The HTTP Rules engine allows users to customize the CDN edge server behavior, e.g. how the CDN will manage cache and redirection. This creates a lot of flexibility and adaptability for different platform websites to integrate with CDN without much hassle. HTTP rules are set in OnApp Control Panel and are specific to each CDN resource.
A CDN resource can be configured with up to 100 rules. This is collectively called a ruleset. A rule consists of conditions and actions. A condition consists of a subject, which determines the value to select, and a predicate, which specifies what to compare the subject against. Conditions are bonded by the connectives “AND” or “OR”. When all the conditions are met, the CDN edge server will perform the actions associated with the rule. The CDN edge server processes these rules from top to bottom order. It ends processing on the first match.
- You can create up to 100 rules per resource
- You can set up to 100 actions per rule
- Values can be up to 1000 characters long
- Rule processing ends after the first match
- You can set the rules for HTTP Pull and HTTP Push resources
For an HTTP Pull caching mechanism, a file larger than 2 GB is served through edge servers but not cached (not even the first 2 GB). If your files are larger than 200 MB, it is recommended to do advance prefetching for smoother delivery.