ΗΛΕΚΤΡΟΝΙΚΟ ΕΜΠΟΡΙΟ Web Services Overview Mary Grammatikou 9/06/2009.

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ΗΛΕΚΤΡΟΝΙΚΟ ΕΜΠΟΡΙΟ ΗΛΕΚΤΡΟΝΙΚΟ ΕΜΠΟΡΙΟ Web Services Overview Web Services Overview Mary Grammatikou www.netmode.ntua.gr 9/06/2009
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Transcript of ΗΛΕΚΤΡΟΝΙΚΟ ΕΜΠΟΡΙΟ Web Services Overview Mary Grammatikou 9/06/2009.

  • Slide 1
  • Web Services Overview Mary Grammatikou www.netmode.ntua.gr 9/06/2009
  • Slide 2
  • What are Web Services? Identified by a URI Interfaces defined using XML Can be discovered by other systems Interact using XML based messages conveyed by Internet protocols
  • Slide 3
  • The components DISCOVERING To discover where you can get web services and what businesses have to offer UDDI DESCRIPTION To describe a web service and how to interact with it WSDL PACKAGING To package your interaction with the Web Service SOAP TRANSPORT To carry the data envelope across the internet HTTP Post To fragment and deliver the http post request to the end point = TCP/IP
  • Slide 4
  • Transport HTTP HTTP POST HTTP GET
  • Slide 5
  • Packaging Soap Used to mean Simple Object Access Protocol From SOAP 1.2 > SOAP is no longer an acronym Two Types of SOAP
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  • Packaging Soap SOAP RPC (Remote Procedure Call): encode and bind data structures into xml encode an RPC call SOAP document style packages xml in an envelope
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  • Packaging Soap 1234
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  • Packaging Soap socks 1
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  • Description WSDL Web Services Description Language Web Services Description Language (WSDL) provides a model and an XML format for describing Web services. w3c.org
  • Slide 10
  • Types XML schema can be used to represent constraints on the content model of the elements in an XML document Elements that contain child elements and / or attributes are defined in a schema document using complex types Elements that dont contain child elements and attributes are defined using simple types
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  • Messages The message element gives information about the data that travels from one endpoint to another The message element depicts an one way message
  • Slide 12 ">
  • Operations The operation element is the action that we call in a WSDL file It can be used instead of a method
  • Slide 13 "> "> " title="Encoding Encoding in the web services is based on SOAP ">
  • Encoding Encoding in the web services is based on SOAP
  • Slide 14 "> "> " title="Endpoint Endpoint is the final URL of any web service ">
  • Endpoint Endpoint is the final URL of any web service
  • Slide 15
  • Discovery UDDI Universal Description, Discovery and Integration A UDDI Server acts as a registry for Web Services and makes them searchable Demonstration: https://uddi.ibm.com/ubr/registry.html
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  • Design Recommendations Create a local class Create a method with the same name
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  • Examples (Java Client) URL endpointURL = new URL(endpoint); Call call = new Call(); call.setSOAPTransport(m_httpconn); call.setTargetObjectURI("MessageService"); call.setMethodName("setMessage"); call.setEncodingStyleURI(Constants.NS_UR I_SOAP_ENC);
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  • Examples (Java Server) A Web service Server is simple: New class with method Then: Register class with soap engine (e.g. axis server)
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  • Security WS Security Standardisation W3C - http://www.w3c.org XML Encryption XML Digital Signatures WS-I - http://www.ws-i.org WS Security Profile OASIS - http://www.oasis-open.org WS-Security SAML - Security Assertion Markup Language XACML - Extensible Access Control Markup Language XKMS - XML Key Management Specification
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  • Security Firewall transparency Double-edged sword Simplifies deployment Opens up potential holes in enterprise security Similar to CGI, etc.
  • Slide 21
  • Real Examples Amazon Web Services API Infrastructure Services Payments and Billing On demand Work force Merchant Services Google Web API Ebay Web services HP & IBM online stores
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  • GoogleAPI Search Requests Search requests submit a query string and a set of parameters to the Google Web APIs service and receive in return a set of search results Cache Requests Cache requests submit a URL to the Google Web APIs service and receive in return the contents of the URL when Google's crawlers last visited the page (if available) Spelling Requests Spelling requests submit a query to the Google Web APIs service and receive in return a suggested spell correction for the query (if available)