I want to return a file in my ASP.Net Web API Controller, but all my approaches return the HttpResponseMessage as JSON.
public async Task<HttpResponseMessage> DownloadAsync(string id)
{
var response = new HttpResponseMessage(HttpStatusCode.OK);
response.Content = new StreamContent({{__insert_stream_here__}});
response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
return response;
}
When I call this endpoint in my browser, the Web API returns the HttpResponseMessage as JSON with the HTTP Content Header set to application/json.
This question is related to
c#
asp.net-core
.net-core
asp.net-core-webapi
If this is ASP.net-Core then you are mixing web API versions. Have the action return a derived IActionResult because in your current code the framework is treating HttpResponseMessage as a model.
[Route("api/[controller]")]
public class DownloadController : Controller {
//GET api/download/12345abc
[HttpGet("{id}"]
public async Task<IActionResult> Download(string id) {
Stream stream = await {{__get_stream_based_on_id_here__}}
if(stream == null)
return NotFound(); // returns a NotFoundResult with Status404NotFound response.
return File(stream, "application/octet-stream"); // returns a FileStreamResult
}
}
You can return FileResult with this methods:
1: Return FileStreamResult
[HttpGet("get-file-stream/{id}"]
public async Task<FileStreamResult> DownloadAsync(string id)
{
var fileName="myfileName.txt";
var mimeType="application/....";
var stream = await GetFileStreamById(id);
return new FileStreamResult(stream, mimeType)
{
FileDownloadName = fileName
};
}
2: Return FileContentResult
[HttpGet("get-file-content/{id}"]
public async Task<FileContentResult> DownloadAsync(string id)
{
var fileName="myfileName.txt";
var mimeType="application/....";
var fileBytes = await GetFileBytesById(id);
return new FileContentResult(fileBytes, mimeType)
{
FileDownloadName = fileName
};
}
Here is a simplistic example of streaming a file:
using System.IO;
using Microsoft.AspNetCore.Mvc;
[HttpGet("{id}")]
public async Task<FileStreamResult> Download(int id)
{
var path = "<Get the file path using the ID>";
var stream = File.OpenRead(path);
return new FileStreamResult(stream, "application/octet-stream");
}
Note:
Be sure to use FileStreamResult from Microsoft.AspNetCore.Mvc and not from System.Web.Mvc.
Source: Stackoverflow.com