How to determine Route Prefix programmatically in asp.net mvc? - c#

I wanted to provide some URL separation for my public/anonymous controllers and views from the admin/authenticated controllers and views. So I ended up using entirely Attribute Routing in order to take more control of my URLs. I wanted my public URLs to start with "~/Admin/etc." while my public URLs would not have any such prefix.
Public Controller (one of several)
[RoutePrefix("Home")]
public class HomeController : Controller
{
[Route("Index")]
public ActionResult Index()
{ //etc. }
}
Admin Controller (one of several)
[RoutePrefix("Admin/People")]
public class PeopleController : Controller
{
[Route("Index")]
public ActionResult Index()
{ //etc. }
}
This allows me to have public URLs such as:
http://myapp/home/someaction
...and admin/authenticated URLs such as:
http://myapp/admin/people/someaction
But now I want to do some dynamic stuff in the views based on whether the user is in the Admin section or the Public section of the site. How can I access this programmatically, properly?
I know I could do something like
if (Request.Url.LocalPath.StartsWith("/Admin"))
...but it feels "hacky." I know I can access the controller and action names via
HttpContext.Current.Request.RequestContext.RouteData.Values
...but the "admin" piece isn't reflected in there, because it's just a route prefix, not an actual controller name.
So, the basic question is, how do I programmatically determine whether the currently loaded view is under the "admin" section or not?

You just need to reflect the RoutePrefixAttribute from the Controller type, and then get its Prefix value. The Controller instance is available on the ViewContext.
This example creates a handy HTML helper that wraps all of the steps into a single call.
using System;
using System.Web.Mvc;
public static class RouteHtmlHelpers
{
public static string GetRoutePrefix(this HtmlHelper helper)
{
// Get the controller type
var controllerType = helper.ViewContext.Controller.GetType();
// Get the RoutePrefix Attribute
var routePrefixAttribute = (RoutePrefixAttribute)Attribute.GetCustomAttribute(
controllerType, typeof(RoutePrefixAttribute));
// Return the prefix that is defined
return routePrefixAttribute.Prefix;
}
}
Then in your view, you just need to call the extension method to get the value of the RoutePrefixAttribute.
#Html.GetRoutePrefix() // Returns "Admin/People"

Related

ASP.NET MVC - Nesting Routes / Controllers

I have an ASP.NET MVC app. I have seen similar question asked. However, I haven't found a good answer. Essentially, I want to use the following routes:
/admin/users
/admin/users/create
/admin/users/[someId]
/admin/roles
/admin/roles/create
/admin/roles/[someId]
I have the following file structure:
/Controllers
AdminController.cs
/Admin
UsersController.cs
RolesController.cs
/Views
/Admin
Index.cshtml
/Users
Index.cshtml
Detail.cshtml
Create.cshtml
/Roles
Index.cshtml
Create.cshtml
Detail.cshtml
When I run my app, I just get The resource cannot be found.
What am I doing wrong? I set breakpoints, but none of them are being hit. It's like the routes aren't mapping to the controllers. I'm not sure what I need to do though.
You do not need to create sub folders for this to work. Just have 2 controllers(UsersController and RolesController) and you can use attribute routing to define the custom routing pattern you want.
Assuming you have attribute routing enabled
public class UsersController : Controller
{
[Route("admin/users")]
public ActionResult Index() { // to do : Return something }
[Route("admin/users/create")]
public ActionResult Create() { // to do : Return something }
[Route("admin/users/{id}")]
public ActionResult View(int id) { // to do : Return something }
}
Or you can do the RoutePrefix on the controller level.
[RoutePrefix("admin/users")]
public class UsersController : Controller
{
[Route("")]
public ActionResult Index() { // to do : Return something }
[Route("create")]
public ActionResult Create() { // to do : Return something }
[Route("{id}")]
public ActionResult View(int id) { // to do : Return something }
}
You can do the samething for the RolesControllers as well.
You can enable attribute routing in the RegisterRoutes method in RouteConfig.cs file.
public static void RegisterRoutes(RouteCollection routes)
{
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
routes.MapMvcAttributeRoutes(); //This line enables attribute routing
//Existing default Route definition goes here
}
You may also consider creating an "Admin" area and put your controllers inside that. Areas are the right solution if you want to logically group similar functionality.
If you do not prefer attribute routing ( why not ?) , you an define these custom route patterns in your RouteConfig. The order in you define the route matters.So make sure you define your specific routes before the default generic one.
You can also override your route tables by decorating your action methods with the RouteAttribute class.
For example:
class AdminController
{
[Route("/admin/users/create")]
public ViewResult CreateUser()
{
...
}
}
This has the advantage of separating the method name from the url component.
You can also route multiple URLs to a single method:
class AdminController
{
[Route("/admin/users/{someId:guid}")]
[Route("/admin/users/{someId:guid}/details")]
public ViewResult UserDetails(Guid someID)
{
...
}
}
As mason said, the file structure isn't important in MVC routing.
If you want to use convention (folder) based routing, you could use MvcCodeRouting to do exactly what you have specified here. It uses namespaces by default, so when you add controllers in a hierarchy, it will generate routes in the same hierarchy automatically. No need to apply the [Route] attribute everywhere and setup your routes manually.

ASP.NET WebAPI 2 Routing

I just have one quick question about what seems to have been a limitation with ASP.NET Web API Attribute Routing, but hoping I just suck at research. In my controller, I'm trying to do something like this:
public class OrdersController : ApiController
{
[HttpGet]
[Route("{apiRoot}/customers/{id:int}/orders")]
public IHttpActionResult GetCustomerOrders(int id) {...}
}
Where {apiRoot} is defined in either a configuration file.
This may not actually be necessary, but I'd like to know how to put a specific path in the route attribute without having to code a static path. Is the general idea here supposed to be that you only put text into the route path, except for your parameters which go in {}?
How about switching to using a RoutePrefix:
[MyRoutePrefix]
public class OrdersController : ApiController
{
[HttpGet]
[Route("customers/{id:int}/orders")]
public IHttpActionResult GetCustomerOrders(int id) {...}
}
public class MyRoutePrefixAttribute : RoutePrefixAttribute
{
public MyRoutePrefixAttribute()
{
Prefix = "the route prefix";
}
}
RoutePrefixAttribute isn't sealed like RouteAttribute so extending it should allow you do what you need. Assuming, of course, that all of the controllers in a single class using the same root path.
Note: I haven't had a chance to try this but given what I know of attribute routing, I don't see why it shouldn't work.

Get Controller Action based on Route

If I have the following controller:
public class RetrievalController : ApiController
{
[Route("api/User")]
public HttpResponseMessage RetrieveSomethingKthx()
{
if (true)
{
return Request.CreateResponse(System.Net.HttpStatusCode.OK);
}
return Request.CreateResponse(System.Net.HttpStatusCode.NotFound);
}
}
Is there a way early on (such as in OWIN) to read the path. E.G.: Request.Path == "http://www.website.com/api/User" and therefore get Reflection Information about that method?
Note that I am not relying on the Route to have the Controller Name or "Action" Name necessarily. I assume something lives in the Web API Routing to pull method info based on the Route.

How to set this Area up in my ASP.NET MVC Application

I'm trying to setup an Area Route in my ASP.NET MVC application.
I'm also using the nuget package AttributeRouting, not the normal MVC register area routes thingy.
From my understanding, area routes look like this : /area/controller/method
What I'm trying to do is :- /api/search/index
which means:
Area => Api
Controller => SearchController
ActionMethod => Index
.
[RouteArea("Api")]
public class SearchController : Controller
{
[POST("Index")]
public JsonResult Index(IndexInputModel indexInputModel) { .. }
}
But that doesn't create that route. This is what it creates: /api/index
The search controller is missing.
I've had a look the docs and noticed the RoutePrefix so I tried this..
[RouteArea("Api")]
[RoutePrefix("Search")]
public class SearchController : Controller
{
[POST("Index")]
public JsonResult Index(IndexInputModel indexInputModel) { .. }
}
and that actually creates the route /api/search/index.
But why do i need to put the RoutePrefix in there? Shouldn't it be smart enough to already figure out that this is a SearchController and create the 3-segment route?
You don't need to put a RoutePrefix anywhere. It's just there as a refactoring/DRY aid. Consider:
[RouteArea("Api")]
public class SearchController : Controller
{
[POST("Search/Index")]
public ActionResult Index() { }
}
If you had a number of actions, maybe you want them all with the "Search" prefix, so you'd do:
[RouteArea("Api")]
[RoutePrefix("Search")]
public class SearchController : Controller
{
[POST("Index")]
public ActionResult Index() { }
// Other actions to prefix....
}
Shouldn't it be smart enough?
Not to be cheeky, but no. AR was never intended to read all your code for you and magically generate routes. It was intended to keep your URLs top of mind, and to do that you should see your URLs. Not that this is the best or only way of doing things, just that was my intent from the get.
The real reason why it isn't smart enough is that the concept of "Area" has nothing to do with URL. An area is a logical unit. You could expose that logical unit without any route prefix (so it would be hanging off ~/) or you could expose it off "This/Is/A/Prefix".
However, if you want it to be smart enough.... I just released v3.4, which will let you do this (if you want to; don't have to):
namespace Krome.Web.Areas.Api
{
[RouteArea]
[RoutePrefix]
public class SearchController : Controller
{
[POST]
public ActionResult Index() { }
}
}
This will yield the following route: ~/Api/Search/Index. The area comes from the last section of the controller's namespace; the route prefix comes from the controller name; and the rest of the url comes from the action name.
One more thing
If you want to get out a route area url and route prefix rat's nest for individual actions in a controller, do this:
[RouteArea("Api")]
[RoutePrefix("Search")]
public class SearchController : Controller
{
[POST("Index")]
public ActionResult Index() { }
[GET("Something")] // yields ~/Api/Search/Something
[GET("NoPrefix", IgnoreRoutePrefix = true)] // yields ~/Api/NoPrefix
[GET("NoAreaUrl", IgnoreAreaUrl = true)] // yields ~/Search/NoAreaUrl
[GET("Absolutely-Pure", IsAbsoluteUrl = true)] // yields ~/Absolutely-Pure
public ActionResult Something() {}
}

Can you overload controller methods in ASP.NET MVC?

I'm curious to see if you can overload controller methods in ASP.NET MVC. Whenever I try, I get the error below. The two methods accept different arguments. Is this something that cannot be done?
The current request for action 'MyMethod' on controller type 'MyController' is ambiguous between the following action methods:
You can use the attribute if you want your code to do overloading.
[ActionName("MyOverloadedName")]
But, you'll have to use a different action name for the same http method (as others have said). So it's just semantics at that point. Would you rather have the name in your code or your attribute?
Phil has an article related to this: http://haacked.com/archive/2008/08/29/how-a-method-becomes-an-action.aspx
Yes. I've been able to do this by setting the HttpGet/HttpPost (or equivalent AcceptVerbs attribute) for each controller method to something distinct, i.e., HttpGet or HttpPost, but not both. That way it can tell based on the type of request which method to use.
[HttpGet]
public ActionResult Show()
{
...
}
[HttpPost]
public ActionResult Show( string userName )
{
...
}
One suggestion I have is that, for a case like this, would be to have a private implementation that both of your public Action methods rely on to avoid duplicating code.
Here's something else you could do... you want a method that is able to have a parameter and not.
Why not try this...
public ActionResult Show( string username = null )
{
...
}
This has worked for me... and in this one method, you can actually test to see if you have the incoming parameter.
Updated to remove the invalid nullable syntax on string and use a default parameter value.
No,No and No. Go and try the controller code below where we have the "LoadCustomer" overloaded.
public class CustomerController : Controller
{
//
// GET: /Customer/
public ActionResult LoadCustomer()
{
return Content("LoadCustomer");
}
public ActionResult LoadCustomer(string str)
{
return Content("LoadCustomer with a string");
}
}
If you try to invoke the "LoadCustomer" action you will get error as shown in the below figure.
Polymorphism is a part of C# programming while HTTP is a protocol. HTTP does not understand polymorphism. HTTP works on the concept's or URL and URL can only have unique name's. So HTTP does not implement polymorphism.
In order to fix the same we need to use "ActionName" attribute.
public class CustomerController : Controller
{
//
// GET: /Customer/
public ActionResult LoadCustomer()
{
return Content("LoadCustomer");
}
[ActionName("LoadCustomerbyName")]
public ActionResult LoadCustomer(string str)
{
return Content("LoadCustomer with a string");
}
}
So now if you make a call to URL "Customer/LoadCustomer" the "LoadCustomer" action will be invoked and with URL structure "Customer/LoadCustomerByName" the "LoadCustomer(string str)" will be invoked.
The above answer i have taken from this codeproject article --> MVC Action overloading
To overcome this problem you can write an ActionMethodSelectorAttribute that examines the MethodInfo for each action and compares it to the posted Form values and then rejects any method for which the form values don't match (excluding the button name, of course).
Here's an example:- http://blog.abodit.com/2010/02/asp-net-mvc-ambiguous-match/
BUT, this isn't a good idea.
As far as I know you can only have the same method when using different http methods.
i.e.
[AcceptVerbs("GET")]
public ActionResult MyAction()
{
}
[AcceptVerbs("POST")]
public ActionResult MyAction(FormResult fm)
{
}
I have achieved this with the help of Attribute Routing in MVC5. Admittedly I am new to MVC coming from a decade of web development using WebForms, but the following has worked for me. Unlike the accepted answer this allows all the overloaded actions to be rendered by the same view file.
First enable Attribute Routing in App_Start/RouteConfig.cs.
public class RouteConfig
{
public static void RegisterRoutes(RouteCollection routes)
{
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
routes.MapMvcAttributeRoutes();
routes.MapRoute(
name: "Default",
url: "{controller}/{action}/{id}",
defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
);
}
}
Optionally decorate your controller class with a default route prefix.
[RoutePrefix("Returns")]
public class ReturnsController : BaseController
{
//.......
Then decorate your controller actions that overload each other with a common route and parameters to suit. Using type constrained parameters you can use the same URI format with IDs of different types.
[HttpGet]
// Returns
public ActionResult Index()
{
//.....
}
[HttpGet]
[Route("View")]
// Returns/View
public ActionResult View()
{
// I wouldn't really do this but it proves the concept.
int id = 7026;
return View(id);
}
[HttpGet]
[Route("View/{id:int}")]
// Returns/View/7003
public ActionResult View(int id)
{
//.....
}
[HttpGet]
[Route("View/{id:Guid}")]
// Returns/View/99300046-0ba4-47db-81bf-ba6e3ac3cf01
public ActionResult View(Guid id)
{
//.....
}
Hope this helps and is not leading somebody down the wrong path. :-)
You could use a single ActionResult to deal with both Post and Get:
public ActionResult Example() {
if (Request.HttpMethod.ToUpperInvariant() == "GET") {
// GET
}
else if (Request.HttpMethod.ToUpperInvariant() == "POST") {
// Post
}
}
Useful if your Get and Post methods have matching signatures.
I've just come across this question and, even though it's quite old now, it's still very relevant. Ironically, the one correct comment in this thread was posted by a self-confessed beginner in MVC when he wrote the post. Even the ASP.NET docs are not entirely correct. I have a large project and I successfully overload action methods.
If one understands routing, beyond the simple {controller}/{action}/{id} default route pattern, it might be obvious that controller actions can be mapped using any unique pattern. Someone here talked about polymorphism and said: "HTTP does not understand polymorphism", but routing has nothing to do with HTTP. It is, simply put, a mechanism for string pattern matching.
The best way to make this work is to use the routing attributes, for example:
[RoutePrefix("cars/{country:length(3)}")]
public class CarHireController
{
[Route("{location}/{page:int=1}", Name = "CarHireLocation")]
public ActionResult Index(string country, string location, int page)
{
return Index(country, location, null, page);
}
[Route("{location}/{subLocation}/{page:int=1}", Name = "CarHireSubLocation")]
public ActionResult Index(string country, string location, string subLocation, int page)
{
//The main work goes here
}
}
These actions will take care of urls like /cars/usa/new-york and /cars/usa/texas/dallas, which will map to the first and second Index actions respectively.
Examining this example controller it's evident that it goes beyond the default route pattern mentioned above. The default works well if your url structure exactly matches your code naming conventions, but this is not always the case. Code should be descriptive of the domain, but urls often need to go further because their content should be based on other criteria, such as SEO requirements.
The benefit of the default routing pattern is that it automatically creates unique routes. This is enforced by the compiler since urls will match unique controller types and members. Rolling your own route patterns will require careful thought to ensure uniqueness and that they work.
Important note The one drawback is that using routing to generate urls for overloaded actions does not work when based on an action name, e.g., when using UrlHelper.Action. But it does work if one uses named routes, e.g., UrlHelper.RouteUrl. And using named routes is, according to well respected sources, the way to go anyhow (http://haacked.com/archive/2010/11/21/named-routes-to-the-rescue.aspx/).
Good luck!
You can use [ActionName("NewActionName")] to use the same method with a different name:
public class HomeController : Controller
{
public ActionResult GetEmpName()
{
return Content("This is the test Message");
}
[ActionName("GetEmpWithCode")]
public ActionResult GetEmpName(string EmpCode)
{
return Content("This is the test Messagewith Overloaded");
}
}
I needed an overload for:
public ActionResult Index(string i);
public ActionResult Index(int groupId, int itemId);
There were few enough arguments where I ended up doing this:
public ActionResult Index(string i, int? groupId, int? itemId)
{
if (!string.IsNullOrWhitespace(i))
{
// parse i for the id
}
else if (groupId.HasValue && itemId.HasValue)
{
// use groupId and itemId for the id
}
}
It's not a perfect solution, especially if you have a lot of arguments, but it works well for me.
I have faced same issue in my application too. Without Modifiyig any Method information, I have provided [ActionName("SomeMeaningfulName")] on Action head. issue resolved
[ActionName("_EmployeeDetailsByModel")]
public PartialViewResult _EmployeeDetails(Employee model)
{
// Some Operation
return PartialView(model);
}
}
[ActionName("_EmployeeDetailsByModelWithPagination")]
public PartialViewResult _EmployeeDetails(Employee model,int Page,int PageSize)
{
// Some Operation
return PartialView(model);
}
Create the base method as virtual
public virtual ActionResult Index()
Create the overridden method as override
public override ActionResult Index()
Edit: This obviously applies only if the override method is in a derived class which appears not to have been the OP's intention.
I like this answer posted in another thread
This is mainly used if you inherit from another controller and want to override an acction from the base controller
ASP.NET MVC - Overriding an action with differing parameters
There is only one public signature allowed for each controller method. If you try to overload it, it will compile, but you're getting the run-time error you've experienced.
If you're not willing to use different verbs (like the [HttpGet] and [HttpPost] attributes) to differentiate overloaded methods (which will work), or change the routing, then what remains is that you can either provide another method with a different name, or you can dispatch inside of the existing method. Here's how I did it:
I once came into a situation where I had to maintain backwards compatibility. The original method expected two parameters, but the new one had only one. Overloading the way I expected did not work because MVC didn't find the entry point any more.
To solve that, I did the following:
Changed the 2 overloaded action methods from public to private
Created one new public method which contained "just" 2 string parameters. That one acted as a dispatcher, i.e.:
public ActionResult DoSomething(string param1, string param2)
{
if (string.IsNullOrEmpty(param2))
{
return DoSomething(ProductName: param1);
}
else
{
int oldId = int.Parse(param1);
return DoSomething(OldParam: param1, OldId: oldId);
}
}
private ActionResult DoSomething(string OldParam, int OldId)
{
// some code here
return Json(result);
}
private ActionResult DoSomething(string ProductName)
{
// some code here
return Json(result);
}
Of course, this is a hack and should be refactored later. But for the time being, it worked for me.
You can also create a dispatcher like:
public ActionResult DoSomething(string action, string param1, string param2)
{
switch (action)
{
case "update":
return UpdateAction(param1, param2);
case "remove":
return DeleteAction(param1);
}
}
You can see, that UpdateAction needs 2 parameters, while DeleteAction just needs one.
Sorry for the delay. I was with the same problem and I found a link with good answers, could that will help new guys
All credits for BinaryIntellect web site and the authors
Basically, there are four situations: using differents verbs, using routing, overload marking with [NoAction] attribute and change the action attribute name with [ActionName]
So, depends that's your requiriments and your situation.
Howsoever, follow the link:
Link:
http://www.binaryintellect.net/articles/8f9d9a8f-7abf-4df6-be8a-9895882ab562.aspx
This answer for those who struggling with the same issue. You can
implement your own custom filter based on
ActionMethodSelectorAttribute. Here I found the best solution
for solving your question. Works fine on .net 5 project.
If you try to implement the same logic as was in web api controllers then use Microsoft.AspNetCore.Mvc.WebApiCompatShim. This nuget package provides compatibility in ASP.NET Core MVC with ASP.NET Web API 2 to simplify migration of existing Web API implementations. Please check this answer but consider that
starting with ASP.NET Core 3.0, the Microsoft.AspNetCore.Mvc.WebApiCompatShim package is no longer available.
If this is an attempt to use one GET action for several views that POST to several actions with different models, then try add a GET action for each POST action that redirects to the first GET to prevent 404 on refresh.
Long shot but common scenario.

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