[OAUTH-WG] SASL / OAuth Binding Request: User Field

[Ryan Troll <[e-mail]>]

I'd like to discuss the possibility of adding a "user" field to the
SASL/OAuth request.  This is based on draft-ietf-kitten-sasl-oauth-00.txt.

*Background*
The contents of this field may be used by the resource provider as a hint
to aid in request routing, and/or data location, without the need
for decrypting the provided access token.  The contents of the user field
is not used to grant access of any kind.


*Proposed Addition*
The text of this addition could look something like this:

Section 3.1 addition / update:

user:  Contains the user ID of the user being authorized

In authorization schemes that use signatures, the client MUST send host,
port number and user key/values, and the server MUST fail authorization
requests requiring signatures that do not have host, port, and user values.


Section 3.2 addition:

If the user field is present, the ID in the user field must match the ID
obtained from the credential for the request to succeed.



*Rationale for Presence of User Field in the Request*
This data is not required by all resource providers, and as such could be a
provider-specific requirement, placed (for example) in the query string.
 By documenting the user field, we encourage resource providers that do
require it to find it in the same location - encouraging inter-operability.

The user identity could be determined via the access token, rather than
requiring it in the request.  However, using the access token to determine
the identity can result in the resource provider decoding the token
multiple times, or making multiple requests to the access provider.  By
pulling this attribute out into the protocol, we may be able to simplify
the resource provider work required when moving to OAuth.


*Rationale for Location of User Field*
This data could be transmitted as part of the path, or a query string
parameter, or in the post body.  This approach, using a header, was
proposed as there are currently no path, query string, or post fields
defined.  Those three locations remain untouched by this proposal.
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Comments?
-R