Web Services Overview

1. Web Services Overview MIS3502: Application Integration and Evaluation David SchuffDavid.Schuff@temple.edu

2. 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

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

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

5. 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!

6. Web Services – An Emerging Standard • Promises a new level of interoperability • 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 http://www.w3.org/TR/wsa-reqs

7. 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

8. 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

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

10. 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 http://www.internetworld.com/dotnet.php?inc=in_focus/031501/03.15.01dotnetintro1.html

11. 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?

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

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

14. With standard messages “computer-to-computer” (no human intervention) J&R’s computer system w/ price information “browser-to-computer” (human intervention) <Price>120</Price><Qty>100</Qty><Ship>4</Ship> Web service Software which can “decode” XML and interacts with ANY web service Best Buy’s computer system w/ price information Web service <Price>150</Price><Qty>75</Qty><Ship>12</Ship> PriceGrabber’s computer system MacMall’s computer system w/ price information <Qty>200</Qty><Price>143</Price><Ship>7.15</Ship> Web service PriceGrabber’s required information from vendors: PriceQuantityShipping cost TigerDirect’s computer system w/ price information Web service <Ship>5</Ship> <Qty>200</Qty><Price>125</Price>

15. 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