Magento hosting services generally use Apache as a web server solution. Magento is written in PHP, and Apache has a mature environment to handle PHP processes.
In order to give fast response to visitors' requests, we will use Apache's mod_deflate to speed up server response.
According to Apache's official documentation (http://httpd.apache.org/docs/2.2/mod/mod_deflate.html), this module provides the deflate output filter that allows output from your server to be compressed before being sent to the client over the network.
To enable this feature on your server, you need to create the .htaccess file and enter the following code:
<IfModule mod_deflate.c>
############################################
## enable apache served files compression
## http://developer.yahoo.com/performance/rules.html#gzip
# Insert filter on all content
SetOutputFilter DEFLATE
# Insert filter on selected content types only
AddOutputFilterByType DEFLATE text/html text/plain text/xml text/css text/javascript
# Netscape 4.x has some problems...
BrowserMatch ^Mozilla/4 gzip-only-text/html
# Netscape 4.06-4.08 have some more problems
BrowserMatch ^Mozilla/4\.0[678] no-gzip
# MSIE masquerades as Netscape, but it is fine
BrowserMatch \bMSIE !no-gzip !gzip-only-text/html
# Don't compress images
SetEnvIfNoCase Request_URI \.(?:gif|jpe?g|png)$ no-gzip dont-vary
# Make sure proxies don't deliver the wrong content
Header append Vary User-Agent env=!dont-vary
</IfModule>This adjustment reduces about 70% of the amount of data delivered.
For further information about the .htaccess and mod_deflate configurations, take a look at the links at http://httpd.apache.org/docs/current/howto/htaccess.html and http://httpd.apache.org/docs/2.2/mod/mod_deflate.html.