Advanced Technologies

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Advanced Technologies

• Web database integration
• XML
• Internet 2 and the push for faster and faster
  connections in the home

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Dynamic Content

• With the exception of some CGI examples, most of
  what we have created so far are static web
  pages. The content of the page remains the same,
  it doesnt vary based on different circumstances
  unless someone manually changes the HTML file
• We need better mechanism to have web pages
  generated dynamically so that their content can
  change automatically without user intervention
• E.g. iSchool Events Calendar
• Often we want to be able to customize a page and
  present information for a particular user, or
  take information from a user, save it in a
  database, let them check or change info in that
  database. So the page presented to the user has
  to be built on the fly
• E.g. MyUW, ecommerce applications, iSchool
  student directory updates

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Integrating databases into a Website is one way
to accomplish this

• Several technologies available
• PHP and MySQL (open source)
• Microsofts ASP or .NET initiative in conjunction
  with a backend database like SQLServer
• ColdFusion
• JSP (Java Server Pages)

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Central concept

• By storing information in a database you can
  track user information and preferences
• Pages can be customized and built on the fly
  for a user based on that information
• Other times the page may be built dynamically
  based on other criteria that isnt related to one
  person (for example the iSchool event calendar
  changes based on the date you are looking at the
  page)

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Cold Fusion Example

• ColdFusion pages end with .cfm rather than .htm
• Server hands these cfm pages off to the
  ColdFusion server for processing
• ColdFusion server parses the page looking for CF
  commands in the file. What it does is a function
  of the ColdFusion commands that are present.
• These commands can query a database for instance
  and then build a table of results
• After processing, an html document is passed back
  to the users browser for display

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.CFM file example

• lthtmlgt
• lth1gtCalendar of Eventslt/h1gtltpgt
• .
• ltcfoutputgt
• Today is DateFormat(Now(), "DDDD, MMMM D,
  YYYY")
• lt/cfoutputgt
• ..
• ltcfquery name"EventList" datasource"events"
  dbtype"ODBC" gt
• SELECT ID, StartDate, EndDate, Title, Abstract
• FROM Events
• WHERE StartDate gt CreateODBCDate(Now())
• ORDER BY StartDate, EndDate, Title
• lt/cfquerygt
• .
• ltcfoutput query"EventList"gt
• StartDate EndDate Title Abstractltpgt
• lt/cfoutputgt
• lt/htmlgt

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Doing this yourself

• Need to make lots of decisions
• What technology to use
• You need to know how to build and query a
  database to start
• Where the database will live
• How the database will get updated
• Do you need to add user authentication to your
  system
• Does the data need to be secured
• Unfortunately at the time it isnt easy to create
  integrated Web/DB applications on the UW central
  servers although that may change in the future
• In the iSchool, students can checkout a server in
  the TE Lab if you want to go it on your own.

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XML

• eXtensible Markup Language

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Presentation Markup vs. Content Markup

• Consider the following HTML
• ltbgtBarker Scottlt/bgt
• That markup (in HTML) tells me that I want some
  text to appear in bold (a presentation format),
  but it tells me nothing about what that text is
• Consider markup that defines content
• ltpersongt
• ltlastNamegtBarkerlt/lastNamegt
• ltfirstNamegtScottlt/firstNamegt
• lt/persongt
• This markup tells me more about content, that
  there is some text Barker that is a lastName
  and there is some text Scott that is a
  firstName and that both of these things are
  elements of something called a person. It says
  nothing about how that content is presented to
  the user.

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XML eXtensible Markup Language

• Designed precisely for this semantic markup
  where we focus on content not presentation
• XML has no pre-defined tags like HTML, you can
  make up your own, whatever you like
• There are no rules that tell a browser how to
  display an XML document, so if you open an XML
  document in a browser you would just see all the
  XML tags
• While HTML documents began with lthtmlgt, XML
  documents begin with
• lt?xml version1.0?gt

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A sample XML document as displayed in the browser
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More on XML tags

• While you can create any tag you like there are
  groups with common interests that have
  established standard tags used to describe
  documents with similar content
• These agreed upon ways to describe documents are
  often called DTDs document type definitions,
  or schemas
• http//www.xml.org/xml/registry.jsp
• Consider if one company marked-up documents using
  a tag like lastName, another used LNAME, another
  used last_name and you want to be able to search
  data from many different documents for a last
  name?
• These DTDs or schemas also may define that the
  elements appear in a certain order, what the
  content may be (like integer, text), if an
  element is required or optional.
• XML documents must be well formed syntactically
  and the DTD or schema insures that it is valid

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Using DTDs and Schemas

• You can create XML documents without having a DTD
  or schema first defined just create the tags
  you need
• One problem with some schemas is that there may
  be competing ones for the same purpose, so it is
  possible that even if you do adhere to a
  particular schema that you wont be able to
  interoperate completely seamlessly with others

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Presenting XML in a browser

• Said that browsers will just display XML
  documents as-is. It is possible however to use
  a style sheet attached to an XML document to
  define how we want that content to be presented
  to the user. Rather than defining how a tag like
  lth1gt will look, we can define how a tag like
  ltlastNamegt will look
• One way to do this is to use a style sheet
• lt?xml version"1.0"?gt
• lt?xml-stylesheet type"text/css"
  href"person.css"?gt
• ltpersongt
• ltlastNamegtBarkerlt/lastNamegt
• ltfirstNamegtScottlt/firstNamegt
• lt/persongt
• With the person.css file looking something
  likeperson border2px black solid
• lastName, firstName
• font12pt Verdana
• padding5px
• colorblue

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XSLT another option

• XSLT eXtensible Stylesheet Language
  Transformation
• Provides a full programming language to transform
  documents in one form to another
• Goes beyond just color or layout changes
• By applying different XSLT sheets the resulting
  document can be completely different from the
  original XML file
• Because of this ability many people suggest
  saving all of your content as XML and then
  applying various XSLT stylesheets to that data to
  use it in different settings
• One version for Print
• Another for the Web
• Maybe even multiple versions for the web
  depending on the capabilities to the end-user
  browser

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Why XML?

• Many advantages to a content based markup rather
  than a presentation based markup
• Can exchange information easily with others
  (Business to Business, B2B applications)
• Can present the same content in different ways to
  different users one presentation format might
  be for Web users, another for print
• Can possibly take advantage of the semantics of a
  document for better searching and retrieval
• Is XML the end of HTML?
• Probably not. LOTS more complex. HTML will be
  around for many years to come.

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The future

• Who knows!

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Consider the pace of change to date!

• The Web has not even been around for 10 years and
  look at the changes it has made already
• Today there are many research efforts proceeding
  to built the next generation Internet (Internet
  2)
• Much of the focus of Internet 2 is on VERY high
  bandwidth and fat pipes, but the nagging question
  that always comes up is what will we do with it?
  What is the next killer application?
• HDTV over the net?
• Remote medical diagnostics or perhaps the ability
  to perform real medical procedures from afar
• Fatter pipes into the home, the possible
  convergence of computing and entertainment
• Better communications that crappy video
  conferencing we have today wont always be so
  crappy!
• The potential to change society for the better
  (or maybe the worse).