Return content with IHttpActionResult for non-OK response

Question

For returning from a Web API 2 controller, I can return content with the response if the response is OK (status 200) like this:

    public IHttpActionResult Get()
    {
        string myResult = ...
        return Ok(myResult);
    }

If possible, I want to use the built-in result types here when possible: https://msdn.microsoft.com/en-us/library/system.web.http.results(v=vs.118).aspx

My question is, for another type of response (not 200), how can I return a message (string) with it? For example, I can do this:

    public IHttpActionResult Get()
    {
       return InternalServerError();
    }

but not this:

    public IHttpActionResult Get()
    {
       return InternalServerError("Message describing the error here");
    }

Ideally I want this to be generalized so that I can send a message back with any of the implementations of IHttpActionResult.

Do I need to do this (and build my own response message):

    public IHttpActionResult Get()
    {
       HttpResponseMessage responseMessage = ...
       return ResponseMessage(responseMessage);
    }

or is there a better way?

Solution 1

I ended up going with the following solution:

public class HttpActionResult : IHttpActionResult
{
    private readonly string _message;
    private readonly HttpStatusCode _statusCode;

    public HttpActionResult(HttpStatusCode statusCode, string message)
    {
        _statusCode = statusCode;
        _message = message;
    }

    public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
    {
        HttpResponseMessage response = new HttpResponseMessage(_statusCode)
        {
            Content = new StringContent(_message)
        };
        return Task.FromResult(response);
    }
}

... which can be used like this:

public IHttpActionResult Get()
{
   return new HttpActionResult(HttpStatusCode.InternalServerError, "error message"); // can use any HTTP status code
}

I'm open to suggestions for improvement. :)

Solution 2

You can use this:

return Content(HttpStatusCode.BadRequest, "Any object");

Solution 3

You can use HttpRequestMessagesExtensions.CreateErrorResponse (System.Net.Http namespace), like so:

public IHttpActionResult Get()
{
   return ResponseMessage(Request.CreateErrorResponse(HttpStatusCode.InternalServerError, "Message describing the error here"));
}

It is preferable to create responses based on the request to take advantage of Web API's content negotiation.

Solution 4

You can also do:

return InternalServerError(new Exception("SOME CUSTOM MESSAGE"));

Solution 5

Simple:

return ResponseMessage(Request.CreateErrorResponse(HttpStatusCode.InternalServerError, "Your message"));

Remember to reference System.Net.Http and System.Net.

View more solutions

Comments

[Milen]

how about this: stackoverflow.com/questions/10732644/…

[Ric]

could you not use ApiController.InternalServerError msdn.microsoft.com/en-us/library/dn292630(v=vs.118).aspx

[mayabelle]

@Milen, Thank you. Something like that might work. The part I don't like is it requires creating a different IHttpActionResult implementation for each existing implementation I want to be able to use.

[mayabelle]

@Ric, no, the parameter is an Exception. I want to set a message as a string. Also, this doesn't address a more general case where the code might not necessarily be internal server error.

[Isaac]

@mayabelle: Did you see Shamil Yakupov`s answer? It's much simpler and concise that the accepted answer.

[mayabelle]

Request.CreateErrorResponse returns an HttpResponseMessage, not IHttpActionResult. What you describe is good practice for creating an HttpResponseMessage but doesn't address my question. Thanks anyway!

[Quoc Nguyen]

@mayabelle you can create IHttpActionResult concrete and wrapped those code like this:

[Thomas.Benz]

Short and simple solution. Having more codes means more bugs and time consuming maintenance.

[Deza]

When im trying this, the returned value of code (where code is a string) in return Content(HttpStatusCode.OK, code) is encapsulated in " which is unexpected, is there any reason for this? eg the value which is returned is "\"value\"" I'm using mvc5

[user1620220]

Because not all errors are the result of bad requests, so a 400 response would be inappropriate. OP specifically gave a 500 response as an example.

[Chemist]

This worked for me but I used Request.CreateResponse so that the error shows as a string instead of under Message key.

[benraay]

Yes it's only possible with BadRequest the other types don't take a message argument

[Etherman]

If you need to do this from outside the ApiController class then you can use: return new NegotiatedContentResult<T>(code, new T(...), controller)

[Etherman]

Shamil Yakupov's answer is the best answer but only from inside the ApiController class - it needs to be rewritten as something like "return new NegotiatedContentResult<T>(code, new T(...), controller)" to be used from outside the controller class. In that case a solution such as this one above may be more readable.

[Sheena Agrawal]

I am getting an error, the snippet is failing. It says 'request' is null. I am trying to use Request.CreateResponse @user1620220

[user1620220]

@SheenaAgrawal This code can only be executed in the context of an HTTP request. If ApiController.Request is null it means you are not in the right context, or something is broken in your WebAPI architecture.

[userSteve]

Yes but its a pain to get that message text back

[LastTribunal]

Content<T> is very useful

[Toolkit]

can i return it from a class library? What do I need to reference?