issue with returning HttpResponseMessage as excel file in WebAPI

Question

I have created WebAPI which returns an excel file using closedxml nuget. Basically it converts my DataTable to excel. I'm referring couple of links below,

1. How to return a file (FileContentResult) in ASP.NET WebAPI

2. Returning binary file from controller in ASP.NET Web API

Issue : excel generated on server path has NO issues. But when I download the same by returning it as HttpResponseMessage via webAPI the excel file is corrupted. It says, "The file is corrupt and cannot be opened" :(

My Code :

    [System.Web.Http.AcceptVerbs("GET", "POST")]
    public HttpResponseMessage ExportExcel()
            {                 
                     DataTable scoredRecords = Getdt();
                     if (scoredRecords.Rows.Count > 0)
                        {
                            var path = @"C:\Raghav\asdf.xlsx";
                            XLWorkbook wb = new XLWorkbook();
                            wb.Worksheets.Add(scoredRecords, "sample");
                            // excel getting generated on server properly-No issues.
                            wb.SaveAs(path);
                            HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
                            var stream = new FileStream(path, FileMode.Open);
                            result.Content = new StreamContent(stream);
                            result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
                            {
                                FileName = "sample.xlsx"
                            };
                            result.Content.Headers.ContentLength = stream.Length;
                            //tried with "application/ms-excel" also
                            result.Content.Headers.ContentType =
                                new MediaTypeHeaderValue("application/octet-stream");
                            return result;
                        }

               }

The generated excel on server has no issues. Only the downloaded excel file via webAPI is corrupted. Unable to figure out the issue.. any help appreciated!! :)

Answer 1

Try this:

    [HttpGet]
    public HttpResponseMessage Export()
    {
        using (var wb = new XLWorkbook())
        using (MemoryStream ms = new MemoryStream())
        {
            wb.Worksheets.Add("sample").FirstCell().SetValue("some value");

            wb.SaveAs(ms);

            HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
            result.Content = new ByteArrayContent(ms.GetBuffer());
            result.Content.Headers.ContentLength = ms.Length;
            result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
            {
                FileName = "sample.xlsx"
            };
            result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
            return result;
        }
    }

Answer 2

One issue I am seeing is that :

 var stream = new FileStream(path, FileMode.Open);

you are sending FileStream. Instead of this, you can try with byte [] :

byte[] excelData  = File.ReadAllBytes(path);
result.Content = new StreamContent(excelData);

You can give a try with this.