1 WSDL Tutorial Heather Kreger (borrowed from Peter Brittenham) Web Services Architect IBM Emerging Technologies

2 WSDL: Web Service Description Language  Standard for describing Web services  Abstract interface for defining operations and their messages Messages contain either document-oriented or procedure- oriented information  Bindings to message formats and protocols  Defines how to locate the endpoint for the service Example: URLs for HTTP  Extensible (SOAP and HTTP extensions are defined)  Written in XML, leverages XML schema  WSDL V1.1 Specification 

3 Usage Scenarios  As IDL (Interface Definition Language)  Allows tools to generate client access code for a service  Examples: IBM WebSphere Studio Application Developer, IBM Web Services Toolkit  Standardized service interface descriptions  Allows advertisement and dynamic discovery of services  Enables dynamic binding to service  Complements UDDI registry

4 Document Content  Abstract Definitions  data type definitions  operation parameters  operation definitions  Concrete Definitions  operation bindings  location/address for each binding  Also:  used to reference other XML documents

5 WSDL Extensibility Elements  Extensibility elements can be specified within these WSDL elements:   /  / /  Binding extensibility defined in the specification for:  SOAP  HTTP  MIME

6 Document Structure [SOAP] [Request] [data] [Response] [EJB] […] Service(s) Supported Protocol(s) Java class method SOAP Request/ response

7 SOAP Binding - RPC Style  Indicates that the Web service is accessed using SOAP V1.1 protocol  Use style="rpc" attribute on SOAP binding element  Example SOAP service method signature:  public float getQuote (String symbol)

8 Example: Stock Quote Service [1] <definitions name="StockQuoteService" targetNamespace=" xmlns:tns=" …>... public float getQuote (String symbol)

9 Example: Stock Quote Service [2]... <soap:binding style="rpc" transport=" /> <soap:body use="encoded" namespace=" encodingStyle="

10 Example: Stock Quote Service [3] … Stock Quote Service -- <soap:address location=" />

11 Message  Defines the messages that are referenced in the input, output, and fault elements within an operation  A message may have one or more parts  Each part contains a reference to a data type  elementReference to XML Schema element using a QName  typeReference to XML Schema simpleType or complexType *

12 PortType  Contains one or more abstract operations  Each operation references one or more messages  Four operation types:  One-waySend message to service and there is no response  Request-responseSend message to service which returns a correlated message  Solicit-responseService sends a message and requestor returns a correlated message  NotificationService sends a message to the requestor

13 PortType  One-way Operation  Request-response Operation * * *

14 Binding  Each binding has an unique name  Referenced by a port element  Contains a reference to one portType  Binding interpreted based on ext. elements * ? ? * *

15 Service  A WSDL document may contain one or more service elements  Each service element may contain one or more ports  A port is named, references one binding, and contains the endpoint for the Web service  Port names must be unique within a service element  Endpoint is specified using an extensibility element *

16 Complex Type Definitions  Complex data types  Defined within the element or by referencing an external XML schema document  AddressBook Example:  public void addEntry(String name, Address address)...

17 AddressBook Service <import location=" namespace=" </portType...

18 SOAP Binding - Document Style  Similar to SOAP Binding with RPC Style  SOAP binding contains style=“document” attribute  This style can also be set on a SOAP body element which is specified with each operation element  Used with Web services that specify XML documents for message content  Example: UDDI Registry Business Name

19 WSDL for UDDI Registry [1] <definitions targetNamespace="urn:uddi-org:inquiry" xmlns:uddi="urn:uddi-org:api_v2" xmlns:tns="urn:uddi-org:inquiry_v2"...> <import namespace="urn:uddi-org:api" location=" />......

20 WSDL for UDDI Registry [2] <soap:binding style="document" transport=" /> <soap:body use="literal" parts="body" namespace="urn:uddi-org:api_v2" />...

21 MIME Binding  Examples of supported MIME types:  multipart/related  text/xml  application/x-www-form-urlencoded  Input or output message can be defined using MIME binding  MIME binding can be combined with SOAP binding to define a service that uses SOAP attachments  Use multipart/related binding  SOAP envelope must be in the root part  Define other parts using MIME binding

22 Attachment Service Interface [1]...

23 Attachment Service Interface [2]...

24 Attachment Service Interface [3] <soap:body parts="fileList" use="encoded" namespace=" encodingStyle=" <soap:body use="encoded“ namespace=“ encodingStyle="

25 WSDL4J  WSDL Java API  WSDL object model  Parse contents of a WSDL document  Programmatically create new WSDL documents  Open source project on IBM developerWorks site   Will be a reference implementation for JSR 110  Primarily a set of Java interfaces that can be implemented by anyone  Java package name: javax.wsdl

26 WSDL4J Example - Find Port // Get WSDLReader WSDLReader wsdlReader = WSDLFactory.newInstance().newWSDLReader(); // Read WSDL service implementation document Definition wsdlDefinition = wsdlReader.readWSDL(null, wsdlURL); // Get the service elements Map services = definition.getServices(); // Get an iterator for the list of services Iterator serviceIterator = services.values().iterator(); boolean bPortFound = false; while ((serviceIterator.hasNext()) && !(bPortFound)) { // Get next service element Service service = (Service) serviceIterator.next(); // Determine if this service element contains the specified port if ((port = service.getPort(portName)) != null) bPortFound = true; }

27 WSDL Resources  WSDL V1.1 Specification   W3C Web Services Description Working Group   WSDL4J Open Source Project  wsdl4j/  Yahoo Group: wsdl 

28 An Overview of Web Services – Part 2  Questions?