BLOGS@DiGiTSS

Apache 2.x is having module mod_deflate (mod_deflate.so) which can compress output irrespective of what scripting language you are using or even if you are serving a static but rich content website. If you are using PHP then there are ways available which can compress the output with buffering help but in that you need to write some code to make it happen but here we just need to enable mod_deflate module and add some configuration parameter and output compression will be taken care of by this module based on configuration provided.

Output compression is effective way of serving faster web-pages when you have content rich website with loads of html data, css and javascript assets in your web-site or web-application. It would help in saving bandwidth and data transfer over the wire (Internet) will be faster for users too. Though it will have impact on server's CPU utilization due to compression but this compression will be on the fly and level of compression will depend on server's load.

Still good practice is to use gzipped javascript assets as they will not be changed dynamically most of the time and we can save server's CPU utilization by not asking Apache to compress javascript files on each request.

To enable Apache > mod_deflate module, make sure you enable module by un-commenting it from httpd.conf file.

LoadModule deflate_module modules/mod_deflate.so

Then change <Directory ...> sections for Document Root in httpd.conf file as following:

#
# This should be changed to whatever you set DocumentRoot to.
#
<Directory "d:/www">
 #
 # Possible values for the Options directive are "None", "All",
 # or any combination of:
 #   Indexes Includes FollowSymLinks SymLinksifOwnerMatch ExecCGI MultiViews
 #
 # Note that "MultiViews" must be named *explicitly* --- "Options All"
 # doesn't give it to you.
 #
 # The Options directive is both complicated and important.  Please see
 # http://httpd.apache.org/docs/2.2/mod/core.html#options
 # for more information.
 #
 Options Indexes FollowSymLinks Includes ExecCGI

 #
 # AllowOverride controls what directives may be placed in .htaccess files.
 # It can be "All", "None", or any combination of the keywords:
 #   Options FileInfo AuthConfig Limit
 #
 AllowOverride All
 AllowOverride FileInfo
 #
 # Controls who can get stuff from this server.
 #
 Order allow,deny
 Allow from all

 AddOutputFilterByType DEFLATE text/plain
 AddOutputFilterByType DEFLATE text/html
 AddOutputFilterByType DEFLATE text/javascript
 AddOutputFilterByType DEFLATE text/css
 AddOutputFilterByType DEFLATE text/xml
 AddOutputFilterByType DEFLATE application/xhtml+xml
 AddOutputFilterByType DEFLATE application/javascript
 AddOutputFilterByType DEFLATE application/xml
 AddOutputFilterByType DEFLATE image/svg+xml
 AddOutputFilterByType DEFLATE application/rss+xml
 AddOutputFilterByType DEFLATE application/atom_xml
 AddOutputFilterByType DEFLATE application/x-javascript
 AddOutputFilterByType DEFLATE application/x-httpd-php
 AddOutputFilterByType DEFLATE application/x-httpd-fastphp
</Directory>

You can change/alter above filters based on your requirement, means that if you don't need some specific file-types not to be compressed then you can remove those filters by just removing those lines from above list. Almost all file-types are added in above mentioned configuration but if anything else needs to be added then just add another line next to if with "AddOutputFilterByType DEFLATE <FILE_TYPE_INFO>".

After making this change restart Apache service and to see the immediate difference go to Information > Document Size option on your Firefox > Web Developer toolbar.

Document Size option in Web Developer toolbar

It will give detailed report of document assets/parts as seen in the next image with size after compression.

Document Size: Report