I also note that there's no issue with Accept if we require the use of the Flattened JSON serialization.
https://i.imgflip.com/25r2ui.jpg https://github.com/ietf-wg-acme/acme/pull/410 On Sun, Mar 4, 2018 at 6:28 PM, Martin Thomson <martin.thom...@gmail.com> wrote: > That's a bit silly. I'll follow-up with httpbis. I think that's an > error, though probably only an error of omission. 7694 was so fixated > on solving the content-coding issue, it neglected the obvious > accompanying fix. > > On Mon, Mar 5, 2018 at 9:38 AM, Richard Barnes <r...@ipv.sx> wrote: > > How about Accept? It looks like 7694 gives the server a way to specify > > encodings, but not the content type. But 7231 says that Accept only > replies > > to response media types. > > > > On Sun, Mar 4, 2018 at 5:33 PM, Martin Thomson <martin.thom...@gmail.com > > > > wrote: > >> > >> 415 is for the case where a client provides bad request content, so yes. > >> See rfc7694 for details. > >> > >> 406 is for failed conneg. Not something you expect to see much here. > >> > >> > >> On 5 Mar. 2018 09:25, "Richard Barnes" <r...@ipv.sx> wrote: > >> > >> The lengths of the emails in this thread illustrate the complexity risk > >> here :) > >> > >> In the interest of simplicity, I would really like to stick to Flattened > >> JSON unless someone has **strong** objections. > >> > >> Logan, to your point about library compatibility, two notes: (1) it's OK > >> if we front-run libraries a little. It's not hard for libraries to > upgrade; > >> this is only formatting, no crypto changes needed. (2) Empirically, > this > >> must not be too big a blocker for people, since as Jacob notes, Let's > >> Encrypt only supports Flattened JSON right now and they've got a bunch > of > >> clients talking to them. > >> > >> As far as headers / response codes: You're correct that 406 is wrong / > 415 > >> is right. But ISTM that Accept is still the right header to say what is > >> right. So the server should return 415+Accept. Copying Thomson to > check > >> our work here. > >> > >> --Richard > >> > >> On Sun, Mar 4, 2018 at 10:43 AM, Logan Widick <logan.wid...@gmail.com> > >> wrote: > >>> > >>> How about this: Specify a default format (either "application/jose" for > >>> Compact Serialization, or "application/jose+json" with Flattened > >>> Serialization - I have no preference which one), with optional support > for > >>> other formats if needed? Even with JOSE libraries that don't support > all > >>> serializations and/or don't provide control over which serialization is > >>> used, a programmer would at least need to know (or experimentally find > out) > >>> if a JSON serialization or if the compact one is being produced. If a > JSON > >>> serialization is selected as the default, a programmer should be able > to > >>> convert between the two JSON serializations easily as needed before > and/or > >>> after using a JOSE library. If a JSON format is declared as the > default but > >>> the JOSE library only has the compact one, or vice-versa, conversion > before > >>> and/or after the JOSE library would be more complex but should still be > >>> doable with guidance. > >>> > >>> The directory meta item could be defined as something like: > >>> > >>> supportedSerializations: An array of supported serialization formats as > >>> described in {{jws-serialization-formats}}. If this is not specified, > assume > >>> that the server only supports [insert selected default here]. > >>> > >>> Then, the JWS Serialization Formats section could be changed to > something > >>> like the following: > >>> > >>> The JSON Web Signature (JWS) specification {{!RFC7515}} contains > multiple > >>> JWS serialization formats. When sending an ACME request with a > non-empty > >>> body, an ACME client implementation SHOULD use the HTTP Content-Type > >>> {{!RFC7231}} header to indicate which JWS serialization format is used > for > >>> encapsulating the ACME request payload. > >>> > >>> Each serialization format defined for use in ACME is described with a > >>> content type, and a series of ACME-specific restrictions on root JWS > and > >>> nested JWS instances. A "root JWS" is a JWS used to encapsulate an > entire > >>> ACME request payload, and a "nested JWS" is a JWS contained within the > ACME > >>> request payload (such as the "externalAccountBinding" described in > >>> {{external-account-binding}} or the "key-change" object described in > >>> {{account-key-roll-over}}). Below are the JWS serialization formats > that are > >>> defined for use in ACME: > >>> > >>> [same list as before but with the default format coming first] > >>> > >>> If no Content-Type is provided, the default serialization type is > [insert > >>> selected default here]. Servers MUST support [insert selected default > here]. > >>> [NOTE: If a JSON format is selected as the default, say that a server > SHOULD > >>> support the other JSON format.] A server MAY support additional > >>> serializations, such as [insert serialization(s) not picked here], by > >>> including a "supportedSerializations" field in the directory "meta" > object > >>> as described in {{directory}}. > >>> > >>> If a server receives a request using a serialization it does not > support, > >>> the server MUST send a response with HTTP status code 415 (Unacceptable > >>> Media Type) and a problem document with error type > >>> "unsupportedSerialization". This problem document SHOULD contain a > >>> "supportedSerializations" array of strings indicating the acceptable > >>> serialization content types. > >>> > >>> [TODO: If a client uses the General JSON Serialization but it turns out > >>> the server only supports the Flattened JSON Serialization (or > vice-versa), > >>> explain that a 415 response indicates that the client will need to > switch > >>> JSON formats] > >>> > >>> [TODO: Insert a sentence or two specifying what happens if a supported > >>> serialization is used but the serialization is malformed? Should this > be 400 > >>> Bad Request + malformed error code + supportedSerializations?] > >>> > >>> In the examples below, JWS objects are shown in the Flattened JSON > >>> serialization, with the protected header and payload expressed as > >>> base64url(content) instead of the actual base64-encoded value, so that > the > >>> content is readable. [Example readability is a very high priority > regardless > >>> of which serialization format is actually chosen as the default, and > the > >>> current convention of Flattened JSON + base64url(content) is about as > >>> readable as it gets, so I don't think any changes will need to be made > here] > >>> > >>> > >>> On Sun, Mar 4, 2018 at 8:33 AM, Jörn Heissler > >>> <acme-sp...@joern.heissler.de> wrote: > >>>> > >>>> On Sun, Mar 04, 2018 at 07:45:36 -0600, Logan Widick wrote: > >>>> > Good catch. Should it be 415 (Unsupported Media Type) plus which of > >>>> > the > >>>> > following (or which combination of the following): > >>>> > > >>>> > - A new problem document field (tentatively named > >>>> > "supportedSerializations": an array of media type strings)? > >>>> > - A new directory field (tentatively named > >>>> > "supportedSerializations": an > >>>> > array of media type strings)? > >>>> > - Should this go in the directory's "meta" object, or in the > >>>> > directory object itself? > >>>> > - A HTTP header? > >>>> > - Something else? > >>>> > >>>> I like the directory approach with meta. Then a client could > >>>> use this information before sending the first POST. Else the client > >>>> would need to change an internal state after receiving the error > >>>> message. For my own client, I'm planning to support the OpenPGP smart > >>>> card. It takes 3 seconds to generate a signature. If a signature is > >>>> wasted to find out that the default serialization is not supported, it > >>>> would be annoying. Having to write a configuration file "use compact > by > >>>> default for CA foo" would be stupid too. > >>>> > >>>> This, and the problem document field. "supportedSerializations" sounds > >>>> fine. > >>>> > >>>> Should the two features be OPTIONAL? > >>>> > >>>> I don't like HTTP headers, it's quite complicated to parse them > >>>> correctly. > >>>> JSON is so much easier. > >>>> > >>>> > >>>> Or... specify that flattened MUST BE used :-) > >>>> > >>>> Cheers > >>>> Joern Heissler > >>> > >>> > >> > >> > > >
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