The Latest Web Developments
Brian Kelly
UK Web FocusUKOLN
University of Bath
Bath, BA2 7AY
UKOLN is supported by:
[email protected]://www.ukoln.ac.uk/
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About Me
Brian Kelly:• UK Web Focus – a JISC-funded post to advise HE
and FE communities on Web developments• Based in UKOLN (UK Office for Library and
Information networking) – a small applied research organisation in University of Bath
• Involved in Web since 1993, while working in Computing Service at University of Leeds
• Close links with Computing Service and Library communities
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About You
What is your involvement with the Web?
What topics would you like covered today?
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Possible Interests
Interests
XML
Hyperlinking
Technologies
File formats
What’s happening to HTML?
Web Architectures
When is it going to stabilise?
Content Management Systems
RDF
Legal issues
Web applications
Web browsers
Netscape or Microsoft?Web Standards
Web Applications
Web Services
Open source vs licensed apps
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Contents
• Standards and the Web• The Original Web Architecture• The Problems• Architectural Developments• Metadata• New Developments• Deployment Issues• Discussion
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Standards, Architectures, Applications, Resources
This talk touches on several areas
Architectures: models for implementing systemsArchitectures: models for implementing systems
Applications: software products used to implement systems
Applications: software products used to implement systems
Standards: concerned with protocols and file formatsStandards: concerned with protocols and file formats
Open standards vs. Proprietary HTML / XML vs. PDFCSS / XSL vs. HTML
Which standards are applicableNT / UnixFile system / database applicationHTML tools / content management
Apache / IISFrontPage / DreamweaverOracle / SQLServerColdFusion vs ASP
Development vs. Migration costsUse of in-house expertiseIn-house vs. out-sourced Licensed vs. open source
Resources: financial and staff costs needed to implement systems
Resources: financial and staff costs needed to implement systems
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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!
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Deployment Issues
What part of the spectrum are you closest to?
Must support standards Go with the marketplace
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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"?
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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?
IBM was the market leader in the 1970s, but lost out in the PC revolutionWhat will happen if Microsoft is split in two?
IBM was the market leader in the 1970s, but lost out in the PC revolutionWhat will happen if Microsoft is split in two?
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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!
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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
PNGHTMLZ39.50Java?
PNGHTMLZ39.50Java?
PNGHTMLHTTP
PNGHTMLHTTP
HTTPURNwhois++
HTTPURNwhois++
HTML extensionsPDF and Java?
HTML extensionsPDF and Java?
Other• Standards bodies
such as ECMA• Community groups
which can agree on, say, profiles
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World Wide Web Consortium
Much of the development of Web standards is being coordinated by the W3C:
W3C (World Wide Web Consortium):• International consortium, with headquarters
at MIT, INRIA and Keio University (Japan)• Coordinates development of web protocols• Four domains:
• Architecture • Technology & Society
• User Interface • Web Accessibility
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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.
A useful overview of Tim Berners-Lee's vision for the Web is given in his book Weaving The Web.
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How Does The Web Work?The Web has 3 fundamental concepts:
• URLs: addresses of resources• HTTP: dialogue between client and server• HTML: format of resources
The Netsoft home page
1 User clicks on link to the address (URL)http://www.netsoft.com/hello.html
2 Browser converts link to HTTP command (METHOD):Connect to computer at www.netsoft.com
GET /hello.html3 Remote computer sends file
<HTML><TITLE>Welcome</TITLE>..<P>Welcome to <B>Netsoft</B>
Welcome toNetsoft
4 Local computer displays HTML file
Web Browser (client)
Web server
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Web Protocols
Web initially based on three simple protocols:
• Data FormatsHTML (HyperText Markup Language) provides the data format for native documents
• AddressingURLs (Uniform Resource Locator) provides an addressing mechanism for web resources
• TransportHTTP (HyperText Transfer Protocol) defines transfer of resources between client and server
Data FormatHTML
AddressingURL
TransportHTTP
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HTML 4.0, CSS 2.0 & DOM 1.0HTML 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
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CSS
CSS:• Cascading Style Sheets• An open standard
developed by W3C• Separates document
structure (defined in HTML/XML) from the appearance
• Makes maintenance of resources much easier
http://www.w3c.org/Style/CSS/http://www.w3c.org/Style/CSS/
<link rel="style" src="sty.css"<h1>Heading</h1><p>…</p>
<link rel="style" src="sty.css"<h1>Heading</h1><p>…</p>
body {background: blue;}h1: {font-family: arial} p: {font-family: times;
text-align: justify}
body {background: blue;}h1: {font-family: arial} p: {font-family: times;
text-align: justify}Imagine 10,000 HTML files .. With 1 CSS file
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LimitationsHTML 4.0 / CSS 2.0 have limitations:
• Difficulties in introducing new elements– Time-consuming standardisation process
(<ABBREV>)– Dictated by browser vendor (<BLINK>,
<MARQUEE>)• Area may be inappropriate for standarisation:
– Covers specialist area (maths, music, ...)– Application-specific (<STUD-NUM>)
• 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 Spice Girls CDs
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XML
XML:• Extensible Markup Language• A lightweight SGML designed for network use• Addresses HTML's lack of evolvability• Arbitrary elements can be defined (<STUDENT-NUMBER>, <PART-NO>, 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
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XML ConceptsWell-formed XML resources:
Make end-tags explicit: <li>...</li>
Make empty elements explicit: <img ... />
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:
<?xml:namespace ns="http://foo.org/1998-001" prefix="i">
<p>Insert <i:PART>M-471</i:PART></p>
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More XML Developments
Momentum behind XML is driving additional standardisation developmentsXML 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
XSLTA language for transforming XML documents into other XML documents
…
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XHTML
XHTML:• Extensible Hypertext Markup Language• HTML represented in XML• Some small changes to HTML:
– Elements in lowercase (<p> not <P>)– Attributes must be quoted (<img src="logo" height="50">– Elements must be closed (< p >..</ p >)– Empty elements must be closed (<img src="logo" . />)
• Gain benefits from XML• Tools available (e.g. HTML-Kit from http://www.chami.com/html-kit/)
• See <http://www.webreference.com/xml/column6/>, <http://groups.yahoo.com/group/XHTML-L/> and <http://www.ariadne.ac.uk/issue27/web-focus/>
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TransportHTTP/0.9 and HTTP/1.0:
Design flaws and implementation problems
HTTP/1.1: Addresses some of these problems 60% server support Performance benefits! (60% packet traffic reduction) Is acting as fire-fighter Not sufficiently flexible or extensible
HTTP/NG: Radical redesign using object-oriented technologies Undergoing trials Gradual transition (using proxies) Moving slowly
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Addressing
URLs (e.g. http://www.bristol-poly.ac.uk/depts/music/) have limitations:
• Lack of long-term persistency– Organisation changes name– Department shut down or merged– 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)
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Addressing - SolutionsPURLs (Persistent URLs):
• Provide single level of redirectionDOIs (Digital Object Identifiers):
• Proposed by publishing industry as a solution• Aimed at supporting rights ownership• Business model needed
OpenURLs• Address mirroring issues
Pragmatic Solution:• URLs don't break - people break them• Design URLs to have long life-span
Further information:<URL: http://www.ukoln.ac.uk/metadata/resources/urn/><URL: http://www.w3.org/Provider/Style/URI>
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Metadata
Metadata - the missing architectural component from the initial implementation of the Web
Metadata -RDF
PICS, TCN,
MCF, DSig,
DC,...Addressing
URL
Data formatHTML
TransportHTTP
Metadata Needs:• Resource discovery• Content filtering• Authentication• Improved navigation• Multiple format support• New devices• Rights management
Metadata Needs:• Resource discovery• Content filtering• Authentication• Improved navigation• Multiple format support• New devices• Rights management
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Metadata Examples
DSig (Digital Signatures initiative):• Key component for providing trust on the web• 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
P3P (Platform for Privacy Preferences):• Developing methods for exchanging Privacy
Practices of Web sites and userNote that discussions about additional rights management metadata are currently taking place
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RDFRDF (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)• Based on a formal data model (direct label graphs)• Applications include:
– cataloging resources – resource discovery– electronic commerce – intelligent agents– intellectual property rights – privacy
• See <URL: http://www.w3.org/Talks/1998/0417-WWW7-RDF>
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RSS – An RDF ApplicationRSS (Rich Site Summary):
• Now an RDF application
• Used for news feeds• Of interest to JISC
(DNER architecture)• Lightweight
approach that we should be investigating
See example of an RSS authoring tool and parser at <http://rssxpress.ukoln.ac.uk/>. Note this service uses CGI – a JavaScript solution is also being developed.
See example of an RSS authoring tool and parser at <http://rssxpress.ukoln.ac.uk/>. Note this service uses CGI – a JavaScript solution is also being developed.
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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
But:• Is RDF too complex?• Will it gain acceptance in the market place?
The jury is till out
But:• Is RDF too complex?• Will it gain acceptance in the market place?
The jury is till out
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Other Web Developments
Many Web standards developments are taking place outside W3C:
• UDDI (Universal Description, Discovery, and Integration) – a way of describing Web services in a machine readable way to facilitate location of services by agents. See <http://www.uddi.org/>
• Biztalk – a framework for developing XML schemas for B2B applications. See <http://www.biztalk.org/>
• SOAP (Simple Object Access Protocol) - an XML protocol for exchange of informationSee <http://www.w3.org/TR/SOAP>
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New Web AreasInitially the Web provided:
• An open environment for• sharing information
And aimed to:• provide a rich publishing and collaborative
environment The Web is now:
• Widely used in closed environments (Intranets and Extranets, for ecommerce, etc.)
• Addressing the missing components from the original architecture
• Addressing universally by providing the infrastructure for support of new devices
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E-commerce
E-commerce:• Requires trust• Requires security• Is there a viable business
model?
Developments:• Digital signatures• Public Key Infrastructure• Athens and Sparta in UK
HE
http://www.w3.org/Signature/http://www.w3.org/Signature/
Example 1
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The Mobile Web
The Mobile Web:• Much hype at present• Have you used it?• Is it usable on such a small screen
with slow network times?• What about the resources need to
build a WAP site and a Web site
Example 2
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The Mobile Web CommentsStore resources in neutral format (XML) and generate WAP and WebXML: open storage formatXSLT: Transform XML
XML
WML filefor WAP
XHTML for Web
XSLTengine
XSLTrules
3G promises multimedia and faster networks
Ebook format
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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?
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What Should I Do?
How can I best exploit new developments?• 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
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Authoring
Authoring Web pages:• Was easy• Becoming more difficult as Web becomes more
complex• More difficult to maintain
For large Web sites there is a need for:• More sophisticated tools e.g. content management
systems• Tailoring content for devices?
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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
browserWeb server
Web server simply sends file to clientFile contains redundant information (for old browsers) plus client interrogation support
HTML / XML /
databaseresource browser
Server proxy
Client proxy
IntelligentWeb server
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Architectural Models – e.g. XML DeploymentAriadne 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/See http://www.ariadne.ac.uk/issue15/what-is/
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Conclusions
To conclude:• The Web will continue to develop• Standards are important• 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
• Metadata is big growth area• Intermediaries may have a role to play in deploying
standards-based solutions• There is a continual need to keep informed
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Questions
Any questions?
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