Ted Ross wrote:
cross-posted to dev...
Bryan Kearney wrote:
I am curious how folks are addressing using QMF in a web application
type model. Assume that I have a webapplication which can host n
users. If the users can access a backend service via QMF and I want to
track on the backend some notion of state and/or who the user is then
I seem to need to do the following:
1) Have one console instance per user.
2) Add the userid (or session id) onto every request and roll my own
session cache.
Has anhyone solved this in a better fashion? This seems analagous to
issues with JDBC drivers.. where I may want to track who the user is
in the DB.. but not open many connections.
-- bk
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This is a good question and it pertains not only to QMF, but more
generally to messaging.
The QPID broker currently authenticates users at connection setup, one
user-id per connection. If authentication fails, the connection is
closed. If it is successful, the authenticated user-id may be used by
the ACL plugin to authorize or forbid specific broker operations.
Message producers may optionally place a user-id into the message header
of a produced message. This is used to annotate the message with the
identity of its originator and can be used by the message's consumers
for security purposes. If this field is set in a message, the broker
compares it to the identity associated with the producer's connection.
If the message contains an identity different from the connection's
identity, the message is rejected. This allows the consumer to trust
the identity as having been authenticated by the broker.
To handle Bryan's scenario, I claim that option (1) is unacceptable as
there may be a large number of identities on the front-end.
A application that provides service to multiple users and uses QPID/QMF
for back-end connectivity should open a single connection to the
messaging broker and, if other QPID/QMF endpoints in the network need
the end-user's identity, the user-id field should carry that identity.
Here are some possible mechanisms to support this (I'm sure there are
more):
A) Authentication at the Client
Add an ACL action that allows a client to set user-ids that are
different from the connection identity. This effectively tells the
broker to trust this producer to authenticate user-ids.
The application would then use whatever authentication system is in
place (presumably the same one used by the broker) to authenticate its
users and would annotate individual messages with the identity of the
end-user associated with the message.
This option would allow the end-user identities to be separate from the
broker-user identities (i.e. the user-ids in the messages could be
completely unknown to the broker).
B) Authenticate Multiple Identities per Connection on the Broker
[I don't care for this one very much]
The broker could provide for some sort of on-the-side SASL exchange for
each user-id to be associated with a connection. Of course, such a SASL
exchange must not involve a security layer.
Thoughts?
Is (A) the ability to authenticate with the bus, and then pass the
"real" user credential over the wire? This model may be good enough for
services exposed over the wire.. but it does not introduce the notion of
a session?
If I look at WSDL and HTTP as parallel technologies for Services exposed
over QMF.. then it seems like we need the ability to pass in a user and
tie him to a session.
Note.. this is different then QMF exposing managed objects.. since the
object handle itself may indicate the session.
-- bk
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