Return file in ASP Net Core Web API

Question

Problem  I want to return a file in my ASP Net Web API Controller  but all my approaches return the HttpResponseMessage as JSON   Code so far  public async Task lt HttpResponseMessage gt  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

User · Answer

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.

User · Answer

You can return FileResult with this methods      1  Return FileStreamResult        HttpGet  get-file-stream  id        public async Task lt FileStreamResult gt  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 lt FileContentResult gt  DownloadAsync string id                var fileName  myfileName txt           var mimeType  application                 var fileBytes   await GetFileBytesById id            return new FileContentResult fileBytes  mimeType                        FileDownloadName   fileName

User · Answer

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 lt IActionResult gt  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

[c#] Return file in ASP.Net Core Web API

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