Is there any in-built function/method to return, IActionResult/ActionResult instead of HttpResponseMessage in .Net Core 3.1 - asp.net-core

Question

My Action method is returning HttpResponseMessage but, I want to get rid off Microsoft.AspNetCore.Mvc.WebApiCompatShim NuGet Package (which is basically provided to bridge the gap while porting Asp.Net Web API code into .Net Core) and use IActionResult/ActionResult instead of HttpResponseMessage.
My Action method looks like this:
[HttpGet]
[Route("GetTemplate")]
public async Task<HttpResponseMessage> GetTemplate(string id) {
var userAgent = this.Request.Headers.UserAgent;
bool IsWindows = true;
if(userAgent.ToString().ToLower().Contains("apple")) {
IsWindows = false; //false
}
var template = await _templateService.GetTemplateContent(id);
HttpResponseMessage responseMsg = new HttpResponseMessage();
if(IsWindows) {
responseMsg.Content = new StringContent(JsonConvert.SerializeObject(template));
responseMsg.RequestMessage = Request;
responseMsg.StatusCode = HttpStatusCode.OK;
responseMsg.Content.Headers.ContentType =
new MediaTypeHeaderValue("application/json");
} else {
responseMsg.Content = new ByteArrayContent(template.ContentBytes);
responseMsg.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment") { FileNameStar = template.Name };
responseMsg.Content.Headers.Add("x-filename", template.Name);
responseMsg.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
responseMsg.Content.Headers.ContentLength = template.ContentBytes.Length;
responseMsg.RequestMessage = Request;
responseMsg.StatusCode = HttpStatusCode.OK;
}
return (responseMsg);
}

Answer 1

Since you aren’t doing anything fancy there, you can translate your return object directly into corresponding action results here. In your case, you want a JsonResult and a FileResult with a custom response header:
[HttpGet]
[Route("GetTemplate")]
public async Task<HttpResponseMessage> GetTemplate(string id)
{
var userAgent = this.Request.Headers.UserAgent;
bool IsWindows = !userAgent.ToString().ToLower().Contains("apple");
var template = await _templateService.GetTemplateContent(id);
if (IsWindows)
{
return Json(template);
}
else
{
Response.Headers.Add("x-filename", template.Name);
return File(template.ContentBytes, "application/octet-stream", template.Name);
}
}
There are a lot similar utility methods on the Controller and ControllerBase type that help you create a variety of different response messages. For most use cases, there should be a built-in way to produce the response.

Answer 2

1stly change the signature of your action to this:
public async Task<IActionResult> GetTemplate
You will then return your data in the response something like this return Ok(data). You do not have to serialize your data, you can send a POCO class. This would represent .StatusCode = HttpStatusCode.OK
If you want to add extra headers to your response, you will do so using the Response field from ControllerBase. Eg. Response.Headers.Add for adding key value pairs to your Response header.