[Openid-specs-ab] proposed POST response type for OAuth/Connect

Vladimir Dzhuvinov / NimbusDS vladimir at nimbusds.com
Fri Oct 18 08:42:22 UTC 2013

Hi Mike, hi guys,

I read the proposed spec and it looks good to me. Making the "what" and
the "how" orthogonal parameters is great.


Vladimir Dzhuvinov : www.NimbusDS.com : vladimir at nimbusds.com

-------- Original Message --------
Subject: Re: [Openid-specs-ab] proposed POST response type for
From: Mike Jones <Michael.Jones at microsoft.com>
Date: Fri, October 18, 2013 8:02 am
To: "<openid-specs-ab at lists.openid.net>"
<openid-specs-ab at lists.openid.net>

  As Breno suggested, I’ve made the proposed changes to the Multiple
Response Types spec.  These changes do two things:
 1.      Disentangle the specification of what parameters are to be
returned (which is done with the response_type parameter) from the
specification of how they are to be returned (which is done with the
response_encoding parameter).
 2.      Define a POST response encoding that can be used to request
that parameters be returned via form POST.
 The response_encoding parameter is only used when a non-default
encoding is requested, so these changes will no effect on current
 I’ve posted an updated version at 
 The .xml source is posted there as well.  Also, diffs from the current
BitBucket version can be viewed as tracked changes in the Word version
 Tomorrow I’ll review the current Connect specs and make the following
related proposed changes:
 ·        Add the response_encodings_supported discovery parameter.
 ·        Review the places where fragment encoding is explicitly or
implicitly specified, making sure the language doesn’t prohibit using
the POST response encoding instead.  (Note that we should do this now,
even should we don’t adopt POST as part of the core now, so we don’t
preclude it in the future.)
 (I’d make these changes now, but it’s probably better that I do it
when I’m not tired.)
 Anyway, this wasn’t hard and the result isn’t difficult to
understand or implement.  (And implementation will remain optional.)
 Thanks to Breno, John, and Brian for the feedback on how this should
work.  Thanks especially to Brian for posting his draft, which I
borrowed some text and the example from.
                                                             -- Mike
 From: Breno de Medeiros [mailto:breno at google.com] 
 Sent: Thursday, October 17, 2013 4:02 PM
 To: Mike Jones
 Cc: Brian Campbell; <openid-specs-ab at lists.openid.net>
 Subject: Re: [Openid-specs-ab] proposed POST response type for
  On Thu, Oct 17, 2013 at 11:37 AM, Mike Jones
<Michael.Jones at microsoft.com> wrote:
   Thanks, Brian.  This is really useful.  I suspect I’ll be using
some of your text in my write-up. J
 I just spent some time on the phone with Breno discussing this and he
agreed that defining a POST response at this point is reasonable.  When
talking about possible ways of specifying the POST response behavior, he
stated the principle that when a behavioral change is being requested,
that this should be done so dynamically, rather than via registration. 
That way, particular clients can be updated to use this behavior without
requiring a new client registration.  (He likes using registration to
specify behavioral restrictions, however, such as requiring particular
signing/encryption algorithms, etc.)
 He said that the way that he’d do it is to include a
“transport=POST” parameter in the authorization request.  So
that’s what I’ll write up.  We could later than define
“transport=postMessage”, “transport=CORS”, etc. if we decide to
do so.

I think this is sufficiently small that we might be able to undertake in
a short time-frame. I believe that POST support will prove useful. I'd
recommend this to be added to the new response types part of the spec:
for a number of reasons: It already has the burden to deal with the
security properties of different encoding formats for different response
types, and would be a small change in scope to change it to talk about
'transport' modes instead of encoding. That spec also has been stable
and changed little for a long time, so the chance that it can be
re-written w/o side-effects is probably higher.
 As an aside, Breno also said that the reason that he thinks Session
Management isn’t yet ready to be final, is that he’d like us to
explore the option of using a CORS transport, rather than postMessage
within Session Management.  I’ll leave it to Breno to say more about
                                                                 -- Mike
 From: openid-specs-ab-bounces at lists.openid.net
[mailto:openid-specs-ab-bounces at lists.openid.net] On Behalf Of Brian
 Sent: Thursday, October 17, 2013 8:56 AM
 To: <openid-specs-ab at lists.openid.net>
 Subject: [Openid-specs-ab] proposed POST response type for
    As discussed during today's call [1], attached is the
pseudo-standard document I wrote up earlier this year describing an HTTP
POST response type (effectively a POST binding) for OAuth/OIDC. 
I know everyone has a lot of docs to read right now but this one is
*very* short and has a good example. 
We've found this approach to work well in practice and be easy to
It can be done as a straight extension, as illustrated with this doc, or
could incorporated into core connect.
As John mentioned, the main drawback of this approach is proliferation
of the Response Types registry. Which is kind of ugly but something that
no one will care much about once it's done. It's also more of a
consequence of the response type constructs put forth by OAuth than it
is with this particular extension.




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