Web Services Description Language

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Nov 3, 2013 (3 years and 7 months ago)

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Web Services
Description Language

(WSDL)


:
-
Shiranchal Taneja

Introduction


The Web Services Description Language
(WSDL) is an XML
-
based language used to
describe the services a business offers and
to provide a way for individuals and other
businesses to access those services
electronically.


WSDL definitions provide documentation for
distributed systems and serve as a recipe
for automating the details involved in
applications communication.

What are Web Services?


Any guess?

Web Services


Definition by Microsoft:
-


“A Web service is a unit of application logic
providing data and services to other
applications. Applications access Web
services via ubiquitous Web protocols and
data formats such as HTTP, XML, and SOAP,
with no need to worry about how each Web
service is implemented.”

WSDL Structure


<types>


<message>


<portType>


<operation>


<binding>


<port>


<service>

<types>


It is the container for all the data type
definitions.


(For maximum platform independence, WSDL
uses XML schema syntax to define data types)

<message>


It defines the data format of each individual
transmission in the communication


Each message can consist of one of more
parts <part>.


Parts can be compared to the parameters of a
function call in a traditional programming
language.

<operation>


A description of an action supported by the
service





For each operation, we define


SOAP action


Input and Output messages









contd…


<operation>
(contd.)


WSDL defines 4 types of operations


One
-
way: The operation can receive a message
but will not return a response.


Request
-
response: The operation receives a
request and returns a response.


Solicit
-
response: The operation can send a
request and will wait for a response.


Notification: The operation sends a message
but will not wait for a response.


<portType>


Defines


each operation that the port exposes.


Messages that are involved with each operation



<binding>


Defines


The message format and


Protocol Details for a web service.


It allows the reuse of the abstract
definitions.

<port>


Is a single endpoint defined as a
combination of a binding and a network
address.

<service>


It is the collection of related end points or
ports.

Where is WSDL commonly used?


WSDL is the cornerstone of the Universal
Description, Discovery, and Integration
(UDDI) initiative spearheaded by Microsoft,
IBM, and Ariba.


UDDI is an XML
-
based registry for
businesses worldwide, which enables
businesses to list themselves and their
services on the Internet. WSDL is the
language used to do this.

References


https://uddi.ibm.com/ubr/registry.html


http://www.Google.co.nz/apis/



http://www.w3.org/TR/wsdl