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Web Services - New York University

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									Web Services
                   Web Services
• New set of XML – based protocols that allow
  internet services to be:
   – Self Describing
      • I.e. there is a method to query them about the parameters that
        are needed to invoke them
   – Automatically discovered
      • I.e. there is a way to determine the existence and location of a
        new service
   – Able to run over any type of connection to any type of
     device
      • Use SOAP to hide network layer, can run over HTTP
     Example of a Car Web Service
• You drive a car from NYC to Boston and want to get a
  cup of coffee
• Coffee sellers: publish/post their services at certain
  registries using a service description language
• You: tell the car to discover the best coffee offering
• Car starts purchasing transaction with the seller
   – invoke the discovered service, put order, pay (credit card)
• Get driving instructions and pick up the coffee
             Purchase Order Example
• Old Purchase order (PO) submission process
   – POs submitted by e-mails
   – E-mails are manually processed and PO entered into firm’s PO
     system (format conversion)
   – Invoices are generated and manually pasted into an e-mail
     message
   – Problem: speed, cost, conversion/spelling errors
• Web service will automate submission process
   –   PO automatically processed
   –   Invoice automatically generated
   –   No human in the loop
   –   Faster, cheaper, more reliable method
        What is a Web Service?
• Definition: A Web service is a software system designed to
  support interoperable machine-to-machine interaction
  over a network. It has an interface described in a machine-
  processable format (specifically WSDL). Other systems
  interact with the Web service in a manner prescribed by its
  description using SOAP-messages, typically conveyed
  using HTTP with an XML serialization in conjunction with
  other Web-related standards. (taken from
  http://www.w3.org/TR/2003/WD-ws-arch-
  20030808/#whatis)
• A new breed of web application. They are self describing,
  self-contained, modular applications that can be published,
  located and invoked across the web
     Key Features of Web Services
• Applications published on the Web that perform
  certain functions, e.g.
  weather reports, stock quotes, travel package
• Other applications discover and invoke them
• Are self-contained, self-described and modular:
  represent black-box functionality
  – defined by messages service accepts & generates
  – is independent of underlying implementation
• Invoked using standard Internet protocols
  – E.g., HTTP protocol and XML data format
            Web Service Models
• Partner: serve known customers, partners and
  remote business units
  – E.g., Continental lets its customers check flight info
    and do upgrades remotely.
• Private: Integrate software apps within a
  company developed on different platforms
  – Build bridges between different apps with Web
    services front ends; EAI
• Public: Offer Web services to the world
  – Register a service with a broker for consumers to find
    them, negotiate terms and use them
  – E.g., get a weather information, buy a product.
      What is a Web Service?
                                              Web
         Open                                Service
          Internet
            Protocols         A programmable application
                              component accessible via standard
                              Internet protocols
   You can ask a site or device for a
    description of its Web Services, or use              UDDI
    a directory service such as UDDI
   Web Services are defined in terms of the    Web Services
    formats and ordering of messages         Description Language

   Web Service consumers can send and                   SOAP
    receive messages using SOAP
   All these capabilities are built using             XML, HTTP
    open Internet protocols
Components and Operations

                    Service Broker   Publish/ Un-publish
          Find




                                                        Service
    Service
                          Bind                         Providers
   Requestors




        Web Services Components and Operations
Building On An XML Foundation
Benefits Of XML Foundation
     User: Beyond browsing
     – Access and act on information
     – Greater control, better decision-making, easier
       collaboration
     – Optimal support for different devices

     Business: Integration by design
     – Best-of-breed internally and externally
     – Business processes and partners
     – Agility to run, adapt business better

     Industry: New opportunities
     – Don’t have to do it all yourself
     – Make your value easier to consume
     – “Plug and play” business relationships
                        SOAP
• Simple Object Access Protocol
  – Allows movement of data defined by XML
  – Describes a message and how it should be treated
  – Has rules for relating data in an application to data in a
    database
  – Has a framework for developing processes and
    procedures that can run on one system while calling
    data from another
• http://www.w3c.org/TR/soap
                  UDDI
• Use SOAP and XML to define ways for
  applications to find out about the existence
  and capabilities of other applications
• Should speed up interactions that use SOAP
  and XML
• http://www.uddi.org
                    WSDL
• Does for web services what XML does for
  data
  – Defines services and describes ways of
    invoking them
  – Provides a complete description of a service,its
    location (i.e., address, port), and a list of
    operations available.
• http://www.w3c.org/TR/wsdl
      Benefits of Web Services
• Business Process Automation
• Enterprise Application Integration
• Freedom to choose the best technology platform in
  each situation
• Promotes Interoperability
• Reduce Complexity through encapsulation
• Increases access points
• Enable Just in Time integration
      Web Services Promise…
• Ability to distribute applications anywhere
  on the Web
• Services can be changed / updated without
  touching the calling application
• Should dramatically increase ease of
  implementing B2B applications
             Issues and Concerns
• New and untested technology
• XML agreements
   – Firms have to agree on document descriptions
• Transaction management
• Security
• Quality of Service (QoS)
   –   Reliability
   –   Scalability
   –   Performance
   –   Availability and Accessibility
                  Summary
• The Web services framework is being defined,
  standardized and supported by the industry at a
  record pace.
• Broad industry acceptance and standard
  compliance will make it ubiquitous.
• Will bring an unprecedented level of
  interoperability to Web applications.
• The benefits of Web services, however, are not
  limited to the Web!
                 Applications
•   Real Time Data – News Stock Quotes
•   Internet Telephony Services
•   Instant Messaging
•   CRM
•   Straight Through Processing
    – Automated end-to-end processing of
      transactions from trade inception to settlement
         Creating Web Services
• ASP.NET
  – Easiest way to create web services
• SOAP Toolkit V2 (VS6) – MSDN
  – http://msdn.microsoft.com/webservices/
• SOAP Toolkits for
  – Apache - http://xml.apache.org/soap/
  – XMethods http://www.xmethods.net
  – …more on google 
Examples of Web Services today
• http://www.amazon.com/webservices
• http://www.weather.com
• http://www.google.com
• http://www.flamenconetworks.com is a firm that
  creates software for development of web services
• MSN network and Verizon Wireless in a joint
  venture to provide wireless data services
  http://www.webservices.org/index.php/article/artic
  leview/408/1/29/
      For more information…
• http://www.ibm.com/software/webservices
• http://java.sun.com/webservices
• http://msdn.microsoft.com/webservices/unde
  rstanding

								
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