Robust Workflow Systems Flexible Geoprocessing Services Geo-enabled Model Web? - Geographical Information Systems: Trends and Technologies - page 184

Web Service Description Language
The Web Service Description Language (WSDL) 20 (Christensen et al. 2001)
is a W3C standard for describing the public interface of web services. It is
an XML-based language to determine the functional properties of a service
such as its method signatures, input and output messages, details of the
transport protocol used (endpoint, SOAP envelope, etc.). In short, a WSDL
document contains all of the public operations or methods offered by a
given service (Fig. 5).
A WSDL document is not intended to be read by humans but to support
interoperable machine-to-machine interactions. Client applications can
automatically gather from a WSDL document the required information
(e.g., data types for input and output messages, communication protocol
used) to query and interact with the corresponding web service. That is the
way how some scientifi c workfl ow systems like Taverna are able to turn
WSDL-based web services into workfl ow tasks.
01 <defi nitions
02 name=“HolaMundo”
03 targetNamespace=“http://xmlns.oracle.com/HolaMundo”
04 xmlns=“http://schemas.xmlsoap.org/wsdl/”
05 xmlns:plnk=“http://schemas.xmlsoap.org/ws/2003/05/partner-link/”
06 xmlns:client=“http://xmlns.oracle.com/HolaMundo”>
07
08 <types>
09 <schema xmlns=“http://www.w3.org/2001/XMLSchema”
10 xmlns:plnk=“http://schemas.xmlsoap.org/ws/2003/05/partner-link/”
11 xmlns:client=“http://xmlns.oracle.com/HolaMundo”>
12 <import namespace=“http://xmlns.oracle.com/HolaMundo” schemaLocation=“HolaMundo.xsd”/>
13 </schema>
14 </types>
15
16 <message name=“HolaMundoRequestMessage”>
17 <part name=“payload” element= “ client:HolaMundoProcessRequest”/>
18 </message>
19
20 <message name=“HolaMundoResponseMessage”>
21 <part name= “payload” element= “ client:HolaMundoProcessResponse”/>
22 </message>
23
24 <portType name=“HolaMundo”>
25 <operation name=“process”>
26 <input message=“client:HolaMundoRequestMessage”/>
27 <output message=“client:HolaMundoResponseMessage”/>
28 </operation>
29 </portType>
30
31 <plnk:partnerLinkType name=“HolaMundo”>
32 <plnk:role name=“HolaMundoProvider”>
33 <plnk:portType name= “ client:HolaMundo”/>
34 </plnk:role>
35 </plnk:partnerLinkType>
36 </defi nitions>
Fig. 5. WSDL description of the WS-BPEL process in Fig. 4.
20 http://www.w3.org/TR/wsdl