At IIW2007

I'm at IIW right now and also hacking away on OpenAuth and Blogs.  Which does make sense since the people I need to talk to about how it should work are mostly here, with the exception of Praveen, who for some inexplicable reason prefers France.

So far so good; this curl command posts a blog entry on my Atom blog service:

curl -k -v -sS --include --location-trusted --request POST --url 'https://monotreme:4279/_atom/collection/blogssmoketester' --data @/tmp/ieRN0zhgh6 --header 'Content-Type: application/atom+xml; charset=utf-8' --header 'Authorization: OpenAuth token="%2FwEAAAAABYgbMtk4J7Zwqd8WHKjNF6fgJSYe4RhTuitkNyip%2BEru%2FY43vaGyE2fTlxKPAEkBC%2Bf5lhWg18CE2gaQtTVQy0rpillqtUVOOtrf1%2BLzE%2BNTcBuFJuLssU%2B6sc0%3D" devid="co1dDRMvlgZJXvWK"'

Note that the token, which gives authorization and authentication, is obtained with a separate login call to an internal OpenAuth server.  It looks like I need both the token and the devid; the devid essentially identifies the agent representing the user.

I should be able to post this curl command line with impunity because it shouldn't expose any private data, unlike the HTTP Basic Auth equivalent which exposes the user's password in nearly clear text.  This also implies that it should be possible to avoid using TLS.

Now, if I had a standard way to get a token for an OpenID session, I could pass that in like so:

Authorization: OpenID token="...."

And my server will advertise that it accepts all three -- Basic, OpenAuth, and OpenID.  I hope to talk with like minded people about this at IIW.

Tags: iiw2007, openauth, openid, Atom, REST

Sun += OpenID

Tim Bray just blogged about openid.sun.com, which is an identity provider for Sun employees only.  Interesting!  Though technically one would like to be able to do independent assertions about user centric identities ("works for Sun" being a reasonable assertion one could make about any identity).  I suppose though that someone could use OP delegation to point http://me.example.org to openid.sun.com and achieve part of the same effect.  And in the end you'll need to rely on something like openid.sun.com to validate assertions presumably.

AOL OpenAuth and Atom Publishing Protocol

I'm looking to see how best to implement Atom-compatible authentication for AOL's OpenAuth service.  The service provides ways for users to authenticate themselves and to grant permissions to services to do things such as read buddy lists on behalf of a user.  These permissions are encapsulated in a portable token which can be passed around.  The primary use cases for this involve pure web based AJAX applications, so making this something that a generic application can deal with isn't fully specified.

So, here are my thoughts.  Let's say the client has a token string which encapsulates authentication and authorization.  They need to send this along with an Atom Publishing Protocol (APP) request. 

Windows Live and GData both implement custom RFC 2617 WWW-Authenticate: header schemes.  Unfortunately they don't follow exactly the same pattern, or I'd just copy it.  But using RFC 2617 is clearly the right approach if the server can support it.  So here's a proposal:

If a client has an OpenAuth token, it sends an Authorization: header.  The format looks like this:

Authorization: OpenAuth token="..."

where ... contains the base64-encoded token data (an opaque string, essentially).

When there is a problem, or the Authorization: header is missing, a 401 response is returned with a WWW-Authenticate: header.

401 Need user consent
...
WWW-Authenticate: OpenAuth realm="RealmString", fault="NeedConsent", url="http://my.screenname.aol.com/blah?a=boof&b=zed&...."

where the status code contains a human readable message, and the WWW-Authenticate header contains the precise fault code -- NeedToken, NeedConsent, ExpiredToken.  If present, the url parameter gives the URL of an HTML page which can be presented to the end user to login or grant permissions.  For example it can point to a login page if the fault is NeedToken.  A client would then need to do the following in response:

1. Append a "&succUrl=..." parameter to the url, telling the OpenAuth service where to go when the user successfully logs in or grants permission. 
   
2. Open a web browser or browser widget control with the given composed URL, and present to the user.
3. Be prepared to handle an invocation of the succUrl with an appended token parameter, giving a new token to use for subsequent requests.

Note that the succUrl can be a javascript: URL, or a custom scheme (e.g., aim:) if your destination client is not a web browser.  Or it could be pointing to a local web server (http://localhost:1080/openauthcallback.cgi) or perhaps other schemes to get the token from point A to point B.  Whatever method is chosen, eventually the client will receive an OpenAuth token that it can use to try (or re-try) the Atom request.

As a wrinkle, to enhance autodiscovery, perhaps we should allow an "Authorization: OpenAuth" header with no token on any request (including HEAD).  The server could then respond with a 401 and fault="NeedToken", telling the client what URL to use for login authentication.  The interesting thing about this is that the protocol is then truly not tied to any particular authentication service -- anyone who implements this fairly simple protocol with opaque tokens can then play with anyone else.  The whole thing could be built on top of OpenID, for example. 

Perhaps this doesn't quite work.  I notice that the Flickr APIs don't do this, and instead have non-browsers establish a session with a client-generated unique key ("frob").  But this requires that users end up looking at a browser screen that tells them to return to their application to re-try the request.  Which the above scheme could certainly do as well, by making the succUrl point at such a page.  So is there a reason why Flickr doesn't redirect?  There's likely a gaping security hole here that I'm just missing.

Web 2.0 Expo: Mashing Up With User-Centric Identity

(Reposted from my dev.aol.com blog):

Praveen Allavilli and I just finished our talk, "Mashing Up With User-Centric Identity", at Web 2.0 Expo. The final presentation (which differs somewhat from the original version we sent to the conference organizers) is available at http://johnpanzer.com/presos/MashWithIdentity.ppt.

People said it went well; I hope so. We think it's important to deal with 'deputization' and user permissions and I hope we can get a widely accepted OpenID extension to do this as well. In the mean time, our OpenAuth APIs show one way it can be done, and they enable some pretty cool mash-ups.

Tags: web20expo, openid, mashups, praveen, presentations, identity, user centric identity

At Web 2.0 Expo: Recordon and Ellis

Implementing OpenID. With cat pictures too!

Tags: openid, web20expo, recordon, ellis

I am so proud of my alma mater...

Donkey Kong re-imaged using 6,400 Post-It 'pixels' at UCSC.  Sweet.

APP Interop Final Score

The APP Interop event was a lot of fun.  Thanks everybody!  I saw a bunch of people who I've only talked to via email.  And a few I haven't seen in a long time... perhaps since the original Atom kick-off at Google many years ago. 

The final score for AOL Journals is 1-1.  If you want to continue testing against our production endpoint, feel free to update the matrix:

service document: https://journals.aol.com/atomprotocol/service.xml
user: atomprotocol
password: password

I also got a chance to play with EC2 (thanks to M. David Peterson) in an attempt to get our latest server available for testing against.  It was tremendous fun to play with EC2 and I'd love to try using it for a real scalable application.  I did eventually get a server up long enough to verify our current bug fixes, but I didn't have time to fix the date bug that James Snell found. 

I've now found 3 bugs in our date parsing code; it seems to be the most fragile part of the parsing by far.  I'd love to see what test cases other people have for dates.  So far I know I need to add both UTC and various timezones, and now I know we need to round fractional seconds.  (Does anybody but James send fractional seconds?)