Feature Request - Add ability to set TTL depending URL/Headers/Cookies

[darkweak]

We want to be able to define the cache TTL depending either one of URL, Headers or Cookies or every ones at the same time.
We could replace the MatchedURL object to another one, like CacheKey with the following structure

type CacheKey struct {
    type  string (eg."headers"|"cookies")
    regex string
}

Or another one with a priority field

type CacheKey struct {
    url      string (eg."/^.+$/")
    cookies  string (eg."/^.+$/")
    priority int
}

Then the YAML could be one of

cache_keys:
  - type: headers
    regex: '/^.+$/'
  - type: cookies
    regex: '/^.+$/'
  - type: headers
    regex: '/^[A-z]+$/'

cache_keys:
  - cookies: '/^.+$/'
    priority: 1
  - url: '/^.+$/'
    priority: 40
  - url: '/nothing$/'
    cookies: '/^Auth.+$/'
    priority: 999

[mattvb91]

I was just about to open a new issue asking if my headers are being ignored from the upstream as it seems to only ever use the config ttl setting and just seen this.

Big thumbs up for this as our backend controls all the caching times through the Cache-Control header