Hi,
Simon Laws schrieb:
> How is knowledge of the agreement passed between service and client in a
> way that means that one client can't pretend to be another?
Unfortunately I have to go more in detail to give you an answer on this
topic.
Web service based application is customized by my policy extension. The
application offers in his composite a gold or silver service, e.g.
CalculatorServiceGold or CalculatorServiceSilver. Every service class
has certain parameters e.g. the policy extension guarantees a response
time for the gold service of at least 15 ms.
I'm using WSAG4J which is an implementation of the WS-Agreement
specification of the Open Grid Forum. WS-Agreement is a Web Services
protocol for establishing agreements between two parties, such as
between a service provider and consumer. A service (like an calculator
web service) creates templates for a service he offers. The template
describes quality of service properties like throughput or response
time. A client creates an agreement with WSAG4J based upon the templates
of an service. The agreement contains the URL for the service.
The policy extension gets a notification through RMI if an agreement was
created for a specific service. The extension is now aware of the
clients ip (since the agreement contains the ip of the client) and the
the service class it will use like the gold service.
This idea/implementation has a few limitations, e.g. if I create
agreements for n-clients I can't separate between them. So far it is
possible to extend WSAG4J and the underlying templates, agreements, etc.
> Unfortunately some of these things, e.g. the token based security
> policy, haven't made it into a release yet. Are you set on using 1.2.1?
> Are you in a position to try things from trunk that are not in a build yet?
Not really. The deadline for my thesis is on the 8th of December 2008.
My thesis is part of an research project and probably I will work at the
university on this topic after the hand over of my thesis.
> We'd have to make a change to the web service binding to pass the
> context containing the IP information into the tuscany message chain. I
> can do that but of course that change would only be available in trunk
> and in our next release.
When will be your next release? Anyway it would be great if you add this
feature since I will work on this topic after my thesis.
> You can get it from msg.from.parameters.callbackReference.uri. This is
> not though a generic solution and only works for services with callback
> interfaces.
It is not really an option for me since the title of my thesis "Design
and implementation of an generic QoS-Proxy for SOA-services".
> Sorry this is a bit of a pain at the moment but you just happen to find
> us in the middle of trying to make what you need work;-)
At the moment I'm trying to build a development version of tuscany but
it is a bit of pain since not everything compiles fine (no offense guys)
for me. I've followed the instructions over here [1]. I'm also trying to
update my policy extension to the development version of Tuscany. There
are a few problems with my old calculator example and the new build of
tuscany and the policy extension.
java.lang.NullPointerException:
at
org.apache.maven.plugin.war.util.WebappStructure.getDependencies(WebappStructure.java:109)
at
org.apache.maven.plugin.war.util.WebappStructure.analyseDependencies(WebappStructure.java:288)
at
org.apache.maven.plugin.war.packaging.DependenciesAnalysisPackagingTask.performPackaging(DependenciesAnalysisPackagingTask.java:46)
at
org.apache.maven.plugin.war.AbstractWarMojo.buildWebapp(AbstractWarMojo.java:439)
at
org.apache.maven.plugin.war.AbstractWarMojo.buildExplodedWebapp(AbstractWarMojo.java:375)
at org.apache.maven.plugin.war.WarMojo.performPackaging(WarMojo.java:181)
at org.apache.maven.plugin.war.WarMojo.execute(WarMojo.java:143)
I will have look on that this evening since I have to finish some other
stuff at the lab in the university.
If the deadline of my thesis is before the release of Tuscany 1.4 it is
probably not an option for me since I have to add an "stable release"
(it has to be an official release) with my thesis. I will give it an try.
Best regards,
Michael
[1] http://tuscany.apache.org/sca-java-development-guide.html
