Simon Willison’s Weblog

17th March 2024 - Link Blog

Add ETag header for static responses. I’ve been procrastinating on adding better caching headers for static assets (JavaScript and CSS) served by Datasette for several years, because I’ve been wanting to implement the perfect solution that sets far-future cache headers on every asset and ensures the URLs change when they are updated.

Agustin Bacigalup just submitted the best kind of pull request: he observed that adding ETag support for static assets would side-step the complexity while adding much of the benefit, and implemented it along with tests.

It’s a substantial performance improvement for any Datasette instance with a number of JavaScript plugins... like the ones we are building on Datasette Cloud. I’m just annoyed we didn’t ship something like this sooner!