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Objectives Web Services 1.What is WS? 2.How does it work? 3.WS in Action 4.An Example in Liferay

What is WS? WS = Web Services A software system designed to support interoperable Machine to Machine interaction over a network (W3C). Web services are frequently just Web APIs that can be accessed over a network, such as the Internet, and executed on a remote system hosting the requested services.

What is WS? Web services platform elements SOAP (Simple Object Access Protocol) – XML plus HTTP UDDI (Universal Description, Discovery and Integration) - a directory service where businesses can register and search for Web services. WSDL (Web Services Description Language) - an XML-based language for describing Web services and how to access them.

What is WS? Additional specifications, WS-* WS-Security - Defines how to use XML Encryption and XML Signature in SOAP to secure message exchanges. WS-Reliability - An OASIS standard protocol for reliable messaging between two Web services. WS-Reliable Messaging - A protocol for reliable messaging between two Web services. WS-Addressing - A way of describing the address of the recipient (and sender) of a message. WS-Transaction - A way of handling transactions.

How WS Works Service Registry Service Requestor Service Provider Bind Find Publish

How WS Works Styles of use Remote procedure calls (RPC) - RPC Web services present a distributed function (or method) call interface that is familiar to many developers. Typically, the basic unit of RPC Web services is the WSDL operation. Service-oriented architecture (SOA) - The basic unit of communication is a message, rather than an operation - "message-oriented" services. Representational state transfer (REST)- RESTful Web services attempt to emulate HTTP and similar protocols by constraining the interface to a set of well- known, standard operations (e.g., GET, PUT, DELETE).

Web Services in Action HTTP, HTTPS, SMTP XML, SOAP, Addressing XSD,WSDL,UDDI,Policy,Metadata Exchange BPEL4WS / WS-BPEL Transports Messaging Transports Composable service assurances Transactions Reliable messaging Security

WSDL & SOAP & UDDI What is it? –WSDL 1.1 Good specification –WSDL 2.0 Much better specifications –JSR 110: Java APIs for WSDL –SOAP 1.1 / 1.2 –UDDI 1.0 / 2.0 / 3.0

An Example in Liferay Alfresco Content UI: Add content: Alfresco Content Link: com.liferay.portlet.alfrescocontent.util.AlfrescoContentUtil org.alfresco.webservice.* at alfresco_client.jar URL: PropsUtil.ALFRESCO_CONTENT_SERVER_URL; Page: portal/portal-web/html/portlet/alfresco_content/init.jsp Portlet Type: Struts portlet at portal/portal-ejb/src com.liferay.portlet.alfrescocontent.action com.liferay.portlet.alfrescocontent.util

An Example in Liferay Code Review – at source-ws/AlfrescoContentUtil.java AuthenticationUtils.startSession(userId, password); RepositoryServiceSoapBindingStub repositoryService = WebServiceFactory.getRepositoryService(); Reference reference = null; if (Validator.isNull(uuid)) { reference = new Reference(_SPACES_STORE, null, null); } else { reference = new Reference(_SPACES_STORE, uuid, null); } QueryResult result = repositoryService.queryChildren(reference); ResultSetRow[] rows = result.getResultSet().getRows();

Review of WS WS - Secure, Reliable, Transacted. –Transports - HTTP, HTTP/S, SMTP –Message Formats – XSD –WS-Addressing WS - a Service-Oriented Architecture. –Services are described by schema and contract not type –Service compatibility is more than type compatibility –Service-orientation assumes that bad things can and will happen –Service-orientation enables flexible binding of services WS-BPEL, BPEL4WS: see next topic

Revision History Jonas Yuan05/30/07Created for Liferay 4.2.2