Attribute Routing Fail in Web API 2 - asp.net

Why does the third route fail in my Web API ?
public class StudentCourseController : ApiController
{
// GET api/student
public IEnumerable<StudentCourse> Get()
{
return StudentCourseRepository.GetAll();
}
// GET api/student/5
public StudentCourse Get(int id)
{
return StudentCourseRepository.GetAll().FirstOrDefault(s => s.Id == id);
}
[Route("StudentAuto/{key}")] // Does not work
public IEnumerable<Student> StudentAuto(string key)
{
return StudentRepository.GetStudentsAuto(key);
}
When i request http://localhost:5198/api/StudentCourse/StudentAuto/mi I get a 404 error.
The detail error shows
Requested URL http://localhost:5198/api/StudentCourse/StudentAuto/mi
Physical Path C:\Users\deb\Desktop\StudentKO\KnockoutMVC\KnockoutMVC\api\StudentCourse\StudentAuto\mi
Logon Method Anonymous
Logon User Anonymous
Did i miss anything ?
thanks

Attribute routing on a method does not work in conjunction with the route constraints for the controller you put into your startup, e.g. "/api/{controller}".
Therefore your [Route("StudentAuto/{key}")] route literally maps to "/StudentAuto/{key}", not "/api/StudentCourse/StudentAuto/{key}".
You can get this to work as you want by adding a [RoutePrefix] (see msdn) to your controller:
[RoutePrefix("api/StudentCourse")]
public class StudentCourseController : ApiController
{
}
Alternatively just set the whole path in your Route attribute:
[Route("api/StudentCourse/StudentAuto/{key}")]
public IEnumerable<Student> StudentAuto(string key)
{
return StudentRepository.GetStudentsAuto(key);
}

Related

ASP.NET Core Web API: Routing by method name?

I remember from ASP.NET Web API that it's sufficient to prefix Web API REST method names with HTTP commands (e.g. GetList() => HTTP GET, Delete() => HTTP DELETE) to have incoming calls appropriately routed.
I also remember that in ASP.NET Web API parameter matching takes place so that even Get(int id) and Get(int id, string name) get automatically and appropriately routed without requiring any attributes.
public class MyController
{
public ActionResult Get(int id) => ...
public ActionResult Get(int id, string name) => ...
public ActionResult DeleteItem(int id) => ...
}
Isn't this all available in ASP.NET Web API Core?
You just need to add the Route to the top of your controller.
Specify the route with api, controller and action:
[Route("api/[controller]/[action]")]
[ApiController]
public class AvailableRoomsController : ControllerBase
{
...
}
Neither could we do action overloads nor prefix action name as Http verb.The way routing works in ASP.NET Core is different than how it did in ASP.NET Web Api.
However, you can simply combine these actions and then branch inside, since all params are optional if you send as querystring
[HttpGet]
public ActionResult<string> Get(int id, string name)
{
if(name == null){..}
else{...}
}
Or you need to use attribute routing to specify each api if you send in route data:
[HttpGet("{id}")]
public ActionResult<string> Get(int id)
{
return "value";
}
[HttpGet("{id}/{name}")]
public ActionResult<string> Get(int id, string name)
{
return name;
}
Refer to Attribute Routing,Web Api Core 2 distinguishing GETs
The aspnetcore webapi controllers do not natively support inference of http verbs by naming convention, but allow you to create your own convention and achieve this behavior.
Create your convention
public class MyConvention : IApplicationModelConvention
{
public void Apply(ApplicationModel application)
{
foreach(var controller in application.Controllers)
{
foreach(var action in controller.Actions)
{
if (action.ActionName.StartsWith("Post"))
{
action.Selectors.First().ActionConstraints.Add(new HttpMethodActionConstraint(new[]{ "POST" }));
}
}
}
}
}
Then register it in Program/Startup:
builder.Services.AddControllers(configure => configure.Conventions.Insert(0, new MyConvention()));
This is available for Core 2 yes, but the way that I know how to do it is something like this
[Route("api/[controller]")]
[ApiController]
public class AvailableRoomsController : ControllerBase
{
private readonly ApplicationContext _context;
public AvailableRoomsController(ApplicationContext context)
{
_context = context;
}
// GET: api/AvailableRooms
[HttpGet]
public async Task<ActionResult<IEnumerable<AvailableRoom>>> GetAvailableRooms()
{
return await _context.AvailableRooms.ToListAsync();
}
// POST: api/AvailableRooms
[HttpPost]
public async Task<ActionResult<AvailableRoom>> PostAvailableRoom(AvailableRoom availableRoom)
{
_context.AvailableRooms.Add(availableRoom);
await _context.SaveChangesAsync();
return CreatedAtAction("GetAvailableRoom", new { id = availableRoom.Id }, availableRoom);
}
[HttpPut] .... etc
}
Now depending on what kind of REST action you specify and what type of model you send to "api/AvailableRooms" if the proper Action exists it will be chosen.
Visual Studio 2019 and I think 2017 can create a controller such as this automatically if you right click your Controllers folder and click Add->Controller and then choose "API Controller with actions, using Entity Framework" and choose one of your Model classes.

problem in httpdelete request asp.net core 2

Hello i am working on asp.net core 2.2 web api , my get request is working fine but i am having problem in HTTPDELETE request, my code for the delete request is as follows
[Route("api/[controller]")]
[ApiController]
public class PatientController : ControllerBase
{
IPatientManager _patientManager;
IEnumerable<Patient> patientList;
public PatientController(IPatientManager patientManager)
{
_patientManager = patientManager;
}
[HttpGet]
public IEnumerable<Patient> Get()
{
return (patientList = _patientManager.GetAllPatients());
}
// DELETE api/values/5
[HttpDelete("api/Patient/{id}")]
public bool Delete(long id)
{
if (_patientManager.DeletePatient(id))
return true;
else
return false;
}
}
}
when i put the request in URL as localhost:3, n922/api/Patient/444373 it gives me HTTP ERROR 404 , my startup.cs file is using the below code for MapRoute
app.UseMvc(opt =>
{
opt.MapRoute("Default",
"{controller=Patient}/{action=Get}/{id?}");
});
to start the my PatientController instead of ValuesController, Please help what is problem where i am doing wrong? TIA
You have a route prefix defined on your controller as api/[controller], which translates to /api/Patient. Then, your route on your action is defined as api/Patient/{id}, which makes the entire route to this action: /api/Patient/api/Patient/{id}. That's obviously not right and is the source of your 404. Change the route to just {id}.
[HttpDelete("{id}")]
public bool Delete(long id)

How to rewrite code to use IAuthorizationFilter with dependency injection instead of AuthorizeAttribute with service location in Asp Net Web Api?

I have the custom AuthorizeAttribute where I need to use one of the business layer services to validate some data in the database before giving user a permission to view the resource. In order to be able to allocate this service within the my AuthorizeAttribute I decided to use service location "anti-pattern", this is the code:
internal class AuthorizeGetGroupByIdAttribute : AuthorizeAttribute
{
private readonly IUserGroupService _userGroupService;
public AuthorizeGetGroupByIdAttribute()
{
_userGroupService = ServiceLocator.Instance.Resolve<IUserGroupService>();
}
//In this method I'm validating whether the user is a member of a group.
//If they are not they won't get a permission to view the resource, which is decorated with this attribute.
protected override bool IsAuthorized(HttpActionContext actionContext)
{
Dictionary<string, string> parameters = actionContext.Request.GetQueryNameValuePairs().ToDictionary(x => x.Key, x => x.Value);
int groupId = int.Parse(parameters["groupId"]);
int currentUserId = HttpContext.Current.User.Identity.GetUserId();
return _userGroupService.IsUserInGroup(currentUserId, groupId);
}
protected override void HandleUnauthorizedRequest(HttpActionContext actionContex)
{
if (!HttpContext.Current.User.Identity.IsAuthenticated)
{
base.HandleUnauthorizedRequest(actionContex);
}
else
{
actionContex.Response = new HttpResponseMessage(HttpStatusCode.Forbidden);
}
}
}
I have couple of other attributes like this in my application. Using service locator is probably not a good approach. After searching the web a little bit I found some people suggesting to use IAuthorizationFilter with dependency injection instead. But I don't know how to write this kind of IAuthorizationFilter. Can you help me writing IAuthorizationFilter that will do the same thing that the AuthorizeAttribute above?
So after struggling for a while I think I managed to resolve this issue. Here are the steps you have to do in order to that:
1) First you have to make GetGroupByIdAttribute passive, and by passive I mean an empty attribute without any logic within it (it will be used strictly for decoration purposes)
public class GetGroupByIdAttribute : Attribute
{
}
2) Then you have to mark a controller method, for which you want to add authorization, with this attribute.
[HttpPost]
[GetGroupById]
public IHttpActionResult GetGroupById(int groupId)
{
//Some code
}
3) In order to write your own IAuthorizationFilter you have to implement its method ExecuteAuthorizationFilterAsync. Here is the full class (I included comments to guide you through the code):
public class GetGroupByIdAuthorizationFilter : IAuthorizationFilter
{
public bool AllowMultiple { get; set; }
private readonly IUserGroupService _userGroupService;
//As you can see I'm using a constructor injection here
public GetGroupByIdAuthorizationFilter(IUserGroupService userGroupService)
{
_userGroupService = userGroupService;
}
public Task<HttpResponseMessage> ExecuteAuthorizationFilterAsync(HttpActionContext actionContext, CancellationToken cancellationToken, Func<Task<HttpResponseMessage>> continuation)
{
//First I check whether the method is marked with the attribute, if it is then check whether the current user has a permission to use this method
if (actionContext.ActionDescriptor.GetCustomAttributes<GetGroupByIdAttribute>().SingleOrDefault() != null)
{
Dictionary<string, string> parameters = actionContext.Request.GetQueryNameValuePairs().ToDictionary(x => x.Key, x => x.Value);
int groupId = int.Parse(parameters["groupId"]);
int currentUserId = HttpContext.Current.User.Identity.GetUserId();
//If the user is not allowed to view view the resource, then return 403 status code forbidden
if (!_userGroupService.IsUserInGroup(currentUserId, groupId))
{
return Task.FromResult(new HttpResponseMessage(HttpStatusCode.Forbidden));
}
}
//If this line was reached it means the user is allowed to use this method, so just return continuation() which basically means continue processing
return continuation();
}
}
4) The last step is to register your filter in the WebApiConfig.
public static class WebApiConfig
{
public static void Register(HttpConfiguration config)
{
// Here I am registering Dependency Resolver
config.DependencyResolver = ServiceLocator.Instance.DependencyResolver;
//Then I resolve the service I want to use (which should be fine because this is basically the start of the application)
var userGroupService = ServiceLocator.Instance.Resolve<IUserGroupService>();
//And finally I'm registering the IAuthorizationFilter I created
config.Filters.Add(new GetGroupByIdAuthorizationFilter(userGroupService));
// Web API routes
config.MapHttpAttributeRoutes();
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{action}/{id}",
defaults: new { id = RouteParameter.Optional }
);
}
}
Now, if needed, I can create additional IActionFilters that use IUserGroupService and then inject this service at the start of the application, from WebApiConfig class, into all filters.
Perhaps try it like shown here:
Add the following public method to your class.
public IFilterMetadata CreateInstance(IServiceProvider serviceProvider)
{
// gets the dependecies from the serviceProvider
// and creates an instance of the filter
return new GetGroupByIdAuthorizationFilter(
(IUserGroupService )serviceProvider.GetService(typeof(IUserGroupService )));
}
Also Add interface IFilterMetadata to your class.
Now when your class is to be created the DI notices that there is a CreateInstance method and will use that rather then the constructor.
Alternatively you can get the interface directly from the DI in your method by calling
context.HttpContext.Features.Get<IUserGroupService>()

Authorization has been denied for this request error when running webapi in MVC project

I have created an ASP.Net MVC project with WebApi option. Then modified the values controller with the code below:
public class ValuesController : ApiController
{
static List<string> data = initList();
private static List<string> initList()
{
var ret = new List<string>();
ret.Add("value1");
ret.Add( "value2" );
return ret;
}
// GET api/values
public IEnumerable<string> Get()
{
return data ;
}
// GET api/values/5
public string Get(int id)
{
return data[id];
}
// POST api/values
public void Post([FromBody]string value)
{
data.Add(value);
}
// PUT api/values/5
public void Put(int id, [FromBody]string value)
{
data[id] = value;
}
// DELETE api/values/5
public void Delete(int id)
{
data.RemoveAt(id);
}
}
When I am running the project and navigating to API/values URL, the following image is showing error.
.
The error description in text is:
<Error>
Authorization has been denied for this request.
</Error>
Have a look at the following article about
Authentication and Authorization in ASP.NET Web API
It will explain the different ways of how to use the [Authorize] and [AllowAnonymous] attribute on your controller/actions and any configurations you would need to do.
The following was taken from the linked article above:
Using the [Authorize] Attribute
Web API provides a built-in authorization filter,
AuthorizeAttribute. This filter checks whether the user is
authenticated. If not, it returns HTTP status code 401 (Unauthorized),
without invoking the action.
You can apply the filter globally, at the controller level, or at the
level of inidivual actions.
Globally: To restrict access for every Web API controller, add the
AuthorizeAttribute filter to the global filter list:
public static void Register(HttpConfiguration config){
config.Filters.Add(new AuthorizeAttribute());
}
Controller: To restrict access for a specific controller, add the
filter as an attribute to the controller:
// Require authorization for all actions on the controller.
[Authorize]
public class ValuesController : ApiController
{
public HttpResponseMessage Get(int id) { ... }
public HttpResponseMessage Post() { ... }
}
Action: To restrict access for specific actions, add the attribute to
the action method:
public class ValuesController : ApiController
{
public HttpResponseMessage Get() { ... }
// Require authorization for a specific action.
[Authorize]
public HttpResponseMessage Post() { ... }
}
Alternatively, you can restrict the controller and then allow
anonymous access to specific actions, by using the [AllowAnonymous]
attribute. In the following example, the Post method is restricted,
but the Get method allows anonymous access.
[Authorize]
public class ValuesController : ApiController {
[AllowAnonymous]
public HttpResponseMessage Get() { ... }
public HttpResponseMessage Post() { ... }
}
In the previous examples, the filter allows any authenticated user to
access the restricted methods; only anonymous users are kept out. You
can also limit access to specific users or to users in specific roles:
// Restrict by user:
[Authorize(Users="Alice,Bob")]
public class ValuesController : ApiController
{
}
// Restrict by role:
[Authorize(Roles="Administrators")]
public class ValuesController : ApiController
{
}
So, I've been dealing with this error for awhile.
I didn't understand it at first, so I just removed and lived with it.
I finally got sick of it, because it's rather stupid. Microsoft wants a user to be authorized before they have signed in.
My error was looking for GET method which asks for HomeTown. In my case, I had changed it to CityCode.
Since the user is not logged in, there is no CityCode to GET. So, you get either a 402 or a 500 Resource Not Found.
I still don't understand it so, I gave CityCode some default data. So, from MeController I put the following code:
Public Function [Get]() As GetViewModel
Dim userInfo As ApplicationUser = UserManager.FindById(User.Identity.GetUserId())
Return New GetViewModel() With {.CityCode = "94110"}
End Function
App loads completely error free now.
This is a quick fix, not a certified solution.

Route all Web API requests to one controller method

Is it possible to customize ASP.NET Web API's routing mechanism to route all requests to the API to one controller method?
If a request comes in to
www.mysite.com/api/products/
or
www.mysite.com/api/otherResource/7
All would be routed to my SuperDuperController's Get() method?
I ran into a case where I needed to do this. (Web API 2)
I first looked into creating custom IHttpControllerSelector and IHttpActionSelectors. However, that was a bit of a murky way around. So I finally settled on this dead simple implementation. All you have to do is setup a wildcard route. Example:
public class SuperDuperController : ApiController
{
[Route("api/{*url}")]
public HttpResponseMessage Get()
{
// url information
Request.RequestUri
// route values, including "url"
Request.GetRouteData().Values
}
}
Any GET request that starts with "api/" will get routed to the above method. That includes the above mentioned URLs in your question. You will have to dig out information from the Request or context objects yourself since this circumvents automatic route value and model parsing.
The good thing about this is you can still use other controllers as well (as long as their routes don't start with "api/").
I don't konw why you would want to do this and I certainly wouldn't recommend routing everything through one controller, however you could achieve this as follows. Assuming you are only ever going to have a resource with an optional id in your calls, add this to your WebApiConfig:
public static class WebApiConfig
{
public static void Register(HttpConfiguration config)
{
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{resource}/{id}",
defaults: new { controller = "SuperDuper", id = RouteParameter.Optional }
);
}
}
Then define your controller method as follows:
public class SuperDuperController : ApiController
{
public IHttpActionResult Get(string resource, int? id = null)
{
return Ok();
}
}
You would need to decide on an appropriate IHttpActionResult to return for each different type of resource.
Alternatively using Attribute Routing, ensure that config.MapHttpAttributeRoutes() is present in your WebApiConfig and add the following attributes to your controller method:
[RoutePrefix("api")]
public class SuperDuperController : ApiController
{
[Route("{resource}/{id?}")]
public IHttpActionResult Get(string resource, int? id = null)
{
return Ok();
}
}

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