Has Anyone Got HTTP Compression Working with ASP.NET? - asp.net

Question

I've spent quite a bit of time on this but seem to be going nowhere. I have a large page that I really want to speed up. The obvious place to start seems to be HTTP compression, but I just can't seem to get it to work for me.
After considerable searching, I've tried several variations of the code below. It kind of works, but after refreshing the browser, the results seem to fall apart. They were turning to garbage when the page used caching. If I turn off caching, then the page seems right but I lose my CSS formatting (stored in a separate file) and get an error that an included JS file contains invalid characters.
Most of the resources I've found on the Web were either very old or focused on accessing IIS directly. My page is running on a shared hosting account and I do not have direct access to IIS7, which it's running on.
protected void Application_BeginRequest(object sender, EventArgs e)
{
// Implement HTTP compression
if (Request["HTTP_X_MICROSOFTAJAX"] == null) // Avoid compressing AJAX calls
{
// Retrieve accepted encodings
string encodings = Request.Headers.Get("Accept-Encoding");
if (encodings != null)
{
// Verify support for or gzip (deflate takes preference)
encodings = encodings.ToLower();
if (encodings.Contains("gzip") || encodings == "*")
{
Response.Filter = new GZipStream(Response.Filter,
CompressionMode.Compress);
Response.AppendHeader("Content-Encoding", "gzip");
Response.Cache.VaryByHeaders["Accept-encoding"] = true;
}
else if (encodings.Contains("deflate"))
{
Response.Filter = new DeflateStream(Response.Filter,
CompressionMode.Compress);
Response.AppendHeader("Content-Encoding", "deflate");
Response.Cache.VaryByHeaders["Accept-encoding"] = true;
}
}
}
}
Is anyone having better success with this?

Answer 1

I've had good results using GZipStream and DeflateStream to write the output directly, although I'm not familiar with the Response.Filter property. Give this a whirl:
string response = "your output body";
string accept = Request.Headers["Accept-Encoding"];
if(accept == null) accept = "";
if (response.Length < 100 || !(accept.Contains("deflate") || accept.Contains("gzip")))
Response.Write(response);
else
{
byte[] compressed;
bool useDeflate = accept.Contains("deflate");
using (MemoryStream stream = new MemoryStream())
{
using (Stream deflate = useDeflate
? (Stream)new DeflateStream(stream, CompressionMode.Compress, true)
: (Stream)new GZipStream(stream, CompressionMode.Compress, true))
using (StreamWriter writer = new StreamWriter(deflate))
writer.Write(response);
compressed = new byte[stream.Length];
stream.Position = 0;
stream.Read(compressed, 0, compressed.Length);
}
Response.Headers["Content-Encoding"] = useDeflate ? "deflate" : "gzip";
Response.BinaryWrite(compressed);
}