HTTP Caching

All hosted NodeJS apps leverage a HTTP cache on Cloudnode. We are using Varnish as a HTTP accelerator. Varnish uses numerous techniques to improve the performance. It even has compiled configuration libraries, in-memory logging, and works hand in hand with the OS for memory management.

Cache Invalidation

The biggest challenge when using caching is the control of the cache TTL and cache invalidation. Varnish only delivers a cached page, when it is absolutely safe to do so. The URL and all parameters have to match for a cache hit. So a Node app can control caching in different ways. Per default no caching takes place, but you should decide which pages or parts of your app could benefit from caching. Your application's response time will improve dramatically when you take the advantage of caching.

Cache TTL Control

Every application that is hosted on Cloudnode, even when running on a custom domain, leverages the caching layer. The time to live, or TTL, can easily be controlled using Node's response.setCacheable() call. By default, pages are not cached. When set to true, pages are cached for a long time, a perfect choice for pictures and other static content. When set to undefined, the cache headers need to be supplied by the application. This option allows custom control of the cache TTL times.