UPDATE: Browsers have been dropping support for raw deflate. zOompf has completed some very thorough research on this very topic here. Unfortunately, it appears that raw deflate is NOT safe to use.
Check http://www.vervestudios.co/projects/compression-tests/results for more results.
Here are the browsers that have been tested:
/* Browser DEFLATE ZLIB */
XP Internet Explorer 6 PASS FAIL
XP Internet Explorer 7 PASS FAIL
XP Internet Explorer 8 PASS FAIL
Vista Internet Explorer 8 PASS FAIL
XP Firefox 3.6.* PASS PASS
XP Firefox 3.5.3 PASS PASS
XP Firefox 3.0.14 PASS PASS
Win 7 Firefox 3.6.* PASS PASS
Vista Firefox 3.6.* PASS PASS
Vista Firefox 3.5.3 PASS PASS
XP Safari 3 PASS PASS
XP Safari 4 PASS PASS
XP Chrome 3.0.195.27 PASS PASS
XP Opera 9 PASS PASS
XP Opera 10 PASS PASS
XP Sea Monkey 1.1.8 PASS PASS
Android 1.6 Browser (v4)* N/A N/A
OS-X Safari 4 PASS PASS
OS X Chrome 7.0.517.44 PASS PASS
OS X Opera 10.63 PASS PASS
iPhone 3.1 Safari PASS PASS
* Android Sends HTTP request header “Accept-Encoding: gzip”. Deflate is not permitted.
I conclude that we can always send raw DEFLATE (when the HTTP request header “Accept-Encoding” contains “deflate”) and the browser will be able to correctly interpret the encoded data. Can someone prove this wrong?
note: .NET’s native implementation of DEFLATE (System.IO.Compression.DeflateStream) is raw DEFLATE. It also sucks. Please use zlib.net for all of your .NET deflating needs.