Downloading an in-memory file using Web Api 2
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At first you think it’s going to be easy to download a file from Web Api, but as I discovered, it was not.
In my case I wanted to load data from the database, perform some processing and return a subset of the data as a file. This meant I needed to send something that was in memory back to the caller as a file; I was NOT loading a file from the disk.
For simplicity I will skip all the database work and processing and jump to the in-memory object and how to return that.
The code is fairly self explanatory.
1using System.IO;
2using System.Net;
3using System.Net.Http;
4using System.Net.Http.Headers;
5using System.Text;
6using System.Web.Http;
7using System.Web.Http.Results;
8
9namespace WebApi2DownloadInMemoryFile.Controllers
10{
11 public class FileDownloadController : ApiController
12 {
13 public IHttpActionResult Get()
14 {
15 string someTextToSendAsAFile = "Hello world";
16 byte[] textAsBytes = Encoding.Unicode.GetBytes(someTextToSendAsAFile);
17
18 MemoryStream stream = new MemoryStream(textAsBytes);
19
20 HttpResponseMessage httpResponseMessage = new HttpResponseMessage(HttpStatusCode.OK)
21 {
22 Content = new StreamContent(stream)
23 };
24 httpResponseMessage.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
25 {
26 FileName = "WebApi2GeneratedFile.txt"
27 };
28 httpResponseMessage.Content.Headers.ContentType = new MediaTypeHeaderValue("text/plain");
29
30 ResponseMessageResult responseMessageResult = ResponseMessage(httpResponseMessage);
31 return responseMessageResult;
32 }
33 }
34}Download full source code