My controller:

public class MyController : ControllerBase
{
  [HttpGet("/getResponse/{userId}")]
  public async Task<MyResponse> GetResponseAsync(long userId)
  {
     return await _myService.GetResponseAsync(userId);
  }
  [HttpGet("/getUser/{userId}")]
  public async Task<MyUser> GetUserAsync(long userId)
  {
     return await _myService.GetUserAsync(userId);
  }
}

though my controller returns an object of MyResponse or MyUser class, I want to return a custom generic response object i.e.

public class ApiResponse
{
  public object Response { get; set; }
  public bool IsSuccess { get; set; }
  public IList<string> Errors { get; set; }
  public ApiResponse(object response, bool success, IList<string> errors = null)
  {
     this.Response = response;
     this.IsSuccess = success;
     this.Errors = errors;
  }
    
  public ApiResponse()
  {
  }
}

I tried to use IActionFilter's OnActionExecuted(ActionExecutedContext context) to read the response object, but I don't see any response of MyUser or MyResponse object in the body when i debug for variable a.

public void OnActionExecuted(ActionExecutedContext context)
        {
            ApiResponse _response = new ApiResponse();
            var httpResponse = context.HttpContext.Response;
            if (httpResponse != null)
            {
                if (httpResponse.StatusCode == 200)
                {
                   var a = httpResponse.Body;
                }
            }
        }

Is there a way to read the type of object and assign that particular object to the ApiResponse.response proeperty?

CodePudding user response：

There are a few types of MVC filters, and IActionFilter is not the best tool for this job. What you want is ResultFilter.

Please take a look at official documentation here https://docs.microsoft.com/en-us/aspnet/core/mvc/controllers/filters?view=aspnetcore-6.0 for more details.

An answer provided here may also be useful for you: https://stackoverflow.com/a/64725441/2895299

However, it is going to work with your filter implementation as well, you're just looking for a response object in wrong place. Your object is going to be accessible under:

context.Result

Response in HttpContext object is going to be accessible later, not at filter stage of MVC pipeline. Please observe, that context.HttpContext.Response.HasStarted is equal to false.

CodePudding user response：

There's already IETF RFC 7807 for HTTP API problem responses, with its own content type, application/problem json. ASP.NET Core uses it to return automatic model validation failure responses.

It's a bad idea to use a custom format when there's a standard that's actually used by clients and libraries.

Example responses can be :

   HTTP/1.1 403 Forbidden
   Content-Type: application/problem json
   Content-Language: en

   {
    "type": "https://example.com/probs/out-of-credit",
    "title": "You do not have enough credit.",
    "detail": "Your current balance is 30, but that costs 50.",
    "instance": "/account/12345/msgs/abc",
    "balance": 30,
    "accounts": ["/account/12345",
                 "/account/67890"]
   }

Or

   HTTP/1.1 400 Bad Request
   Content-Type: application/problem json
   Content-Language: en

   {
   "type": "https://example.net/validation-error",
   "title": "Your request parameters didn't validate.",
   "invalid-params": [ {
                         "name": "age",
                         "reason": "must be a positive integer"
                       },
                       {
                         "name": "color",
                         "reason": "must be 'green', 'red' or 'blue'"}
                     ]
   }

ASP.NET Core uses the ProblemDetails and the more specific ValidationProblemDetails classes to report errors.

It's possible to send a Problem or ValidationProblem response using the Problem or ValidationProblem functions, eg:

var details=new ValidationProblemDetails(someDictionary);
return ValidationProblem(details);

The Handle errors in ASP.NET Core web APIs article shows how ASP.NET Core can be configured to returns customized ProblemDetails for specific exceptions