Compression is not working - asp.net

Question

I need to compress all dynamic content of my data export site.
I've tried numerous ways, nothing works. Chrome shows that content is not compressed and "Content-Encoding" header is not present.
Trying to do it like this as the last resort method (before writing any response):
context.Response.Filter = new DeflateStream(context.Response.Filter, CompressionMode.Compress);
context.Response.AppendHeader("Content-Encoding", "deflate");
Logging shows that this code is executed correctly.
However, Chrome shows that content is not compressed, again.
UPD when using IIS built-in compression, it seems to work and request tracing shows "DYNAMIC_COMPRESSION_SUCCESS". However, IE still shows that response is not compressed. The same when I'm requesting the page from the server itself using localhost name.
Any ideas?

Answer 1

If you want to do this manually first check the compression is supported,
public static bool IsGZipSupported()
{
string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"];
if (!string.IsNullOrEmpty(AcceptEncoding) &&
(AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate")))
return true;
return false;
}
And compress your response,
public static void GZipEncodePage()
{
if (IsGZipSupported()) {
HttpResponse Response = HttpContext.Current.Response;
string AcceptEncoding = HttpContext.Current.Request.Headers("Accept-Encoding");
if (AcceptEncoding.Contains("gzip")) {
Response.Filter = new System.IO.Compression.GZipStream(Response.Filter, System.IO.Compression.CompressionMode.Compress);
Response.AppendHeader("Content-Encoding", "gzip");
} else {
Response.Filter = new System.IO.Compression.DeflateStream(Response.Filter, System.IO.Compression.CompressionMode.Compress);
Response.AppendHeader("Content-Encoding", "deflate");
}
You can check filter is attached just before the headers are sent to the client
protected void Application_PreSendRequestHeaders()
{
HttpResponse response = HttpContext.Current.Response;
if (response.Filter is GZipStream && response.Headers["Content-encoding"] != "gzip")
response.AppendHeader("Content-encoding", "gzip");
else if (response.Filter is DeflateStream && response.Headers["Content-encoding"] != "deflate")
response.AppendHeader("Content-encoding", "deflate");
}
For more information check this posts;
ASP.NET GZip Encoding Caveats
Built-in GZip/Deflate Compression on IIS 7.x
Benefits and Drawbacks of IIS 7 Compression

Answer 2

Instead of trying to do this manually I would rely on the pre-written (and tested) Microsoft code built into IIS that will do this for you:
Install Dynamic Content Compression on the machine (bullet 5 in the link) and enable it in IIS. IIS will now handle compression for on both static and dynamic content. Less code to maintain (and invariably have bugs) is always a good thing!

Answer 3

If you are using IIS7+, there's an Compression option. Navigate to your site, in the right main window, click "Compression", and check all 2 checkboxes:
Enable dynamic content compression
Enable static content compression