1. CSE 636 Data Integration
Web Services

2. What is a Web Service
A web service is a network accessible interface to application functionality
Application interoperability across different platforms
Built using standard Internet technologies
Clients of web services do NOT need to know how they are implemented
Network
Web
Service  
Application
Client
Application
Code

3. Web Services Related Standards
Web Services Description Language (WSDL) 1.1
(03/01)
Version 2.0 under development
Simple Object Access Protocol (SOAP)
Universal Description, Discovery and Integration (UDDI)

4. Web Service Technology Stack
Client
Discovery
Shopping web service?
UDDI
WSDL URIs
Web Service
Description
WSDL
WSDL
SOAP/HTTP request
Proxy
Messaging
SOAP/HTTP response
Transport
HyperText Transfer Protocol (HTTP)

5. Part 1: Web Service Methods
Client
Discovery
Shopping web service?
UDDI
WSDL URIs
Web Service
Description
WSDL
WSDL
SOAP/HTTP request
Proxy
Messaging
SOAP/HTTP response
Transport
HyperText Transfer Protocol (HTTP)

6. Part 2: Web Service Description
Client
Discovery
Shopping web service?
UDDI
WSDL URIs
Web Service
Description
WSDL
WSDL
SOAP/HTTP request
Proxy
Messaging
SOAP/HTTP response
Transport
HyperText Transfer Protocol (HTTP)

7. Part 3: Proxy to Access Web Service
Client
Discovery
Shopping web service?
UDDI
WSDL URIs
Web Service
Description
WSDL
WSDL
SOAP/HTTP request
Proxy
Messaging
SOAP/HTTP response
Transport
HyperText Transfer Protocol (HTTP)

8. Part 4: Client to Invoke Proxy
Web
Service
Client
Discovery
Shopping web service?
UDDI
WSDL URIs
Web Service
Description
WSDL
WSDL
SOAP/HTTP request
Proxy
Messaging
SOAP/HTTP response
Transport
HyperText Transfer Protocol (HTTP)

9. Data Services Architecture
Web Application Server
Web Service
Web
Service
Client
WSDL
WSDL
Parameterized
XQuery
Expressions
Parameter Instantiation
SOAP/HTTP request
SOAP/HTTP response
Query Result
Query Execution
XML Database
XML
Schema
XML
File

10. Web Services Definition Language (WSDL)
Defines services as collections of network endpoints
Consists of abstract definitions
Types
Messages
Port Types & Operations
and concrete implementations
Bindings
Services & Ports
Broken into pieces for reuse purposes

11. Port Types & Operations
Port Type: An abstract set of operations supported
Operation: An abstract description of an action supported
<portType name="AddressBook">
<operation name="addEntry">
<input message="tns:AddEntryRequest"/>
<output message="tns:empty"/>
</operation>
<operation name="getAddressFromName">
<input message="tns:GetAddressFromNameRequest"/>
<output message="tns:GetAddressFromNameResponse"/>
</portType>
Programming languages refer to a port type as a class, and to an operation as a method

12. Messages Abstract, typed definitions of the data being communicated
<message name="empty"/>
<message name="AddEntryRequest">
<part name="address" type="tns:address"/>
</message>
<message name="GetAddressFromNameRequest">
<part name="name" element="tns:entryName"/>
<message name="GetAddressFromNameResponse">

13. Types Data type definitions using the XML Schema type system
<xs:schema targetNamespace="urn:AddressFetcher"
xmlns:xs="
<xs:element name="entryName" type="xs:string"/>
<xs:complexType name="address">
<xs:all>
<xs:element name="streetNum" type="xs:int"/>
<xs:element name="streetName" type="xs:string"/>
<xs:element name="city" type="xs:string"/>
<xs:element name="state" type="xs:string"/>
<xs:element name="zip" type="xs:int"/>
<xs:element name="phoneNumber" type="xs:int"/>
</xs:all>
</xs:complexType>
</xs:schema>
</types>

14. WSDL File Structure Type Definitions Message Declarations
<definitions name="urn:AddressFetcher"
targetNamespace="urn:AddressFetcher"
xmlns:tns="urn:AddressFetcher"
xmlns:xs="
xmlns:soap="
xmlns="
<types>…</types>
<message name="AddEntryRequest">…</message> …
<portType name="AddressBook">…</portType>
<binding>…</binding>
<service>…</service>
</definitions>
Type Definitions
Message Declarations
Port Type Declarations
Binding Declarations
Service Declaration

15. Bindings
Concrete protocol and data format specifications for a particular port type
<binding name="AddressBookSOAPBinding" type="tns:AddressBook">
<soap:binding
style="document"
transport="
<operation name="getAddressFromName">
<soap:operation soapAction=""/>
<input>
<soap:body use="literal"/>
</input>
<output>
</output>
</operation> …
</binding>

16. Services & Ports
Port: a single endpoint defined as a combination of a binding and a network address
Service: a collection of related endpoints
<service name="AddressBookService">
<port name="AddressBook" binding="tns:AddressBookSOAPBinding">
<soap:address location="
</port>
</service>

17. Not Discussed Types of operations: Alternative Bindings: SOAP UDDI
One-way: The endpoint receives a message
Request-response: The endpoint receives a message, and sends a correlated message
Solicit-response: The endpoint sends a message, and receives a correlated message
Notification: The endpoint sends a message
Alternative Bindings:
HTTP: Using GET and POST
MIME
SOAP
RPC-Style Web Services
UDDI