1. Web Services Primer Overview of Web Services
Alphabet Soup (XML SOAP WSDL UDDI)
Software Architecture
Haven't we seen this before??
Two views
Are Web Services the Future?? (Some of this material is lifted from Chris Ellsworth’s Intro. to Web Services podcast.)

2. Overview of Web Services
Provide a means for distributed computing
Based on Internet standards
Platform and language independent
A web service is a software unit which is exposed on the web through SOAP, described by a WSDL file, and registered in a UDDI directory.

3. Basic Web Service Architecture

4. Alphabet Soup XML – eXtended Markup Language
Structured, hierarchical document spec: <mytag> </mytag>
WSDL – Web Service Description Language
Written in XML
Describes web services (location, methods, params, types, etc.)
SOAP – Simple Object Access Protocol
XML based message format for web service communications
UDDI - Universal Description, Discovery and Integration
Registries of published web services (MS, IBM)

5. Basic Web Service Architecture
UDDI
SOAP
WSDL

6. We’ve seen program units before!
Within a single application
Procedures, objects, etc.
NOT language, platform independent
Cooperating and separate program units
JNI (on same machine)
Remote Procedure Call (RPC)
Very low-level
Client must know about server (methods, types, ports, etc.)
Other middlewares (CORBA, DCOM+, etc.)

7. Web Services Add ... More decoupling between client and server units
More independence, flexibility
Standard communication method
HTTP uses port 80
No special server configuration (firewalls, etc.)
Discovery (like Java's reflection)
The WSDL file allows a client to learn about what services are available and how to use them.

8. A “Building Blocks” View
Client
Web Service
WSDL
SOAP
XML

9. A “Functional” View Web Server 1. HTTP request w/ SOAP payload
5. HTML reply w/ SOAP payload
4. SOAP
reply
2. SOAP r eq
Client
HTML
3. Web
Method
Web Service

10. Web Services: The Future ??
Customer – Retailer – Wholesaler – Producer
“Value-added” products/hardware (think Dell)

11. Web Services: The Future ??
Customer – Retailer – Wholesaler – Producer
“Value-added” products/hardware (think Dell)
Customer - Software Inc. - Service Provider
“Value-added” information!!

12. Web Services: The Future ??
Customer – Retailer – Wholesaler – Producer
“Value-added” products/hardware (think Dell)
Customer - Software Inc. - Service Provider
“Value-added” information!!
Google web service – search results
Amazon web service – product details
MapPoint web service – maps/directions

13. The “Not-So” Old Days
Your sites/applications pushed custom parameters to other sites, then watched customers go there
Consider a “BookBroker” website/application
A link to MapQuest for a map to nearest bookstore
A link to Amazon for book info
A link to Google for search results of book clubs
Customer leaves your site, goes there, hopefully comes back.

14. The “Not-So” Far Away Days
Your BookBroker site integrates the MapPoint, Google, and Amazon web services into your site.
Customers never have to leave!
Your site sends request to web service, gets back result data and integrates that data back into your site.

15. Web Services: Show Me the $$ !
Customer – Retailer – Wholesaler – Producer
“Value-added” products/hardware (think Dell)
Customer - Software Inc. - Service Provider
“Value-added” information!!

16. Web Service Providers Make $$$
Microsoft Map Point
Must purchase a license (free developer account!)
(But, Free to qualified education institutions)
Google Search
Up to 1,000 free queries per day (10/31/06)
Amazon Web Services
Some free, some have costs (WebSearch: $0.30/1000)