How to return file from ASP.net 5 web api

Question

Created wep api in asp.net 5. I am tring to return file response for Post request. But instead of file the response looks like `

{
  "version": {
    "major": 1,
    "minor": 1,
    "build": -1,
    "revision": -1,
    "majorRevision": -1,
    "minorRevision": -1
  },
  "content": {
    "headers": [
      {
        "key": "Content-Disposition",
        "value": [
          "attachment; filename=test.pdf"
        ]
      },
      {
        "key": "Content-Type",
        "value": [
          "application/pdf"
        ]
      }
    ]
  },
  "statusCode": 200,
  "reasonPhrase": "OK",
  "headers": [],
  "requestMessage": null,
  "isSuccessStatusCode": true
}`

Code:

    public HttpResponseMessage Post([FromBody]DocumentViewModel vm)
    {
        try
        {
            if (ModelState.IsValid)
            {

                var Document = _repository.GetDocumentByGuid(vm.DocumentGuid, User.Identity.Name);
                var Params = Helper.ClientInputToRealValues(vm.Parameters, Document.DataFields);
                var file = Helper.GeneratePdf(Helper.InsertValues(Params, Document.Content));                 

                var result = new HttpResponseMessage(HttpStatusCode.OK)
                {
                    Content = new ByteArrayContent(System.IO.File.ReadAllBytes(file))
                };
                result.Content.Headers.ContentDisposition = new System.Net.Http.Headers.ContentDispositionHeaderValue("attachment")
                {
                    FileName = "test.pdf"
                };
                result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/pdf");
                return result;

            }

        }
        catch (Exception ex)
        {
            Response.StatusCode = (int)HttpStatusCode.BadRequest;
            return null;
        }
        Response.StatusCode = (int)HttpStatusCode.BadRequest;
        return null;

    }

How can I return the real file as the response instead of JSON ?I am using Postman as test client.

Perhaps this can help: stackoverflow.com/questions/9541351/… — jpgrassi
– jpgrassi, Commented Jan 18, 2016 at 11:17

Community · Accepted Answer · 2017-05-23 12:17:46Z

4

used IActionResult instead of HttpResponseMessage. And returned FileStreamResult, and got it working.

Got a new problem, the file is not the one I open with the stream from server. But will create a new question for that.

Continues : Return file from ASP.NET 5 Web API

Thanks

edited May 23, 2017 at 12:17

CommunityBot

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answered Jan 18, 2016 at 13:51

Joonas Püüa

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Comments

Florian Winter · Accepted Answer · 2019-07-30 11:19:49Z

3

This is the "low-level" HTTP approach, which should work with both ASP.NET WebAPI or ASP.NET MVC.

[HttpGet]
public HttpResponseMessage Download()
{
  var fs = new FileStream(myfileInfo.FullName, FileMode.Open, FileAccess.Read, FileShare.Read, 32768, true);
  var response = new HttpResponseMessage {
    Content = new StreamContent(fs);
  }
  response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");
  response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
  return response;
}

edited Jul 30, 2019 at 11:19

Florian Winter

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answered Dec 16, 2016 at 12:49

MoSad

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3 Comments

Florian Winter Over a year ago

Wouldn't fs.Dispose() close the file before WebAPI has a chance to use the file stream? If not, then how does Dispose() work in this scenario?

Florian Winter Over a year ago

To answer my question above: You do not need to (and probably shouldn't) call Dispose on the stream you pass to StreamContent. I will edit your answer. See stackoverflow.com/a/38788127/2279059

Florian Winter Over a year ago

It's still not WebAPI, because this.Request.CreateResponse does not exist in a WebAPI controller.

Mogsdad · Accepted Answer · 2016-04-17 02:55:30Z

2

Does setting HttpContext.Response.ContentType = "application/pdf" help at all?

This should fit your needs:

public FileResult TestDownload()
    {
        HttpContext.Response.ContentType = "application/pdf";
        FileContentResult result = new FileContentResult(System.IO.File.ReadAllBytes("YOUR PATH TO PDF"), "application/pdf")
        {
            FileDownloadName = "test.pdf"
        };

        return result;                                
    }

edited Apr 17, 2016 at 2:55

Mogsdad

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answered Jan 18, 2016 at 12:33

Ian Auty

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4 Comments

Ian Auty Over a year ago

Does "headers": [], have anything populated now? As I can see from your initial post that it's empty. What build of asp.net 5 are you using, and is it full .net or coreclr?

Joonas Püüa Over a year ago

Nope, it remains empty.

Joonas Püüa Over a year ago

Full - dnx451 ,build rc1-final

Joonas Püüa Over a year ago

If I add the header manually to HttpResponseMessage like that: result.Headers.Add("Content-Type", "application/pdf"); it throws : "Misused header name. Make sure request headers are used with HttpRequestMessage, response headers with HttpResponseMessage, and content headers with HttpContent objects."

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