- From: Mark Nottingham <mnot@mnot.net>
- Date: Tue, 31 Jan 2017 18:28:17 +1100
- To: Martin Thomson <martin.thomson@gmail.com>
- Cc: Ilya Grigorik <ilya@igvita.com>, "ietf-http-wg@w3.org Group" <ietf-http-wg@w3.org>
> On 24 Dec 2016, at 2:14 am, Mark Nottingham <mnot@mnot.net> wrote: > > >> On 13 Dec. 2016, at 7:31 pm, Martin Thomson <martin.thomson@gmail.com> wrote: >> >> On 6 December 2016 at 08:51, Ilya Grigorik <ilya@igvita.com> wrote: >>> Background: https://github.com/httpwg/http-extensions/issues/168 >>> >>> We didn't intend Save-Data to be a list.. The goal was to allow attributes >>> on the single token defined in CH. I'll defer to Mark on Key. >> >> >> Whether you have a list or not, Save-Data has some odd semantics when >> it comes to extension. How do I model the following variants? >> >> Save-Data: on >> Save-Data: on;video-only >> Save-Data: on;exclude-video >> Save-Data: on;compress-video-more >> >> Assuming that the extensions are not understood, we end up in an odd >> place. I see several conclusions: >> >> 1. unknown extensions are ignored >> 2. unknown extensions can only increase the amount of compression; and >> are ignored otherwise (see compress-video-more) >> 3. unknown extensions cause the entire clause to be ignored >> >> Option 1 seems to be what we have right now, but that doesn't give a >> client any way to request selective compression (the >> video-only/not-video example). >> >> Option 2 might allow a client to request more aggressive compression, >> but it does nothing to address the case where a client wants video >> compression, but would prefer not to have images degraded by >> compression. >> >> Option 3 might be combined with a comma-separated list to allow >> clients to provide a fallback strategy. >> >> There's also probably something more complex as well. > > I think there's also an Option 4: extensions can only be defined by a sd-token, when it is defined. I.e., this extension syntax is for the use of future sd-tokens, not for arbitrary extension independent of them. > > That's what I'd assumed when we defined the syntax; regardless of the intent, we should write something down about how the extension point is used. Is this workable for everyone? -- Mark Nottingham https://www.mnot.net/
Received on Tuesday, 31 January 2017 07:28:49 UTC