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Subject: RE: [wsrp][markup] First conference call (Summary)
It's not necessarily an easy problem to call from SOAP to servlets. Axis may
do what Thomas states, but that's no guarantee that it's a ubiquitous
capability of all SOAP servers. In addition, even if we assume the SOAP
request is sent over HTTP and the server gives the programmer access to the
RequestDispatcher, it's not clear how a SOAP message should be reconstituted
in a normal and repeatable way into something that the servlets treat as an
HTTP request without a standardized definition, certainly not without
jeopardizing both server-side implementation portability and alot of
repetitive coding.
This kind of implementation can be done, but it's not a good mechanism for
implementing portlets. To make it simple and transparent, there really needs
to be a portlet container unless portlets are just web applications as Sasha
seems to be suggesting.
Sasha, what you are describing is essentially the way Plumtree's portal
architecture is built? Do people use, for example, HTTP proxy caching agents
between portlets and portals routinely? I don't really see a problem if the
portal framework has different or new cache management rules for WSRP as
this is an implementation detail of the framework.
With respect to action handling, this should be the responsibility of a
portlet container, which in Java is already being defined. Again, I don't
see a huge problem: hand the action URL from the SOAP handler to the
container and return the result. It's only becomes a problem if you take the
position that WSRP servlets should be implemented as regular web apps based
on servlets.
I agree that session is a problem, since we want it to be replicated or
fault tolerant in the same way we expect servlet sessions to be (though
persistent state strikes me as being no different). Session could be
eliminated as a problem in Java if the portlet container is in fact a
container rather than a web application.
Greg
-----Original Message-----
From: Sasha Aickin [mailto:AlexanderA@plumtree.com]
Sent: Tuesday, April 23, 2002 11:36 PM
To: Thomas Schaeck
Cc: Eilon Reshef; PAVLIK,GREGORY (HP-NewJersey,ex2); Takao Mohri; WSRP
Mailing List (E-mail)
Subject: RE: [wsrp][markup] First conference call (Summary)
Thomas,
I realize that it is possible to implement WSRP services on Java
application servers in the way that you suggest, but it seems to me that
a lot of web application programming paradigms will be so different in
that scenario that developers will not be able to leverage their web app
development experience, tools, and knowledge.
One example is state and session management. Currently, servlets depend
on the app server's native session support, which is usually implemented
with cookies (or URL rewriting). Several people on our TC have
suggested using a token in the WSRP API as a way to manage states and
sessions instead of cookies. When we use the paradigm you suggest (SOAP
code dispatching out to a servlet), which notion of state/session
management would we expose to the servlet? If we use the app server's
native cookie-based session management, then the servlet needs to have
knowledge about how to extract the WSRP state/session token. If,
instead, we expose the WSRP session management to the servlet, then we
will have changed the semantics of the way the servlet works, and
someone may have to write a whole new session mechanism which uses WSRP
tokens as their key.
Caching is another thing that we are in danger of rewriting. Standard
HTTP/HTML web apps have fairly well developed ideas of how caching
should be done, and those mechanisms have proved remarkably successful
in scaling up the web. However, HTTP caching is not generally used in
SOAP calls for many reasons, chief among them being that it is not clear
when two SOAP requests correspond to the same call into a Web Service
(whereas HTTP can specify this with the Vary header). This suggests to
me that either WSRP will not support HTTP-type caching capabilities (the
kind of features exposed by the Expires, Last-Mod, Etag, and Vary
headers) and will therefore be less feature rich, or we will spend quite
a while spec'ing out caching rules in our protocol. If we do spec out
caching rules in our protocol, we would then need to build
infrastructure so that web apps written in servlets could easily exploit
those caching mechanisms. We would also have to implement caches that
understood our new type of SOAP based cache rules (and potentially even
try to convince proxy server makers to do the same). This is a
tremendous amount of work to just get to the level of functionality we
already have with HTTP/HTML web apps.
Action handling is yet another problem that we are looking to rewrite.
With an HTTP/HTML web app, user actions are generally handled by links
and forms. However, since a web service will generally always be at the
same URL, links in the markup will need to be transformed according to
some scheme to become arguments to the web service. I could see your
SOAP to servlet scheme taking in an URL argument to the web service and
dispatching to a servlet which corresponds to the URL, but this would be
both cumbersome to implement and difficult to make work with relative
URLs. We are looking at adding several levels of transformation and
indirection to standard HTML/HTTP links, and I don't see that action
handling in web services gains any interesting functionality above and
beyond links in HTML/HTTP.
My basic point is that, by using SOAP (and decoupling markup from HTTP),
we are losing many solutions to common problems that are standard in the
HTTP/HTML application world, and I am not clear that we are gaining that
much in terms of functionality. By porting concepts like session
management, caching, and action handling to web services, we will need
to build and test new development tools, provide documentation for
development best practices, and train developers in our new solutions to
these problems. This seems to me like a major problem for our spec, and
one which will potentially be a large barrier to entry for developers.
What do people think about this?
Cheers,
Sasha.
-----Original Message-----
From: Thomas Schaeck [mailto:SCHAECK@de.ibm.com]
Sent: Saturday, April 13, 2002 12:53 PM
To: Sasha Aickin
Cc: Eilon Reshef; PAVLIK,GREGORY (HP-NewJersey,ex2); Takao Mohri; WSRP
Mailing List (E-mail)
Subject: RE: [wsrp][markup] First conference call (Summary)
Just as a comment - it will be quite easy to implement WSRP services as
servlets running on a normal application server, all one has to do is to
call from the SOAP code (e.g. SOAP4J or AXIS) into the servlet container
using the request dispatcher that can be obtained within a provider for
the
SOAP code. Similar things are probably possible on .NET. So when
starting
from scratch, developing WSRP services will be about as simple or hard
as
developing web apps.
But of course it is true that existing web apps need to be changed to
run
as WSRP services...
Best regards,
Thomas
Sasha Aickin <AlexanderA@plumtree.com> on 04/12/2002 05:48:27 AM
Please respond to Sasha Aickin <AlexanderA@plumtree.com>
To: Eilon Reshef <eilon.reshef@webcollage.com>, "PAVLIK,GREGORY
(HP-NewJersey,ex2)" <gregory_pavlik@hp.com>, Thomas
Schaeck/Germany/IBM@IBMDE, Takao Mohri
<mohri.takao@jp.fujitsu.com>
cc: "WSRP Mailing List (E-mail)" <wsrp@lists.oasis-open.org>
Subject: RE: [wsrp][markup] First conference call (Summary)
Eilon,
While this is true (and I'm generally a big fan of integrating with
existing systems), supporting HTML doesn't seem like the big barrier to
supporting JSP and Perl scripts. The big problem with that, it seems,
is
that we've committed ourselves to the SOAP web services world.
Rewriting
a web app to be a web service is decidely non-trivial; you can lose out
on
a lot of things that J2EE server and IIS give you for free (session
management being a huge one), and fitting in with the web service
programming paradigms is very different than writing a web app page.
As a sidenote, I have to admit that sometimes I get frustrated that we
are
trying to solve a lot of problems that have already been solved with
standard web app development tools. Session management,
authentication,
privacy, efficient caching, and other issues are all fairly well
understood using the basic HTML/HTTP solution, and I feel like we're
rewriting a lot of that. Not only is it a lot of work, it will be hard
for us to document and for developers to learn. Does anyone else
sometimes feel this way, or am I the only one?
That all being said, I think that we have to support HTML if only for
the
huge amount of developer knowledge of HTML (vs. XHTML).
Cheers,
Sasha.
-----Original Message-----
From: Eilon Reshef [mailto:eilon.reshef@webcollage.com]
Sent: Wednesday, April 10, 2002 8:58 AM
To: 'PAVLIK,GREGORY (HP-NewJersey,ex2)'; 'Thomas Schaeck'; 'Takao
Mohri'
Cc: 'WSRP Mailing List (E-mail)'
Subject: RE: [wsrp][markup] First conference call (Summary)
I do believe we have to offer a migration path for people that have or
even prefer plain old HTML - expecting everybody to go back to their
Perl
scripts and JSP templates and rework them might provide a barrier to
entry
that we can avoid by simply supporting HTML.
-----Original Message-----
From: PAVLIK,GREGORY (HP-NewJersey,ex2) [mailto:gregory_pavlik@hp.com]
Sent: Wednesday, April 10, 2002 11:48 AM
To: 'Thomas Schaeck'; Takao Mohri
Cc: PAVLIK,GREGORY (HP-NewJersey,ex2); WSRP Mailing List (E-mail)
Subject: RE: [wsrp][markup] First conference call (Summary)
Is there a general statement on whether the markup subcommittee intends
to
treat HTML and XHTML interchangeably? My initial thought was that WSRP
would
do better to standardize on XHTML, which would have a number of
advantages
including the ability of the consumer to treat the fragment as an XML
fragment. It's not terribly difficult to tidy up a piece of HTML and
repurpose it as well-formed/valid XHTML when dealing with legacy
content.
An
early focus on XHTML might position us better for dealing with devices
in
the long run, as it appears that WML and cHTML are going to be
secondary
targets for the TC.
Greg
-----Original Message-----
From: Thomas Schaeck [mailto:SCHAECK@de.ibm.com]
Sent: Tuesday, April 09, 2002 5:43 PM
To: Takao Mohri
Cc: PAVLIK,GREGORY (HP-NewJersey,ex2); WSRP Mailing List (E-mail)
Subject: Re: [wsrp][markup] First conference call (Summary)
There is not something like "the markup language of WSRP", the WSRP
protocol needs not to be tied to any particular markup language, the
protocol and the markup exchanged can be viewed as orthogonal.
However, WSRP will need to define rules for valid markup fragments and
common styles with the priorities
1. (X)HTML
2. WML, cHTML, VoiceXML...
It would be interesting to see the rules that would define valid XHTML
Basic fragments.
Takao, could you post an XHTML Basic example document to the mailing
list
and an outline of fragment rules for XHTML Basic ? Which tags would be
allowed in aggregatable XHTML Basic fragments and which tags would not
be
allowed to use in fragments ?
Best regards,
Thomas
Takao Mohri <mohri.takao@jp.fujitsu.com> on 04/09/2002 01:26:58 PM
Please respond to Takao Mohri <mohri.takao@jp.fujitsu.com>
To: "PAVLIK,GREGORY (HP-NewJersey,ex2)" <gregory_pavlik@hp.com>
cc: "WSRP Mailing List (E-mail)" <wsrp@lists.oasis-open.org>
Subject: Re: [wsrp][markup] First conference call (Summary)
Greg,
Yes, as you mentioned, XHTML Basic is becoming a standard for cellular
phones.
In WAP 2.0, XHTML Mobile Profile (an extention of XHTML Basic) is a
standard markup language. In Japan, cellular phones that support WAP
2.0
are already on sale by KDDI. NTT Docomo also has announced support of
WAP
2.0.
In the near future, WAP 2.0, i.e, XTHML Basic will be used by many
mobile
devices.
If the markup language of WSRP is based on XHTML Basic,
it makes support of mobile devices much easier.
Regards,
Takao
"PAVLIK,GREGORY (HP-NewJersey,ex2)" wrote:
>
> Gino,
>
> Could you clarify if your intent is to consider XHMTL/XHTML Basic as
a
part
> of the HTML focus? This wasn't clear from the notes. There appears to
be
a
> broad convergence in the mobile space, both with respect to WML and
NTT
> Docomo, to standardizing on XHTML Basic + CSS. XHTML is going to be
here
on
> the device very soon, perhaps quicker than on the desktop, making
this a
> relatively high priority item. Fujitsu may have some comments on this
as
> well.
>
> Greg
>
> -----Original Message-----
> From: Gino Filicetti [mailto:gfilicetti@bowstreet.com]
> Sent: Friday, April 05, 2002 3:22 PM
> To: WSRP Mailing List (E-mail)
> Subject: [wsrp][markup] First conference call (Summary)
>
> Team,
>
> Attached are the meeting notes from today's Markup Subcommittee
meeting.
> Comments and suggestions are welcome.
>
> One thing I did notice was that there were quite a few participants
today
> that aren't on the actual list of official members for this team.
Since
this
> team is quite small, I think it'd be great if we could get some of
you
to
> officially join and help out with the effort. Unfortunately, I wasn't
able
> to capture the names of ALL the attendees this time around (I'll be
sure
to
> record the con-call next time), but please send me an email so we can
add
> your name to official list and flesh out the team a little more.
>
> Currently, the official list is:
>
> Gino Filicetti
> David Taieb
> Khurram Mahmood
> Susan Levine
> Michael Hillerman
>
> Thanks,
>
> . . . . . . . . . . . . . . . . . . . . . . . .
> Gino Filicetti | Software Engineer
> One Harbour Place, Portsmouth, NH 03801
> T 603.559.1692 | gfilicetti@bowstreet.com
> w w w . b o w s t r e e t . c o m
>
> ----------------------------------------------------------------
> To subscribe or unsubscribe from this elist use the subscription
> manager: <http://lists.oasis-open.org/ob/adm.pl>
// Takao MOHRI (mohri.takao@jp.fujitsu.com)
// FUJITSU LABORATORIES LTD.
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