Most of my Flash apps or websites use XML files, either for communication or initial data. They can get quite large, reaching about 100 kb or more is not seldom. You might say: so what?! 100 kb is like nothing for a bandwidth nowadays! Well, if you’ve every used iPhone tethering in an area where there is no 3g network, you start appreciating every single byte you won’t have to suck from the net. (On a side note: That’s when Opera really comes in handy.)
XML files compress really well
Because XML usually contains a lot of repetitive elements (noticably tags and attributes), they are like a compressor’s darling. Just zip a few of your XML files and you’ll see. Now I kind of always thought that on nowadays webservers gzip compression is activated by default anyway. Which was wrong, at least for quite a bunch of servers I use.
Activate GZip compression
If your server installation contains the deflate module (which is the case for all of the ones I use), then you can simply add the following line to your .htaccess file:
# compress all html, plain text, xml, css and javascript:
AddOutputFilterByType DEFLATE text/html text/plain text/xml text/css application/x-javascript
AddOutputFilterByType DEFLATE text/html text/plain text/xml text/css application/x-javascript
I’ve also tried more complex constructs found on the web, but they resulted in «Internal server errors» which is why I’ll go along with this simple one for now.
*The effects are dramatic! I usually get about 70% – 80% of reduction for non-minimized files, *
Examples
Uncompressed Compressed Reduction
Javascript minimized MooTools YUI compressed 66,867 20,964 68.6%
Javascript minimized MooTools uncompressed 102,991 27,599 73.2%
XML/CSS combined A larger initial XML file for a Flash website of mine 84,316 18,229 78.4%
XML/CSS combined A larger initial XML file for a Flash website of mine 84,316 18,229 78.4%
HTML A swiss news website, 20 Minuten 148,587 29,385 80.2%
HTML My blogs home page 51,638 12,991 74.8%
Tools
If you want to test your website, these pages are very informative (first one is faster, second one more informative): http://www.whatsmyip.org/http_compression/
http://www.gidnetwork.com/tools/gzip-test.php I also like this one, although it only gives you little info on content-encoding. But very much on top of that :-) http://www.wmtips.com/tools/info/ This little Firefox addon will tell you wether any site you visit has GZip activated: https://addons.mozilla.org/en-US/firefox/addon/54647 (Content Encoding Detector)
Conclusion
HTML websites will profit a lot from this compression, as well as Flash sites (if just for your swfobject.js) that use textual communication. And best of all: it won’t need any kungfu effort on your side! And: practically all browsers support it. (I’ve only heard of problems with IE6, but then, you know, f*** IE6)
Update:
A more complete solution for your .htaccess file:
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE image/x-icon
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE text/javascript
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript
AddOutputFilterByType DEFLATE text/x-js
AddOutputFilterByType DEFLATE text/ecmascript
AddOutputFilterByType DEFLATE application/ecmascript
AddOutputFilterByType DEFLATE text/vbscript
AddOutputFilterByType DEFLATE text/fluffscript
AddOutputFilterByType DEFLATE image/svg+xml
AddOutputFilterByType DEFLATE application/x-font-ttf
AddOutputFilterByType DEFLATE application/x-font
AddOutputFilterByType DEFLATE font/opentype
AddOutputFilterByType DEFLATE font/otf
AddOutputFilterByType DEFLATE font/ttf
AddOutputFilterByType DEFLATE application/x-font-truetype
AddOutputFilterByType DEFLATE application/x-font-opentype
AddOutputFilterByType DEFLATE application/vnd.ms-fontobject
AddOutputFilterByType DEFLATE application/vnd.oasis.opendocument.formula-template
(Source)