Contact emailsdome...@chromium.org, jbro...@chromium.org, liviuti...@chromium.org
Explainerhttps://github.com/WICG/nav-speculation/blob/main/no-vary-search.md Specificationhttps://wicg.github.io/nav-speculation/no-vary-search.html Summary Enables prefetch to match even if URL query parameters change. The No-Vary-Search HTTP response header declares that some or all parts of a URL's query can be ignored for cache matching purposes. It can declare that the order of query parameter keys should not cause cache misses, that specific query parameters should not cause cache misses or that only certain known query parameters should cause cache misses. It could apply to multiple caches, but this entry refers to support for prefetch cache. We would like to ship "No-Vary-Search support in navigation prefetch cache" together with "No-Vary-Search Hint for Prefetch Speculation Rules" ( https://chromestatus.com/feature/4887338302308352). Blink componentInternals>Preload <https://bugs.chromium.org/p/chromium/issues/list?q=component:Internals%3EPreload> TAG reviewhttps://github.com/w3ctag/design-reviews/issues/797 TAG review statusPositive. Chromium Trial NameNoVarySearchPrefetch Link to origin trial feedback summary https://github.com/WICG/nav-speculation/issues Origin Trial documentation link https://developer.chrome.com/origintrials/#/view_trial/4146689356901384193 Risks Interoperability and Compatibility *Gecko*: No signal ( https://github.com/mozilla/standards-positions/issues/717) *WebKit*: No signal ( https://github.com/WebKit/standards-positions/issues/106) *Web developers*: Google Search has been experimenting with No-Vary-Search header / Speculation Rules "expects_no_vary_search". This functionality helps Google Search to match prefetched content to the next user navigation. Developers can use parameters in the prefetched URL that are not needed when navigating to the actual link (e.g. the source of the link click). The server can customize behavior using these parameters without causing a cache miss in the browser. "expects_no_vary_search" addition to Speculation Rules allows the browser to completely handle the case where the user navigates to a URL that is currently prefetched by waiting for the ongoing prefetch instead of directly requesting the page from the server. Google Search conducted experiments prefetching Search results pages from the search box and other links that lead to another Search results page. There was significant latency improvement for navigating to Search result pages prefetched using No-Vary-Search header and "expects_no_vary_search". *Other signals*: No-Vary-Search header has been discussed, together with No-Vary-Search Hint for Prefetch Speculation Rules at Web Perf WG meeting at TPAC 2023 <https://docs.google.com/presentation/d/1GK92nCORW5vKd7LgGtTsgy35eqTV7P71l05pHsni8ok/edit#slide=id.g240fd6541f7_0_31> . Ergonomics No-Vary-Search will be used in tandem with Speculation Rules ( https://wicg.github.io/nav-speculation/speculation-rules.html). The default usage of No-Vary-Search will not make it hard for Chrome to maintain good performance. Activation It will not be challenging for developers to take advantage of this feature immediately. Security See: https://github.com/WICG/nav-speculation/blob/main/no-vary-search-security-privacy-questionnaire.md WebView application risks Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications? None Debuggability The website owner can debug the feature in DevTools by making sure that, when navigating to a prefetched page by using a URL that matches under No-Vary-Search conditions, the navigation happens from the prefetch cache by looking at the Size column in the Network tab. In case of success, when hovering over the Size column in the Network tab of Dev Tools, they should see: "Served from prefetch cache, resource size: yyyB". No-Vary-Search header value for the prefetch is available on the Network tab. Developers can also use the preloading panel (https://crbug.com/1361483) which shows all ongoing preloads. Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?Yes Is this feature fully tested by web-platform-tests <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md> ?Yes https://wpt.fyi/results/speculation-rules/prefetch/no-vary-search?label=experimental&label=master&aligned Flag name on chrome://flags Finch feature nameNoVarySearchPrefetch Requires code in //chrome?False Tracking bughttps://bugs.chromium.org/p/chromium/issues/detail?id=1378075 Non-OSS dependencies Does the feature depend on any code or APIs outside the Chromium open source repository and its open-source dependencies to function? No. Estimated milestones Shipping on desktop 121 OriginTrial desktop last 120 OriginTrial desktop first 110 DevTrial on desktop 110 Shipping on Android 121 OriginTrial Android last 120 OriginTrial Android first 110 DevTrial on Android 110 Shipping on WebView 121 OriginTrial webView last 120 OriginTrial webView first 110 Anticipated spec changes Open questions about a feature may be a source of future web compat or interop issues. Please list open issues (e.g. links to known github issues in the project for the feature specification) whose resolution may introduce web compat/interop risk (e.g., changing to naming or structure of the API in a non-backward-compatible way). None. Link to entry on the Chrome Platform Status https://chromestatus.com/feature/5071247189213184 Links to previous Intent discussionsIntent to prototype: https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAHaAqYKutrvgMxR%3DnfAQOfBHNJo9ifrmFRSbiE0heDyeW0uKJA%40mail.gmail.com Intent to Experiment: https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAHaAqYLGT%2BV3_u_oumjHCZD05RRYY5guMjz1vb7501sNF1CANg%40mail.gmail.com Intent to Extend Experiment: https://groups.google.com/a/chromium.org/g/blink-dev/c/7oMlGWmVv2Q/m/B2PACBSnBgAJ -- You received this message because you are subscribed to the Google Groups "blink-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to blink-dev+unsubscr...@chromium.org. To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAHaAqYKL2psmkYpQQ6KjrM_41yt8f%3DvH_-m0%3DT4idWT4zSumHw%40mail.gmail.com.
