Use case for Headers getAll

[xtuc]

Since https://github.com/whatwg/fetch/commit/42464c8c3d2fd3437a19fc6afd2438a0fd42dde8 Headers.prototype.getAll has been deprecated/removed from the spec and implementations.

I understand that in browsers (including service workers) filtered responses don't include headers that could benefit from the getAll method. However, some JavaScript environment doesn't need to filter response/request headers, like serverless plateforms (for instance Cloudflare Workers) or maybe Nodejs at some point.

For example editing Cookie headers:

const h = new Headers;
h.append("Set-Cookie", "a=1; Expires=Wed, 21 Oct 2015 07:28:00 GMT");
h.append("Set-Cookie", "b=1; Expires=Wed, 21 Oct 2015 07:28:00 GMT");

h.get("Set-Cookie")
// a=1; Expires=Wed, 21 Oct 2015 07:28:00 GMT, b=1; Expires=Wed, 21 Oct 2015 07:28:00 GMT

Spliting the combined header value by , will give an invalid result. Instead getAll could be used to retrieve the individual headers.

[Mouvedia]

what about X-Robots-Tag for example where rules specified without a user agent are valid for all

console.log(
  new Headers([
    ['x-robots-tag', 'noindex'],
    ['x-robots-tag', 'unavailable_after: 25 Jun 2099 15:00:00'],
    ['x-robots-tag', 'somebot: nofollow'],
    ['x-robots-tag', 'otherbot: noindex, nofollow'],
    ['x-robots-tag', 'noarchive'],
  ]).get('x-robots-tag')
  ==
  'noindex, unavailable_after: 25 Jun 2099 15:00:00, somebot: nofollow, otherbot: noindex, nofollow, noarchive'
)

You always have to put the *bot last in your array. i.e. noindex, noarchive should be the first 2 in your output It doesn't fix , nofollow though.

[med-ab]

. i.e. noindex, noarchive should be the first 2 in your output

they "should" but what to do when a server sends them after other ua rules?

[annevk]

https://httpwg.org/specs/rfc9110.html#rfc.section.5.3