Web Services Brian A LaMacchia Software Architect bal microsoft com Windows Trusted Platform Technologies Microsoft Corporation CPSC 155b E Commerce Doing Business on the Internet March 27 2003 Five Questions What is a Web Service Why are Web Services interesting Why should I care about them What e commerce business models do Web Services enable What security and privacy issues need to be addressed for Web Services to be successful What the heck is Microsoft s NET Platform all about and how does NET relate to Web Services What is a Web Service Software Design Principles Abstraction Componentization We abstract reuse useful functions all the time in programs Abstraction hides implementation details We share code among programs by creating reusable software components Save time coding debugging testing Reusable components have value You can sell components You can given them away to sell something else Ex Device drivers Components are local Executable components must live on your local machine Not so great if the data is remote Ex Stock analysis component Wants as much historical data as possible Is everyone going to cache the last 100 years of the NYSE on their hard disks Ex complex searches against the NYT archives Want code to run on the server Saved by the Web Web Usage Today Web usage today is browser oriented Users browse for information Vast databases are accessed through HTML gateways user friendly displays Example Yahoo s stock ticker Yahoo has tons of stock price history sitting behind http quote yahoo com That info is easily available to anyone who browses to the right page But look at how the info is presented Yahoo s Stock Ticker Screen scraping Data is formatted for easy use by people not programs Programs need to mimic users to Scrape the screen Parse make use of the data Call server side functions plot a chart compute something perform a search etc Download the HTML and then pattern match against it Inefficient and fragile Data type semantics are lost We need a better mechanism for making Web published data and component software functions available to programs What is a Web Service Software components application logic accessible via standard Web protocols Available to any client that speaks the necessary Web protocols XML SOAP Programming the Web Better remote procedure calls over the Web Web sites with no user interface Platform independent components Enable highly distributed systems Finding talking to Web Services Clients need answers to three separate questions What services are available How do I communicate with this particular service Let s talk Give me some data Three Standards UDDI Universal Description Discovery and Integration WSDL Web Service Description Language Document describing the message exchange contract SOAP Simple Object Access Protocol Yellow pages directory for services XML based protocol for messaging All based on XML the foundation Web Services In Practice Find a Service http www uddi org UDDI Link to WSDL document Web Service Consumer How do we talk WSDL http yourservice com WSDL XML with service descriptions Web Service Let me talk to you SOAP http yourservice com svc1 XML SOAP BODY Design Time or Dynamic Runtime Why are Web Services interesting For Developers Access to a Web wide library of software components Smart development tools can Help you locate useful Web Services Download Web Service descriptions WSDL Automatically generate code to talk to the Web Service On the server side automatically generate service description for a service you write For Businesses Three keys to next generation applications Any to Any integration Integral assumption of development Must tie together islands of data devices OS businesses people Intelligent devices Many types with varying capabilities but all speak common protocols Anytime anywhere access Access and action Open and accessible to all Open internet based standards Broad accessibility New Applications Shift to decentralized distributed Span multiple clients servers services Federate across organizations Build systems that play in larger solutions Company A Mobile Employees Consumers Partners Company B Mobile Employees Consumers Partners Customers Partners Suppliers Web Services Simple Customer Scenario Mobile Sales Client Company Quote Engine Web Service Reseller Partner Web Site Call Center Client The same Web Service Enabled an intranet application Embedded in a mobile offline solution Published over the Internet to a partner What e commerce business models do Web Services enable How do I make money from Web Services Every data exchange is potentially a revenue opportunity Both the raw data and the exchange translation can have value Ex stock quotes are essentially free but stock alerts sent to my phone have value Still need someone willing to buy it Web Services help in two ways Increase availability of data It s on the web Enabled clients potential customer pool for your data Next Gen Web Applications Other Services Smarter Smarter Clients Clients Standard Standard Browsers Browsers Applications Become Programmable Web Services XML XML HTML BizBiz Logic Biz Web Service Tier TierLogic Logic OS OS OS Services Services Services XML Public Web Services XML NET Services XML Internal Services XML ML X Smarter Servers Smarter Open Internet Devices Data Hosts Devices Communications Protocols Richer More Applications Leverage HTTP SMTP XML SOAP Productive User Globally Available Experience Federated Web Services Revenue models Short term will likely look similar to current DRM content models Long term might change depending on micro payments New twist aggregating clients services Subscriptions Per copy per transaction depending on overall value of the copy transaction Perhaps some metered usage There s money in creating clients that are smart about how they combine data from various services ex comparison shoppers Prob no advertising revenue no eyeballs What security and privacy issues need to be addressed for Web Services to be successful Security Privacy Protocol level Integrity secrecy of message traffic Authentication Data level Integrity secrecy of collected data Data privacy Collection sharing of information Integrity secrecy of message traffic Need robust security protocols for SOAP messages XML Digital Signature standard XML Encryption standard in process Need protocol pieces Replay attack defenses etc This is all do able just requires effort leading to an interoperable standard WS