Enable before cache execution
Before cache execution is enabled at the Pull Zone level and applies to the script linked to that Pull Zone. Navigate to your Pull Zone, then go to General > Origin and enable Run script before cache. For standalone scripts, you can use the same Pull Zone toggle or enable it directly in the script settings.Middleware scripts
When before cache execution is enabled, middleware scripts gain access to two additional hooks that run on the client side of the cache:onClientRequest: runs on every incoming request before the cache lookup. Modify the request or short-circuit by returning a response directly.onClientResponse: runs just before the response is sent to the client, including responses served from the cache.