Correct way to return HttpResponseMessage as IActionResult in .Net Core 2.2

Question

In .Net Core 2.2. I am creating a API Controller that routes the request to another Http endpoint based on payload.

  [Route("api/v1")]   public class RoutesController : Controller   {       [HttpPost]       [Route("routes")]       public async Task<IActionResult> Routes([FromBody]JObject request)       {                           var httpClient = new HttpClient();          // here based on request httpCLient will make `POST` or `GET` or `PUT` request         // and returns `Task<HttpResponseMessage>`. Lets assume its making `GET`          // call         Task<HttpResponseMessage> response = await          httpClient.GetAsync(request["resource"]);                     /*  ??? what is the correct way to return response as `IActionResult`*/       }           } 

based on SO post i can do this

        return StatusCode((int)response.StatusCode, response); 

However i am not sure sending HttpResponseMessage as ObjectResult is correct way.

I also want to make sure content negotiation will work.

Answer 1

public class HttpResponseMessageResult : IActionResult {     private readonly HttpResponseMessage _responseMessage;      public HttpResponseMessageResult(HttpResponseMessage responseMessage)     {         _responseMessage = responseMessage; // could add throw if null     }      public async Task ExecuteResultAsync(ActionContext context)     {         var response = context.HttpContext.Response;           if (_responseMessage == null)         {             var message = "Response message cannot be null";              throw new InvalidOperationException(message);         }          using (_responseMessage)         {             response.StatusCode = (int)_responseMessage.StatusCode;              var responseFeature = context.HttpContext.Features.Get<IHttpResponseFeature>();             if (responseFeature != null)             {                 responseFeature.ReasonPhrase = _responseMessage.ReasonPhrase;             }              var responseHeaders = _responseMessage.Headers;              // Ignore the Transfer-Encoding header if it is just "chunked".             // We let the host decide about whether the response should be chunked or not.             if (responseHeaders.TransferEncodingChunked == true &&                 responseHeaders.TransferEncoding.Count == 1)             {                 responseHeaders.TransferEncoding.Clear();             }              foreach (var header in responseHeaders)             {                 response.Headers.Append(header.Key, header.Value.ToArray());             }              if (_responseMessage.Content != null)             {                 var contentHeaders = _responseMessage.Content.Headers;                  // Copy the response content headers only after ensuring they are complete.                 // We ask for Content-Length first because HttpContent lazily computes this                 // and only afterwards writes the value into the content headers.                 var unused = contentHeaders.ContentLength;                  foreach (var header in contentHeaders)                 {                     response.Headers.Append(header.Key, header.Value.ToArray());                 }                  await _responseMessage.Content.CopyToAsync(response.Body);             }         }     } 

Answer 2

You can create a custom IActionResult that will wrap transfere logic.

public async Task<IActionResult> Routes([FromBody]JObject request) {     var httpClient = new HttpClient();      HttpResponseMessage response = await httpClient.GetAsync("");      // Here we ask the framework to dispose the response object a the end of the user resquest     this.HttpContext.Response.RegisterForDispose(response);      return new HttpResponseMessageResult(response); }  public class HttpResponseMessageResult : IActionResult {     private readonly HttpResponseMessage _responseMessage;      public HttpResponseMessageResult(HttpResponseMessage responseMessage)     {         _responseMessage = responseMessage; // could add throw if null     }      public async Task ExecuteResultAsync(ActionContext context)     {         context.HttpContext.Response.StatusCode = (int)_responseMessage.StatusCode;          foreach (var header in _responseMessage.Headers)         {             context.HttpContext.Response.Headers.TryAdd(header.Key, new StringValues(header.Value.ToArray()));         }          if(_responseMessage.Content != null)         {             using (var stream = await _responseMessage.Content.ReadAsStreamAsync())             {                 await stream.CopyToAsync(context.HttpContext.Response.Body);                 await context.HttpContext.Response.Body.FlushAsync();             }         }     } }