1. WS/XML Service Utility Library (WS and LEGO?)
Aleksander Slominski

2. XML Web Services Fusion
Transport
(ex. HTTP)
Security
(XML dsig.)
WS/XML Service
RPC
style
Reliable
Messaging
Type
Mapping
Future? WS-Stuff

3. WS/LEGO Game Puzzle of WS-Standards? How to connect blocks?
XML Infoset
Unlimited Number Of Connections
As much as you need?!
Build Your Own LEGO Set
Keep Experimenting!
LEGO comes from Danish words "LEg GOdt" meaning "play well". Ironically, in Latin the lego means "I study" or "I put together"

4. More Bricks, More Fun Reliable Messaging Layer RPC Layer DSig Layer
HTTP Transport
SMTP Transport

5. Virtual Laboratory Toolset: Very Quick XML Service Creation
Allow Building Any Kind of XML Services
From XML router to RMI runtime
Encourage Experimentations
Set of Small Modules
Allow Easy Code Recombination
XML Infoset as connecting glue

6. XSUL Layers Client Stack Server Stack Soap RPC Client
Invoke Java interface
Type Mapping
(XML  Java)
Soap RPC Service
Use Java Object
Invoker
send XML document
Processor
receive XML document
Pluggable
Module
SOAP/HTTP Invoker
SOAP/HTTP Processor
Globus / XML
Digital sig.
HTTP 1.x Client
(HTTP 1.x POST/GET)
HTTP 1.x Server
(HTTP 1.x POST/GET)
Common / Utility
Legend:
depends on
XML Infoset

7. Modules
Theory vs. Practice

8. HTTP Client
private HttpClientConnectionManager connMgr = HttpClientConnectionManager.newInstance();
HttpClientRequest req = connMgr.connect(host, port, 4 * 60 * 1000);
req.setRequestLine("POST", requestUri, "HTTP/1.0");
HttpClientResponse resp = req.sendHeaders();
OutputStream out = resp.getBodyOutputStream();
Writer utf8Writer = new Utf8Writer(out, 8*1024);
… more

9. Invoker (SOAP 1.1 / HTTP)
Soap11HttpDynamicInfosetInvoker invoker = new Soap11HttpDynamicInfosetInvoker()
invoker.setLocation("
XmlElement request = builder.parseFragmentFromReader(new
StringReader("<getN><arg>/hello</></>"));
XmlElement response = invoker.invokeMessage(request);

10. SOAP RPC Client
TypeHandlerRegistry typeMapping = XsdTypeHandlerRegistry.getInstance();
Soap11InvocationHandler handler = new Soap11InvocationHandler(invoker, typeMapping);
XDirectoryService ref = (XDirectoryService) Proxy.newProxyInstance(
Thread.currentThread().getContextClassLoader(),
new Class[] { XDirectoryService.class },
handler);
XmlNode result = ref.getNode("/hello");

11. Client Stack RPC Client Invoker (SOAP 1.1 / HTTP) HTTP Client
Translates Java Interface into XML message
Invoker (SOAP 1.1 / HTTP)
XML Message is wrapped into SOAP 1.1 Envelope and serialized into transport output stream
HTTP Client
Actual sending happens here!
Design Issues
Can add new transport (new invoker)?
Can inject XML processing layers?
XML transformations: digital signatures?

12. Adding DSig Module To Client App
Soap11HttpDynamicInfosetInvoker invoker = new Soap11HttpDynamicInfosetInvoker() {
public XmlDocument invokeXml(XmlDocument request)
throws DynamicInfosetInvokerException {
// WSRMHandler.getInstance().augmentRequest(request);
XmlDocument signedRequest =
GlobusCredSOAPEnvelopeSigner.getInstance().signSoapMessage(request);
XmlDocument response = super.invokeXml(signedRequest);
GlobusCredSOAPEnvelopeVerifier.getInstance().verifySoapMessage(response);
// WSRMHandler.getInstance().processResponse(response);
return response; } };

13. HTTP Server server = new HttpMiniServer(serverPort);
servlet= new MyServlet();
server.useServlet(servlet);
server.startServer();
class MyServlet extends HttpMiniServlet {
public void service(HttpServerRequest req,
HttpServerResponse res) {
… more }

14. Processor (SOAP 1.1 / HTTP)
Soap11HttpDynamicInfosetProcessor processor = new Soap11HttpDynamicInfosetProcessor() {
public XmlElement processMessage(XmlElement message) {
message.setParent(null);
message.setName(message.getName()+"Response");
return message; } };
processor.setServerPort(port);
processor.start();
Full SOAP Echo Service Impl!

15. SOAP RPC Server
TypeHandlerRegistry typeMapping = XsdTypeHandlerRegistry.getInstance()
XDirectoryService serviceLogic = new XDirectoryServiceImpl();
final Soap11ReflectionBasedService service =
new Soap11ReflectionBasedService(serviceLogic, typeMapping); …
Soap11HttpDynamicInfosetProcessor processor = new Soap11HttpDynamicInfosetProcessor() {
public XmlElement processMessage(XmlElement requestMsg)
XmlElement responseMsg = service.processMessage(requestMsg);
return responseMsg; } };

16. Server Stack RPC Server Processor (SOAP 1.1 / HTTP) HTTP Server
User Java Reflection to convert XML message into Java invocation
Processor (SOAP 1.1 / HTTP)
Accept XML Message that is wrapped into SOAP 1.1 Envelope and unwrap it
HTTP Server
Listen for XML messages!
Design Issues
Can add new transport (new listening server)
Can inject XML processing layers
XML transformations: digital signatures and authorization checks?

17. Using DSig/Authz in App
Soap11HttpDynamicInfosetProcessor processor = new Soap11HttpDynamicInfosetProcessor() {
public XmlDocument processSoap11Envelope(XmlElement envelope) {
XmlDocument respDoc = null;
SignatureInfo si = SOAPEnvelopeVerifier.getInstance().verifySoapMessage(envelope);
if(!isAuthorized(si.getSubjectDn(), envelope)) {
XmlDocument fault =
Soap11Util.wrapBodyContent(Soap11Util.generateSoap11Fault(
XmlConstants.NS_URI_SOAP11, "Client", "unathorized access"));
respDoc = fault;
} else {
respDoc = super.processSoap11Envelope(envelope); }
XmlDocument signedDoc =
GlobusCredSOAPEnvelopeSigner.getInstance().signSoapMessage(respDoc);
return signedDoc; };

18. WORK IN PROGRESS!!! OSS site (CVS hosted in SourceForge)
WikiWiki And Blog
portal.extreme.indiana.edu:3456/xsul
Place to Track Progress And Gather Feedback
Bugzilla
Your Feedback is Welcome
Use Modules and Build Your Own Module

19. Conclusions Encourages experimentation Easy to add new modules
LEGO “experience”
Easy to add new modules
WS-RM, WSS4J, WSDL Invoker, …
Better Than CORBA?
Maybe …
… but higher “playability” level 
Add what needed
Piece by piece …

20. Addendum
As More is Better …

21. Adding Caching to Improve DSig Performance
Soap11HttpDynamicInfosetProcessor processor = new Soap11HttpDynamicInfosetProcessor() {
public XmlDocument processSoap11Envelope(XmlElement envelope) {
XmlDocument respDoc = null;
if( (respDoc = lookupCachedResponse(envelope) ) != null ) {
{ //NOTE: needs to check that request is idempotent and resource is not changed!
return respDoc; }
SignatureInfo si = GlobusCredSOAPEnvelopeVerifier.getInstance().verifySoapMessage(envelope);
if(!isAuthorized(si.getSubjectDn(), envelope)) {
XmlDocument fault =
Soap11Util.wrapBodyContent(Soap11Util.generateSoap11Fault(
XmlConstants.NS_URI_SOAP11, "Client", "unathorized access"));
respDoc = fault;
} else {
XmlDocument respDoc = super.processSoap11Envelope(envelope);
XmlDocument signedDoc =
GlobusCredSOAPEnvelopeSigner.getInstance().signSoapMessage(respDoc);
return signedDoc; };

22. DSig Steps Breakdown Client Server Generate SOAP call Sign Send … wait
Receive
Verify DSig
Pass result
Receive SOAP Message
Verify DSig
Reflection Based Invocation
Sign
Send SOAP Message

23. RPC Client implementation details (Using Dynamic Proxy, without WSDL)
class Soap11InvocationHandler implements InvocationHandler {
public Object invoke(Object proxy, Method method, Object[] params) throws Throwable {
String methodName = method.getName();
XmlElement request = builder.newFragment( methodName );
for (int i = 0; i < params.length; i++) {
XmlElement param = registry.javaToXmlElement(params[i],null, "param"+i);
request.addChild(param); }
XmlElement response = invoker.invokeMessage(request);
// map back to Java return type or Exception if S:Fault …

24. Client Side APIs WSDL/RMI
GlobalWeatherSoap gws = (GlobalWeatherSoap) WsdlNaming.lookup("
String s = gws.GetWeather(cityName, countryName)
WSDL/Dynamic Proxy Stub
GlobalWeatherSoap ref = (GlobalWeatherSoap)
WsdlNaming.lookup(" GlobalWeatherSoap.class);
WSDL/Dynamic Invocation Interface (DII)
WsdlDynamicInfosetInvoker dii =
WsdlNaming.lookup("
//NOTE: invoke() uses new JDK 1.5 multi args. “...” instead new Object[] {});
XmlElement result = dii.invoke("GetWeather", cityName, countryName);
String cityName = result.string("cityName");