C# Stream Response from 3rd party, minimal buffering

Question

Our ASP.NET MVC endpoint is a behaving as a proxy to another 3rd party HTTP endpoint, which returns about 400MB of XML document generated dynamically.

Is there a way

Answer 1

You can reduce the memory footprint by not buffering and just copying the stream directly to output stream, an quick n' dirty example of this here:

    public async Task Download()
    {
        using (var httpClient = new System.Net.Http.HttpClient())
        {
            using (
                var stream = await httpClient.GetStreamAsync(
                    "https://ckannet-storage.commondatastorage.googleapis.com/2012-10-22T184507/aft4.tsv.gz"
                    ))
            {
                Response.ContentType = "application/octet-stream";
                Response.Buffer = false;
                Response.BufferOutput = false;
                await stream.CopyToAsync(Response.OutputStream);
            }
            return new HttpStatusCodeResult(200);
        }
    }

If you want to reduce the footprint even more you can set a lower buffer size with the CopyToAsync(Stream, Int32) overload, default is 81920 bytes.