issue_comments

Hah, found a TODO about this: https://github.com/simonw/datasette/blob/c5791156d92615f25696ba93dae5bb2dcc192c98/datasette/app.py#L997-L999

It sounds like you can workaround this with Varnish configuration for the moment, but I'm going to bump this up the list of things to fix - it's particularly relevant now as I'd like to get a solution in place before Datasette 1.0, since it's likely to be beneficial to plugins and hence should be part of the stable, documented plugin interface.

The existing app_css_hash already isn't good enough, because I built that before table.js existed, and that file should obviously be smartly cached too.

I agree: this is bad.

Ideally, content served from /static/ would apply best practices for static content serving - which to my mind means the following:

• Where possible, serve with a far-future cache expiry header and use an asset URL that changes when the file itself changes
• For assets without that, support conditional GET to avoid transferring the whole asset if it hasn't changed
• Some kind of sensible mechanism for setting cache TTLs on assets that don't have a unique-file-per-version - in particular assets that might be served from plugins.

Datasette half-implemented the first of these: if you view source on https://latest.datasette.io/ you'll see it links to /-/static/app.css?cead5a - which in the template looks like this:

https://github.com/simonw/datasette/blob/dd94157f8958bdfe9f45575add934ccf1aba6d63/datasette/templates/base.html#L5

I had forgotten I had implemented this! Here is how it is calculated:

https://github.com/simonw/datasette/blob/458f03ad3a454d271f47a643f4530bd8b60ddb76/datasette/app.py#L510-L516

So app.css right now could be safely served with a far-future cache header... only it isn't: ~ % curl -i 'https://latest.datasette.io/-/static/app.css?cead5a' HTTP/2 200 content-type: text/css x-databases: _memory, _internal, fixtures, extra_database x-cloud-trace-context: 9ddc825620eb53d30fc127d1c750f342 date: Sat, 05 Mar 2022 01:01:53 GMT server: Google Frontend content-length: 16178 The larger question though is what to do about other assets. I'm particularly interested in plugin assets, since visualization plugins like datasette-vega and datasette-cluster-map ship with large amounts of JavaScript and I'd really like that to be sensibly cached by default.