eScience Lectures Notes : XML, RSS etc

Slide 1 : 1/19: XML RSS etc

COMP1710 Tools for New Media and Web

 

XML RSS etc

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Slide 2 : ToC : XML, RSS etc

Table of Contents (19 slides) for the presentation :

XML, RSS etc

Slide 3 : 3/19: XML, RSS, podcasts etc

In this lecture:

XML, RSS, podcasts etc

XML: eXtensible Markup Language

RSS: Really Simple Syndication

Podcasts: sound on the Web

 

Slide 4 : 4/19: Intro to XML

eXtensible Markup Language (XML)

is a standard which defines the syntax for document markup. (See also the Markdown language.)

XML can be used by all sorts of documents, including:

XML understood by a variety of platforms:`

XML can be used to communicate between computing platforms

Many libraries for programmers to use

 

References: XML content mostly from a guest lecture by Eric McCreath

Slide 5 : 5/19: XML Format

XML Format

XML is plain text with tags to mark up the contents

    <person>
        Tom Gedeon
    </person>

(Tags must match, but names can be user chosen.)

    <person>
        <personal_name>Tom</personal_name>
        <family_name>Gedeon</family_name>
        <phone_extension>51052</phone_extension>
    </person>

(No white space in the tag names.)

 

Slide 6 : 6/19: XML declaration

XML documents should have an XML declaration on the first line, although this is not strictly needed

    <?xml version="1.0" encoding="US-ASCII" standalone="yes"?>
    <person>
       <personal_name>Tom</personal_name>
       <family_name>Gedeon</family_name>
       <phone_number>51052</phone_number>
    </person>

XML documents should be well formed (conform to XML syntax rules):

XML documents should be valid (conform to some semantic rules).

 

Slide 7 : 7/19: More XML stuff

Other items you may find in XML documents:

Empty elements

Processing instructions

Tag attributes

    <person>
        <mac_user/>
        <personal_name><?php print $name; ?></personal_name>
        <phone_number type="ext">51052</phone_number>
    </person>

 

Slide 8 : 8/19: XHTML

XHTML

XHTML is an XML version of HTML

HTML is already a lot like XML, with some minor textual but important differences:

 

See also the W3C HTML and XHTML FAQ.

Slide 9 : 9/19: HTML vs XHTML

You have to look closely to notice the difference:

There are also validation services.

 

Slide 10 : 10/19: XML on the Web

XML on the Web

XML may be served up directly from a web server along with a CSS style sheet

The browser can transform the XML into HTML (or XHTML)

 

Slide 11 : 11/19: RSS: Really Simple Syndication

RSS: Really Simple Syndication

RSS is an XML format for publishing short news-like articles

Is used in a number of different ways:

Aggregators are also referred to as

 

Slide 12 : 12/19: Using RSS feeds

Using RSS feeds

Benefits of using RSS feeds: you don't have the overhead of loading the entire website if you only want to read headline news or just the newest blog post from your friend.

Easiest way to use: modern browsers supports RSS subscription. This is called Live Bookmark.

Web based aggregators (e.g. Google Reader or Bloglines) which enable you to organise a number of different RSS feeds. They highlight unread items and give you a uniform organised interface into this information.

Benefit - your list of feeds won't be tied to one computer, since it is all kept on the web, you'll never loose your info

Desktop aggregators - applictions you have to download, they manage your feeds similarly to Mail readers manage your email

Benefit - does not clutter your bookmarks, downloaded info is kept on your computer so you don't need to be online to access old ones. If Internet connection access time is limited, you can get online, update your feeds, then unplug and read all the news you want.

 

Reference

Slide 13 : 13/19: RSS format

RSS is a very simple XML format

A feed comprises a channel, which has a title, link, description, and (optional) language, followed by a series of items, each of which have a title, link, and description.

Here is a fictitious COMP1710 RSS feed:

    <rss version="0.91">
        <channel>
            <title>COMP1710 News</title>
            <link>http://cs.anu.edu.au/students/comp1710.com/</link>
            <description>Features COMP1710 news.</description>
            <language>en-us</language>

            <item>
                <title>Last week of Lectures!</title>
                <link>http://escience.anu.edu.au/nm</link>
                <description>The last lecture reviews the course and has exam hints.</description>
            </item>

            <item>
                <title>Lab marks</title>
                <link>http://cs.anu.edu.au/streams</link>
                <description>Please check you lab marks, a blank means nothing was submitted.</description>
            </item>

        </channel>
    </rss>

The RSS 2.0 format is slightly more verbose.

 

Reference: sample RSS channel.

Slide 14 : 14/19: Push technology

Push technology

Push: a communication protocol - request comes from the publisher, or central server

Pull: request originates with the receiver, or client.

Examples of push:

All "true" push media present practical difficulties because the server is responsible for remembering who the subscribers are,
and for remembering the latest address that each subscriber should be contacted at.

Examples of pull:

Reference: Wikipedia on push technology

 

Slide 15 : 15/19: Sound: What For?

Sound: What For ?

Conveying Information

After action from the user

Setting a Mood / Providing personal touch

Capture attention

This should be used carefully ...

as it can be very annoying

Cf. Minority Report

Explaining a process

Usually, with a video or animation

 

Slide 16 : 16/19: Podcasting

Podcasting is just audio via RSS

Components:

A how-to page with technical details, and another (less clear) one with minimal technical detail

A Video podcast is just video via RSS ...

 

Slide 17 : 17/19: Twitter and other microblogging services

Twitter and other microblogging services

What?

"Twitter is a service for friends, family, and co-workers to communicate and stay connected through the exchange of quick, frequent answers to one simple question: What are you doing?"

Wikipedia says Twitter has been described as akin to a web-based IRC client. Twitter uses the Ruby on Rails web framework.

Twitter messages may be tagged using hashtags, a word or phrase prefixed with a #, such as #beer.This enables tweets on a specific subject to be found by simply searching for their common hashtag, provided that the user has tagged his or her tweet.

The @ sign before a username, such as @example, is used to distinguish a reply directed at a particular user. A message preceded by the @username prefix can still be read by anyone, but is treated as directed firstly to the user in question

"In February 2009, the Australian Country Fire Authority used Twitter to send out regular alerts and updates regarding the 2009 Victorian bushfires. During this time the Prime Minister of Australia, Kevin Rudd, also used his Twitter account to send out information on the fires, how to donate money and blood, and where to seek emergency help."

Private information:

"Twitter may sell, transfer or otherwise share some or all of its assets, including your personally identifiable information, in connection with a merger, acquisition, reorganization or sale of assets or in the event of bankruptcy."

Many Twitter look-alikes, extensions

E.g. How to Create an RSS-Enabled, Micro-Blog with Twitter

 

Slide 18 : 18/19: Mashups

Mashups recombine and modify existing digital media

 

Slide 19 : ToC : XML, RSS etc

Table of Contents (19 slides) for the presentation :

XML, RSS etc