December 2, 2023 at 11:54AM
Google Chrome is changing how its Back/Forward Cache works by ignoring the “Cache-control: no-store” header on HTTPS pages, allowing such pages to be cached for faster navigation. This move aims to improve browsing speed by enabling instant page restoration, though it raises concerns about outdated data and broken developer assumptions regarding cache behavior. Google plans to test and evaluate the impact before wider implementation.
Meeting Takeaways:
1. Google Chrome is planning to update its Back/Forward Cache (BFCache) to store pages in cache even when webmasters use the “Cache-control: no-store” header, which traditionally indicates a page should not be stored in browser cache.
2. BFCache retains a complete snapshot of a page as users navigate away, allowing for faster page restoration during back/forward navigations.
3. The primary aim of the proposed change is to enhance user experience by enabling instant navigation without undermining the security of sensitive data accessed previously.
4. Google acknowledges there might be challenges with server-side changes where the user loses access to the page, which the current BFCache behavior could impact by potentially showing outdated or inaccessible data.
5. Google intends to first roll out the feature in test channels to collect data and evaluate the impact before a wider release.
6. Concerns have been raised regarding the implications of this change on developer expectations, with some believing that the “Cache-control: no-store” header’s original promise to not cache pages is being altered.
7. Google argues that the header was only meant to control HTTP caching and not BFCache, as they are different, and developers should not expect the “Cache-control: no-store” header to prevent a page from being stored in BFCache.
8. By revising the interaction between BFCache and the “Cache-control: no-store” directive, Google’s goal is to improve the responsiveness of web browsing while still respecting user privacy and security.