SUB CODE:IT0407 SUB NAME:INTEGRATIVE PROGRAMMING & TECHNOLOGIES SEM : VII. N.J.Subashini Assistant Professor,(Sr. G) SRM University, Kattankulathur

Transcription

1 SUB CODE:IT0407 SUB NAME:INTEGRATIVE PROGRAMMING & TECHNOLOGIES SEM : VII N.J.Subashini Assistant Professor,(Sr. G) SRM University, Kattankulathur 12/26/2012 1

2 UNIT V 12/26/2012 2

3 UNIT 5 WEB SERVICES ARCHITECTURE AND TECHNOLOGIES 9 SOAP: Anatomy of a SOAP Message Encoding Message Exchange Model Communication SOAP messaging SOAP Binding for Transport protocols Security Building SOAP web services. Description and Discovery of web services: WSDL: Anatomy of a WSDL Definition Document WSDL Bindings Tools Future and Limitations of WSDL UDDI: UDDI Registries Programming in UDDI Inquiry API Publishing API Implementation of UDDI Workflow of UDDI. 12/26/2012 3

4 Description and Discovery of web services WSDL UDDI 12/26/2012 4

5 WSDL 12/26/2012 5

6 History: Before WSDL, service providers used their own way to describe service Description files are inconsistent and incompatible to each other Microsoft and IBM then proposed to combine their technologies SCL (SOAP Contract Language SCL) and NASSL (Network Accessible Services Specification Language) to WSDL WSDL 1.0 (Sept. 2000) has been developed by IBM, Microsoft, and Ariba to describe Web Services for their SOAP toolkit. It was built by combining two service description languages: NASSL (Network Application Service Specification Language) from IBM and SDL (Service Description Language) from Microsoft. 12/26/2012 6

7 Abstract: WSDL stands for Web Services Description Language WSDL is an XML based protocol for information exchange in decentralized and distributed environments. WSDL is the standard format for describing a web service. WSDL definition describes how to access a web service and what operations it will perform. WSDL is a language for describing how to interface with XML based services. WSDL is an integral part of UDDI, an XML based worldwide business registry. WSDL is the language that UDDI uses. WSDL was developed jointly by Microsoft and IBM. WSDL is a w3c recommendation 12/26/2012 7

8 WSDL represents a contract between the service requestor and the service provider Using WSDL, a client can locate a Web service and invoke any of its publicly available function With WSDL aware tools, the whole process can be done automatically WSDL describes four critical pieces of data Interface information describing all publicly available functions Data type information for all messages and message responses Binding information about the transport protocol to be used Address information for locating the specified service 12/26/2012 8

9 A WSDL definition contains four important pieces of information about the Web service: Interface information describing all the publicly available functions Data type information for the incoming (request) and outgoing (response) messages to these functions Binding information about the protocol to be used for invoking the specified Web service Address information for locating the specified Web service 12/26/2012 9

10 Working of WSDL 12/26/

11 Web Service Life Cycle Figure 5.1 illustrates the steps of the Web service life cycle. 12/26/

12 In Figure 5.1, all of the communication over the wire takes place on SOAP. The following list explains the steps depicted in Figure 5.1: Step 1 illustrates a service provider publishing its Web service to a UDDI registry. This is when the service provider would create a WSDL definition and publish a link to this definition along with the rest of the Web service information to a UDDI registry. Step 2 illustrates an interested service user locating the Web service and finally obtaining information about invoking the Web service from the published WSDL definition. This step involves downloading a WSDL definition to the service user system and deserializing WSDL to a Java class (or any other language). This Java interface serves as a proxy to the actual Web service. It consists of the binding information of the Web service. 12/26/

13 Step 3 shows the service user binding at runtime to the Web service. In this step, the service user s application would make use of the Java interface representing WSDL as a proxy, in order to bind to the Web service. Step 4 finally shows the service user invoking the Web service based on the service invocation information it extracted from the Web service WSDL definition. This is when the service user s application would make use of the Java interface representing WSDL as a proxy, in order to invoke the methods/functions exposed by the Web service. 12/26/

14 WSDL Service Description A WSDL service description is an XML document conformant to the WSDL schema definition. This document, without any extensions, is not a complete service description, since it only covers the functional part. WSDL is the IDL for Web Services describing: 1) what a service does the operations (methods) the service provides, and the data (arguments and returns) needed to invoke them 2) how a service is accessed details about data formats and protocols necessary to access the service operations 3) where a service is located details of the protocol specific network address, such as a URL 12/26/

15 WSDL and IDLs As WSDL describes service interfaces, it has a role and purpose similar to that of an IDL in conventional middleware platforms, but: 12/26/

16 Anatomy of a WSDL Definition Document A WSDL definition document consists of the following seven key structural elements: 12/26/

17 WSDL Structure Abstract 12/26/

18 WSDL Structure Concrete 12/26/

19 <definitions>. A WSDL document is a set of definitions. These definitions are defined inside the <definitions> element, which is the root element in a WSDL document. It defines the name of the Web service and also declares the namespaces that are used throughout the rest of the WSDL document. <types>. This element defines all of the data types that would be used to describe the messages that are exchanged between the Web service and the service user. WSDL does not mandate the use of a specific typing system. However, as per the WSDL specification, XML Schema is the default typing system. <porttype>. This element defines the abstract definition of the operations supported by a Web service, by combining various request and response messages defined by <message> elements. Each operation refers to an i/p msg and an o/p msg. 12/26/

20 <message>. This element represents a logical definition of the data being transmitted between the Web service and the service user. This element describes a one way message, which may represent a request or response sent to or from the Web service. It contains zero or more message <part> elements, which basically refer to the request parameters or response return values. <binding>. This element specifies a concrete protocol and data format used for representing the operations and messages defined by a particular <porttype>, on the wire. <port>. This element specifies an address for binding to the Web service. <service>. This element aggregates a set of related <port> elements, each which uniquely specify the binding information of the Web service. A <service> consisting of multiple <port> elements essentially represents the capability of the service to be invoked over multiple bindings. 12/26/

21 WSDL Information Model 12/26/ IT0407 Integrative Programming and Technologies Prepared By

22 WSDL Document Example 1 12/26/ IT0407 Integrative Programming and Technologies Prepared By

23 WSDL Document Example 2 12/26/ IT0407 Integrative Programming and Technologies Prepared By

24 Working of WSDL A client can invoke a web service using SOAP, HTTP GET/POST and MIME. WSDL Document Structure <definition> Root element <types> Provides data type definitions <message> Represents the abstract definition of the data being transmitted <porttype> Defines a set of abstract operations <binding> Specifies concrete protocol and data format specifications for the operations and messages defined by a particular porttype <port> Specifies an address for a binding <service> Used to aggregate a set of related ports. 12/26/

25 WSDL Document Structure 12/26/

26 Definitions Element 12/26/

27 Definitions Example 12/26/

28 Namespace The XML namespace prefix are used to indicate the namespace of the element being defined All WSDL elements belong to the WSDL namespace, defined as For WSDL SOAP binding, For WSDL HTTP GET and POST binding, For WSDL MIME binding, 12/26/

29 Types Element 12/26/

30 Types Example 12/26/

31 Message Element 12/26/

32 Message Part Example 12/26/

33 PortType Element 12/26/

34 Operation Element 12/26/

35 PortType Operation Example 12/26/

36 Abstract Concrete Definitions 12/26/

37 Binding Element 1 12/26/

38 Binding Element 2 12/26/

39 Binding Protocol 12/26/

40 SOAP Binding Protocol 12/26/

41 SOAP Binding Protocol Example 12/26/

42 Different Styles and Restrictions 12/26/

43 Binding Protocol 12/26/

44 SOAP Binding Protocol 12/26/

45 SOAP Binding Protocol Example 12/26/

46 Different Styles and Restrictions 12/26/

47 Binding Protocol Operations 12/26/

48 Binding Protocol Encoding Rules 12/26/

49 Operation Encoding Example 12/26/

50 Binding Protocol Body Example 12/26/

51 Port Element 12/26/

52 Port Example 12/26/

53 Service Element 12/26/

54 Service Example 12/26/

55 Import Element 12/26/

56 Import Example 12/26/

57 Transmission Primitives 1 12/26/

58 Transmission Primitives 2 12/26/

59 Operations and PortType WSDL has four transmission primitives that an endpoint can support: One Way The endpoint receives a message <wsdl:input> Request response The endpoint receives a message and sends a correlated message <wsdl:input>,<wsdl:output>,<wsdl:fault> Solicit response The endpoint sends a message and receives a correlated message <wsdl:output>, <wsdl:input>, <wsdl:fault> Notification The endpoint sends a message <wsdl:output> 12/26/

60 Limitations of WSDL WSDL 1.1 has an obvious limitation: its incapability of being able to describe complex business Web services, which typically are constituted by orchestrating multiple finer grained Web services. This drawback is due to the lack of support for workflow descriptions in WSDL. To overcome these limitations of WSDL, standards such as ebxml Collaborative Protocol Profile/Collaborative Protocol Agreement (CCP/A), Business Process Specification Schema (BPSS), and Web Services Choreography Interface (WSCI) can be leveraged. An EbXML set of technologies can be used to build business Web services. 12/26/

61 UDDI 12/26/