How to deal with the result that i wanted in asp.net web api - asp.net

Question

I'm trying to write web api for app developers,and i want the api result like the sample below
When Exception:
{
"StatusCode": "0",
"Message": "There's exception when calling web api"
}
Normal: the Result in the json string was the return type in the web api action.
{
"StatusCode": "1",
"Message": "Action completed successful",
"Result": {}
}
If the action is:
public DemoController : ApiController
{
public class DemoModel
{
public string X {get;set;}
public int Y {get;set;}
}
[HttpGet]
public DemoModel GetModel(int id)
{
return new DemoModel() { X = "Demo return string" , Y = 1234};
}
}
The Json string should be the sample below when calling the action successfully.
{
"StatusCode": "1",
"Message": "Action completed successful",
"Result": {
"X": "Demo return string",
"Y": 1234
}
}
and when exception, should be :
{
"StatusCode": "0",
"Message": "There's exception when calling web api"
}
So,the app developers could see the return type details in the web api help page.
Is that easy to implement?and how to do (no detail,just logic,also detail is better.)
thanks for everyone !

Answer 1

You should create DelegatingHandler to wrapper your all response from server:
public class WrappingResponseHandler : DelegatingHandler
{
protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request,
CancellationToken cancellationToken)
{
HttpResponseMessage response = await base.SendAsync(request, cancellationToken);
return BuildApiResponse(request, response);
}
private static HttpResponseMessage BuildApiResponse(HttpRequestMessage request, HttpResponseMessage response)
{
object result;
string message = null;
int status;
if (response.TryGetContentValue(out result) == false || response.IsSuccessStatusCode == false)
{
var error = result as HttpError;
if (error != null)
{
result = null;
}
message = "There's exception when calling web api";
status = 0;
}
else
{
message = "Action completed successful";
status = 1;
}
HttpResponseMessage newResponse = request.CreateResponse(response.StatusCode,
new ApiResponse() { Message = message, Result = result, StatusCode = status });
foreach (KeyValuePair<string, IEnumerable<string>> header in response.Headers)
{
newResponse.Headers.Add(header.Key, header.Value);
}
return newResponse;
}
public class ApiResponse
{
public int StatusCode { get; set; }
public string Message { get; set; }
public object Result { get; set; }
}
}
And add this handler in WebApiConfig:
public static class WebApiConfig
{
public static void Register(HttpConfiguration config)
{
config.MessageHandlers.Add(new WrappingResponseHandler()); //here
// Web API configuration and services
// Configure Web API to use only bearer token authentication.
config.SuppressDefaultHostAuthentication();
config.Filters.Add(new HostAuthenticationFilter(OAuthDefaults.AuthenticationType));
// Web API routes
config.MapHttpAttributeRoutes();
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = RouteParameter.Optional }
);
}
}
And nothing would have to change and add controllers.

Answer 2

Using IHttpActionResult would really helpful esp if your thinking of app developers. It works very with Http response code like 200(Ok), 500(Internal Server Error), 404(Not Found) etc
Here is simple code example, where your getting product and returning appropriate response based on returns
public IHttpActionResult Get (int id)
{
Product product = _repository.Get (id);
if (product == null)
{
return NotFound(); // Returns a NotFoundResult
}
return Ok(product); // Returns an OkNegotiatedContentResult
}
More on this Action Results on Web Api 2, you can even write custom action result.
When app client consumes, it gets proper HTTP response code, any response object or message along.