使用 IHttpActionResult 为非 OK 响应返回内容

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

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 response message):

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

or is there a better way?

Answer 1

你可以使用这个：

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

Answer 2

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.

Answer 3

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. :)

Answer 4

你也可以这样做：

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

Answer 5

Simple:

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

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

Answer 6

Anyone who is interested in returning anything with any statuscode with returning ResponseMessage:

//CreateResponse(HttpStatusCode, T value)
return ResponseMessage(Request.CreateResponse(HttpStatusCode.XX, object));

Answer 7

In ASP.NET Web API 2, you can wrap any ResponseMessage in a ResponseMessageResult :

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

In some cases this may be the simplest way to get the desired result, although generally it might be preferable to use the various results in System.Web.Http.Results .

Answer 8

I would recommend reading this post. There are tons of ways to use existing HttpResponse as suggested, but if you want to take advantage of Web Api 2, then look at using some of the built-in IHttpActionResult options such as

return Ok() 

or

return NotFound()

Choose the right return type for Web Api Controllers

Answer 9

A more detailed example with support of HTTP code not defined in C# HttpStatusCode .

public class MyController : ApiController
{
    public IHttpActionResult Get()
    {
        HttpStatusCode codeNotDefined = (HttpStatusCode)429;
        return Content(codeNotDefined, "message to be sent in response body");
    }
}

Content is a virtual method defined in abstract class ApiController , the base of the controller. See the declaration as below:

protected internal virtual NegotiatedContentResult<T> Content<T>(HttpStatusCode statusCode, T value);

Answer 10

Below code / class really helpful to handle all type of responses. May be success or fail etc.

Why should I use this? :

Suppose I am consuming web API service. There are some possibilities of output as below:

1. You might not get any result because of validation error
2. You will get expected result
3. You will get error.

So here I have solution to handle all the scenarios. Also I tried to maintain uniformity in the output. You can give remark or actual error message. The web service consumer can only check IsSuccess true or not else will sure there is problem, and act as per situation. There should be perfect communication between web API developer and web API consumer. If result is not generating then why. The comment or exception will acknowledge and they will act accordingly. Hence this is best solution for web API consumer / user.

Single response for all all type of results.

  public class Response
    {
        /// <summary>
        /// Gets or sets a value indicating whether this instance is success.
        /// </summary>
        /// <value>
        /// <c>true</c> if this instance is success; otherwise, <c>false</c>.
        /// </value>
        public bool IsSuccess { get; set; } = false;
    
        /// <summary>
        /// Actual response if succeed 
        /// </summary>
        /// <value>
        /// Actual response if succeed 
        /// </value>
        public object Data { get; set; } = null;
    
        /// <summary>
        /// Remark if anythig to convey
        /// </summary>
        /// <value>
        /// Remark if anythig to convey
        /// </value>
        public string Remark { get; set; } = string.Empty;
        /// <summary>
        /// Gets or sets the error message.
        /// </summary>
        /// <value>
        /// The error message.
        /// </value>
        public object ErrorMessage { get; set; } = null;
    
       
    }  
    



[HttpGet]
        public IHttpActionResult Employees()
        {
            Response _res = new Response();
            try
            { 
                DalTest objDal = new DalTest(); 
                _res.Data = objDal.GetTestData();
                _res.IsSuccess = true;
                return Request.CreateResponse(HttpStatusCode.OK, _res);
            }
            catch (Exception ex)
            {
                _res.IsSuccess = false;
                _res.ErrorMessage = ex;
                return ResponseMessage(Request.CreateResponse(HttpStatusCode.InternalServerError, _res )); 
            } 
        }

You are welcome to give suggestion if any :)

I am happy if anyone is using and get benefited. Write me if any addition or modification makes this more improved, on akhandagale65@gmail.com.

Answer 11

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

public class NotFoundPlainTextActionResult : IHttpActionResult
{
    public NotFoundPlainTextActionResult(HttpRequestMessage request, string message)
    {
        Request = request;
        Message = message;
    }

    public string Message { get; private set; }
    public HttpRequestMessage Request { get; private set; }

    public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
    {
        return Task.FromResult(ExecuteResult());
    }

    public HttpResponseMessage ExecuteResult()
    {
        var response = new HttpResponseMessage();

        if (!string.IsNullOrWhiteSpace(Message))
            //response.Content = new StringContent(Message);
            response = Request.CreateErrorResponse(HttpStatusCode.NotFound, new Exception(Message));

        response.RequestMessage = Request;
        return response;
    }
}

Answer 12

I had the same problem. I want to create custom result for my api controllers, to call them like return Ok("some text");

Then i did this: 1) Create custom result type with singletone

public sealed class EmptyResult : IHttpActionResult
{
    public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
    {
        return Task.FromResult(new HttpResponseMessage(System.Net.HttpStatusCode.NoContent) { Content = new StringContent("Empty result") });
    }
}

2) Create custom controller with new method:

public class CustomApiController : ApiController
{
    public IHttpActionResult EmptyResult()
    {
        return new EmptyResult();
    }
}

And then i can call them in my controllers, like this:

public IHttpActionResult SomeMethod()
    {
       return EmptyResult();
    }

Answer 13

this answer is based on Shamil Yakupov answer, with real object instead of string.

using System.Dynamic;

dynamic response = new ExpandoObject();
response.message = "Email address already exist";

return Content<object>(HttpStatusCode.BadRequest, response);

Answer 14

For exceptions, I usually do

 catch (Exception ex)
        {
            return InternalServerError(new ApplicationException("Something went wrong in this request. internal exception: " + ex.Message));
        }

Answer 15

Sorry for the late answer why don't you simple use

return BadRequest("your message");

I use it for all my IHttpActionResult errors its working well

here is the documentation : https://msdn.microsoft.com/en-us/library/system.web.http.apicontroller.badrequest(v=vs.118).aspx

Answer 16

你可以使用这个：

return BadRequest("No data is present in table!!");