Edge Side Includes integration

Introduction

ESI - or Edge Side Includes - is a high performance caching solution for Authenticated users.

Typically, pages which are personalised for authenticated users (even minor personalisations, such as a block which says "Logged in as manarth") will prevent high-performance reverse-proxies from efficiently caching the page, because messages intended for one user could then be seen by another.

ESI addresses this issue by allowing personalised sections to be replaced with a special tag which is interpreted by the proxy - for example:

<esi src="http://example.com/esi/block/xxxxxx" />

The reverse proxy fetches the personalised content from the URL provided, merges it with the already-cached page (and often caches the contents of the ESI tag separately), and returns the final page to the user

This technique can easily improve performance by 10x, 100x, maybe even more.

Supported proxies

• Varnish is the only mainstream reverse proxy with inbuilt ESI support. Recommended.
• Akamai's services include support for ESI

If you know of any other proxies which provide native ESI support, please let us know!

Maintenance / Development status

The D6 branch is minimally maintained.
We're working on porting ESI to Drupal 7, which will provide an even faster implementation, and pluggability (so the module can support views, panels, and other modules, in addition to the core block module).

Sponsors

This project was created by Axis Twelve Ltd

This project is sponsored by Department for Education (UK)

Downloads