Web Services - WSDL Dr. Schahram Dustdar
Overview What is WSDL? WSDL alternatives? WSDL discussion: pro‘s & con‘s WSDL structure
What is WSDL? Web Services Description Language An XML format for describing network services as a set of endpoints operating on messages containing either documentoriented or procedure-oriented information Bindings are described in conjunction with SOAP 1.1, HTTP GET/POST and MIME data and protocol formats WSDL documents provide
documentation for distributed systems to communicate A recipe for automating the details involved in applications communication
WSDL documents don‘t provide
Security information QoS information
What is WSDL? WSDL 1.1 submitted to W3C Describes
Types Messages Port Types (Groups of operations)
Bindings (port type associated with protocol) Ports (associations of bindings with network address) Services (groups of ports)
WSDL alternatives? e-speak (Hewlett Packard) Rosetta-net RDF
WSDL pro‘s Fits with SOAP (but not tied to it) Flexible and layered
Example:WSDL & WebSphere Application Server
WSDL Structure WSDL identifies 4 elements of a service description
Reuseable Descriptions Type/Message Definitions Abstract Interface Descriptions Reuseable Protocol Bindings
Service Deployment Endpoints of Deployed Services
WSDL Dokumentaufbau
Message Patterns - Overview
Message Patterns One-Way
Analog zu Fire- and- Forget Die Message wird vesendet; es wird keine Antwort erwartet.
Request/Response
Analog zu RPC Der Sender sendet eine Message der Receiver sendet eine Antwort darauf.
Solicit Response (noch offen)
Ein Request ohne Daten für eine Response. Das Inverse einer One- Way Message
Notification (noch offen)
Mehrere Empfänger für eine Message (broadcast ähnlich) Analog zu Publish/ Subscribe
Message Patterns 1/2
Message Patterns 2/2
Scenario
WSDL tags
WSDL Structure Abstract Description
Concrete Description
Simple Web Service example
WSDL for example 1/3
WSDL for example 2/3
WSDL for example 3/3
Reuseable WSDL Specs as tModels (WSDL und UDDI) UDDI tModels provide a base for technical service descripions WSDL provides an XML schema for defining reuseable technical specifications A tModel that references a WSDL provides a mechanism (via UDDI) by which compliant services can be located and invoked