Configuration concept

Helicon Jet is configured on three different levels:

  • Directory & file level configuration
  • File extension & MIME type level configuration
  • User agents level configuration

To provide directory or file level configuration Helicon Jet uses a Directiry (URL) pattern concept. This means that there is a list of patterns which then will be matched against requested resource path and administrators can specify separate settings for each pattern in the list. Why didn’t we use a tree-style navigation to configure compression for specific directory or file? Because URL patterns are more flexible and powerful - they support wildcards (* and ?) and regular expressions. With patterns you can target not only a specific file or directory, but also file types or complex web site areas. You can do more with the less work and always have a single point to access all compression settings on the site so you don’t need to navigate through entire directory structure of your web site to find what has changed there. Please read Directory (URL) pattern for more information.

On the directory (URL) pattern level you can specify a compression level / processor utilization level for static and dynamic pages separately. This value does not mean an exact compression level being applied to every file, but a relative level from 0 to 9. Each type of compressed content in result will have it’s own compression level according to the settings in the Extension/MIME type configuration, but multiplied on 1/9*(directory level compression). So this setting determine a relative processor utilization policy, where 9 means maximum allowed compression for each type of content and thus maximum processor utilization and 0 means no compression will be applied.

File extension & MIME type configuration defines content-specific compression settings for getting the best performance and compression ratio for entire web site and specific content types.

User agents configuration defines a list of exclusions to address some client browser incompatibility issues. Under each user agent pattern you can set separate exclusion list for a specific file or content types.

When you use IIS Snap-in extension to configure Helicon Jet, it saves all changes to a text configuration file. Helicon Jet compression module loads this file every time it is changed. You don’t need to restart IIS to load your configuration changes. Under the hood Helicon Jet ISAPI compression filter uses only a text configuration, so you can edit this file manually or even install Helicon Jet ISAPI filter manually on your server and edit configuration file through the FTP.

Configuration file can be placed either in the Helicon Jet installation folder or in the .helicon directory under web site root folder. Placing it under web site root folder is very useful in shared hosting installation scenarions because it allows user to edit Helicon Jet configurations through FTP without server administrator involved. The configuration file name under the web site root should be HeliconJet.ini. Helicon Jet uses active configuration file name and location to create a folder to store temporary files and cache. So if you put configuration file under the web site root, then cache and other temporary files will be created in the Helicon Jet folder under the root folder of your web site.