I am creating REST Services. Here I want to create a Post service. Data is inserted into a database, but in response I got this error
UrlHelper.Link must not return null..
My Code
[HttpPost]
[Route("api/CourseRegistrations")]
[ResponseType(typeof(CourseRegistration))]
public IHttpActionResult PostCourseRegistration(CourseRegistration courseRegistration)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
db.CourseRegistrations.Add(courseRegistration);
db.SaveChanges();
return CreatedAtRoute("DefaultApi", new { id = courseRegistration.course_id }, courseRegistration);
}
I assumed you're using default setting inside WebApiConfig class in App_Start folder like this:
public static class WebApiConfig {
public static void Register(HttpConfiguration config) {
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = RouteParameter.Optional }
);
}
}
Thus it is necessary to provide controller name parameter in CreatedAtRoute method, as in example below:
return CreatedAtRoute("DefaultApi", new { controller = "ApiControllerName", id = courseRegistration.course_id }, courseRegistration);
However, since RouteAttribute is present, it indicates that attribute routing is enabled, then you should provide route name for GET route with proper parameter name and then set POST route as shown in example below:
// GET method
[HttpGet]
[Route("api/CourseRegistrations/{id}", Name = "GetCourseRegistrationById")]
[ResponseType(typeof(CourseRegistration))]
public IHttpActionResult GetCourseRegistration(int id)
{
// do something
}
// POST method
[HttpPost]
[Route("api/CourseRegistrations")]
public IHttpActionResult PostCourseRegistration(CourseRegistration courseRegistration)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
db.CourseRegistrations.Add(courseRegistration);
db.SaveChanges();
// replace 'DefaultApi' with route name for redirect to GET method
return CreatedAtRoute("GetCourseRegistrationById", new { id = courseRegistration.course_id }, courseRegistration);
}
Note:
1) The parameter name contained inside CreatedAtRoute must match with target parameter name used in action method, otherwise the UrlHelper.Link() method will return null.
2) The route name in RouteAttribute should be different from action method name to avoid confusion.
Reference:
Attribute Routing in ASP.NET Web API 2: Route Names
Related issue:
Attribute Routing and CreatedAtRoute
http://localhost:2000/api/{Controller}
I need to create index page.
URI : http://localhost:2000/api
config.MapHttpAttributeRoutes();
config.Routes.MapHttpRoute(
name: "api",
routeTemplate: "api"
);
And the api
[RoutePrefix("api")]
public class Api
{
[HttpGet]
public HttpResponseMessage Get()
{
var result = new HttpResponseMessage(HttpStatusCode.OK);
result.Content = new ByteArrayContent(Encoding.ASCII.GetBytes("API"));
return result;
}
}
But when I open http://localhost:2000/api, it's not working.
No HTTP resource was found that matches the request URI http://localhost:2000/api.
Need to make sure you follow the suggested syntax for API controllers.
[RoutePrefix("api")]
public class MyApiController: ApiController {
[HttpGet]
[Route("")] // GET api
public IHttpActionResult Get() {
return Ok("API");
}
}
Which includes having your controller derived from ApiController.
If using attribute routing with route prefix you still need to provide a route on the action.
[Route("")] in this case above will act as the default rout for that controller.
I'm trying to get this method to work:
public class DocumentenController : ApiController
{
[HttpPost]
[Route("DeleteDocument/{name}/{planId}")]
public IHttpActionResult DeleteDocument(string name, int planId)
{
_documentenProvider.DeleteDocument(planId, name);
return Ok();
}
}
This is the WebApiConfig :
config.MapHttpAttributeRoutes();
config.Routes.MapHttpRoute(
name: "ActionApi",
routeTemplate: UrlPrefix + "/{controller}/{action}/{id}",
defaults: new {id = RouteParameter.Optional}
);
But I get a 404 when I call it like this using a post:
http://localhost/QS-documenten/api/documenten/deletedocument/testing/10600349
What is the proper way do solve this?
The URL in example does not match attribute route on controller.
To get
http://localhost/QS-documenten/api/documenten/deletedocument/testing/10600349
to work, assuming that http://localhost/QS-documenten is the host and root folder, and that api/documenten is the api prefix then add a route prefix to the controller...
[RoutePrefix("api/Documenten")]
public class DocumentenController : ApiController {
//eg POST api/documenten/deletedocument/testing/10600349
[HttpPost]
[Route("DeleteDocument/{name}/{planId}")]
public IHttpActionResult DeleteDocument(string name, int planId) {
_documentenProvider.DeleteDocument(planId, name);
return Ok();
}
}
Source: Attribute Routing in ASP.NET Web API 2 : Route Prefixes
You must send your request as follows:
http://localhost/QS-documenten/deletedocument/testing/10600349
When you use route attribute, the custom route override default api routing configuration.
Refer to the official ASP.NET attribute routing documentation, it seems that Route attribute can be used without RoutePrefix.
But, in my webapi controller, below cases are happened.
1. Not working. (error: No matched http route found)
public class GroupController : ApiController
{
[Route("api/group/{id}/register")]
public IHttpActionResult Post(int id, InputModel model)
{
return Ok();
}
}
2. Working good.
[RoutePrefix("api/group")]
public class GroupController : ApiController
{
[Route("{id}/register")]
public IHttpActionResult Post(int id, InputModel model)
{
return Ok();
}
}
Is it right that Route attribute should be used with RoutePrefix, or what am I missing?
In addition, below code is my WebApi route config in WebApiConfig.Register class.
// Web API routes
config.MapHttpAttributeRoutes();
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}/{subId}",
defaults: new { id = RouteParameter.Optional, subId = RouteParameter.Optional }
);
I'm converting from the WCF Web API to the new ASP.NET MVC 4 Web API. I have a UsersController, and I want to have a method named Authenticate. I see examples of how to do GetAll, GetOne, Post, and Delete, however what if I want to add extra methods into these services? For instance, my UsersService should have a method called Authenticate where they pass in a username and password, however it doesn't work.
public class UsersController : BaseApiController
{
public string GetAll()
{
return "getall!";
}
public string Get(int id)
{
return "get 1! " + id;
}
public User GetAuthenticate(string userName, string password, string applicationName)
{
LogWriter.Write(String.Format("Received authenticate request for username {0} and password {1} and application {2}",
userName, password, applicationName));
//check if valid leapfrog login.
var decodedUsername = userName.Replace("%40", "#");
var encodedPassword = password.Length > 0 ? Utility.HashString(password) : String.Empty;
var leapFrogUsers = LeapFrogUserData.FindAll(decodedUsername, encodedPassword);
if (leapFrogUsers.Count > 0)
{
return new User
{
Id = (uint)leapFrogUsers[0].Id,
Guid = leapFrogUsers[0].Guid
};
}
else
throw new HttpResponseException("Invalid login credentials");
}
}
I can browse to myapi/api/users/ and it will call GetAll and I can browse to myapi/api/users/1 and it will call Get, however if I call myapi/api/users/authenticate?username={0}&password={1} then it will call Get (NOT Authenticate) and error:
The parameters dictionary contains a null entry for parameter 'id' of non-nullable type 'System.Int32' for method 'System.String Get(Int32)' in 'Navtrak.Services.WCF.NavtrakAPI.Controllers.UsersController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter.
How can I call custom method names such as Authenticate?
By default the route configuration follows RESTFul conventions meaning that it will accept only the Get, Post, Put and Delete action names (look at the route in global.asax => by default it doesn't allow you to specify any action name => it uses the HTTP verb to dispatch). So when you send a GET request to /api/users/authenticate you are basically calling the Get(int id) action and passing id=authenticate which obviously crashes because your Get action expects an integer.
If you want to have different action names than the standard ones you could modify your route definition in global.asax:
Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{action}/{id}",
defaults: new { action = "get", id = RouteParameter.Optional }
);
Now you can navigate to /api/users/getauthenticate to authenticate the user.
This is the best method I have come up with so far to incorporate extra GET methods while supporting the normal REST methods as well. Add the following routes to your WebApiConfig:
routes.MapHttpRoute("DefaultApiWithId", "Api/{controller}/{id}", new { id = RouteParameter.Optional }, new { id = #"\d+" });
routes.MapHttpRoute("DefaultApiWithAction", "Api/{controller}/{action}");
routes.MapHttpRoute("DefaultApiGet", "Api/{controller}", new { action = "Get" }, new { httpMethod = new HttpMethodConstraint(HttpMethod.Get) });
routes.MapHttpRoute("DefaultApiPost", "Api/{controller}", new {action = "Post"}, new {httpMethod = new HttpMethodConstraint(HttpMethod.Post)});
I verified this solution with the test class below. I was able to successfully hit each method in my controller below:
public class TestController : ApiController
{
public string Get()
{
return string.Empty;
}
public string Get(int id)
{
return string.Empty;
}
public string GetAll()
{
return string.Empty;
}
public void Post([FromBody]string value)
{
}
public void Put(int id, [FromBody]string value)
{
}
public void Delete(int id)
{
}
}
I verified that it supports the following requests:
GET /Test
GET /Test/1
GET /Test/GetAll
POST /Test
PUT /Test/1
DELETE /Test/1
Note That if your extra GET actions do not begin with 'Get' you may want to add an HttpGet attribute to the method.
I am days into the MVC4 world.
For what its worth, I have a SitesAPIController, and I needed a custom method, that could be called like:
http://localhost:9000/api/SitesAPI/Disposition/0
With different values for the last parameter to get record with different dispositions.
What Finally worked for me was:
The method in the SitesAPIController:
// GET api/SitesAPI/Disposition/1
[ActionName("Disposition")]
[HttpGet]
public Site Disposition(int disposition)
{
Site site = db.Sites.Where(s => s.Disposition == disposition).First();
return site;
}
And this in the WebApiConfig.cs
// this was already there
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = RouteParameter.Optional }
);
// this i added
config.Routes.MapHttpRoute(
name: "Action",
routeTemplate: "api/{controller}/{action}/{disposition}"
);
For as long as I was naming the {disposition} as {id} i was encountering:
{
"Message": "No HTTP resource was found that matches the request URI 'http://localhost:9000/api/SitesAPI/Disposition/0'.",
"MessageDetail": "No action was found on the controller 'SitesAPI' that matches the request."
}
When I renamed it to {disposition} it started working. So apparently the parameter name is matched with the value in the placeholder.
Feel free to edit this answer to make it more accurate/explanatory.
Web Api by default expects URL in the form of api/{controller}/{id}, to override this default routing. you can set routing with any of below two ways.
First option:
Add below route registration in WebApiConfig.cs
config.Routes.MapHttpRoute(
name: "CustomApi",
routeTemplate: "api/{controller}/{action}/{id}",
defaults: new { id = RouteParameter.Optional }
);
Decorate your action method with HttpGet and parameters as below
[HttpGet]
public HttpResponseMessage ReadMyData(string param1,
string param2, string param3)
{
// your code here
}
for calling above method url will be like below
http://localhost:[yourport]/api/MyData/ReadMyData?param1=value1¶m2=value2¶m3=value3
Second option
Add route prefix to Controller class and Decorate your action method with HttpGet as below.
In this case no need change any WebApiConfig.cs. It can have default routing.
[RoutePrefix("api/{controller}/{action}")]
public class MyDataController : ApiController
{
[HttpGet]
public HttpResponseMessage ReadMyData(string param1,
string param2, string param3)
{
// your code here
}
}
for calling above method url will be like below
http://localhost:[yourport]/api/MyData/ReadMyData?param1=value1¶m2=value2¶m3=value3
In case you're using ASP.NET 5 with ASP.NET MVC 6, most of these answers simply won't work because you'll normally let MVC create the appropriate route collection for you (using the default RESTful conventions), meaning that you won't find any Routes.MapRoute() call to edit at will.
The ConfigureServices() method invoked by the Startup.cs file will register MVC with the Dependency Injection framework built into ASP.NET 5: that way, when you call ApplicationBuilder.UseMvc() later in that class, the MVC framework will automatically add these default routes to your app. We can take a look of what happens behind the hood by looking at the UseMvc() method implementation within the framework source code:
public static IApplicationBuilder UseMvc(
[NotNull] this IApplicationBuilder app,
[NotNull] Action<IRouteBuilder> configureRoutes)
{
// Verify if AddMvc was done before calling UseMvc
// We use the MvcMarkerService to make sure if all the services were added.
MvcServicesHelper.ThrowIfMvcNotRegistered(app.ApplicationServices);
var routes = new RouteBuilder
{
DefaultHandler = new MvcRouteHandler(),
ServiceProvider = app.ApplicationServices
};
configureRoutes(routes);
// Adding the attribute route comes after running the user-code because
// we want to respect any changes to the DefaultHandler.
routes.Routes.Insert(0, AttributeRouting.CreateAttributeMegaRoute(
routes.DefaultHandler,
app.ApplicationServices));
return app.UseRouter(routes.Build());
}
The good thing about this is that the framework now handles all the hard work, iterating through all the Controller's Actions and setting up their default routes, thus saving you some redundant work.
The bad thing is, there's little or no documentation about how you could add your own routes. Luckily enough, you can easily do that by using either a Convention-Based and/or an Attribute-Based approach (aka Attribute Routing).
Convention-Based
In your Startup.cs class, replace this:
app.UseMvc();
with this:
app.UseMvc(routes =>
{
// Route Sample A
routes.MapRoute(
name: "RouteSampleA",
template: "MyOwnGet",
defaults: new { controller = "Items", action = "Get" }
);
// Route Sample B
routes.MapRoute(
name: "RouteSampleB",
template: "MyOwnPost",
defaults: new { controller = "Items", action = "Post" }
);
});
Attribute-Based
A great thing about MVC6 is that you can also define routes on a per-controller basis by decorating either the Controller class and/or the Action methods with the appropriate RouteAttribute and/or HttpGet / HttpPost template parameters, such as the following:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNet.Mvc;
namespace MyNamespace.Controllers
{
[Route("api/[controller]")]
public class ItemsController : Controller
{
// GET: api/items
[HttpGet()]
public IEnumerable<string> Get()
{
return GetLatestItems();
}
// GET: api/items/5
[HttpGet("{num}")]
public IEnumerable<string> Get(int num)
{
return GetLatestItems(5);
}
// GET: api/items/GetLatestItems
[HttpGet("GetLatestItems")]
public IEnumerable<string> GetLatestItems()
{
return GetLatestItems(5);
}
// GET api/items/GetLatestItems/5
[HttpGet("GetLatestItems/{num}")]
public IEnumerable<string> GetLatestItems(int num)
{
return new string[] { "test", "test2" };
}
// POST: /api/items/PostSomething
[HttpPost("PostSomething")]
public IActionResult Post([FromBody]string someData)
{
return Content("OK, got it!");
}
}
}
This controller will handle the following requests:
[GET] api/items
[GET] api/items/5
[GET] api/items/GetLatestItems
[GET] api/items/GetLatestItems/5
[POST] api/items/PostSomething
Also notice that if you use the two approaches togheter, Attribute-based routes (when defined) would override Convention-based ones, and both of them would override the default routes defined by UseMvc().
For more info, you can also read the following post on my blog.
See this article for a longer discussion of named actions. It also shows that you can use the [HttpGet] attribute instead of prefixing the action name with "get".
http://www.asp.net/web-api/overview/web-api-routing-and-actions/routing-in-aspnet-web-api
Web APi 2 and later versions support a new type of routing, called attribute routing. As the name implies, attribute routing uses attributes to define routes. Attribute routing gives you more control over the URIs in your web API. For example, you can easily create URIs that describe hierarchies of resources.
For example:
[Route("customers/{customerId}/orders")]
public IEnumerable<Order> GetOrdersByCustomer(int customerId) { ... }
Will perfect and you don't need any extra code for example in WebApiConfig.cs.
Just you have to be sure web api routing is enabled or not in WebApiConfig.cs , if not you can activate like below:
// Web API routes
config.MapHttpAttributeRoutes();
You don't have to do something more or change something in WebApiConfig.cs. For more details you can have a look this article.
Just modify your WebAPIConfig.cs as bellow
Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{action}/{id}",
defaults: new { action = "get", id = RouteParameter.Optional });
Then implement your API as bellow
// GET: api/Controller_Name/Show/1
[ActionName("Show")]
[HttpGet]
public EventPlanner Id(int id){}