Returning http status code from Web Api controller

Question

I m trying to return a status code of 304 not modified for a GET method in a web api controller     The only way I succeeded was something like this     public class TryController   ApiController         public User GetUser int userId  DateTime lastModifiedAtClient                  var user   new DataEntities   Users First p   gt  p Id    userId            if  user LastModified  lt   lastModifiedAtClient                           throw new HttpResponseException HttpStatusCode NotModified                       return user                 The problem here is that it s not an exception  It s just not modified so the client cache is OK   I also want the return type to be a User  as all the web api examples shows with GET  not return HttpResponseMessage or something like this

User · Accepted Answer

I did not know the answer so asked the ASP.NET team here.

So the trick is to change the signature to HttpResponseMessage and use Request.CreateResponse.

[ResponseType(typeof(User))]
public HttpResponseMessage GetUser(HttpRequestMessage request, int userId, DateTime lastModifiedAtClient)
{
    var user = new DataEntities().Users.First(p => p.Id == userId);
    if (user.LastModified <= lastModifiedAtClient)
    {
         return new HttpResponseMessage(HttpStatusCode.NotModified);
    }
    return request.CreateResponse(HttpStatusCode.OK, user);
}

User · Answer

You can also do the following if you want to preserve the action signature as returning User   public User GetUser int userId  DateTime lastModifiedAtClient     If you want to return something other than 200 then you throw an HttpResponseException in your action and pass in the HttpResponseMessage you want to send to the client

User · Answer

public HttpResponseMessage Post Article article        HttpResponseMessage response   Request CreateResponse lt Article gt  HttpStatusCode Created  article        string uriToTheCreatedItem   Url Route null  new   id   article Id         response Headers Location   new Uri Request RequestUri  uriToTheCreatedItem        return response

User · Answer

An update to  Aliostads answer using the more moden IHttpActionResult introduced in Web API 2   https   docs microsoft com en-us aspnet web-api overview getting-started-with-aspnet-web-api action-results ihttpactionresult  public class TryController   ApiController       public IHttpActionResult GetUser int userId  DateTime lastModifiedAtClient                var user   new DataEntities   Users First p   gt  p Id    userId           if  user LastModified  lt   lastModifiedAtClient                        return StatusCode HttpStatusCode NotModified                  If you would like to return a Http Status code with any object instead                 return Content HttpStatusCode InternalServerError   My Message                      return Ok user

User · Answer

net core 2 2 returning 304 status code  This is using an ApiController        HttpGet      public ActionResult lt YOUROBJECT gt  Get                 return StatusCode 304           Optionally you can return an object with the response       HttpGet      public ActionResult lt YOUROBJECT gt  Get                 return StatusCode 304  YOUROBJECT

User · Answer

I hate bumping old articles but this is the first result for this in google search and I had a heck of a time with this problem  even with the support of you guys   So here goes nothing     Hopefully my solution will help those that also was confused   namespace MyApplication WebAPI Controllers       public class BaseController   ApiController               public T SendResponse lt T gt  T response  HttpStatusCode statusCode   HttpStatusCode OK                        if  statusCode    HttpStatusCode OK                                   leave it up to microsoft to make this way more complicated than it needs to be                    seriously i used to be able to just set the status and leave it at that but nooo    now                     i need to throw an exception                  var badResponse                       new HttpResponseMessage statusCode                                                Content    new StringContent JsonConvert SerializeObject response   Encoding UTF8   application json                                           throw new HttpResponseException badResponse                             return response                      and then just inherit from the BaseController    RoutePrefix  api devicemanagement    public class DeviceManagementController   BaseController        and then using it   HttpGet   Route  device search  property   value     public SearchForDeviceResponse SearchForDevice string property  string value          todo  limit search property here      var response   new SearchForDeviceResponse         var results    deviceManagementBusiness SearchForDevices property  value        response Success   true      response Data   results       var statusCode   results    null     results Any     HttpStatusCode NoContent   HttpStatusCode OK       return SendResponse response  statusCode

User · Answer

In MVC 5  things got easier   return new StatusCodeResult HttpStatusCode NotModified  this

User · Answer

Another option   return new NotModified        public class NotModified   IHttpActionResult       public Task lt HttpResponseMessage gt  ExecuteAsync CancellationToken cancellationToken                var response   new HttpResponseMessage HttpStatusCode NotModified           return Task FromResult response

User · Answer

I don t like having to change my signature to use the HttpCreateResponse type  so I came up with a little bit of an extended solution to hide that   public class HttpActionResult   IHttpActionResult       public HttpActionResult HttpRequestMessage request    this request  HttpStatusCode OK                   public HttpActionResult HttpRequestMessage request  HttpStatusCode code    this request  code  null                   public HttpActionResult HttpRequestMessage request  HttpStatusCode code  object result                Request   request          Code   code          Result   result             public HttpRequestMessage Request   get        public HttpStatusCode Code   get        public object Result   get         public Task lt HttpResponseMessage gt  ExecuteAsync CancellationToken cancellationToken                return Task FromResult Request CreateResponse Code  Result              You can then add a method to your ApiController  or better your base controller  like this   protected IHttpActionResult CustomResult HttpStatusCode code  object data            Request here is the property on the controller      return new HttpActionResult Request  code  data       Then you can return it just like any of the built in methods    HttpPost  public IHttpActionResult Post Model model        return model Id    1                   Ok                     CustomResult HttpStatusCode NotAcceptable  new                        data   model                       error    The ID needs to be 1

User · Answer

If you need to return an IHttpActionResult and want to return the error code plus a message  use   return ResponseMessage Request CreateErrorResponse HttpStatusCode NotModified   Error message here

User · Answer

For ASP NET Web Api 2  this post from MS suggests to change the method s return type to IHttpActionResult  You can then return a built in IHttpActionResult implementation like Ok  BadRequest  etc  see here  or return your own implementation   For your code  it could be done like   public IHttpActionResult GetUser int userId  DateTime lastModifiedAtClient        var user   new DataEntities   Users First p   gt  p Id    userId       if  user LastModified  lt   lastModifiedAtClient                return StatusCode HttpStatusCode NotModified             return Ok user

User · Answer

Change the GetXxx API method to return HttpResponseMessage and then return a typed version for the full response and the untyped version for the NotModified response       public HttpResponseMessage GetComputingDevice string id                ComputingDevice computingDevice                db Devices OfType lt ComputingDevice gt                     SingleOrDefault c   gt  c AssetId    id            if  computingDevice    null                        return this Request CreateResponse HttpStatusCode NotFound                      if  this Request ClientHasStaleData computingDevice ModifiedDate                         return this Request CreateResponse lt ComputingDevice gt                   HttpStatusCode OK  computingDevice                     else                       return this Request CreateResponse HttpStatusCode NotModified                      The ClientHasStale data is my extension for checking ETag and IfModifiedSince headers   The MVC framework should still serialize and return your object   NOTE  I think the generic version is being removed in some future version of the Web API

User · Answer

Try this    return new ContentResult          StatusCode   404       Content    Not found

User · Answer

I know there are several good answers here but this is what I needed so I figured I d add this code in case anyone else needs to return whatever status code and response body they wanted in 4 7 x with webAPI  public class DuplicateResponseResult lt TResponse gt    IHttpActionResult       private TResponse  response      private HttpStatusCode  statusCode      private HttpRequestMessage  httpRequestMessage      public DuplicateResponseResult HttpRequestMessage httpRequestMessage  TResponse response  HttpStatusCode statusCode                 httpRequestMessage   httpRequestMessage           response   response           statusCode   statusCode             public Task lt HttpResponseMessage gt  ExecuteAsync CancellationToken cancellationToken                var response   new HttpResponseMessage  statusCode           return Task FromResult  httpRequestMessage CreateResponse  statusCode   response

[c#] Returning http status code from Web Api controller

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