Compression is not working

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?

As ZiyaSAL points out, the browser must first indicate that it accepts compressed content. Have you checked the headers sent from the browser to the server? This related question might help: http://stackoverflow.com/q/897989/64096 — Marnix van Valen, Jul 05 '12 at 09:11

John Culviner · Answer 1 · 2012-07-05T16:11:02.270

4

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!

edited Jul 05 '12 at 16:11

answered Jun 22 '12 at 06:28

John Culviner

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ziyasal · Answer 2 · 2012-07-01T11:59:35.493

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;

score -1 · Answer 3 · answered Jul 02 '12 at 06:21

-1

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

answered Jul 02 '12 at 06:21

Edi Wang

3,547
6
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Compression is not working

3 Answers3

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