ISWC GoodRelations Tutorial Part 4

The Web of Data for E-Commerce in Brief

A Hands-on Introduction to the GoodRelations Ontology,
RDFa, and Yahoo! SearchMonkey

October 25, 2009
Westfields Conference Center near Washington, DC, USA

Martin Hepp
Universität der Bundeswehr München, Munich, Germany

Richard Cyganiak
Digital Enterprise Research Institute (DERI), Ireland

Logistics
08:30-10:30 Overview and Motivation: Why the Web of Data is Now 30’
Quick Review of Prerequisites 15’
The GoodRelations Ontology: E-Commerce on the Web of Data 75’
10:30-10:45 Coffee Break
10:45-12:30 RDFa: Bridging the Web of Documents with the Web of Data 45’
Expressing GoodRelations in RDFa: A Running Example 30’
GoodRelations – Advanced Topics 30’
12:30-13:30 Lunch Break
13:30-16:00 Hands-on Exercise: Annotating a Web Shop 60’
Querying the Web of Data for Offerings – SPARQL 15’
Querying the Web of Data – Exercises 15’
16:00-16:30 Coffee Break
16:30-18:00 Publishing Semantic Web Data: Make Your RDF Available 30’
Yahoo SearchMonkey and Yahoo BOSS 45’
Discussion, Conclusion, Feedback Round 15’
2

SPARQL

Query Language
Endpoint Specification

25.10.2009 3

SPARQL: Query Language Specification

http://www.w3.org/TR/rdf-sparql-query/
25.10.2009 4

SPARQL Query Structure
# comments
PREFIX gr:<http://purl.org/goodrelations/v1#>

SELECT ?var1 ?var2 WHERE
{?var1 rdf:type gr:Offering.
?var1 gr:validThrough ?var2.
FILTER (?date <
"2009-05-25T00:00:00Z"^^xsd:dateTime)}

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SPARQL: Matching Literals
PREFIX xsd:<http://www.w3.org/2001/XMLSchema#>

SELECT ?v WHERE {
?v ?p "abc"^^xsd:datatype }

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SPARQL: Matching Strings
PREFIX dc: <http://purl.org/dc/elements/1.1/>
SELECT ?title
WHERE { ?x dc:title ?title
FILTER regex(?title, "^SPARQL")
}

^= Starts with

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SPARQL Query
# find expired offerings:
PREFIX gr:<http://purl.org/
goodrelations/v1#>
SELECT ?o, ?date WHERE
{?o rdf:type gr:Offering.
?o gr:validThrough ?date.
FILTER (?date <
"2009-05-25T00:00:00Z"^^xsd:dateTime
)}
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SPARQL Query
# find label for UPC/EAN "0001067792600“
PREFIX gr:<http://purl.org/goodrelations/
v1#>
PREFIX xsd:<http://www.w3.org/2001/
XMLSchema#>
SELECT ?uri, ?label WHERE
{?uri rdf:type gr:ProductOrServiceModel.
?uri gr:hasEAN_UCC-13
"0001067792600"^^xsd:string.
?uri rdfs:label ?label}

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Quizzes
• Why is it important to use the OPTIONAL
clause for patterns that cannot be
assumed to be found?
• What is a Semantic Sitemap?

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Publishing Data on the Semantic Web

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Publishing RDF Data on the Web
• Publishing RDF/XML files
• RDFa - Embedding RDF in XHTML
• dataRSS

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Step 1: Publish File
Save the RDF/XML file under the filename
• semanticweb.rdf
in the root directory of your Web server so
that it becomes available as
• http://example.org/semanticweb.rdf

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Point to RDF/XML from HTML/XHTML
• Add a link element pointing to this file to
the header of your main Web page (or
other pages, too):
<html lang="en">
<head>
<title></title>
<link rel="meta"
type="application/rdf+xml"
title="RDF/XML data for ***your company
name***" href="http://www.example.org/semanticweb.rdf" />
</head>
...
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Notify Semantic Web Search Engines
To do so, simply paste the URI
• http://example.org/semanticweb.rdf
into the respective fields of the following
submission pages:
• http://pingthesemanticweb.com/
• http://sindice.com/main/submit
• http://swoogle.umbc.edu/index.php?
option=com_swoogle_service&service=submit

25.10.2009 15

Server Configuration
• Rewrite
– http://example.org/semanticweb to
– http://example.org/semanticweb.rdf
• Correct media type rdf+xml
– The content type (media type) of the file
returned must be set correctly to "rdf+xml".

25.10.2009 16

Web Page
Content Negotiation
HTML/
XHTML
Meta-Data
RDF/XML http GET

Web

? Server

Returns
Web Page
HTML/
XHTML
Meta-Data
RDF/XML

25.10.2009 17

Server Configuration
On Appache servers, simply edit
the .htaccess file:
#Rewrite rule to serve RDF/XML content from the
vocabulary URI
RewriteRule ^semanticweb$ semanticweb.rdf

#Directive to ensure *.rdf files served as
appropriate content type
#if not present in main apache config
AddType application/rdf+xml .rdf

25.10.2009 18

Publishing RDF/XML Data on MS IIS Platforms
• Ionics Isapi Rewrite Filter for IIS 5.0 and IIS 6.0
– http://iirf.codeplex.com/
• Microsoft URL Rewrite Module for IIS 7.0
– http://support.microsoft.com/kb/324064
(Thanks to Christophe Debruyne and Robert
Meersman for the hint!)
• ModRewrite
– http://www.micronovae.com/ModRewrite/
ModRewrite.html
(Thanks to Sergio Fernández for the link!)
25.10.2009 19

Semantic Sitemaps
• Efficient means of telling a Semantic Web
search engine which RDF files are
available

http://sw.deri.org/2007/07/sitemapextension/

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Additional Information
• Cool URIs for the Semantic Web, W3C
Interest Group Note 03 December 2008
http://www.w3.org/TR/cooluris/

25.10.2009 21

RDFa: Bridging the Web of
Documents with the Web of Data

Martin Hepp

25.10.2009 22

Learning Goal
• Understand the data quality problems that
can result from the „naive“ Semantic Web
• Understand the RDFa syntax for
embedding RDF data into XHTML
documents
• Be able to express GoodRelations data in
RDFa

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Data Redundancy and Data Quality Problems
Addresses Addresses Addresses

Copy of Copy of Time
Addresses Addresses

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Data Redundancy in the Semantic Web
Web Page Web Page
HTML/ HTML/
XHTML XHTML

Meta-Data Meta-Data Time
RDF/XML RDF/XML

25.10.2009 25

Embedding RDF in XHTML
• Being able to represent meaning and rendering
information in a single document

http GET
XHTML + Web
RDFa Server
XHTML +
Returns RDFa

25.10.2009 26

=
+ XHTML
Resource Description Framework
in attributes
25.10.2009 27

What is RDFa?
• From the Web of Documents' point-of-
view: a set of new (X)HTML attributes to
express metadata within (X)HTML
• From the Web of Data point-of-view: a
serialization format for RDF (such as RDF/
XML, etc.), where the RDF triples are
"embedded" into (X)HTML

25.10.2009 28

Yahoo SearchMonkey
Currently considers RDF data only if
• submitted via the (proprietary) dataRSS
feed format or if
• embedded inside XHTML pages via
RDFa.

http://www.ebusiness-unibw.org/tools/rdf2datarss/
25.10.2009 29

RDF in Attributes
<h1 property="dc:title">GoodRelations
RDFa minimal example</h1>

25.10.2009 30

Subject – Predicate – Object
• @about (URIorSafeCURIE) … for setting
the subject of a statement
• @typeof (CURIEs) … for setting the
type(s) of a resource (syntactic sugar)
• @href/@resource (URIorSafeCURIE) …
for setting the object of a statement

25.10.2009 31

• @property (CURIEs) … for relating a
resource to a literal value, that is, for
datatype properties
• @rel/@rev (reserved word | CURIE)+ …
for relating a resource to another resource,
that is, for object properties

25.10.2009 32

• @content (CDATA) … for setting a literal
object value
• @datatype (CURIE) … for the datatype of
a literal object value - if not specified, then
the default value is xsd:string

25.10.2009 33

DOCTYPE
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML
+RDFa 1.0//EN" "http://www.w3.org/MarkUp/
DTD/xhtml-rdfa-1.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
<head profile="http://www.w3.org/1999/xhtml/
vocab">
<title>GoodRelations RDFa minimal
example</title>
</head>
(…)
25.10.2009 34

Example - Markup
• http://www.w3.org/TR/xhtml-rdfa-primer/
alice-example.html
• Install Operator on FF
• Debug page

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RDFa: Simplistic Usage
Reusing existing text and values at their original position

25.10.2009 36

RDFa: Snippet Style
Embedding additional meta-data in the same document,
but detached from the human-readable content

25.10.2009 37

RDF2RDFa Tool: Snippets

http://www.ebusiness-unibw.org/tools/rdf2rdfa/
25.10.2009 38

Quizzes
• Why is RDFa important to simplify the
creation of Semantic Web content?
• How does RDFa contribute to a better
quality of Semantic Web data?
• What is the main principle of RDFa?
• Name the key elements and give a simple
example of using RDFa.

25.10.2009 39

Hands-on Exercises: Creating,
Publishing, and Querying

Martin Hepp

25.10.2009 40

Step-by-Step (1)
• Data Sources • Data Delivery Options
– Form-based data entry
– RDFa: Embedding meta-
– RDBMS data in XHTML
– XML, e.g. BMEcat – RDF/XML: Extra file
– CSV – dataRSS: Yahoo feed
– Google CSV, RSS 1.0, format
RSS 2.0
• Amount of Detail and
Data Model
– What shall be included?
– How shall the type of
products be represented?
41

Step-by-Step (2)
• Update Mechanism & Data Management
– PHP on demand
– Script-based data dump
• Publishing the Data
– Server configuration
– Notifying Semantic Web crawlers, Yahoo, …
– Semantic Sitemaps
• Applications

42

GoodRelations Annotator

http://www.ebusiness-unibw.org/tools/goodrelations-annotator/
43

osCommerce Extension

http://code.google.com/p/goodrelations-for-oscommerce/

44

Joomla/VirtueMart Extension

http://code.google.com/p/goodrelations-for-joomla/

45

Google Product Feed Converter

http://tr.im/sLcX
25.10.2009 46

BMEcat2GoodRelations
• Converts complete catalogs from the popular
BMEcat XML Schema into GoodRelations

http://www.ebusiness-unibw.org/tools/bmecat2goodrelations/
25.10.2009 47

GoodRelations in MediaWiki

http://www.ebusiness-unibw.org/wiki/RDFaInMediaWiki

25.10.2009 48

GoodRelations in Oxid eSales
• Popular shop
software
• Free recipe for adding
GoodRelations,
developed by Daniel
Bingel

http://www.ebusiness-unibw.org/wiki/GoodRelations4Oxid

25.10.2009 49

GoodRelations Validator

http://www.ebusiness-unibw.org/tools/goodrelations-validator/
50

GoodRelations CookBook

http://www.ebusiness-unibw.org/wiki/GoodRelations#Recipes_and_Examples
25.10.2009 51

Task 1
• Use the GoodRelations Annotator to
create a description for your business or a
business that you know.

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Task 2
• Using Turtle & GoodRelations, describe the
following business.
– Miller Tax Consulting Inc., having two stores, selling
office supplies and tax consultancy
• Convert the Turtle to RDF/XML and validate it.
• Convert the RDF/XML to RDFa using
RDF2RDFa and paste it into a page of your
choice.

25.10.2009 53

Task 3
• Query the SPARQL endpoint at
http://loc.openlinksw.com/sparql
for the product properties and values for the
product with the EAN/UPC code
8714574993836.

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Thank you.

25.10.2009 55

ISWC GoodRelations Tutorial Part 4

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ISWC GoodRelations Tutorial Part 4