I am struggling to understand the exact behavior of the “Edge Cache TTL page rule”. There seems to be no documentation explicitly saying whether this acts a fallback or an override for responses that return no cache control headers from the origin.
The problem is, I wanted to use this page rule globally as a fallback while allowing some pages to opt out at the origin using
cache-control: max-age=0, no-cache, no-store, must-revalidate, private. As it does have the desired effect on the Cache Everything page rule (page won’t be cached) I expected the Edge Cache TTL page rule to also be ignored if
cache-control: no-cache is present, but the experience shows that this is not the case, no-cache pages are still edge-cached.
I found an older blog post here from 2013 that suggests that the Edge Cache TTL page rule is actually an override:
See “Respect all existing headers” on the screenshot that is unfortunately no longer part of the user interface.
Unfortunately, both links in that blog post in this sentence are broken: " You can find more information in our knowledge base articles here and here".
Are there any better sources on expected behavior of this rule?