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Subject: RE: [wsia][wsrp][wsrp-wsia joint interfaces] Merged interfaces document
Thanks for the kind words ... there have been a lot of discussions on the
conceptual level between this version and the previous. Also, Carsten was
instrumental in helping merge in the WSRP concepts.
To ask your questions about sessions in a stronger way:
- Can a Consumer FORCE a Producer to do sessions in a manner the Producer
does not want?
This would include either requiring sharing OR requiring session
independence. I think the answer has to be no. The Consumer does get to
indicate preference (it is where the knowledge of the aggregated page lives
and this is often important in guiding these decisions), but in the end the
Producer is the one who creates and manages sessions. For example, It would
not be hard to enforce Producer policies of only 1 session per logged on
user OR that each user/entity pairing have a unique session.
If there are some natural ways to eliminate the need for arrays in the
interface, I think it would be a cleaner interface. Arrays came in at this
time due to the request to desing a highly efficient interface and we are
starting to settle many of the pending issues on a conceptual level. SOAP
does not directly support multiple operations in a network roundtrip, but
most of the interesting cases do live on top of the http protocol. If
reasonable support exists there, this may suffice for the efficiency
concerns.
Eilon Reshef
<eilon.reshef@webc To: wsia@lists.oasis-open.org, wsrp@lists.oasis-open.org
ollage.com> cc:
Subject: RE: [wsia] [wsrp] [wsrp-wsia joint interfaces] Merged
06/10/2002 02:31 interfaces document
PM
Rich,
Kudos on the last version of the spec, it reads great and much clearer and
cleaner than previous versions.
I would like to add my own two questions based on an initial reading of the
document.
The semantics of "session"
Does a session span all the different portlets/templates/instances provided
by a single service? If so, that means that extra care is needed in the
case where Producers don't want to share sessions. The most natural example
that comes to mind is a simple SOAP gateway that relays requests to
multiple even-more-remote Producers. In this case, the gateway has to
implement the semantics of session aggregation or do some other
manipulation of the message body.
Multiple parameters using arrays
I concur with a previous comment that it seems unnatural to duplicate every
parameter of every call just for the sake of a single network
communication. Beyond being unnatural, this also requires the Consumer do
to work, and apropos an earlier discussion, would practically preclude
using SOAP exceptions (if the Consumer gets an exception, this essentially
means that one of of the many services may have failed, and this isn't the
regular semantics of exceptions).
Unless I am missing something, this networking issue can be solved by the
layer that created it (the transport layer) using for example HTTP 1.1.
Although existing SOAP frameworks probably don't have built-in support for
this, since we are talking about a single generic proxy for all WSRP
services, I see no reason why this should be particularly challenging to
accomplish. This would also allow multiplexing of different calls (to
operations with different signature) without requiring to open a new
connection.
In general (regarding both of those comments), let's not forget that portal
interoperability is an important objective of this committee - but it's
just one. The other, which is as important, is to allow ISVs and end
customers to create portlets that can work across portals. We have to
ensure that the specification does not practically preclude this second
objective by optimizing the interface for the first.
Eilon