Return JSON with error status code MVC

Question

I was trying to return an error to the call to the controller as advised in This link so that client can take appropriate action   The controller is called by javascript via jquery AJAX  I am getting the Json object back only if I don t set the status to error  Here is the sample code  if  response errors Length  gt  0     Response StatusCode    int HttpStatusCode BadRequest  return Json response     I get the Json if I don t set the statuscode  If I set the status code I get the status code back but not the Json error object   Update I want to send an Error object as JSON so that it can be handled error callback of ajax

User · Answer

Building on the answer from Richard Garside, here's the ASP.Net Core version

public class JsonErrorResult : JsonResult
{
    private readonly HttpStatusCode _statusCode;

    public JsonErrorResult(object json) : this(json, HttpStatusCode.InternalServerError)
    {
    }

    public JsonErrorResult(object json, HttpStatusCode statusCode) : base(json)
    {
        _statusCode = statusCode;
    }

    public override void ExecuteResult(ActionContext context)
    {
        context.HttpContext.Response.StatusCode = (int)_statusCode;
        base.ExecuteResult(context);
    }

    public override Task ExecuteResultAsync(ActionContext context)
    {
        context.HttpContext.Response.StatusCode = (int)_statusCode;
        return base.ExecuteResultAsync(context);
    }
}

Then in your controller, return as follows:

// Set a json object to return. The status code defaults to 500
return new JsonErrorResult(new { message = "Sorry, an internal error occurred."});

// Or you can override the status code
return new JsonErrorResult(new { foo = "bar"}, HttpStatusCode.NotFound);

User · Answer

You have to return JSON error object yourself after setting the StatusCode  like so      if  BadRequest        Dictionary lt string  object gt  error   new Dictionary lt string  object gt         error Add  ErrorCode   -1       error Add  ErrorMessage    Something really bad happened        return Json error       Another way is to have a JsonErrorModel and populate it  public class JsonErrorModel       public int ErrorCode   get  set        public string ErrorMessage   get  set       public ActionResult SomeMethod          if  BadRequest                var error   new JsonErrorModel                       ErrorCode   -1              ErrorMessage    Something really bad happened                      return Json error               Return valid response     Take a look at the answer here as well

User · Answer

The thing that worked for me  and that I took from another stackoverflow response   is to set the flag   Response TrySkipIisCustomErrors   true

User · Answer

Several of the responses rely on an exception being thrown and having it handled in the OnException override  In my case  I wanted to return statuses such as bad request if the user  say  had passed in a bad ID  What works for me is to use the ControllerContext   var jsonResult   new JsonResult   JsonRequestBehavior   JsonRequestBehavior AllowGet  Data    whoops      ControllerContext HttpContext Response StatusCode    int HttpStatusCode BadRequest   return jsonResult

User · Answer

A simple way to send a error to Json is control Http Status Code of response object and set a custom error message   Controller  public JsonResult Create MyObject myObject         AllFine   return Json new   IsCreated   True  Content   ViewGenerator myObject         Use input may be wrong but nothing crashed   return Json new   IsCreated   False  Content   ViewGenerator myObject           Error   Response StatusCode    int HttpStatusCode InternalServerError    return Json new   IsCreated   false  ErrorMessage    My error message        JS    ajax        type   POST        dataType   json        url   MyController Create        data  JSON stringify myObject        success  function  result           if result IsCreated                   ALL FINE             else                  Use input may be wrong but nothing crashed                  error  function  error                alert  Error     erro responseJSON ErrorMessage      Error

User · Answer

And if your needs aren t as complex as Sarath s you can get away with something even simpler      MyError  public JsonResult Error string objectToUpdate       throw new Exception  ERROR        public class MyErrorAttribute   FilterAttribute  IExceptionFilter      public virtual void OnException ExceptionContext filterContext             if  filterContext    null                   throw new ArgumentNullException  filterContext                  if  filterContext Exception    null                   filterContext ExceptionHandled   true           filterContext HttpContext Response Clear             filterContext HttpContext Response TrySkipIisCustomErrors   true           filterContext HttpContext Response StatusCode    int System Net HttpStatusCode InternalServerError           filterContext Result   new JsonResult     Data   filterContext Exception Message

User · Answer

You need to decide if you want  HTTP level error   that what error codes are for  or  application level error   that what your custom JSON response is for     Most high level objects using HTTP will never look into response stream if error code set to something that is not 2xx  success range   In your case you are explicitly setting error code to failure  I think 403 or 500  and force XMLHttp object to ignore body of the response   To fix - either handle error conditions on client side or not set error code and return JSON with error information  see Sbossb reply for details

User · Answer

There is a very elegant solution to this problem  just configure your site via web config    lt system webServer gt       lt httpErrors errorMode  DetailedLocalOnly  existingResponse  PassThrough   gt   lt  system webServer gt    Source  https   serverfault com questions 123729 iis-is-overriding-my-response-content-if-i-manually-set-the-response-statuscode

User · Answer

I found the solution here  I had to create a action filter to override the default behaviour of MVC  Here is my exception class  class ValidationException   ApplicationException       public JsonResult exceptionDetails      public ValidationException JsonResult exceptionDetails                this exceptionDetails   exceptionDetails            public ValidationException string message    base message          public ValidationException string message  Exception inner    base message  inner          protected ValidationException      System Runtime Serialization SerializationInfo info      System Runtime Serialization StreamingContext context            base info  context          Note that I have constructor which initializes my JSON  Here is the action filter  public class HandleUIExceptionAttribute   FilterAttribute  IExceptionFilter       public virtual void OnException ExceptionContext filterContext                if  filterContext    null                        throw new ArgumentNullException  filterContext                      if  filterContext Exception    null                        filterContext ExceptionHandled   true              filterContext HttpContext Response Clear                filterContext HttpContext Response TrySkipIisCustomErrors   true              filterContext HttpContext Response StatusCode    int System Net HttpStatusCode InternalServerError              filterContext Result     ValidationException filterContext Exception  myJsonError                    Now that I have the action filter   I will decorate my controller with the filter attribute   HandleUIException  public JsonResult UpdateName string objectToUpdate       var response   myClient ValidateObject objectToUpdate      if  response errors Length  gt  0       throw new ValidationException Json response        When the error is thrown the action filter which implements IExceptionFilter get called and I get back the Json on the client on error callback

User · Answer

The neatest solution I ve found is to create your own JsonResult that extends the original implementation and allows you to specify a HttpStatusCode   public class JsonHttpStatusResult   JsonResult       private readonly HttpStatusCode  httpStatus       public JsonHttpStatusResult object data  HttpStatusCode httpStatus                Data   data           httpStatus   httpStatus             public override void ExecuteResult ControllerContext context                context RequestContext HttpContext Response StatusCode    int  httpStatus          base ExecuteResult context             You can then use this in your controller action like so   if thereWereErrors        var errorModel   new   error    There was an error         return new JsonHttpStatusResult errorModel  HttpStatusCode InternalServerError

User · Answer

I was running Asp Net Web Api 5 2 7 and it looks like the JsonResult class has changed to use generics and an asynchronous execute method   I ended up altering Richard Garside s solution   public class JsonHttpStatusResult lt T gt    JsonResult lt T gt        private readonly HttpStatusCode  httpStatus       public JsonHttpStatusResult T content  JsonSerializerSettings serializer  Encoding encoding  ApiController controller  HttpStatusCode httpStatus         base content  serializer  encoding  controller                 httpStatus   httpStatus             public override Task lt HttpResponseMessage gt  ExecuteAsync CancellationToken cancellationToken                var returnTask   base ExecuteAsync cancellationToken           returnTask Result StatusCode   HttpStatusCode BadRequest          return returnTask            Following Richard s example  you could then use this class like this   if thereWereErrors        var errorModel   new CustomErrorModel  There was an error        return new JsonHttpStatusResult lt CustomErrorModel gt  errorModel  new JsonSerializerSettings    new UTF8Encoding    this  HttpStatusCode InternalServerError       Unfortunately  you can t use an anonymous type for the content  as you need to pass a concrete type  ex  CustomErrorType  to the JsonHttpStatusResult initializer   If you want to use anonymous types  or you just want to be really slick  you can build on this solution by subclassing ApiController to add an HttpStatusCode param to the Json methods     public abstract class MyApiController   ApiController       protected internal virtual JsonHttpStatusResult lt T gt  Json lt T gt  T content  HttpStatusCode httpStatus  JsonSerializerSettings serializerSettings  Encoding encoding                return new JsonHttpStatusResult lt T gt  content  httpStatus  serializerSettings  encoding  this              protected internal JsonHttpStatusResult lt T gt  Json lt T gt  T content  HttpStatusCode httpStatus  JsonSerializerSettings serializerSettings                return Json content  httpStatus  serializerSettings  new UTF8Encoding                protected internal JsonHttpStatusResult lt T gt  Json lt T gt  T content  HttpStatusCode httpStatus                return Json content  httpStatus  new JsonSerializerSettings               Then you can use it with an anonymous type like this   if thereWereErrors        var errorModel   new   error    There was an error         return Json errorModel  HttpStatusCode InternalServerError

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