Open schlessera opened 3 years ago
Related issue in Node.JS optimizer: https://github.com/ampproject/amp-toolbox/issues/960
Sorry I missed this. For reference, in Google this was originally added in http://cl/239478133 per http://b/118606783.
Since you landed a fix on the optimizer, I think it makes sense to do the same here, and it seems safe to do so.
I think this combined preconnect and dns-prefetch resource hint is not always doing what it is supposed to do depending on the browser:
https://github.com/ampproject/amppackager/blob/f1d819c86e9ab7f1f1a6578b7b4017e60fa02dc8/transformer/transformers/linktag.go#L69
As far as I can tell, the
dns-prefetch
is meant to be the fallback in case thepreconnect
is not supported (as thepreconnect
would include a DNS resolution). However, thedns-prefetch
is mentioned first, which seems odd.Also, according to web.dev, best practice is to use two separate hints with the
dns-prefetch
as the second hint serving as a fallback, as using a combined hint will break in Safari: https://web.dev/preconnect-and-dns-prefetch/#resolve-domain-name-early-with-reldns-prefetch