I'm working on a web service using ASP.NET MVC's new WebAPI that will serve up binary files, mostly .cab
and .exe
files.
The following controller method seems to work, meaning that it returns a file, but it's setting the content type to application/json
:
public HttpResponseMessage<Stream> Post(string version, string environment, string filetype)
{
var path = @"C:\Temp\test.exe";
var stream = new FileStream(path, FileMode.Open);
return new HttpResponseMessage<Stream>(stream, new MediaTypeHeaderValue("application/octet-stream"));
}
Is there a better way to do this?
Try using a simple HttpResponseMessage
with its Content
property set to a StreamContent
:
// using System.IO;
// using System.Net.Http;
// using System.Net.Http.Headers;
public HttpResponseMessage Post(string version, string environment,
string filetype)
{
var path = @"C:\Temp\test.exe";
HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
var stream = new FileStream(path, FileMode.Open, FileAccess.Read);
result.Content = new StreamContent(stream);
result.Content.Headers.ContentType =
new MediaTypeHeaderValue("application/octet-stream");
return result;
}
A few things to note about the stream
used:
You must not call stream.Dispose()
, since Web API still needs to be able to access it when it processes the controller method's result
to send data back to the client. Therefore, do not use a using (var stream = …)
block. Web API will dispose the stream for you.
Make sure that the stream has its current position set to 0 (i.e. the beginning of the stream's data). In the above example, this is a given since you've only just opened the file. However, in other scenarios (such as when you first write some binary data to a MemoryStream
), make sure to stream.Seek(0, SeekOrigin.Begin);
or set stream.Position = 0;
With file streams, explicitly specifying FileAccess.Read
permission can help prevent access rights issues on web servers; IIS application pool accounts are often given only read / list / execute access rights to the wwwroot.