public HttpResponseMessage DownloadFile([FromUri] string id)
{
string authorizationString = DecodeAuthorizationString();
SPHelper.SetSharePointCredentials(authorizationString);
ListItem item = SPHelper.FindFile(id.ToGuid());
string fileName = item["FileLeafRef"].ToString();
string contentType = System.Web.MimeMapping.GetMimeMapping(fileName);
HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
Byte[] bytes = SPHelper.DownloadFile(item);
response.Content = new ByteArrayContent(bytes);
response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");
response.Content.Headers.ContentType = new MediaTypeHeaderValue(contentType);
response.Content.Headers.ContentDisposition.FileName = fileName;
return(response);
}