FileHelper read to stream and download with web api

Question

I have a list of objects which I want to download as csv file via Web Api. However when I test this with Swagger I get no csv download. What am I doing wrong? DailyReportContent contains 2 objects.

This is my code so far:

public IActionResult GetDailyReport(DateTime invoiceDate)
{
    var dailyReportContent = new List<DailyReportModel>().....

    // create csv file
    var engine = new FileHelperEngine<DailyReportModel>
    {
        HeaderText = "headers.."
    };

    using (var stream = new MemoryStream())
    using (var streamWriter = new StreamWriter(stream))
    {
        engine.WriteStream(streamWriter, dailyReportContent);

        var result = new HttpResponseMessage(HttpStatusCode.OK);
        result.Content = new StreamContent(stream);
        result.Content.Headers.ContentType = new MediaTypeHeaderValue("text/csv");
        result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment") { FileName = "DailyReports.csv" };

        return Ok(result);
    }
}

And this is the response in Swagger:

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

EDIT: Even if I add this:

 stream.Flush();
 streamWriter.Flush();

 var reader = new StreamReader(stream);
 var readResult = reader.ReadToEnd();

The readResult is empty. So I guess there goes something wrong when writing the stream?

PitAttack76 · Accepted Answer · 2019-04-26 13:54:38Z

1

Fixed it like this:

var csvContent = LoadcsvContent();

var engine = new FileHelperEngine<DailyReportModel>
{
    HeaderText = "......."
};

var stream = new MemoryStream();
TextWriter streamWriter = new StreamWriter(stream);
engine.WriteStream(streamWriter, csvContent);

streamWriter.Flush();
stream.Seek(0, SeekOrigin.Begin);

return File(await stream, "text/csv", $"Report_{invoiceDate:yyyyMMdd}.csv");

Works like a charm now. Swagger output:

answered Apr 26, 2019 at 13:54

PitAttack76

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Comments

Craig H · Accepted Answer · 2019-04-25 16:27:11Z

0

I think you need to

return result;

Returning "Ok( < object > )" will return a response message containing the object.
You have already created your response message and specified all the content.
So I think you are returning an OK response, containing another OK response message.

answered Apr 25, 2019 at 16:27

Craig H

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2 Comments

PitAttack76 Over a year ago

Nope, doesn't help. gives me exact the same response and no download csv file. :(

Craig H Over a year ago

What if you call the endpoint with a browser - do you get the file downloaded?

jidh · Accepted Answer · 2019-04-26 14:28:47Z

0

In ASP.NetCore we have return File(ret, "application/octet-stream", fileName);

Return a file with the type we needed, in my case for an .msi package I use "application/octet-stream" for you you may either specify the return type as .CSV here in controller level or on the global level in WebApiConfig class for Formatters

answered Apr 26, 2019 at 14:28

jidh

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