Logo Questions Linux Laravel Mysql Ubuntu Git Menu
HTML CSS JAVASCRIPT SQL PYTHON PHP BOOTSTRAP JAVA JQUERY R React Kotlin
 

Deflate compression browser compatibility and advantages over GZIP

Tags:

optimization

compression

gzip

zlib

deflate

People also ask

What is the difference between gzip and DEFLATE?

gzip is based on the DEFLATE algorithm, which is a combination of LZ77 and Huffman coding. DEFLATE was intended as a replacement for LZW and other patent-encumbered data compression algorithms which, at the time, limited the usability of compress and other popular archivers.

Do any browsers not support gzip?

All modern browsers can handle a gzip encoded response. In fact, if you look at their requests, they'll have a header that says something along the lines of Accept-Encoding: gzip which is their way of saying to the server that they can handle gzipped responses.

What does gzip DEFLATE mean?

It means the client can accept a response which has been compressed using the DEFLATE algorithm.

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.


The Android 1.6 browser (v4) fails both the zlib and the deflate test on your page. I've added it to your list.


Isn't it the case that AddOutputFilterByType DEFLATE using mod_deflate sends by gzip by default?

Related questions

In ArrayBlockingQueue, why copy final member field into local final variable?
Why would code actively try to prevent tail-call optimization?
foldl is tail recursive, so how come foldr runs faster than foldl?
Why does adding inline assembly comments cause such radical change in GCC's generated code?
Field vs Property. Optimisation of performance
MySql views performance [closed]
How to calculate percentage improvement in response time for performance testing
Fastest way to put contents of Set<String> to a single String with words separated by a whitespace?
Get coefficients estimated by maximum likelihood into a stargazer table
Why are operators so much slower than method calls? (structs are slower only on older JITs)
Fastest way to strip all non-printable characters from a Java String
PostgreSQL temporary tables
Saturating subtract/add for unsigned bytes
delete all from table
Java Integer compareTo() - why use comparison vs. subtraction?
Why GDB jumps unpredictably between lines and prints variables as "<value optimized out>"?
When is optimisation premature?
Why does this Haskell code run slower with -O?
What are stalled-cycles-frontend and stalled-cycles-backend in 'perf stat' result?
When is not a good time to use python generators?

Donate For Us

If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!