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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