Hey Kouhei, Thanks for highlighting that there's an opt-out option now. I'm a little concerned that it requires servers to avoid sending a response at all, forcing an early decision by the infrastructure rather than allowing pages requested this way to be prefetched by not prerendered (by, e.g., sending a response header that says "prefetch is fine, but please don't render me").
Are there plans for such a header? It would go a long way to making me comfortable with this feature. Regards On Tuesday, March 15, 2022 at 7:10:12 AM UTC-7 Kouhei Ueno wrote: > Hi, > > While we are discussing, we would like to continue the incremental roll > out of the feature to non-Stable channels. As of now, we are testing out > the feature on 60% of Dev/Canary channels, and 60% of Beta channels. The > rollout is limited to Android Chrome (limitation of the current > implementation). > > We expect the rollout to affect at most a tiny fraction of the Internet > traffic generated by Chrome. The population of the Beta/Dev/Canary channels > combined is less than a few percent of Stable population, and the > navigation subject to prerendering on Prerendering-enabled Chrome is less > than a percent. > > Let me try to summarize the state of the discussion here (including the > questions we’ve received out-of-band). > > Q: Do you offer an opt-out mechanism to developers? > > A: Yes. The opt-out mechanism is now covered in this section > <https://github.com/WICG/nav-speculation/blob/main/ua-initiated-prerendering.md#opting-out> > > of the explainer. > > Q: What can we do about prerender breaking “switch to already open tab” on > WhatsApp? > > A: We are updating the BroadcastChannel interaction [spec > <https://github.com/WICG/nav-speculation/issues/141>, implementation > <https://chromium-review.googlesource.com/c/chromium/src/+/3517385>]. In > addition, we are delaying ServiceWorker#postMessage too, to address a > similar issue [crbug <https://crbug.com/1305120>] > > Q: Can Enterprise disable the feature by a policy? > > A: Yes - we respect the existing NetworkPredictionOptions > <https://chromeenterprise.google/policies/#NetworkPredictionOptions> > group policy. > > Q: What is the status of https://github.com/whatwg/html/issues/7533? > > A: The issue is a general “call for feedback” issue. Individual issues are > tracked on wicg/nav-speculation issue tracker > <https://github.com/WICG/nav-speculation/issues>. > > Q: Since prerendering risks breaking certain websites, what are the > mitigation measures planned? > > A: > > Prerendering is not entirely new. It used to be available in Chrome M13 > until M63 and has been available in many other browsers such as: Safari > since at least 2014 > <https://forums.macrumors.com/threads/safari-trying-to-pre-load-urls.1736761/>, > > Opera from 2017 > <https://www.ghacks.net/2017/02/07/opera-43-better-performance-classic-link-selection/#:~:text=cursor%20vertically%20instead.-,Instant%20Page%20Loading,-Instant%20Page%20Loading>, > > and more recently launched in Edge. We assume that the risk of breakage is > relatively low given these pre-existing conditions. That said, we will > remain prudent while relaunching this feature. > > > 1. > > Take a slow and transparent approach to our rollout: > 1. > > We’ll be careful around ramping up the experiment group population > that we will be monitoring the metrics and user reports closely. > 2. > > We’ll also be transparent about the rollout config on this > blink-dev thread. > 3. > > We’ll be keeping in touch with various partners to ensure that > everything is good on their end. > 2. > > Before going to Stable, we’ll publish a heads-up article on one of our > blogs with the following content: > 1. > > What’s being experimented with (e.g. prerendering on Chrome for > Android from the Omnibox) > 2. > > Things to know about this feature (e.g. how it triggers, how it > manifests itself, how it works) > 3. > > How to do hands-on testing, what to do if something breaks (e.g. > opt-out), how to share feedback to help us get this right. > 3. > > Being as conservative as other prerendering browsers (such as Edge and > Safari), as well as having the following extra mitigations: > 1. > > Allowing developers to opt-outs. > 2. > > Disabling prerendering on features known to be problematic or > surprising (e.g. BroadcastChannel, Media, and Sensor APIs) > > > -- > > Kouhei, on behalf of the Prerender2 team > > > On Mon, Feb 21, 2022 at 1:48 AM Coco Trana <cocotra...@gmail.com> wrote: > >> >> El dom., 20 de febrero de 2022 3:34 a. m., Noam Rosenthal < >> noam.j.rosent...@gmail.com> escribió: >> > >>> >>> On Sun, Feb 20, 2022 at 12:10 PM Jacob G <kurtext...@gmail.com> wrote: >>> >>>> Maybe a weird side-effect, but think of web.whatsapp.com: You have the >>>> tab open already, open a new tab, enter web.whatsapp.com, so you'll >>>> get an action item in the omnibox to switch to the already open tab - but >>>> with prerendering this leads to web.whatsapp.com showing you've opened >>>> the site in a new tab (even though you didn't - it got prerendered), >>>> making >>>> the "switch to already open tab" suggestion useless. >>>> Is this something site maintainers will have to fix or on the chromium >>>> side? (Prerendering interaction with already open tabs) >>>> >>> This is exactly the open issue discussed here: >>> https://github.com/WICG/nav-speculation/issues/141 >>> We want the default behavior to not create unexpected behavior such as >>> the ones you've described. >>> >>>> -- >>> >> 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/CAGttnEWV-HxsXds4W-ZcH_Aro4uvG1%2BjLmkM9io6xApi8LpjGA%40mail.gmail.com >>> >>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAGttnEWV-HxsXds4W-ZcH_Aro4uvG1%2BjLmkM9io6xApi8LpjGA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >>> >> > > -- > kouhei > -- 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/e22243e0-f7b6-403b-a646-407a959556bdn%40chromium.org.
