1. Standards For Building Web Sites Brian KellyEmail Address UK Web Focus B.Kelly@ukoln.ac.uk UKOLN University of Bath http://www.ukoln.ac.uk/ UKOLN is funded by Resource: The Council for Museums, Archives and Libraries, the Joint Information Systems Committee (JISC) of the Higher Education Funding Councils, as well as by project funding from the JISC and the European Union. UKOLN also receives support from the University of Bath where it is based.

2. 2 Contents Introduction Web Standards Overview Web Standards: Data Formats Transport Addressing Metadata Deployment Issues Questions Aims of Talk To describe standards bodies involved with the Web To review key Web standards To report on developments to Web standards To briefly address implementation models Aims of Talk To describe standards bodies involved with the Web To review key Web standards To report on developments to Web standards To briefly address implementation models

3. 3 UK Web Focus / W3C UK Web Focus: JISC funded post based at UKOLN (Bath Univ) Advises UK HE community on web issues Represents JISC on W3C UKOLN UK Office for Library and Information Networking Applied research (e.g. JISC and EU-funded projects) and dissemination W3C ( World Wide Web Consortium ): International consortium, with headquarters at MIT, INRIA and Keio University (Japan) Coordinates development of web protocols and file formats

4. 4 Standards, Architectures, Applications, Resources This talk is concerned primarily with the standards used to develop web services Architectures: models for implementing systems Applications: software products used to implement systems Standards: concerned with protocols and file formats Open standards vs. Proprietary HTML / XML vs. PDF CSS / XSL vs. HTML NT / Unix File system / database application HTML tools / content management Apache / IIS FrontPage / Dreamweaver Oracle / SQLServer Development vs. Migration costs Use of in-house expertise In-house vs. out-sourced Licensed vs. open source Resources: financial and staff costs needed to implement systems

5. 5 Standards Need for standards to provide: Platform independence Application independence Avoidance of patented technologies Flexibility ("evolvability" - Tim Berners-Lee) Architectural integrity Long-term access to data Ideally look at standards first, then find applications which support the standards Difficult to achieve this ideal!

6. 6 Standardisation W3C Produces W3C Recommendations on Web protocols Managed approach to developments Protocols initially developed by W3C members Decisions made by W3C, influenced by member and public review IETF Produces Internet Drafts on Internet protocols Bottom-up approach to developments Protocols developed by interested individuals "Rough consensus and working code" ISO Produces ISO Standards Can be slow moving and bureaucratic Produce robust standards Proprietary De facto standards Often initially appealing (cf PowerPoint) May emerge as standards PNG HTML Z39.50 Java? PNG HTML Z39.50 Java? PNG HTML HTTP PNG HTML HTTP URN whois++ HTTP URN whois++ HTML extensions PDF and Java? HTML extensions PDF and Java? Other Standards bodies such as ECMA Community groups which can agree on, say, profiles

7. 7 The Web Vision Tim Berners-Lee's vision for the Web: Automation of information management: If a decision can be made by machine, it should All structured data formats should be based on XML Migrate HTML to XML All logical assertions to map onto RDF model All metadata to use RDF A useful overview of Tim Berners-Lee's vision for the Web is given in his book Weaving The Web.

8. 8 Web Protocols Web initially based on three simple protocols: Data Formats HTML (HyperText Markup Language) provides the data format for native documents Addressing URLs (Uniform Resource Locator) provides an addressing mechanism for web resources Transport HTTP (HyperText Transfer Protocol) defines transfer of resources between client and server Data Format HTML Addressing URL Transport HTTP

9. 9 HTML History HTML 1.0Unpublished specification. DTD developed by Tim Berners-Lee (CERN). HTML 2.0Spec. based on innovations from NCSA (forms and inline images!) HTML 3.0Proposed spec. (renamed from HTML+). Very comprehensive Failed to complete IETF standardisation Little implementation experience ProprietaryIntroduction of proprietary HTML elements by Netscape and Microsoft (browser wars) HTML 3.2Spec. based on description of mainstream innovations in marketplace HTML 4.0Current recommendation

10. 10 Problems with Extensions Device Dependency Resources are dependent on a particular browser Platform dependency Costs Read costs in supporting multiple architectures Potential costs in re-engineering Architecture Proprietary innovations have been flawed: –Merging content and appearance –Maintenance of resources Accessibility problems: –Poor support for access by disabled But: Experiments are needed

11. 11 HTML 4.0, CSS 2.0 and DOM HTML 4.0 used in conjunction with CSS 2.0 (Cascading Style Sheets) and DOM 1.0 provides an architecturally pure, yet functionally rich environment HTML 4.0 Improved forms Hooks for stylesheets Hooks for scripting languages Table enhancements Better printing CSS 2.0 Support for all HTML formatting Positioning of HTML elements Multiple media support CSS Problems Changes during CSS development Netscape & IE incompatibilities Continued use of browsers with known bugs CSS Problems Changes during CSS development Netscape & IE incompatibilities Continued use of browsers with known bugs DOM 1.0 Document Object Model Hooks for scripting languages Permits changes to HTML & CSS properties and content

12. 12 HTML Limitations HTML 4.0 / CSS 2.0 have limitations: Difficulties in introducing new elements –Time-consuming standardisation process ( ) –Dictated by browser vendor (, ) Area may be inappropriate for standarisation: –Covers specialist area (maths, music,...) –Application-specific ( ) HTML is a display (output) format HTML's lack of arbitrary structure limits functionality: –Find all memos copied to John Smith –How many unique tracks on Jackson Browne CDs

13. 13 XML XML: Extensible Markup Language A lightweight SGML designed for network use Addresses HTML's lack of evolvability Arbitrary elements can be defined (,, etc) Agreement achieved quickly - XML 1.0 became W3C Recommendation in Feb 1998 Support from industry (SGML vendors, Microsoft, etc.) Support in Netscape 6 (?) and IE 5

14. 14 XML Concepts Well-formed XML resources: Make end-tags explicit:... Make empty elements explicit: Quote attributes <img src="logo.gif" height="20" Use consistent upper/lower case Valid XML resources: Need DTD XML Namespaces: Mechanism for ensuring unique XML elements : Insert M-471

15. 15 XLink, XPointer and XSL XLink will provide sophisticated hyperlinking missing in HTML: Links that lead user to multiple destinations Bidirectional links Links with special behaviors: –Expand-in-place / Replace / Create new window –Link on load / Link on user action Link databases XPointer will provide access to arbitrary portions of XML resource XSL stylesheet language will provide extensibility and transformation facilities (e.g. create a table of contents) England France

16. 16 More XML Developments Momentum behind XML is driving additional standardisation developments XML Path A language for addressing parts of an XML document, designed to be used by XSLT and XPointer XML Schemas (Ii) Defining the nature of XML schemas and their component parts XML Schemas (II) Facilities for defining datatypes to be used in XML Schemas and other XML specifications XSLT A language for transforming XML documents into other XML documents XML Infospace An abstract data set containing the information available from an XML document

17. 17 XHTML XHTML: Extensible Hypertext Markup Language HTML represented in XML Some small changes to HTML: –Elements in lowercase ( not ) –Attributes must be quoted ( –Elements must be closed (.. ) –Empty elements must be closed ( ) Gain benefits from XML Tools available (e.g. HTML-Kit from http://www.chami.com/html-kit/ ) See and

18. 18 Addressing URLs (e.g. http://www.bristol-poly.ac.uk/depts/music/ ) have limitations: Lack of long-term persistency –Organisation changes name –Department scrapped –Directory structure reorganised Inability to support multiple versions of resources (mirroring) URNs (Uniform Resource Names): Proposed as solution Difficult to implement (no W3C activity in this area)

19. 19 Addressing - Solutions DOIs (Document Object Identifiers): Proposed by publishing industry as a solution Aimed at supporting rights ownership Business model needed PURLs (Persistent URLs): Provide single level of redirection Cache support: National caches could provide simple URN support For further information see:

20. 20 Transport HTTP/0.9 and HTTP/1.0: Made the Web popular  Design flaws and implementation problems caused poor performance HTTP/1.1: Addresses some of these problems 60% server support, client & proxy support beginning Performance benefits! (optimised implementation reduces packet traffic by 2/3)  Is acting as fire-fighter  Poor usage counting  Not sufficiently flexible or extensible

21. 21 HTTP/NG HTTP/NG: Ideas for next generation of HTTP Produced various studies and reports No longer being developed within W3C Work now being coordinated by the IETF

22. 22 Metadata Metadata - the missing architectural component from the initial implementation of the web Metadata PICS, DSig, DSig, DC,... Addressing URL Data format HTML Transport HTTP Metadata Needs: Resource discovery Content filtering Authentication Improved navigation Multiple format support Rights management Metadata Needs: Resource discovery Content filtering Authentication Improved navigation Multiple format support Rights management

23. 23 Privacy P3P (Platform for Privacy Preferences): Example of a metadata application Privacy concerns are a current barrier to Web development (esp. in US) P3P project developing methods for exchanging Privacy Practices of Web sites and user Documents on architecture and vocabulary available See

24. 24 Digital Signatures DSig ( Digital Signatures initiative ): Key component for providing trust on the web DSig 1.0 is based on PICS DSig 2.0 will be based on RDF and will support signed assertion: –This page is from the University of Bath –This page is a legally-binding list of courses provided by the University See

25. 25 RDF RDF (Resource Description Framework): Highlight of WWW 7 conference Provides a metadata framework ("machine understandable metadata for the web") Based on ideas from content rating (PICS), resource discovery (Dublin Core) and site mapping (MCF) Applications include: –cataloging resources– resource discovery –electronic commerce– intelligent agents –digital signatures– content rating –intellectual property rights– privacy See

26. 26 RDF Model RDF: Based on a formal data model (direct label graphs) Syntax for interchange of data Schema model Resource Value PropertyType Property page.html £0.05 Cost 11-May-98 ValidUntil RDF Data Model page.html £0.05 11-May-98 Property Cost InstanceOf ValidUntil Value PropObj Cost PropName

27. 27 RDF Example Example of Dublin Core metadata in RDF The W3C Folio 1999 W3C Communications Team 1999-03-10 Web development, World Wide Web Consortium, Interoperability of the Web RDF has been used to express data about the W3C Folio. The basic concept is that metadata about this item on the Web is described through a collection of properties called an RDF Description. Notice that RDF uses the familiar XML syntax. This example also illustrates XML Namespaces. See

28. 28 RDF Conclusion  RDF is a general-purpose framework  RDF provides structured, machine- understandable metadata for the Web  Metadata vocabularies can be developed without central coordination  RDF Schemas describe the meaning of each property name  Signed RDF is the basis for trust

29. 29 Deployment Issues What part of the spectrum are you closest to? Must support standardsGo with the marketplace

30. 30 I Support Standards But: You probably use PowerPoint, don't you? Software vendors will subtly suck you into use of proprietary features Home-grown solutions can be expensive (where are all the good Perl / C programmers willing to work on short-term contracts for a pittance in Universities?) Standards may not take off – remember Coloured Book network protocols? Proprietary solutions may become standardised Standards may not yet be available (or finalised) Do users want standards? Will "We support standards" conflict with "Our services are based on user requirements"?

31. 31 I Follow The Marketplace Good New Labour philosophy, but: Can you trust your software vendor? Will your software vendor be around in a few years time ("I only buy Rover") Will your system be interoperable? What happens when you want to interwork with partners or your organisation merges / is taken over? What happens when you want to extend your system beyond the limits set by your software vendor?

32. 32 Some Difficulties We should acknowledge some difficulties in a standards-based approach: Keeping up-to-date (look at nos. of documents at http://www.w3c.org/TR/ and size of http://www.diffuse.org/standards.html ) Spotting the winning standards Implementing the standard in a timely way Dealing with the problems of the software vendor Resources!

33. 33 Is It Worth It? Has the Web stabilised? Are you thinking about WAP services? Will you want to (be forced to) make your web service accessible? Will you want to deploy personalised interfaces (e.g. My.Oxford.ac.uk ) Will your web service move from information provision to e-business? Do you want your University web site to use business-to-business (B2B) protocols to automate transfer of link and news items to HERO (neé HE Mall)?

34. 34 What Should I Do? What approaches should I use? Storing information in a structured format makes subsequent redevelopment easier Be driven initially by standards and architectural considerations, not by applications Consider use of more sophisticated web management tools, rather than HTML authoring tools An organisational standards guidelines document (part of a Web Strategy document) may be useful Don't work in isolation: –Monitor standards development (e.g. W3C) –Listen to others in your community –Talk and discuss issues within your community

35. 35 Architectural Models There is a need for more intelligent software which can process structured resources or reformat unstructured ones Intermediaries can provide functionality not available at client: DOI support XML support Format conversion Intermediaries can provide functionality not available at client: DOI support XML support Format conversion HTML resource browser Web server Web server simply sends file to client File contains redundant information (for old browsers) plus client interrogation support HTML / XML / database resource browser Server proxy Client proxy Intelligent Web server

36. 36 Architectural Models – e.g. XML Deployment Ariadne issue 14 has article on "What Is XML?" Describes how XML support can be provided: Natively by new browsers Back end conversion of XML - HTML Client-side conversion of XML - HTML / CSS Java rendering of XML Examples of intermediaries See http://www.ariadne.ac.uk/issue15/what-is/

37. 37 Conclusions To conclude: Standards are important, especially for large organisation and national initiatives Proprietary solutions are often tempting because: –They are available –They are often well-marketed and well-supported –They may become standardised –Solutions based on standards may not be properly supported by applications Intermediaries may have a role to play in deploying standards-based solutions

38. 38 Further Information W3C web site: W3C Tech Reports: "The Development Of Web Protocols And Formats", Exploit Interactive issue 1, "Wilde's WWW: Technical Foundations of the World Wide Web", Erik Wilde, ISBN 3-540-64285-4 Diffuse Project web site: "On Julius Caesar, Queen Eanfleda, and the lessons from time past" Brian Meek, KCL

39. 39 Community Information Discuss standards, architectures and applications on various mailing lists: website-info-mgt Mailbase list web-support Mailbase list See Participate in the Institutional Web Management workshop (Bath University, 7-9 th Sept) – details will be announced on website-info-mgt Mailbase list

40. 40 Question Time Any questions?