Xml.ppt

Xml.ppt

• 1.
  Web Services andXML,SOA Submitted To : Gautam Buddha University, Greater Noida Ms. Rashmi Singh Submitted By : Praveen M.Tech(AIR) 225/PAI/002
• 2.
  Web Services -Definition from W3C “ A Web service is a software system identified by a URI, whose public interfaces and bindings are defined and described using XML. Its definition can be discovered by other software systems. These systems may then interact with the Web service in a manner prescribed by its definition, using XML based messages conveyed by internet protocols.”
• 3.
  Service Oriented Architectures Technologies capableof: •Exchanging messages •Describing Web services •Publishing and discovering Web service descriptions Component Role Operation service requestor retrieves a service description A service publishes its description One-way, conversational, many-to-many
• 4.
  Web Services – ArchitecturalExtensions  Incorporates additional features and functionality by extending technologies and components defined within the basic architecture, such as:  Asynchronous messaging  Attachment – typical usage : associating binary data with SOAP messages.  Caching  Message exchange pattern (MEP) - Describes a generalized pattern of message exchange between two services. e.g. : one-way, request/response, publish/subscribe, and broadcast.  Reliable message - implementation of Reliable Messaging one MEP is a series of requests between two nodes with an acknowledgement SOAP Module.  Message confidentiality – Can transmit the message via SSL or TLS, or have a SOAP Module provides for encryption and decryption.  Message integrity – Can have a SOAP Module use digital signature.  Session
• 5.
  The Complete WebServices "Stack" More mature technologies
• 6.
  The Wire Stack •Transport:HTTP is the de facto, other may be supported. •Packaging: SOAP is the de facto standard for XML messaging. •Extensions : Additional information attached to web services messages.
• 7.
  The Description Stack Itis actually a stack of description documents defined using XML Schema. Satisfied by WSDL minimum service description necessary to support interoperable Web services. facts, or assertions, and rules that apply to a particular Web service Input/ Output rendering Not fully specified
• 8.
  The Discovery Stack Service can be published using a variety of mechanisms:  Direct publish: description sent directly to requestor;  WSIL : HTTP GET retrieves descriptions from URL;  Universal Description, Discovery and Integration (UDDI) registries: a Web-based distributed directory.  Service requestors can retrieve a service description at design time (search by interface) or runtime (by communication and QoS) from a Web page (URL), a service description repository, a simple service registry or a UDDI registry. Discovery depends on how services are published; WSIL : de-centralized service discovery method
• 9.
  The technology sofar The WS technology is completely based on XML. Therefore, both the data format and the interaction protocols are XML-based:  customized XML -> data format  SOAP -> communication protocol  WSDL -> the Interface definition language  WSIL/UDDI -> standards for services discovery The lowest-level layers (the transport layer) should exploit some existing Internet protocols, like HTTP or SMTP
• 10.
  What is XML XMLis a simple tag-based language for describing information in a structured way. Basic elements:  Tags  Attributes  Text <xhtml:table><xhtml:tr> <xhtml:td width="40%">LastName</xhtml:td> <xhtml:td width="60%">Allen</xhtml:td> </xhtml:tr></xhtml:table> StartTag Text EndTag Attributes LastName Allen
• 11.
  How to workon XML The tree-like structure of XML makes developers life hard. In practice there is not a standard way for editing and analysing, but the best method depends on your need. Just choose among:  SAX -> call-back-based parser  DOM -> tree representation  XSLT -> “XML to XML” conversion  XPATH -> queries  XML Binding -> transparent conversion to objects
• 12.
  Simple Object AccessProtocol SOAP is a technology to support the exchange of XML-coded messages over a transport protocol, such as HTTP and SMTP. (wire stack) HTTP server Skeleton Server HTTP client Stub Client   XML XML   POST… HTTP 1.1 200 OK   SOAP SOAP   HTTP SOAP XML Protocols Folding SOAP basic mechanism
• 13.
  Simple Object AccessProtocol A SOAP runtime engine basically adds a XML envelope to an existing XML document SOAP Envelope XML Document <soap:Envelope> <soap:Header> <axis:SessionKey> SDHH37TYEW7R7 </axis:SessionKey> </soap:Header> <soap:Body> <GetPrice> <Item>Apples</Item> </GetPrice> </soap:Body> </soap:Envelope> SOAP Body SOAP Header Communicatio n Info Example Document Container Session, Authentication, Routing, Security
• 14.
  SOAP Encoding Dealing directlywith XML messages is not easy. Therefore, SOAP provides a “RPC emulation” technology The result: developers work with web services like with traditional RPC (e.g. CORBA,DCOM,DCE) The “RPC emulation” is named SOAP encoding. Fundamentally it is a set of rules to map a procedure invocation to a XML document.
• 15.
  SOAP Encoding The rules: method name -> first level element in the SOAP Body  arguments identifiers -> second level elements  arguments values -> third level elements  arguments types -> attribute xsi:type ClockService.getTime(location="USA"); <soap:Body> <getTime> <location xsi:type="xsd:string">USA</path> </getTime> </soap:Body> Service Request
• 16.
  Web Service DescriptionLanguage WSDL is a standard format to describe a Web Service (description stack) A WSDL document is composed by two sections:  An abstract interface section -> like in traditional IDL, it defines the signatures of procedures (RPC-style) or messages (document-style)  A deployment section -> it defines the service location and the supported transport protocols Fundamentally a client uses the WSDL to create the stub or to dinamically decode messages.
• 17.
  Web Service IntrospectionLanguage WSIL and UDDI are the standard way to search Web Services. (Discovery stack) WSIL is the decentralized approach. Fundamentally a WSIL document contains a directory of the Web Services deployed on a server. It is analogous to the index.html document for web pages. In the future, specific crawlers will browse the Internet looking for WSIL documents, like Google does today for web pages.
• 18.
  Web Service IntrospectionLanguage <inspection> <abstract>Acme Industries Public Web Services</abstract> <service> <name>Store Finder Service</name> <abstract> A service to perform a geographical search of Acme stores. </abstract> <description location="http://example.org/services/storefinder.wsdl"/> </service> <link location="http://example.org/services/ecommerce.wsil"/> </inspection> Service name Service location and description Link to an other WSIL page
• 19.
  UDDI UDDI is acomplimentary approach for searching based on a centralized repository. The repository is an “electronic yellow pages” for firms that offer web services online. Besides the names of services and their WSDL descriptors, firms can add a description of their business, phone numbers, addresses... UDDI repositories are offered by many agencies - e.g. IBM, Microsoft and HP.
• 20.
  Thank You