C# WEB API response downloads 0 size file

Question

My below API action is supposed to send a zip file (max 100mb) as the result. There are no errors thrown in the code, however the file downloaded is 0 size. I checked the content length and there is value in the content length. what could be the reason.

[HttpGet]
        [Route("AsyncDownloadFile")]
        public async Task<HttpResponseMessage> AsyncDownloadFile(int ModuleID, string LicenseKey, string Version)
        {
            try
            {
                ClientOutletsDAL co = new ClientOutletsDAL();
                //var localFilePath = "path/zz.zip"

                HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
                new StreamContent(new FileStream(localFilePath, FileMode.Open, FileAccess.Read));

                Stream streamToCopyTo= new MemoryStream();
                using (FileStream fs = new FileStream(localFilePath, FileMode.Open, FileAccess.Read, FileShare.Read, 4096, true))
                {
                     await fs.CopyToAsync(streamToCopyTo);
                }
                response.Content = new StreamContent(streamToCopyTo);
                //Set the Response Content Length.
                response.Content.Headers.ContentLength = streamToCopyTo.Length;
                response.Content.Headers.ContentDisposition = new System.Net.Http.Headers.ContentDispositionHeaderValue("attachment");
                response.Content.Headers.ContentDisposition.FileName = Path.GetFileName(localFilePath);
                response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/zip");

                return response;
            }

            catch (Exception ex)
            {
                HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.InternalServerError, ex.Message );
                return response;
            }
        }

I bet you have to reset stream position to 0 `streamToCopyTo` after you copied file stream — Irdis, May 13 '20 at 13:06

score 1 · Answer 1 · answered May 13 '20 at 13:20

1

The issue was solved by adding

streamToCopyTo.Position = 0;

after

response.Content = new StreamContent(streamToCopyTo);

answered May 13 '20 at 13:20

Sin

1,836
2
17
24

score -1 · Answer 2 · answered May 13 '20 at 13:08

-1

I notice you have the following in your code

 new StreamContent(new FileStream(localFilePath, FileMode.Open, FileAccess.Read));

but it is not used but it appears to be trying to open the same file so I wonder if you its a file share issue.

Also, do you have permissions for sure (just checking) and lastly, have you stepped through this code to verify that streamToCopyTo has data in it?

Cheers

answered May 13 '20 at 13:08

M M E G

24
4

HI Issue was because streamToCopyTo.Position = 0; missing – Sin May 13 '20 at 13:19

C# WEB API response downloads 0 size file

2 Answers2