6.3. WSDL document

发布时间 :2023-12-29 23:00:02 UTC      

An WSDL document is just a simple XML document.

It contains a series of definitions that describe a web service.

6.3.1. WSDL document structure

WSDL documents use these main elements to describe a web service:

element

Define

<portType>

Actions performed by web service

< message >

Messages used by web service

< types >

Data types used by web service

< binding >

Communication protocols used by web service

The main structure of an WSDL document is something like this:

WSDL document instance

<definitions><types>data type
definitions........</types><message>definition of the data being
communicated....</message><portType>set of
operations......</portType><binding>protocol and data format
specification....</binding></definitions>

WSDL documents can contain other elements, such as extension element, and a service element, which combines several web services definitions into a single WSDL document.

6.3.2. WSDL port

<portType> Element is the most important WSDL element.

It describes a web service, actions that can be performed, and related messages.

You can put <portType> Element is compared to a function library (or a module, or a class) in a traditional programming language.

6.3.3. WSDL message

<message> Element defines the data element of an operation.

Each message consists of one or more parts. These parts can be compared to the parameters of a function call in a traditional programming language.

6.3.4. WSDL types

<types> Element defines the data type used by web service.

For maximum platform neutrality, WSDL uses XML Schema syntax to define data types.

6.3.5. WSDL Bindings

<binding> Element defines the message format and protocol details for each port.

6.3.6. WSDL instance

This is a simplified fragment of an WSDL document:

Example

<messagename="getTermRequest"><partname="term"type="xs:string"/></message><messagename="getTermResponse"><partname="value"type="xs:string"/></message><portTypename="glossaryTerms"><operationname="getTerm"><inputmessage="getTermRequest"/><outputmessage="getTermResponse"/></operation></portType>

In this case, the <portType> element defines “glossaryTerms” as the name of a port and “getTerm” as the name of an operation.

The operation “getTerm” has an input message named “getTermRequest” and an output message named “getTermResponse”.

<message> Element defines the part of each message and the associated data type.

Compared to traditional programming, glossaryTerms is a function library, while “getTerm” takes input parameters “getTermRequest” and return parameters. A function of getTermResponse .

Principles, Technologies, and Methods of Geographic Information Systems  102

In recent years, Geographic Information Systems (GIS) have undergone rapid development in both theoretical and practical dimensions. GIS has been widely applied for modeling and decision-making support across various fields such as urban management, regional planning, and environmental remediation, establishing geographic information as a vital component of the information era. The introduction of the “Digital Earth” concept has further accelerated the advancement of GIS, which serves as its technical foundation. Concurrently, scholars have been dedicated to theoretical research in areas like spatial cognition, spatial data uncertainty, and the formalization of spatial relationships. This reflects the dual nature of GIS as both an applied technology and an academic discipline, with the two aspects forming a mutually reinforcing cycle of progress.