Add Vary header on outer response. about nginx-sxg-module HOT 2 CLOSED

I think, using nginx feature like add_header vary accept; may be enough.

from nginx-sxg-module.

+1.

If the module is turned on, accept should always be added to Vary header automatically regardless of response type. Because this might cause serving a wrong content from the nginx if developer forget adding the header, let's say serving SXG response to a non-supported browser such as Safari. It can be critical for them. I'm not sure it's related or not, but the header can be one of there formats

One single header has multiple values

Vary: Accept, Accept-Encoding

Send two separate headers:

Vary: Accept
Vary: Accept-Encoding

https://tools.ietf.org/html/rfc7230#section-3.2.2

Also, be careful not to override existing Vary header from upstream. Just appending a new header sounds fair? It looks amppackager simply add the header.
https://github.com/ampproject/amppackager

from nginx-sxg-module.