How to return HTTP 500 from ASP.NET Core RC2 Web Api?

From what I can see there are helper methods inside the ControllerBase class. Just use the StatusCode method:

[HttpPost]
public IActionResult Post([FromBody] string something)
{    
    //...
    try
    {
        DoSomething();
    }
    catch(Exception e)
    {
         LogException(e);
         return StatusCode(500);
    }
}

You may also use the StatusCode(int statusCode, object value) overload which also negotiates the content.

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You could use Microsoft.AspNetCore.Mvc.ControllerBase.StatusCode and Microsoft.AspNetCore.Http.StatusCodes to form your response, if you don't wish to hardcode specific numbers.

return  StatusCode(StatusCodes.Status500InternalServerError);

UPDATE: Aug 2019

Perhaps not directly related to the original question but when trying to achieve the same result with Microsoft Azure Functions I found that I had to construct a new StatusCodeResult object found in the Microsoft.AspNetCore.Mvc.Core assembly. My code now looks like this;

return new StatusCodeResult(StatusCodes.Status500InternalServerError);

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If you need a body in your response, you can call

return StatusCode(StatusCodes.Status500InternalServerError, responseObject);

This will return a 500 with the response object...

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For aspnetcore-3.1, you can also use Problem() like below;

https://docs.microsoft.com/en-us/aspnet/core/web-api/handle-errors?view=aspnetcore-3.1

 [Route("/error-local-development")]
public IActionResult ErrorLocalDevelopment(
    [FromServices] IWebHostEnvironment webHostEnvironment)
{
    if (webHostEnvironment.EnvironmentName != "Development")
    {
        throw new InvalidOperationException(
            "This shouldn't be invoked in non-development environments.");
    }

    var context = HttpContext.Features.Get<IExceptionHandlerFeature>();

    return Problem(
        detail: context.Error.StackTrace,
        title: context.Error.Message);
}

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A better way to handle this as of now (1.1) is to do this in Startup.cs's Configure():

app.UseExceptionHandler("/Error");

This will execute the route for /Error. This will save you from adding try-catch blocks to every action you write.

Of course, you'll need to add an ErrorController similar to this:

[Route("[controller]")]
public class ErrorController : Controller
{
    [Route("")]
    [AllowAnonymous]
    public IActionResult Get()
    {
        return StatusCode(StatusCodes.Status500InternalServerError);
    }
}

More information here.

In case you want to get the actual exception data, you may add this to the above Get() right before the return statement.

// Get the details of the exception that occurred
var exceptionFeature = HttpContext.Features.Get<IExceptionHandlerPathFeature>();

if (exceptionFeature != null)
{
    // Get which route the exception occurred at
    string routeWhereExceptionOccurred = exceptionFeature.Path;

    // Get the exception that occurred
    Exception exceptionThatOccurred = exceptionFeature.Error;

    // TODO: Do something with the exception
    // Log it with Serilog?
    // Send an e-mail, text, fax, or carrier pidgeon?  Maybe all of the above?
    // Whatever you do, be careful to catch any exceptions, otherwise you'll end up with a blank page and throwing a 500
}

Above snippet taken from Scott Sauber's blog.

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How about creating a custom ObjectResult class that represents an Internal Server Error like the one for OkObjectResult? You can put a simple method in your own base class so that you can easily generate the InternalServerError and return it just like you do Ok() or BadRequest().

[Route("api/[controller]")]
[ApiController]
public class MyController : MyControllerBase
{
    [HttpGet]
    [Route("{key}")]
    public IActionResult Get(int key)
    {
        try
        {
            //do something that fails
        }
        catch (Exception e)
        {
            LogException(e);
            return InternalServerError();
        }
    }
}

public class MyControllerBase : ControllerBase
{
    public InternalServerErrorObjectResult InternalServerError()
    {
        return new InternalServerErrorObjectResult();
    }

    public InternalServerErrorObjectResult InternalServerError(object value)
    {
        return new InternalServerErrorObjectResult(value);
    }
}

public class InternalServerErrorObjectResult : ObjectResult
{
    public InternalServerErrorObjectResult(object value) : base(value)
    {
        StatusCode = StatusCodes.Status500InternalServerError;
    }

    public InternalServerErrorObjectResult() : this(null)
    {
        StatusCode = StatusCodes.Status500InternalServerError;
    }
}

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return StatusCode((int)HttpStatusCode.InternalServerError, e);

Should be used in non-ASP.NET contexts (see other answers for ASP.NET Core).

HttpStatusCode is an enumeration in System.Net.

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When you want to return a JSON response in MVC .Net Core You can also use:

Response.StatusCode = (int)HttpStatusCode.InternalServerError;//Equals to HTTPResponse 500
return Json(new { responseText = "my error" });

This will return both JSON result and HTTPStatus. I use it for returning results to jQuery.ajax().

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The built-in Problem()-method of Microsoft.AspNetCore.Mvc will return a "problem detail"-response based on RFC 7807 (in ASP.NET Core 3.0 and later). It will always return status-code 500 as long as no other status is explicitly set.

[HttpPost]
public IActionResult Post([FromBody] string value)
{
    try
    {
        // ...
    }
    catch (Exception ex)
    {
        return Problem(
            //all parameters are optional:
            //detail: "Error while processing posted data."; //an explanation, ex.Stacktrace, ...
            //instance: "/city/London"  //A reference that identifies the specific occurrence of the problem
            //title: "An error occured." //a short title, maybe ex.Message
            //statusCode: StatusCodes.Status504GatewayTimeout, //will always return code 500 if not explicitly set
            //type: "http://example.com/errors/error-123-details"  //a reference to more information
            );
    }           
}

Without setting any parameters it will return this:

{
    "type": "https://tools.ietf.org/html/rfc7231#section-6.6.1",
    "title": "An error occured while processing your request.",
    "status": 500,
    "traceId": "|fadaed95-4d06eb16160e4996."
}

More infos about "problem details" parameters: https://docs.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.mvc.problemdetails?view=aspnetcore-5.0

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For API Responses (using net core), I have tried this and seems that it is working fine:

var err = Content(JsonConvert.SerializeObject(response, SerializerSettings), "application/x-javascript", contentEncoding: System.Text.Encoding.UTF8);
err.StatusCode = StatusCodes.Status500InternalServerError;
return err;

You just need to create a response object first, then respond this. Doing this, we can retain the content type, encoding, and add a status code as well.

Just adding this for future reference to anybody who is stuck as well and wants a quick and easy way to do this.

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