WSDL

1
WSDL

• Charles Bernard

2
Roadmap

• WSDL defined
• High-level diagram and design
• Individual primary elements w/examples
• Final diagram
• Small demonstration
• Real-world examples

3
What is WSDL?

• In brief
• It stands for Web Services Description Language
• It is written in XML
• It is an XML document
• It is used to describe Web services
• It is used to locate Web services
• WDSL helps a client locate a web service and
  invoke any of its publicly available functions
• Client program connecting to a web service can
  read the WSDL to determine what functions are
  available on the server
• Current version is 2.0 W3C recommended
• Version 1.1 is not endorsed by the W3C

4
Where does it fit in?
5
How does it describe Web Services?

• WSDL uses four major XML elements in its
  description
• ltportTypegt
• ltmessagegt
• ltbindinggt
• lttypesgt
• A WSDL document can also contain other elements
• Extension elements
• Service elements - make it possible to group
  together the definitions of several web services
  in one single WSDL document

6
What does a WSDL look like?

• ltdefinitionsgt
• ltportTypegt
• lt/portTypegt
• ltmessagegt
• lt/messagegt
• lttypesgt
• lt/typesgt
• ltbindinggt
• lt/bindinggt
• lt/definitionsgt

7
ltportTypegt Element

• This is probably the most important element
• Describes the web service
• Operations that can be performed
• Messages that are involved
• Comparable to a function/method library in a
  programming language
• A port is defined by associating a network
  address with a reusable binding
• Types of operations
• One-way
• Can receive a message, but will not return a
  message
• Example use receiving request to insert a new
  value in a database
• Request-response
• Can receive a request and will return a response
• Example use receiving a request for a value from
  a database and sending it back in a response
• Solicit-response
• Can send a request and will wait for a response
• Example use requesting a value from a database
  and having it sent back in the response
• Notification
• Can send a message, but will not wait for a
  response
• Example use inserting a new value in a database

8
ltmessagegt Element

• Defines the data elements of an operation
• Each message can have one or more parts
• Each part is comparable to a function/method call
  in a programming language

9
ltportTypegt and ltmessagegt in Action

• ltportType name"glossaryTerms"gt
• ltoperation name"setTerm"gt
• ltinput name"newTerm" message"newTermValues"/gt
  
• lt/operationgt
• lt/portType gt
• ltmessage name"newTermValues"gt
• ltpart name"term" type"xsstring"/gt
• ltpart name"value" type"xsstring"/gt
• lt/messagegt

Defines a one-way operation setTerm
10
More Examples

• ltportType name"glossaryTerms"gtltoperation
  name"getTerm"gt ltinput message"getTermRequest"/gt
  ltoutput message"getTermResponse"/gtlt/operationgt
  
• lt/portTypegt
• ltmessage name"getTermRequest"gt
• ltpart name"term" type"xsstring"/gt
• lt/messagegt
• ltmessage name"getTermResponse"gt
• ltpart name"value" type"xsstring"/gt
• lt/messagegt

Lists operations that can be performed
Defines parts of each message and data types
11
ltbindinggt Element

• Defines the message format and protocol details
  for each port
• Has two attributes
• Name Can be set to any value, which represents
  the name of the binding
• Type Points to the port for the binding
• When using SOAP, a ltsoapbindinggt sub-element is
  used to set the style and transport values with
  elements
• Style with value of either rpc or document
• Transport defines the SOAP protocol to use
• (like HTTP)

12
ltbindinggt in Action

• ltbinding type"glossaryTerms" name"b1"gt
• ltsoapbinding style"document"
  transport"http//schemas.xmlsoap.org/soap/http"
  /gt
• ltoperationgt
• ltsoapoperation soapAction"http//exampl
  e.com/getTerm"/gt
• ltinputgt
• ltsoapbody use"literal"/gt
• lt/inputgt
• ltoutputgt
• ltsoapbody use"literal"/gt
• lt/outputgt
• lt/operationgt
• lt/bindinggt
• ltportType name"glossaryTerms"gtltoperation
  name"getTerm"gtltinput message"getTermRequest"/gt
  ltoutput message"getTermResponse"/gtlt/operationgt
• lt/portTypegt
• ltmessage name"getTermRequest"gt
• ltpart name"term" type"xsstring"/gt
• lt/messagegt
• ltmessage name"getTermResponse"gt

Encoding technique
13
lttypesgt and ltservicegt Elements

• lttypesgt
• Defines the data types that are used by the web
  service
• XML Schema syntax is used to define data types
• ltservicegt
• Provides a physical address at which the service
  can be accessed
• ltportgt - sub-element of service that contains the
  location information
• ltservice nameGlossaryTermsService"gt
• ltport nameGlossaryTermsSoapHttpPort"
  binding"tnsGlossaryTermsSoapBinding"gt
• ltsoapaddress location"http//localhost
  8080/webservice/GlossaryTermsService"/gt
• lt/portgt
• lt/servicegt

14
Final Overview
Web Services Platform
Enterprise System
WSDL
ServiceDeployment
XML Schema Library
Book.xsd
types
binding
operation
Java Method
15
Demo

• Small Demonstration
• Travel Reservation Service in NetBeans 6.0
• Real-world Examples
• Google Search
• http//api.google.com/GoogleSearch.wsdl
• Amazon Search
• http//soap.amazon.com/schemas2/AmazonWebServices.
  wsdl

16
References

• W3Schools WSDL - http//www.w3schools.com/wsdl/def
  ault.asp
• Vijay Gehlot CSC 9010 Introduction Slide-set
• Hansen, Mark D. SOA Using Java Web Services.
  Prentice HallUpper Saddle River, NJ. 2007.