WSDL

title

Web Services Basics For Non-programmers

author

Pete George (NobleProg Ltd)

Day One Revision ⌘

1. Introduction
2. Service-Oriented Architecture
3. Web Services Overview
4. XML
5. SOAP

SOA & Web Services ⌘

Service-Oriented Architecture

Without Agreed standards

Atomic

Interoperability

Service Request

Loose coupling

Brittleness

Hide information (service abstraction)

10. Are reusable services: a. used many times b. used in multiple processes

b. Used in multiple processes

Name the features ⌘

1. <?xml version="1.0" encoding="utf-8"?>
2. <mySoap:Envelope
3. xmlns:mySoap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:wsx="http://www.webserviceX.NET">
4. <mySoap:Header/>
5. <mySoap:Body>
6. <wsx:GetAtomicNumber>
7. <wsx:ElementName>Oxygen</wsx:ElementName>
8. </wsx:GetAtomicNumber>
9. </mySoap:Body>
10. </mySoap:Envelope>

Name the features (answers) ⌘

1. Prolog
2. Root Element
3. SOAP Envelope
4. Namespace Declaration
5. Attribute
6. SOAP Header
7. SOAP Body
8. Body Block
9. Element
10. Namespace

Day Two Schedule ⌘

1. WSDL
2. Handling Binary Content
3. RESTfull Web Services
4. Other Technologies
5. Conclusion

WSDL ⌘

WSDL Metaphor ⌘

• XML = Language of message

-English

• SOAP = Style of message

-Business letter

• WSDL = specific instructions on what to write + what the response will be

11/18/2013 Pete George NobleProg Dear Sir

NobleProg Chiswick 123456789 123456789 someone@nobleprog.com

Interface Definition Language ⌘

• Defines language for ORB interfaces (e.g. CORBA)
• Objects have defined contract with outside world

-Methods

-Method parameters

-Return values

• Usually interface investigated during programming

Web Services Description Language ⌘

• Standardized way to describe a Web service
• Not language-specific

-Describes data to be passed

-Describes method for passing data

• The basis of the original Web services specification
• WSDL 2.0 Became W3C recommendation 2007
• Originally used in conjunction with UDDI

UDDI Registry ⌘

• Universal Description, Discovery, and Integration
• Intended to provide way to discover Web services

-contact information for organisations

-services available from organisations

• Not been widely implemented

WSDL with UDDI ⌘

1. Services Described Using WSDL ⌘

• Service Provider describes its service using WSDL
• Definition published to registry of services
• Registry uses UDDI

2. Registry Services Queried ⌘

• Service Consumer issues one or more queries to registry:

-to locate a service

-to determine how to communicate with service

3. WSDL Service Details Supplied ⌘

• Registry provides response to Consumer queries
• i.e WSDL section containing details of the Provider’s requests and responses

4. Service Request Sent ⌘

• Service Consumer has WSDL request details passed from UDDI registry
• Service Consumer sends XML request

5. Service Response Returned ⌘

• Service Provider sends XML request
• Service Consumer knows from WSDL details (passed from UDDI Registry) what response message should look like

WSDL without UDDI ⌘

1. Service Request Sent ⌘

• Service Consumer knows WSDL request details
• Service Consumer sends XML request

2. Service Response Returned ⌘

• Service Provider sends XML request
• Service Consumer knows from WSDL details what response message should look like

Obtaining WSDL ⌘

• Usually by simple request, e.g.

GET

http://www.webservicex.net/periodictable.asmx?wsdl

<definitions> ⌘

• Root Element
• Includes Namespace declarations
• Includes WSDL and SOAP declarations

Periodic Table <definitions> ⌘

<types> ⌘

• WSDL file builds up in levels – starts with data types
• Defined in terms of XML Schema

Periodic Table <types> ⌘

<wsdl:definitions xmlns:s="http://www.w3.org/2001/XMLSchema">
 <wsdl:types>
   <s:schema
     <s:element name="GetAtomicNumber">
       <s:complexType>
         <s:sequence>
           <s:element minOccurs="0" maxOccurs="1" name="ElementName" type="s:string" />
         </s:sequence>
       </s:complexType>
     </s:element>

<messages> ⌘

• Defines content

-What the message is

-What kind of data it holds

Periodic Table <messages> ⌘

Periodic Table SOAP message ⌘

• Can be translated into SOAP message, e.g.

<portType> ⌘

• Define individual operations provided by service

-Input and Output operations

-Consist of messages

<portType> ⌘

<binding> ⌘

• Binds operations to protocol, includes:

-<soap:binding>

• specifies binding to SOAP
• Transport type, e.g. HTTP

-<soap:operation>

• Specifies SOAPAction header – redundant

-<soap:body>

• Define how messages are presented
• Literal or encoded

<binding> ⌘

<service> ⌘

• <port> How to send the information

-Binding information, e.g. <wsdl:port name="periodictableSoap" binding="tns:periodictableSoap">

• <soap:address> Where to send the information

-Location of the Web service, e.g.

<soap:address location="http://www.webservicex.net/periodictable.asmx" />

<service> ⌘

<wsdl:service name="periodictable">
   <wsdl:port name="periodictableSoap" 			binding="tns:periodictableSoap">
     <soap:address location="http://www.webservicex.net/periodictable.asmx" />
   </wsdl:port>

Summary Exercise 1 ⌘

Using the JMeter test tool, create a SOAP Service Request to retrieve the weight of an atom from the Periodic Table Web service.

See:

http://www.webservicex.net/periodictable.asmx?wsdl

(you might like to open the WSDL in a separate JMeter instance while you work)

1. Start from PortType = "periodictableSoap"
2. Create Message
3. Use appropriate Types

Summary Exercise 2 ⌘

Confirm Exercise 1 SOAP message is correct:

1. Pull Periodic Table WSDL into SoapUI
2. Execute Ex1 SOAP message in JMeter. Compare Response Message with expected Response message in WSDL.
3. Repeat exercise with own WSDL.