks now and this is the closest I got of getting UserId in one place (when resolving ICurrentContext from AutoFac through lambda).
NOTE: Wherever there is usage of GetUserId, it can be replaced with original GetUserId (which returns string) implementation. The reason I'm using GetUserId is because I've rewritten ASP.NET to some extent for using ints instead of strings for TKey. I've done this based on following article: http://www.asp.net/identity/overview/extensibility/change-primary-key-for-users-in-aspnet-identity

The User property of the controller is not populated until the Initialize method is called which happens after the constructor is invoked, hence thats why the Identity is not yet populated with the authorzied user data.

I realized that removing config.SuppressDefaultHostAuthentication() allowed me to get the Identity in the constructor much earlier. However, I wouldnt suggest doing this if you are using Token Authentication.

Thread.CurrentPrincipical is available throughout the pipeline, you could skip the User registration below:
valueRepository.SetUser(User);
and access
Thread.CurrentPrincipical
In the repository instead, making the repository context aware. Furthermore, you could add a context layer.

If nothing of the above solutions work try this one:
public ActionResult GetFiles()
{
...
string domainID = System.Web.HttpContext.Current.Request.LogonUserIdentity.Name;
...
}