This repository is a reproduction for Chromium issue 1380505. The issue is that it is not possible to catch both HTML and JSON responses for the same URL. Requesting both resources invalidate any cached version of each other.
To run, you should use Go:
go run main.go
And then open http://localhost:8000/ in Chromium. Open network tab in DevTools.
The first time you should see three requests made, one for / for text/html, another for /data.json
for application/json and another for /data.json for text/html. In the server's terminal you should see
something like:
2023/07/20 11:51:04 Listening on :8000
2023/07/20 11:51:12 Serving HTML at /
2023/07/20 11:51:12 Serving JSON at /data.json
2023/07/20 11:51:12 Serving HTML at /data.json
Loading the page again should ideally not make any requests (handled all from cache) given that all responses
are set to immutable Cache-Control response header, or at least there should be only request for /
(as it is the main requested page) made.
You see every time you open the page three requests made to the server.
Etags do not help. immutable Cache-Control header does not help. A browser still make requests.
Tested on Chromium 114.0.5735.198. Firefox 115.0.2 behaves the same.