In an Azure Mobile App using the .NET backend, I need one controller to look up an entity handled by a second controller. For example, in the Todo Quickstart project from the Azure team, imagine adding a UserController which handles user management. In TodoItemController, I need to call UserController.GetUser(id) to check if a user is authorized to post a new TodoItem.
In TodoItemController.cs:
var userController = new UserController();
var user = userController.GetUser("12345");
if (user.IsAuthorized)
{
// Insert TodoItem
}
The above code throws an exception when TableController.Lookup() is called in UserController.GetUser(). The exception says that the request parameter cannot be null. My guess is that something is missing because I created the UserController myself, instead of it being created by the framework.
How can I make this work?
This appears to work in TodoItemController.cs:
var context = new todoProjectContext();
var userDomainManager = new EntityDomainManager<User>(context, Request);
var user = userDomainManager.Lookup(id).Queryable.FirstOrDefault();
if (user.isAuthorized)
{
// Insert item
}
Not sure it's the best solution though.
Related
I have users in our app, who are mapped to companies. When a user logs in and starts to make requests I want a way to validate if that user is currently mapped to the company for access to company resources.
The idea I had was to create a whole controller just to manage all of this, but someone mentioned ActionFilters as a much better and cleaner option, I have to agree after looking at it.
The idea is to have the controller setup as:
controller - action - CompanyId - ReportId
So any request to root the system would just look up if there are any companies mapped to that logged in user.
But if the request included CompanyId then they'd go to that company's “portal” account page. It's really any request that includes CompanyId where I want the actionFilter to make a determination on if that user is allowed access.
Request comes in...
There is a CompanyId in the request!
ActionFilter:
Look up in db for all users assigned to that CompanyId. Is current user within that list? No? = kick'em out.
I tried to type in a code example, but the system told me to manually indent each line by 4 spaces, I was doing it from memory anyways so no idea how helpful it would have been anyways.
You could get your action parameters in your action filter and then get your database via HttpContext.RequestServices.GetRequiredService<ApplicationDbContext>().Refer to here.
public class TestActionFilter:Attribute,IActionFilter
{
public void OnActionExecuting(ActionExecutingContext context)
{
//If companyId is action parameter
var companyId= context.ActionArguments["companyId"].ToString();
//If companyId1 is query string
var companyId1= context.HttpContext.Request.Query["companyId1"].ToString();
//If companyId2 is in request header
var companyId2= context.HttpContext.Request.Headers["companyId2"].ToString();
//get your dbcontext
var db = context.HttpContext.RequestServices.GetRequiredService<ApplicationDbContext>();
//EF core logic
//...
}
public void OnActionExecuted(ActionExecutedContext context)
{
}
}
You could use it on action directly using [TestActionFilter] attribute or set as global filter
services.AddMvc(options =>
{
options.Filters.Add(new TestActionFilter()); // an instance
});
I am building a web service using ServiceStack which has to support multiple vendors. The web service provides largely the same functionality to all vendors with some exceptions here and there.
In order to re-use as much functionality as possible I have come up with the following URL scheme:
http://localhost/brand1/templates
http://localhost/brand2/templates
"brand1" and "brand2" are not services but "templates" is. The Templates service's request DTO's will have a property called "Brand" like so:
[Route("/{Brand}/templates", "GET")]
public class GetTemplates
{
public Brand Brand { get; set; }
}
So in the Templates service I know which brand I am dealing with. This scheme works well.
What I cannot figure out though is this. The user of the service has to be authenticated and I cannot figure out how to handle the redirection of the service after the user has been authenticated since I have to pass along the brand information. I have created my own CustomAuthProvider class that inherits CredentialsAuthProvider. In the TryAuthenticate method I can set the authService.GetSession().ReferrerUrl property to the correct brand if I know what it was.
The only way I have found so far to get this information is to register a PreRequestFilter. My thinking here was that since the URL (e.g. http://localhost/brand1/templates) contains the brand I can store it in my own AuthUserSession class. I can't figure out how to do this. I have a "SessionFactory" method that I pass to the AuthFeature constructor. But what should I do in there? How do I get to the brand that I've obtained in the PreRequestFilter? Is it safe to store it in a field of the AppHost? I think not because of concurrency issues. How do I tie the PreRequestFilter to the SessionFactory method?
I hope I am explaining my problem clearly enough?
I was overthinking the solution because I didn't realize that I had all the information I needed in the IServiceBase parameter of the TryAuthenticate method of the CredentialsAuthProvider class.
In the end I came to the following solution:
public class CustomCredentialsAuthProvider : CredentialsAuthProvider
{
public override bool TryAuthenticate(IServiceBase authService,
string userName, string password)
{
var session = authService.GetSession();
var origQuery = authService.Request.UrlReferrer.Query;
session.ReferrerUrl = "/error";
var queryString = origQuery.Substring(10); // strip "redirect="
var decodedUrl = HttpUtility.UrlDecode(queryString);
if (!string.IsNullOrWhiteSpace(decodedUrl))
{
var query = new Uri(decodedUrl);
session.ReferrerUrl = query.AbsolutePath;
}
return DoAuthentication(userName, password);
}
}
The different places where you can set the Url to redirect to during ServiceStack Authentication, in order of precedence are:
The Session.ReferrerUrl Url if it's populated
The Continue QueryString, FormData param when making the request to /auth (i.e Authenticate.Continue property)
The HTTP Referer HTTP Header
The CallbackUrl of the current AuthProvider used
I have a wish list, that is throughout the shopping pages. I need to know if this makes sense/the proper way of structuring.
Store the wish list as a session, when a user adds/deletes a new item it updates the session by an ajax call that just returns true/false if successful. On the partial view of the wish list component, I check for the session and cast it to my viewModel (which the session is based on) or serialize it for my knockout.
Let me know if this makes sense, otherwise I can post some code samples
It's hard to say without having a look at your basic structure, and not knowing you exact needs.
I don't know if you know this, but you can actually access the Session directly in Views:
#{
var wishlist = (WishList)HttpContext.Current.Session["Wishlist"];
}
It's fine to use Ajax to update it server side; and then you can return a partial view from the controller, to use however you like in the Ajax success call.
I hope this makes sense.
To begin with, if the wishlist is only supposed to exist for the duration of their visit then storing it in a session would be the best thing to do. However if the wishlist is supposed to live longer than a single visit and should be available to the user upon their return then I would suggest storing it in the database against the user's credentials/account (this is presuming they have an account).
As for the session itself, whilst you can access session data from a view I would not suggest it as you start to have a dependency on the session and before long you'll have code such as this scattered throughout your views.
var wishlist = (WishList)HttpContext.Current.Session["Wishlist"];
What happens when you want to change the way the wishlist works and instead have it database driven as you'd now like to persist the wishlist? You'll have to go through all of your views updating the references to the session.
Instead I would opt for registering your session with your IoC container of choice and injecting it using dependency injection, here is a simple example of how to register the session with StructureMap:
public class WebsiteRegistry : Registry
{
public WebsiteRegistry()
{
this.For<IUserWishlist>().HybridHttpOrThreadLocalScoped().Use(() => GetUserWishlistFromSession());
}
public static IUserWishlist GetUserWishlistFromSession()
{
var session = HttpContext.Current.Session;
if (session["WishList"] != null)
{
return session["WishList"] as IUserWishlist;
}
/* Create new empty session object */
session["WishList"] = new UserWishlist();
return session["WishList"] as IUserWishlist;
}
}
Now you're able to inject your wishlist into your controller and pass the data to your view via a view model. And as you're now programming against an interface instead of an implementation you could easily change how the wishlist is persisted without needing to change any code that references the wishlist.
public class WishlistController : Controller {
private readonly IUserWishlist userWishlist;
public void WishlistController(IUserWishlist userWishlist) {
this.userWishlist= userWishlist;
}
public ActionResult ViewProfile()
{
...
var viewModel = new UserWishlistViewModel {
wishlist = this.userWishlist.GetWishList()
}
...
}
}
I've written a more detailed example up in a blog post that might be of interest which can be read here. I hope this helps!
I'm creating a CMS using ASP.NET MVC, and by design, I've decided that each plugin (add-on) should have a key in the incoming HTTP request. Thus, I have this general route in my host application:
{pluginKey}/{controller}/{action}/{id}
I've created a custom controller factory which implements IControllerFactory and of course, it has a method to create controllers base on the ReqeustContext and controller name. However, I want to create an artificial HttpContext (alongside all other relevant objects like HttpRequest, RequestContext, RouteData, etc.) so that controllers of plugins won't misinterpret these URL segments wrongly. In other words, I want to cut the first part of the incoming URL, and make plugins think that they're processing this URL:
{controller}/{action}/{id}
How can I achieve this?
While you could create a new implementation of all the context classes, it seems like a bit of overkill. Why not use a derived Route Handler that applies the filtering functionality before returning the HttpHandler? Here's an example:
// To avoid conflicts with similarly named controllers, I find it to be good practice
// to create a route constraint with the set of all plugin names. If you don't have
// this function already, you should be able to access it with reflection (one time
// per app lifecycle) or you hard-code them. The point is to have a regex which ensures
// only valid plugins will get selected
string[] pluginNames = GetPluginNames();
string pluginNameRegex = string.Join("|",pluginNames);
Route pluginRoute = new Route (
url: "{pluginKey}/{controller}/{action}/{id}",
defaults: null,
constraints: new RouteValueDictionary(new { pluginKey = pluginNameRegex }),
routeHandler: new PluginRouteHandler()
});
// The custom route handler can modify your route data after receiving the RequestContext
// and then send it to the appropriate location. Here's an example (markdown code/untested)
// Note: You don't have to inherit from MvcRouteHandler (you could just implement IRouteHandler
// but I'm assuming you want Mvc functionality as the fallback)
public class PluginRouteHandler : MvcRouteHandler
{
public PluginRouteHandler(IControllerFactory controllerFactory)
: base(controllerFactory)
{}
protected override IHttpHandler GetHttpHandler(RequestContext requestContext){
if(ValidatePluginRoute(requestContext))
{
// we are going to remove the pluginKey from the RequestContext, It's probably wise
// to go ahead and add it to HttpContext.Items, in case you need the data later
requestContext.HttpContext.Items["pluginKey"] = requestContext.RouteData.Values["pluginKey"];
// now let's get ride of it, so your controller factory will process the
// requestContext as you have described.
requestContext.Values.Remove("pluginKey");
// the route will now be interpreted as described so let the flow go to the MvcRouteHandler's method
}
return base.GetHttpHandler(requestContext);
}
static bool ValidatePluginRoute(RequestContext requestContext){
return requestContext.RouteData.ContainsKey("pluginKey");
}
}
I am new to Autofac and IoC so now I try to build my firs ASP.NET MVC 3 application with IoC.
Here with this code I try manually to register ProductController (in Global.asax).
protected void AutofacIocRegistration()
{
var builder = new ContainerBuilder();
//PRODUCT CONTROLLER
var registration = builder.Register(c => new ProductsController(c.Resolve<IProductRepository>()));
builder.RegisterType<ProductsController>().InstancePerHttpRequest();
SqlProductsRepository productRepository = new SqlProductsRepository(DATABASE_CONNECTION);
builder.RegisterInstance(new ProductsController(productRepository));
IContainer container = builder.Build();
DependencyResolver.SetResolver(new AutofacDependencyResolver(container));
}
When I build the application for the first time, I get list of 4 products in the HTML page (as I expected), but when I refresh the page or go "next" to other list of products then I get the error
A single instance of controller
'WebUI.Controllers.ProductsController'
cannot be used to handle multiple
requests. If a custom controller
factory is in use, make sure that it
creates a new instance of the
controller for each request.
As you can see in this code
builder.RegisterType<ProductsController>().InstancePerHttpRequest();
I try to solve this with InstancePerHttpRequest() method but unsuccessful, if you have any suggestion please post.
Thanks for any help in advance.
use the below method to register your controllers
builder.RegisterControllers(Assembly.GetExecutingAssembly());
if you are using constructor injection in the controllers you can register your repository like this
builder.RegisterType<SqlProductsRepository>().As<IProductRepository>();
this way it will create the object graph when it needs to create the controller