Justin Tilton instructional media magic, inc.

1
CSG Mini-Workshop Web Services
Justin Tiltoninstructional media magic,
inc. As presented at theCommon Solutions Group
Meeting May 9, 2002 Chicago, Illinois
2
Overview

• Data XML
• Validation Schema
• Transport SOAP
• Security SAML
• Description WSDL
• Directory UDDI
• Transformation XSLT

3
DataXML Overview
4
XML is for structuring data 1

• Structured data includes things like
• spreadsheets, address books, configuration
  parameters, financial transactions, and technical
  drawings
• XML is a set of rules for designing text formats
  that let you structure your data.
• XML is not a programming language, and you don't
  have to be a programmer to use it or learn it

5
XML is for structuring data 2

• XML makes it easier for a computer to generate
  data, read data, and ensure that the data
  structure is unambiguous
• XML avoids common pitfalls in language design
• it is extensible
• it is platform-independent
• and it supports internationalization and
  localization

6
XML is a family of technologies 1

• XML 1.0 is the specification that defines what
  "tags" and "attributes" are
• Xlink describes a standard way to add hyperlinks
  to an XML file
• XPointer and XFragments are syntaxes in
  development for pointing to parts of an XML
  document
• XSL is the advanced language for expressing style
  sheets. It is based on XSLT

7
XML is a family of technologies 2

• XSLT is a transformation language used for
  rearranging, adding and deleting tags and
  attributes
• XPath is a language for navigating in an XML
  document
• XML Schemas help developers to precisely define
  the structures of their own XML-based formats.
• XQuery provides flexible query facilities to
  extract data from real and virtual documents on
  the Web
• XML Signatures provide integrity, message
  authentication, and signer authentication
  services for an XML document

8
XML is new, but not that new

• Development of XML started in 1996 and has been a
  W3C Recommendation since February 1998
• Before XML there was SGML, developed in the early
  '80s, and widely used for large documentation
  projects
• The development of HTML started in 1990.
• The designers of XML simply took the best parts
  of SGML, guided by the experience with HTML, and
  produced something very powerful

9
HTML and XHTML

• The successor to HTML is XHTML
• XHTML has almost all of the same elements as
  HTML, but the syntax has been changed slightly to
  conform to the rules of XML
• XHTML allows "ltpgt", but not "ltrgt" since ltpgt is
  defined in XHTML and ltrgt is not
• XHTML says that "ltpgt" stands for "paragraph", and
  not for "price", "person", or anything else
• Emerging applications such as uPortal are using
  XHTML to output content to browsers

10
XML has namespaces

• To eliminate name confusion when combining
  documents, XML provides a namespace mechanism
• XSL and RDF are good examples of XML-based
  formats that use namespaces
• XML Schema is designed to support modularity by
  defining XML document structures, making it easy
  to combine two schemas to produce a merged
  document structure.

11
XML is license-free

• XML is license-free, platform-independent and
  well-supported
• A large and growing community of tools and
  engineers experienced in the technology
• Since XML is license-free, you can build your own
  software around it without fees

12
An example of XML element

• lt?xml version"1.0"?gt
• ltbreakfast_menugt
• ltfoodgt
• ltnamegtBelgian Waffleslt/namegt
• ltpricegt
• ltamountgt5.95lt/amountgt
• ltcurrencygtUS Dollarslt/currencygt
• lt/pricegt
• ltdescriptiongttwo of our famous Belgian
  Waffles with plenty of real maple
  syruplt/descriptiongt
• ltcaloriesgt650lt/caloriesgt
• lt/foodgt
• ltfoodgt
• ltnamegtStrawberry Belgian Waffleslt/namegt
• ltpricegt
• ltamountgt7.95lt/amountgt
• ltcurrencygtUS Dollarslt/currencygt
• lt/pricegt
• ltdescriptiongtlight Belgian waffles covered
  with
• strawberries and whipped creamlt/descriptiongt

13
An example of XML attribute

• lt?xml version"1.0"?gt
• ltbreakfast_menugt
• ltfoodgt
• ltnamegtBelgian Waffleslt/namegt
• ltprice currency"US Dollars"gt5.95lt/pricegt
• ltdescriptiongttwo of our famous Belgian
  Waffles with plenty of real maple
  syruplt/descriptiongt
• ltcaloriesgt650lt/caloriesgt
• lt/foodgt
• ltfoodgt
• ltnamegtStrawberry Belgian Waffleslt/namegt
• ltprice currency"US Dollars"gt7.95lt/pricegt
• ltdescriptiongtlight Belgian waffles covered
  with
• strawberries and whipped creamlt/descriptiongt
• ltcaloriesgt900lt/caloriesgt
• lt/foodgt

14
ValidationXML Schema Overview
15
What is an XML Schema?

• XML Schema is an XML based alternative to
  Document Type Definition (DTD)
• The purpose of an XML Schema is to define the
  legal building blocks of an XML document, just
  like a DTD.

16
An XML Schema defines

• Elements and attributes that can appear in a
  document
• Simple child-parent element relationships
• The sequence in which the child elements can
  appear
• The number of child elements
• Whether an element is empty or can include text
• Data types for elements and attributes
• Default values for elements and attributes

17
XML Schemas replacing DTDs

• We think that very soon XML Schemas will be used
  in most Web applications as a replacement for
  DTDs. Here are some reasons
• XML Schemas are richer than DTDs
• XML Schemas are written in XML
• XML Schemas support data types
• XML Schemas support namespaces
• XML Schemas are extensible to future additions

18
XML Schema Data Types

• With data type support it is easier to
• Describe permissible document content
• Validate the correctness of data
• Work with data from a database
• Define data facets (restrictions on data)
• Define data patterns (data formats)
• Convert data between different data types

19
Why Schema is important

• A well-formed XML document is a document that
  conforms to the XML syntax rules
• Even if documents are Well-Formed they can still
  contain errors, and those errors can have serious
  consequences.
• With XML Schemas, most of these errors can be
  caught by your validating software.

20
XML Schema Practical
21
The simplest element definition

• A schema specifies a set of valid top-level
  elements.
• In the simplest case, we can define an element to
  describe a name of the city
• Schema
• ltxsdelement name"city" type"xsdstring"/gt
• Document
• ltcitygtWashingtonlt/citygt

22
Another element definition

• A schema specifies a set of valid top-level
  elements.
• Complex types can define elements with children
• Schema
• ltxsdelement name"note"gt
• ltxsdcomplexTypegt
• ltxsdsequencegt
• ltxsdelement name"to" type"xsdstring"/gt
• ltxsdelement name"from" type"xsdstring"/gt
• ltxsdelement name"heading" type"xsdstring"/gt
  
• ltxsdelement name"body" type"xsdstring"/gt
• lt/xsdsequencegt
• lt/xsdcomplexTypegt
• lt/xsdelementgt

23
Another element definition

• A schema specifies a set of valid top-level
  elements.
• Complex types can define elements with children
• Document
• ltnotegt
• lttogtSamlt/togt
• ltfromgtJacklt/fromgt
• ltheadinggtYour presentationlt/headinggt
• ltbodygtPlease update section IIlt/bodygt
• lt/notegt

24
TransportSOAP Overview
25
What is SOAP?

• SOAP is an XML based protocol to let software
  components and applications communicate using
  standard Internet HTTP
• SOAP stands for Simple Object Access Protocol

26
SOAP is

• A communication protocol
• For communication between applications
• A format for sending messages
• Designed to communicate via internet
• Platform independent
• Language independent
• Based on XML
• Simple and extensible
• Remote procedure call protocol
• SOAP will be developed as a W3C standard

27
Why SOAP?

• SOAP is Transport Protocol independent
• Transport protocol chosen according to network
  architecture and type of exchange
• Real time over the internet might use HTTP, where
  a batch processing application might use SMTP
• SOAP provides a way to communicate between
  applications running on different operating
  systems, with different technologies and
  different programming languages

28
SOAP was Proposed

• UserLand, Ariba, Commerce One, Compaq,
  Developmentor, HP, IBM, IONA, Lotus, Microsoft,
  and SAP proposed SOAP to W3C, in May 2000
• The ebXML Plenary voted on 16 February 2001 to
  use SOAP 1.1 and SOAP With Attachments as part of
  the ebXML transport specification
• Anyone using the transport portion of ebXML will
  therefore be using SOAP

29
SOAP Building Blocks

• A SOAP message is an ordinary XML document.
• The XML document contains the following XML
  elements
• A SOAP envelope, that defines the content of the
  message
• A SOAP header (optional), that contains header
  information such as credentials
• A SOAP body, that contains request and response
  information

30
Syntax Rules

• A SOAP message
• Must be encoded using XML
• Must have a SOAP envelope
• Can have a SOAP header
• Must have a SOAP body
• Must use the SOAP envelope namespaces
• Must use the SOAP encoding namespace
• Must NOT contain a DTD reference
• Must NOT contain XML processing instructions

31
SOAP Request Example

• ltsoapEnvelopegt
• ltsoapBodygt
• ltGetPricegt
• ltItemgtAppleslt/Itemgt
• lt/GetPricegt
• lt/soapBodygt
• lt/soapEnvelopegt

32
SOAP Template

• ltsoapEnvelopexmlnssoap"http//schemas.xmlsoap.
  org/soap/envelope/soapencodingStyle"http//sc
  hemas.xmlsoap.org/soap/encoding/"gt
• ltsoapHeadergtlt/soapHeadergt
• ltsoapBodygtlt/soapBodygt
• ltsoapFaultgtlt/soapFaultgt
• lt/soapEnvelopegt

33
The Envelope Element

• The ltEnvelopegt element must be the root element
  of a SOAP message
• It defines the XML document as a SOAP message.

34
The Header Element

• The ltHeadergt element can contain additional,
  application specific information about the SOAP
  message
• For example, the Header element can contain
  information about the language and currency
  values used in the SOAP message
• Optionally, the header can carry authorization
  authentication information

35
The Body Element

• The ltBodygt must be present in a SOAP message
• It contains the actual SOAP message or payload

36
A SOAP Example 1

• The SOAP request
• ltsoapEnvelopegt
• ltsoapBodygt
• ltxmlnsm"http//www.stock.org/stock" /gt
• ltmGetStockPricegt
• ltmStockNamegtIBMlt/mStockNamegt
• lt/mGetStockPricegt
• lt/soapBodygt
• lt/soapEnvelopegt

37
A SOAP Example 2

• The SOAP response
• ltsoapEnvelopegt
• ltsoapBodygt
• ltxmlnsm"http//www.stock.org/stock" /gt
• ltmGetStockPriceResponsegt
• ltmPricegt34.5lt/mPricegt
• lt/mGetStockPriceResponsegt
• lt/soapBodygt
• lt/soapEnvelopegt

38
SAML Assertion

• ltSAMLgt
• ltAssertionIDgt
• http//www.bizexchange.test/assertion/AE0221
• lt/AssertionIDgt
• ltIssuergt URNdns-datewww.bizexchange.test2001
  -01-0319283
• lt/Issuergt
• ltConditionsgt
• ltAudiencegt
• http//www.bizexchange.test/rule_book.html
• lt/Audiencegt
• lt/Conditionsgt
• ltSubjectgt
• ltAccountgtAlicelt/Accountgt
• lt/Subjectgt
• ltResourcesgt
• ltstringgthttp//www.elsevier.com/Journal_X/lt/st
  ringgt ltstringgthttps//www.SantaMariaUniversity.ed
  u/SIS/lt/stringgt
• lt/Resourcesgt
• lt/SAMLgt

39
Building web services

• Web services architecture overview

find
2
UDDI Service
Web service requestor
look up web service
bind
3
4
call
Call Web Service
publish
1
Retrieve WSDLDefinition
Register Web Service(at development time)
Web service provider
WSDL Document
40
WSDL

• Web Services Description Language
• Language describing what services are available
  and how they can be accessed
• Messages being sent
• End-points for message processing
• WSDL makes it easy for client applications to use
  a web sevice

41
WSDL

• WSDL document structure
• ltdefinitionsgt root element
• lttypes/gt data type definitions
• ltmessage/gt abstract message definitions
• ltportType/gt set of abstract operations
• ltbinding/gt protocols for a portType
• ltservicegt grouping of related ports
• ltport/gt network address for a binding
• lt/servicegt
• lt/definitionsgt

42
UDDI

• Universal Description, Discovery and Integration
• A web services registry system
• White pages general information
• Yellow pages service classifications
• Green pages operation rules

43
UDDI Registry organization
contact phone address e-mail
keyedReference tModelKey keyName keyValue
businessService serviceKey tModelKey name
description bindingTemplates
keyedReference tModelKey keyName keyValue
44
UDDI SOAP API

• Registry API
• Find methods
• find_business
• find_service
• find_binding
• find_tModel
• Get methods
• get_businessDetail
• get_serviceDetail
• get_bindingDetail
• get_tModelDetail

• Inquiry API
• Save methods
• save_business
• save_service
• save_binding
• save_tModel
• Delete methods
• delete_business
• delete_service
• delete_binding
• delete_tModel

45
The Meteor Channel an example of Web services
46
Meteor in a nutshell
Lender
XML
47
Diagram of Meteor Concept
Web Services HTML
Meteor XML
Student Access Provider Data Provider
48
As implemented ...
Web Services Secure HTML
Meteor Secure XML
Standard Browser
uPortal
Meteor SOAP
Meteor SOAP
Database
49
Data from multiple sources, locations
50
Meteor Channel in the uPortal
51
The End

• Justin Tilton
• jet_at_immagic.com