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Semantic Markup: RDFa, Microformats, and Atom

Learn about RDFa, Microformats, and Atom, three semantic markup technologies that enhance the way information is represented and understood on the web.

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Semantic Markup: RDFa, Microformats, and Atom

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  1. RDFa, Microformats, and Atom Semantic Web Presented by: AnuradhaKandula Instructor: Steven Seida

  2. Background • Why do we need semantic markup?

  3. To an English-speaking person, the same information could be represented as: “The title of this resource, published by Wikipedia, is ‘Tony Benn’ ” • The purpose of RDF is to provide an encoding and interpretation mechanism so that resources can be described in a way that particular software can understand it

  4. RDFa • RDFa (or Resource Description Framework - in - attributes) is a W3C Recommendation that adds a set of attribute level extensions to XHTML for embedding rich metadata within Web documents.

  5. Essence • The essence of RDFa is to provide a set of attributes that can be used to carry metadata in an XML language (hence the 'a' in RDFa). • These attributes are: • about – a URI or CURIE specifying the resource the metadata is about; in its absence it defaults to the current document

  6. Essence (cont.) • rel and rev – specifying a relationship or reverse-relationship with another resource • href, src and resource – specifying the partner resource • property – specifying a property for the content of an element • content – optional attribute that overrides the content of the element when using the property attribute • datatype – optional attribute that specifies the datatype of text specified for use with the property attribute • typeof – optional attribute that specifies the RDF type(s) of the subject (the resource that the metadata is about).

  7. Examples of RDFa(FOAF profile using RDFa) • <htmlxmlns:foaf="http://xmlns.com/foaf/0.1/"> • <head> • <title>Mark Birbeck's profile</title> • <linkrel="foaf:primaryTopicfoaf:maker"href="#me"/> • </head> • <body> • <divabout=“#me"typeof=foaf:Person"> • <spanproperty="foaf:name">"Mark Birbeck</span> • <arel="foaf:weblog"href="http://internet-apps.blogspot.com/">XForms and Internet Applications</a> • <arel="foaf:knows"href="http://www.w3.org/People/Ivan/#me">Ivan Herman</a> • <spanrel="foaf:img"> • <imgsrc="http://www.formsplayer.com/files/pictures/picture-11.jpg"/> • </span> • <spanrel="foaf:holdsAccount"> • <spantypeof="foaf:OnlineAccount"> • <arel="foaf:accountServiceHomepage"ref="http://twitter.com/">Twitter</a> • <spanproperty="foaf:accountName">markbirbeck</span> • </span> • </span> • </div> • </body> • </html>

  8. Benefits of RDFa • Publisher Independence - each site can use its own standards • Data Reuse - data is not duplicated. Separate XML and HTML sections are not required for the same content. • Schema Modularity - The attributes are reusable

  9. Evolvability - additional fields can be added and XML transforms can extract the semantics of the data from an XHTML file

  10. Microformat • A microformat is a web-based approach to semantic markup that seeks to re-use existing XHTML and HTML tags to convey metadata and other attributes. This approach allows information intended for end-users (such as contact information, geographic coordinates, calendar events, and the like) to also be automatically processed by software.

  11. Designed for humans first and machines second, microformats are a set of simple, open data formats built upon existing and widely adopted standards. Instead of throwing away what works today, microformats intend to solve simpler problems first by adapting to current behaviors and usage patterns (e.g. XHTML, blogging).

  12. The microformats principles • Solve a specific problem • Start as simple as possible • Design for humans first, machines second • Reuse building blocks from widely adopted standards • Modularity / embeddability • Enable and encourage decentralized development, content, services

  13. hCardmicroformat markup

  14. Browser support • Operator for Firefox • Oomph for Internet Explorer • hCard exported to formats compatible with contact management • hCalendar exported to formats compatible with calander utilities • geographical coordinates to Google Maps

  15. Atom • Atom is an XML-based document format that describes lists of related information known as "feeds". Feeds are composed of a number of items, known as "entries", each with an extensible set of attached metadata. For example, each entry has a title. • The primary use case that Atom addresses is the syndication of Web content such as weblogs and news headlines to Web sites as well as directly to user agents.

  16. Atom is a simple way to read and write information on the web, allowing you to easily keep track of more sites in less time, and to seamlessly share your words and ideas by publishing to the web.

  17. Web feeds allow software programs to check for updates published on a website. To provide a web feed, a site owner may use specialized software (such as a content management system) that publishes a list (or "feed") of recent articles or content in a standardized, machine-readable format.

  18. A feed contains entries, which may be headlines, full-text articles, excerpts, summaries, and/or links to content on a website, along with various metadata.

  19. Usage Web feeds are used by the blogging community to share recent entries' headlines, full text, and even attached multimedia files. These providers allow other websites to incorporate the blog's "syndicated" headline or headline-and-short-summary feeds under various usage agreements. Atom and other web syndication formats are now used for many purposes, including journalism, marketing, bug-reports, or any other activity involving periodic updates or publications. Atom also provides a standard way to export an entire blog, or parts of it, for backup or for importing into other blogging systems.

  20. It is common to find web feeds on major Web sites, as well as many smaller ones. Some websites let people choose between RSS or Atom formatted web feeds; others offer only RSS or only Atom. In particular, many blog and wiki sites offer their web feeds in the Atom format.

  21. Feed reader A feed reader or "aggregator" program can be used to check feeds and display new articles. Client-side readers may also be designed as standalone programs or as extensions to existing programs like web browsers. Browsers are moving toward integrated feed reader functions.

  22. Single-entry Atom Feed Document <?xml version="1.0" encoding="utf-8"?> <feed xmlns="http://www.w3.org/2005/Atom"> <title>Example Feed</title> <link href="http://example.org/"/> <updated>2003-12-13T18:30:02Z</updated> <author> <name>John Doe</name> </author> <id>urn:uuid:60a76c80-d399-11d9-b93C-0003939e0af6</id> <entry> <title>Atom-Powered Robots Run Amok</title> <link href="http://example.org/2003/12/13/atom03"/> <id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id> <updated>2003-12-13T18:30:02Z</updated> <summary>Some text.</summary> </entry> </feed>

  23. The "atom:feed" Element • atom:feed elements MUST contain one or more atom:author elements, unless all of the atom:feed element's child atom:entry elements contain at least one atom:author element. • atom:feed elements MAY contain any number of atom:category elements. • atom:feed elements MAY contain any number of atom:contributor elements. • atom:feed elements MUST NOT contain more than one atom:generator element. • atom:feed elements MUST NOT contain more than one atom:icon element. • atom:feed elements MUST NOT contain more than one atom:logo element. • atom:feed elements MUST contain exactly one atom:id element.

  24. More information on atoms at: http://www.ietf.org/rfc/rfc4287

  25. Queries?

  26. Thank You !

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