Web Services Overview MIS3502: Application Integration and Evaluation David Schuff

Standard messaging Scenario: The supply chain A large retailer (Wal-Mart) wants to Maintain optimal inventory levels Order from multiple vendors Dynamically adjust product mix A vendor (Proctor and Gamble) wants to Service multiple suppliers Maintain service level

Why we like standard messages (web services or not)… Old n’ busted... (nonstandard) New hotness... (standard) “I have know four different languages!” “Now I only have to know two languages – my own and the common language” Consider a situation where we want to communicate across languages… English French German Italian Spanish English French German Italian Spanish Esperanto

Why we like standard messages (web services or not)… Old n’ busted... (nonstandard) New hotness... (standard) “I have to know the message formats of six banks!” “I only need to know the common format for all banks!” Consider a point of sale system that debits directly from a particular bank account… Standard message format

What if all don’t use the standard message? Then they don’t! Adhering to the standard is a business issue, not a technology issue Businesses can still choose to send and receive nonstandard messages But if no one follows it, the standard is pointless!

Web Services – An Emerging Standard o Promises a new level of interoperability o A Web service is a software application identified by a URL, whose interfaces and bindings are capable of being defined, described, and discovered as XML artifacts. A Web service supports direct interactions with other software agents using XML based messages exchanged via internet-based protocols. Source: World Wide Web Consortium

What’s a Web Service? “Wrapping up” application functionality (as an object) and running it on a server Allowing people to access that object by Sending information (inputs) Receiving information (outputs) Big Idea: Anyone can write an application to communicate directly with a web service No intermediate application (i.e., web page) is necessary

What’s different about Web Services? Everything is based on open standards Instead of sending proprietary messages between clients and servers, it sends messages in a standard format for example, HTTP is an agreed-upon standard for the transportation of data different EDI systems may transport data differently Messages sent in plain (but encrypted) text, making them easy to send and receive

Review: A Web Service is not a Web Site User Google.com (the site) Google Search Engine (the service) Application Google Search (the service) Using a web site Using a web service interacts with interacts directly with without human intervention

Web Services Technologies HTTP (Hypertext Transfer Protocol) Handle the transportation of data XML (Extensible Markup Language) Formatting of messages SOAP (Simple Object Access Protocol) Handle the sending and receiving of messages between objects UDDI (Universal Description, Discovery, and Integration) Registration of services for discovery by other components

Web services example: PriceGrabber.com What they do Aggregates prices from vendors Presents them in one place for comparison Provides customer ratings of vendors The problem How do you easily interact with multiple vendors?

Without web services Custom software to communicate with J&R PriceGrabber’s computer system J&R’s computer system w/ price information Best Buy’s computer system w/ price information MacMall’s computer system w/ price information TigerDirect’s computer system w/ price information Custom software to communicate with Best Buy Custom software to communicate with MacMall Custom software to communicate with TigerDirect “computer-to-computer” (no human intervention) “computer-to-computer” (no human intervention) “browser-to- computer” (human intervention) “browser-to- computer” (human intervention)

Without standard messages PriceGrabber’s computer system J&R’s computer system w/ price information Best Buy’s computer system w/ price information MacMall’s computer system w/ price information TigerDirect’s computer system w/ price information Price: $120 Quantity: 100 Shipping: $4.00 Price: $120 Quantity: 100 Shipping: $4.00 Price: 150 In-stock: Yes Shipping: 12 Price: 150 In-stock: Yes Shipping: 12 Shipping: 5% Cost: $143 Qty: 200 Shipping: 5% Cost: $143 Qty: 200 $125, 200, $5 PriceGrabber’s required information from vendors: Price: Quantity: Shipping cost: PriceGrabber’s required information from vendors: Price: Quantity: Shipping cost: Software to translate data from J&R Software to translate data from Best Buy Software to translate data from MacMall Software to translate data from TigerDirect “computer-to-computer” (no human intervention) “computer-to-computer” (no human intervention) “browser-to- computer” (human intervention) “browser-to- computer” (human intervention)

With standard messages PriceGrabber’s computer system J&R’s computer system w/ price information Best Buy’s computer system w/ price information MacMall’s computer system w/ price information TigerDirect’s computer system w/ price information PriceGrabber’s required information from vendors: Price Quantity Shipping cost PriceGrabber’s required information from vendors: Price Quantity Shipping cost Software which can “decode” XML and interacts with ANY web service “computer-to-computer” (no human intervention) “computer-to-computer” (no human intervention) “browser-to- computer” (human intervention) “browser-to- computer” (human intervention) Web service

Summary of Web Services Web services use web-based standards (XML, HTTP) These standards make it easier to develop standard formats for business messages XML is an easy, standard way to define data HTTP is an easy, standard way to exchange data