[contents]
Copyright © 2005 W3C ® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark, document use rules apply.
This document provides an introductory guide to the Evaluation and Report Language (EARL) 1.0, and shall be used as an accompanying document to the normative document Evaluation and Report Language (EARL) 1.0 Schema. The Evaluation and Report Language is a framework targeted to express test results. Although the term test can be taken in its widest acception, EARL is targeted to report and exchange results of tests of Web applications and resources. EARL intends to provide a vendor neutral and platform independent format. [Editor's note: synchronize with EARL 1.0 Schema.]
This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.
[Editor's note: describe intent of this working draft and propose feedback questions. Synchronize with EARL 1.0 Schema.]
Please send comments to the mailing list of the ERT WG. The archives for this list are publicly available.
This is a W3C Working Draft of the Evaluation and Report Language (EARL) 1.0 Guide. This document will be published and maintained as a W3C Recommendation after review and refinement. Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.
This document was produced under the 5 February 2004 W3C Patent Policy. The Working Group maintains a public list of patent disclosures relevant to this document; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) with respect to this specification should disclose the information in accordance with section 6 of the W3C Patent Policy.
This document has been produced as part of the W3C Web Accessibility Initiative (WAI). The goals of the Evaluation and Repair Tools Working Group (ERT WG) are discussed in the Working Group charter. The ERT WG is part of the WAI Technical Activity.
This document provides an introductory guide to the Evaluation and Report Language (EARL) 1.0, and shall be used as an accompanying document to the normative document Evaluation and Report Language (EARL) 1.0 Schema.
[Editor's note: ...]
The objectives of this document are:
Although this document does not assume any previous knowledge of EARL, the following knowledge is assumed:
The Evaluation and Report Language (EARL) is a framework targeted to express and compare test results. EARL builds on top of the Resource Description Framework [RDF], which is the basis for the Semantic Web. It is not the object of this document to introduce the reader to the intricacies of RDF, and some basic knowledge must be assumed as a pre-requisite (see, e.g., [RDF-PRIMER] for more information). As any RDF vocabulary, EARL is not more than a collection of statements about resources, each with a subject, a predicate (or a verb) and an object. These statements can be serialized in many ways (RDF/XML or Notation 3, N3). A typical EARL report could contain the following statements (oversimplifying the notation and not including namespaces):
<#someone> <#checks> <#resource> . <#resource> <#fails> <#test> .
From these simple two statements, it can be inferred already the main components of an EARL Report (wrapped up in an assertion):
This structure shows the universal applicability of EARL and its ability to refer to any type of test: bug reports, software unit tests, test suite evaluations, conformance claims or even tests outside the world of software and the World Wide Web (although for such cases, there might be too open issues for its full aplicability). It must be stressed again the semantic nature of EARL: its purpose is to facilitate the extraction and comparison of test results by humans and especially by tools (the semantic Web paradigm); it is not simply an storage of information, for which some other XML application might be more suitable.
Summarising, the objectives of EARL are to:
It is also remarkable that the extensibility of RDF (or EARL) allows to tool vendors or developers the addition of new functionalities to the vocabulary, without losing any of the aforementioned characteristics, as other testers might ignore those extensions that they do not understand when processing third party results.
The applicability of EARL to different scenarios can be seen in the following use cases:
[Editor's note: Maybe add some more exotic scenario outside the Web and software development.]
EARL is flexible enough to respond to the needs of a variety of audiences involved in a testing or quality assurance process. Typical profiles are:
A generic testing process has several steps. Typically, a test process consists of the following phases (see Figure 1):
EARL is targeted to the phase #4, and supports the rest of the following ones, by providing the necessary information for the semantic interpretation of the test results.
[Editor's note: Add figure.]
EARL is not an standalone technology, and builds on top of many existing vocabularies that cover some of its needs for metadata definition. This approach avoids the re-creation of applications already established and tested like the Dublin Core elements. The referenced specifications are:
RDF can be serialized in different ways, but the XML representation [RDF/XML] is the preferred method and will be used throughout this document. However, even when selecting this approach, there are many equivalent ways to express an RDF model.
Table 1 presents the core namespaces used by EARL. The prefix refers to the convention used in this document to denote a given namespace, and can be freely modified.
Namespace prefix | Namespace URI | Description |
---|---|---|
earl | http://www.w3.org/WAI/ER/EARL/nmg-strawman# |
The default EARL namespace. Where RDF terms are used in their abbreviated form (e.g., Assertion or foaf:Person), if no namespace is provided the term is in the EARL namespace. |
rdf | http://www.w3.org/1999/02/22-rdf-syntax-ns# |
Default RDF namespace [RDF]. |
rdfs | http://www.w3.org/2000/01/rdf-schema# |
Default RDF schema namespace [RDFS]. |
owl | http://www.w3.org/2002/07/owl# |
Default OWL namespace [OWL]. |
dc | http://purl.org/dc/elements/1.1/ |
Dublin Core Metadata Element Set namespace. |
dct | http://purl.org/dc/terms/ |
Dublin Core Metadata Terms namespace. |
foaf | http://xmlns.com/foaf/0.1/ |
FOAF namespace. |
[Editor's note: Versioning terms during the process of developing the vocabulary is an issue the group is working on. It is possible that a new namespace will be used for a final version of the vocabulary.]
[Editor's note: Short introduction on the RDF/XML serialization.]
Let us start building our first EARL report with its root element. The root element of any EARL report is an RDF node, as with any RDF vocabulary. There, we declare the corresponding namespaces, as described in Table 1, plus any custom namespace used to define additional classes and or properties.
Example 3.1. The root element of an EARL report.
<rdf:RDF xmlns:earl="http://www.w3.org/WAI/ER/EARL/nmg-strawman#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"> <!-- ... --> </rd:RDF>
Once we have defined the root element, let us build in a step-by-step the different components of an EARL report. Let us assume we want to express the results of an XHTML validation in a given document with the W3C HTML Validator in EARL. The tested document has the following HTML code:
Example 3.2. An XHTML document to be validated.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html lang="en" xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head> <title>Example of project pages</title> </head> <body> <h1>Project description</h1> <h2>My project name</h2> <p>The strategic goal of this project is to make you understand EARL.</p> <ul> <li>Here comes objective 1. <li>Here comes objective 2.</li> </ul> <p alt="what?">And goodbye ...</p> </body> </html>
This document has three errors that will constitute the basis of our EARL report:
Let us start by defining who (or what) run
the test. In the EARL jargon, that is an Assertor
. There are two types of
Assertors, SingleAssertor
and CompoundAssertor
. Assuming the
test was run by a person with the W3C HTML Validator, we can use a
CompoundAssertor
with the following structure.
Example 3.3. EARL report with a compound assertor.
<rdf:RDF xmlns:earl="http://www.w3.org/WAI/ER/EARL/nmg-strawman#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dct="http://purl.org/dc/terms/" xmlns:foaf="http://xmlns.com/foaf/0.1/"> <earl:CompoundAssertor rdf:nodeID="assertor_01"> <dc:title>John Doe and the W3C HTML Validator</dc:title> <earl:mainAssertor rdf:nodeID="johnDoe" /> <earl:helpAssertor rdf:resource="http://validator.w3.org/about.html#" /> </earl:CompoundAssertor> <earl:mainAssertor rdf:about="http://validator.w3.org/about.html#"> <dc:title xml:lang="en">W3C HTML Validator</dc:title> <dc:description xml:lang="en"> W3C Markup Validation Service, a free service that checks Web documents in formats like HTML and XHTML for conformance to W3C Recommendations and other standards. </dc:description> <!-- TODO: earl:uri ?? --> <dc:location rdf:resource="http://validator.w3.org/" /> <dct:hasVersion>0.7.1</dct:hasVersion> </earl:mainAssertor> <foaf:Person rdf:nodeID="johnDoe"> <foaf:name>John Doe</foaf:name> <foaf:mbox rdf:resource="mailto:john@example.org" /> </foaf:Person> <!-- ... --> </rdf:RDF>
Notice that this is only one of multiple serializations via an anonymous node. This representation is equivalent, for instance, to the following:
Example 3.4. EARL report with an alternative serialization of compound assertors.
<rdf:RDF xmlns:earl="http://www.w3.org/WAI/ER/EARL/nmg-strawman#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dct="http://purl.org/dc/terms/" xmlns:foaf="http://xmlns.com/foaf/0.1/"> <earl:CompoundAssertor rdf:nodeID="assertor_01"> <dc:title>John Doe and the W3C HTML Validator</dc:title> <earl:mainAssertor> <foaf:Person> <foaf:name>John Doe</foaf:name> <foaf:mbox rdf:resource="mailto:john@example.org" /> </foaf:Person> </earl:mainAssertor> <earl:helpAssertor rdf:resource="http://validator.w3.org/about.html#" /> </earl:CompoundAssertor> <earl:mainAssertor rdf:about="http://validator.w3.org/about.html#"> <dc:title xml:lang="en">W3C HTML Validator</dc:title> <dc:description xml:lang="en"> W3C Markup Validation Service, a free service that checks Web documents in formats like HTML and XHTML for conformance to W3C Recommendations and other standards. </dc:description> <!-- TODO: earl:uri ?? --> <dc:location rdf:resource="http://validator.w3.org/" /> <dct:hasVersion>0.7.1</dct:hasVersion> </earl:mainAssertor> <!-- ... --> </rdf:RDF>
The next step is to define the tested
resource. For that, EARL offers the TestSubject
class. This class
is a generic wrapper for things to be tested like Web resources
(WebContent
) or software (Software
). For our first example,
let us use the generic TestSubject
class, which must have a Dublin Core
date property:
Example 3.5. EARL report with a test subject.
<rdf:RDF xmlns:earl="http://www.w3.org/WAI/ER/EARL/nmg-strawman#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dct="http://purl.org/dc/terms/" xmlns:foaf="http://xmlns.com/foaf/0.1/"> <earl:TestSubject rdf:about="http://example.org/resource/index.html"> <dc:date>2006-02-14</dc:date> <dc:title xml:lang="en">Project Description</dc:title> </earl:TestSubject> <!-- ... --> </rdf:RDF>
The third step is to define the used
criterion for testing the given resource. In our example, we are testing
validity with XHTML 1.0 Strict, which could be expressed in the following way via the
TestRequirement
class:
Example 3.6. EARL report displaying the test requirement for validation.
<rdf:RDF xmlns:earl="http://www.w3.org/WAI/ER/EARL/nmg-strawman#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dct="http://purl.org/dc/terms/" xmlns:foaf="http://xmlns.com/foaf/0.1/"> <earl:TestRequirement rdf:about="http://www.w3.org/TR/xhtml1/dtds.html#a_dtd_XHTML-1.0-Strict"> <dc:title xml:lang="en">XHTML 1.0 Strict Document Type Definition</dc:title> <dc:description xml:lang="en"> DTD for XHTML 1.0 Strict. </dc:description> <dct:isPartOf rdf:resource="http://www.w3.org/TR/xhtml1/" /> </earl:TestRequirement> <!-- ... --> </rdf:RDF>
[Editor's note: Pending consensus on definition of test case and test requirements.]
Before we build up our assertion
about our hypothetical evaluation, let us construct the result of the
test with the three errors highlighted by the validator. This is done via the
TestResult
class.
Example 3.7. EARL report displaying different error results from the validation test.
<rdf:RDF xmlns:earl="http://www.w3.org/WAI/ER/EARL/nmg-strawman#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dct="http://purl.org/dc/terms/" xmlns:foaf="http://xmlns.com/foaf/0.1/"> <earl:TestResult rdf:ID="error_1"> <earl:validity rdf:resource="http://www.w3.org/WAI/ER/EARL/nmg-strawman#fail" /> <dc:description rdf:parseType="Literal"> <div xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"> <p>Error - Line 14 column 7: document type does not allow element <code>li</code> here; missing one of <code>ul</code>, <code>ol</code> start-tag. </p> </div> </dc:description> </earl:TestResult> <earl:TestResult rdf:ID="error_2"> <earl:validity rdf:resource="http://www.w3.org/WAI/ER/EARL/nmg-strawman#fail" /> <dc:description rdf:parseType="Literal"> <div xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"> <p>Error - Line 15 column 6: end tag for <code>li</code> omitted, but OMITTAG NO was specified. </p> </div> </dc:description> </earl:TestResult> <earl:TestResult rdf:ID="error_3"> <earl:validity rdf:resource="http://www.w3.org/WAI/ER/EARL/nmg-strawman#fail" /> <dc:description rdf:parseType="Literal"> <div xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"> <p>Error - Line 16 column 9: there is no attribute <code>alt</code>. </p> </div> </dc:description> </earl:TestResult> <!-- ... --> </rdf:RDF>
[Editor's note: Comment on location of errors in test subject pending.]
For the sake of completeness, we have included the three
validation errors. We might need only one of them to build up our assertion. The
assertion is the core of EARL, and allows to put together all
pieces of the puzzle. An Assertion
must have the following
properties:
earl:assertedBy
- The Assertion
must be asserted by an
assertor. The assertor is a human or software, or groups of these, that determine
the result.earl:subject
- The thing that is being tested against some given
requirements or test cases.earl:requirement
- The requirement that is used to test a
subject.earl:result
- The result of the test, i.e., whether the subject
passes or fails the test case (or there is some other result).Example 3.8. An EARL assertion pointing to components defined in the previous examples.
<rdf:RDF xmlns:earl="http://www.w3.org/WAI/ER/EARL/nmg-strawman#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dct="http://purl.org/dc/terms/" xmlns:foaf="http://xmlns.com/foaf/0.1/"> <earl:Assertion rdf:ID="assertion_1"> <earl:assertedBy rdf:nodeID="assertor_01" /> <earl:subject rdf:resource="http://example.org/resource/index.html" /> <earl:testcase rdf:resource="http://www.w3.org/TR/xhtml1/dtds.html#a_dtd_XHTML-1.0-Strict" /> <earl:result rdf:resource="#error_1" /> </earl:Assertion> <!-- ... --> </rdf:RDF>
[Editor's note: Adding a list with the three assertions ??]
We can now put together all the elements of our first EARL report:
Example 3.9. Our first complete EARL report.
<rdf:RDF xmlns:earl="http://www.w3.org/WAI/ER/EARL/nmg-strawman#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dct="http://purl.org/dc/terms/" xmlns:foaf="http://xmlns.com/foaf/0.1/"> <earl:Assertion rdf:ID="assertion_1"> <earl:assertedBy rdf:nodeID="assertor_01" /> <earl:subject rdf:resource="http://example.org/resource/index.html" /> <earl:testcase rdf:resource="http://www.w3.org/TR/xhtml1/dtds.html#a_dtd_XHTML-1.0-Strict" /> <earl:result rdf:resource="#error_1" /> </earl:Assertion> <earl:Assertion rdf:ID="assertion_2"> <earl:assertedBy rdf:nodeID="assertor_01" /> <earl:subject rdf:resource="http://example.org/resource/index.html" /> <earl:testcase rdf:resource="http://www.w3.org/TR/xhtml1/dtds.html#a_dtd_XHTML-1.0-Strict" /> <earl:result rdf:resource="#error_2" /> </earl:Assertion> <earl:Assertion rdf:ID="assertion_3"> <earl:assertedBy rdf:nodeID="assertor_01" /> <earl:subject rdf:resource="http://example.org/resource/index.html" /> <earl:testcase rdf:resource="http://www.w3.org/TR/xhtml1/dtds.html#a_dtd_XHTML-1.0-Strict" /> <earl:result rdf:resource="#error_3" /> </earl:Assertion> <earl:CompoundAssertor rdf:nodeID="assertor_01"> <dc:title>John Doe and the W3C HTML Validator</dc:title> <earl:mainAssertor rdf:nodeID="johnDoe" /> <earl:helpAssertor rdf:resource="http://validator.w3.org/about.html#" /> </earl:CompoundAssertor> <earl:mainAssertor rdf:about="http://validator.w3.org/about.html#"> <dc:title xml:lang="en">W3C HTML Validator</dc:title> <dc:description xml:lang="en"> W3C Markup Validation Service, a free service that checks Web documents in formats like HTML and XHTML for conformance to W3C Recommendations and other standards. </dc:description> <!-- TODO: earl:uri ?? --> <dc:location rdf:resource="http://validator.w3.org/" /> <dct:hasVersion>0.7.1</dct:hasVersion> </earl:mainAssertor> <foaf:Person rdf:nodeID="johnDoe"> <foaf:name>John Doe</foaf:name> <foaf:mbox rdf:resource="mailto:john@example.org" /> </foaf:Person> <earl:TestSubject rdf:about="http://example.org/resource/index.html"> <dc:date>2006-02-14</dc:date> <dc:title xml:lang="en">Project Description</dc:title> </earl:TestSubject> <earl:TestRequirement rdf:about="http://www.w3.org/TR/xhtml1/dtds.html#a_dtd_XHTML-1.0-Strict"> <dc:title xml:lang="en">XHTML 1.0 Strict Document Type Definition</dc:title> <dc:description xml:lang="en"> DTD for XHTML 1.0 Strict. </dc:description> <dct:isPartOf rdf:resource="http://www.w3.org/TR/xhtml1/" /> </earl:TestRequirement> <earl:TestResult rdf:ID="error_1"> <earl:validity rdf:resource="http://www.w3.org/WAI/ER/EARL/nmg-strawman#fail" /> <dc:description rdf:parseType="Literal"> <div xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"> <p>Error - Line 14 column 7: document type does not allow element <code>li</code> here; missing one of <code>ul</code>, <code>ol</code> start-tag. </p> </div> </dc:description> </earl:TestResult> <earl:TestResult rdf:ID="error_2"> <earl:validity rdf:resource="http://www.w3.org/WAI/ER/EARL/nmg-strawman#fail" /> <dc:description rdf:parseType="Literal"> <div xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"> <p>Error - Line 15 column 6: end tag for <code>li</code> omitted, but OMITTAG NO was specified. </p> </div> </dc:description> </earl:TestResult> <earl:TestResult rdf:ID="error_3"> <earl:validity rdf:resource="http://www.w3.org/WAI/ER/EARL/nmg-strawman#fail" /> <dc:description rdf:parseType="Literal"> <div xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"> <p>Error - Line 16 column 9: there is no attribute <code>alt</code>. </p> </div> </dc:description> </earl:TestResult> </rdf:RDF>
In this section we have reviewed all the necessary steps to build an EARL report. As mentioned already several times, Example 3.9 is only one of the multiple serializations that allow us to express the corresponding RDF graph.
[Editor's note: Insert an image with the corresponding RDF graph.]
The previous section introduced us to the core components of an EARL report. In this section we will review the core classes and properties of EARL, together with some clarifications on its usage. The decomposition of every class is followed by the set of RDF properties the class must or may have.
The
earl:Assertion
class is used to declare an statement about the results of a
test. As shown in Section 2, an Assertion binds together the
four components of EARL: the assertor, the subject, the test requirement and its result
(see Example 3.8). It is therefore the fundamental unit of an
EARL statement or set of
statements.
An Assertion
must have at least the following
properties:
Assertor
s.TestSubject
s (also Software
and
WebContent
can be referenced here).TestRequirement
s.TestResult
s.An Assertion
may also include the following optional
properties:
TestMode
instance.Example 3.10.
XXX
The earl:Assertor
class is the person, tool or combinations thereof, that performs the test and expresses
the results via one or several Assertion
s. We have the following types:
earl:SingleAssertor
- The Assertor
is unique.It can be of the following types:
[Editor's note: the use of FOAF is subject to review of the stability of these terms.]
[Editor's note: the current requirements on properties to identify the tester are subject to revision.]
Assertor
is a human being. This uses the
FOAF vocabulary term foaf:Person
to describe a
person. There should be identifying information including a name, and a uniquely
identifying property such as email address or an encrypted email address. The
properties foaf:name
, foaf:mbox
and
foaf:mbox_sha1sum
are defined by FOAF [FOAF].Assertor
is an Agent, as defined in [FOAF]. foaf:Person
is a subclass of this class,
which also has subclasses of foaf:Organisation
and
foaf:Group
.Example 3.11. Example of a FOAF Person description.
<rdf:RDF xmlns:earl="http://www.w3.org/WAI/ER/EARL/nmg-strawman#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:foaf="http://xmlns.com/foaf/0.1/"> <foaf:Person rdf:ID="jd"> <foaf:name>John Doe</foaf:name> <foaf:givenname>John</foaf:givenname> <foaf:family_name>Doe</foaf:family_name> <foaf:mbox rdf:resource="mailto:johndoe@example.org" /> <foaf:mbox_sha1sum>d44df295919cbbe85586fc33742abbe6a9737a2b</foaf:mbox_sha1sum> </foaf:Person> </rdf:RDF>
earl:CompoundAssertor
- The Assertor
is a compound
group of persons and/or software tools. Each group must have at least one primary
Assertor and may have a secondary Assertor, identified, respectively, by the
properties:SingleAssertor
).SingleAssertor
).Additionally, there is an optional description identified by the Dublin
Core dc:description
property.
Since the range of both of these properties is the earl:Assertor
class, the instances can be a Person, Agent, Software, or recursively another
CompoundAssertor
.
[Editor's note:
.]
[Editor's note: An aggregation example. E.g., validation and accessibility report.]
Example x.x.
XXX
Although EARL is designed to cover a wide range of testing scenarios, it cannot fulfill the requirements of all possible applications. However, as with any Semantic Web application, it can be easily extended. In this section, we will present two examples showing the extensibility potential of EARL in two scenarios:
WebContent
class to provide a full description of the
tested Web resource when HTTP content negotiation occurs. For that, we will make use
of [HTTPRDF]earl:WebContent
As mentioned earlier, there are occasions where
a URI is not sufficient to uniquely identify a Web Resource. For instance, the site may
offer multi-lingual versions of its content according to the user preferences set up in
her browse. To that end, we will use the W3C Note [HTTPRDF],
where all HTTP headers can be expressed via RDF via modeling HTTP request/response
pairs. Let us assume we are accessing the URI http://www.example.org:80/
.
The Vary
header in the response indicates content negotiation. Thus, it is
essential to record the two request headers (Accept
and
Accept-Language
) that were used in the negotiation process.
Example 6.1.
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:earl="http://www.w3.org/WAI/ER/EARL/nmg-strawman#" xmlns:http="http://www.w3.org/1999/xx/http#"> <earl:WebContent rdf:about="http://www.example.org/"> <earl:httpRequest> <http:GetRequest> <http:host>www.example.org</http:host> <http:port>80</http:port> <http:absPath>/</http:absPath> <http:version>1.1</http:version> <http:accept>text/html;q=1.0, */*;q=0.01</http:accept> <http:acceptLanguage>de-DE;q=1.0, de;q=0.75, en-GB;q=0.5, en;q=0.25, *;q=0.01</http:acceptLanguage> </http:GetRequest> </earl:httpRequest> <earl:httpResponse> <http:Response> <http:contentType>text/html;charset=utf-8</http:contentType> <http:vary>accept, accept-language</http:vary> <http:body rdf:parseType="Resource"> <http:bodyContent><![CDATA[aksgbq3833o3gbo4zgblakc8t9ut2]]></http:bodyContent> <http:bodyEncoding>Base64</http:bodyEncoding> </http:body> </http:Response> </earl:httpResponse> </earl:WebContent> </rdf:RDF>
This simple example shows how to use [HTTPRDF] to distinguish different resources served by the same URI.
earl:TestResult
Location of errors within documents is a
critical issue when following quality assurance methods to monitor Web sites or when
benchmarking tools against a test suite to compare capabilities of tools. This example
shows an approach to extend the TestResult
class to support [XPath] expressions for any markup document. To do that, we first
specify two RDF Schemas to express XPath and the corresponding namespace
mappings.
First, we define an XPath
class (in the exemplary
namespace http://www.example.org/ns/xpath#
) with two properties:
xpath:expression
for the XPath expression, andns:namespace
for referencing a prefix-namespace mapping
(optional).xpath:xpath
is an optional property added to
TestResult
to reference XPath expressions.Example 6.2. The XPath
class schema.
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:owl="http://www.w3.org/2002/07/owl#" xmlns:xpath="http://www.example.org/ns/xpath#" xmlns:ns="http://www.example.org/ns/namespace#"> <rdfs:Class rdf:about="http://www.example.org/ns/xpath#XPath"> <rdfs:label xml:lang="en">The XPath Class</rdfs:label> <rdfs:subClassOf rdf:parseType="Collection"> <owl:Restriction> <owl:onProperty rdf:resource="http://www.example.org/ns/xpath#expression"/> <owl:minCardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:minCardinality> <owl:maxCardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:maxCardinality> </owl:Restriction> <owl:Restriction> <owl:onProperty rdf:resource="http://www.example.org/ns/namespace#namespace"/> <owl:minCardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">0</owl:minCardinality> </owl:Restriction> </rdfs:subClassOf> </rdfs:Class> <rdf:Property rdf:about="http://www.example.org/ns/xpath#expression"> <rdfs:label xml:lang="en">XPath expression</rdfs:label> <rdfs:domain rdf:resource="http://www.example.org/ns/xpath#XPath"/> </rdf:Property> <rdf:Property rdf:about="http://www.example.org/ns/xpath#xpath"> <rdfs:label xml:lang="en">XPath</rdfs:label> <rdfs:range rdf:resource="http://www.example.org/ns/xpath#XPath" /> </rdf:Property> </rdf:RDF>
The prefix-namespace mapping is done with a
Namespace
class (in the exemplary namespace
http://www.example.org/ns/namespace#
) containing two properties:
ns:prefix
for the namespace prefix, andns:uri
for the namespace URI.Example 6.3. The Namespace
class schema.
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:owl="http://www.w3.org/2002/07/owl#" xmlns:ns="http://www.example.org/ns/namespace#"> <rdfs:Class rdf:about="http://www.example.org/ns/namespace#Namespace"> <rdfs:label xml:lang="en">A namespace</rdfs:label> <rdfs:subClassOf rdf:parseType="Collection"> <owl:Restriction> <owl:onProperty rdf:resource="http://www.example.org/ns/namespace#prefix"/> <owl:minCardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:minCardinality> </owl:Restriction> <owl:Restriction> <owl:onProperty rdf:resource="http://www.example.org/ns/namespace#uri"/> <owl:minCardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:minCardinality> <owl:maxCardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:maxCardinality> </owl:Restriction> </rdfs:subClassOf> </rdfs:Class> <rdf:Property rdf:about="http://www.example.org/ns/namespace#prefix"> <rdfs:label xml:lang="en">Namespace prefix</rdfs:label> <rdfs:domain rdf:resource="http://www.example.org/ns/namespace#Namespace"/> </rdf:Property> <rdf:Property rdf:about="http://www.example.org/ns/namespace#uri"> <rdfs:label xml:lang="en">Namespace URI</rdfs:label> <rdfs:domain rdf:resource="http://www.example.org/ns/namespace#Namespace"/> </rdf:Property> <rdf:Property rdf:about="http://www.example.org/ns/namespace#namespace"> <rdfs:label xml:lang="en">Namespace</rdfs:label> <rdfs:range rdf:resource="http://www.example.org/ns/namespace#Namespace"/> </rdf:Property> </rdf:RDF>
Let us take our Example 3.2 and try to express the results with our new classes. Let us define:
ns:prefix
as x
, andns:uri
as http://www.w3.org/1999/xhtml
.Then we can re-state our TestResults as follows:
Example 6.4. Extending TestResult
s by
providing concrete error locations via XPath expressions.
<rdf:RDF xmlns:earl="http://www.w3.org/WAI/ER/EARL/nmg-strawman#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dct="http://purl.org/dc/terms/" xmlns:foaf="http://xmlns.com/foaf/0.1/" xmlns:xpath="http://www.example.org/ns/xpath#" xmlns:ns="http://www.example.org/ns/namespace#"> <earl:TestResult rdf:ID="error_1"> <earl:validity rdf:resource="http://www.w3.org/WAI/ER/EARL/nmg-strawman#fail" /> <dc:description rdf:parseType="Literal"> <div xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"> <p>Error: document type does not allow element <code>li</code> here; missing one of <code>ul</code>, <code>ol</code> start-tag. </p> </div> </dc:description> <xpath:xpath rdf:resource="#loc_1" /> </earl:TestResult> <earl:TestResult rdf:ID="error_2"> <earl:validity rdf:resource="http://www.w3.org/WAI/ER/EARL/nmg-strawman#fail" /> <dc:description rdf:parseType="Literal"> <div xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"> <p>Error: end tag for <code>li</code> omitted, but OMITTAG NO was specified. </p> </div> </dc:description> <xpath:xpath rdf:resource="#loc_2" /> </earl:TestResult> <earl:TestResult rdf:ID="error_3"> <earl:validity rdf:resource="http://www.w3.org/WAI/ER/EARL/nmg-strawman#fail" /> <dc:description rdf:parseType="Literal"> <div xml:lang="en" xmlns="http://www.w3.org/1999/xhtml"> <p>Error: there is no attribute <code>alt</code>.</p> </div> </dc:description> <xpath:xpath rdf:resource="#loc_3" /> </earl:TestResult> <xpath:XPath rdf:ID="loc_1"> <xpath:expression>/x:html/x:body/x:ul/x:li[1]</xpath:expression> <ns:namespace rdf:resource="http://www.example.org/ns0" /> </xpath:XPath> <xpath:XPath rdf:ID="loc_2"> <xpath:expression>/x:html/x:body/x:ul/x:li[2]</xpath:expression> <ns:namespace rdf:resource="http://www.example.org/ns0" /> </xpath:XPath> <xpath:XPath rdf:ID="loc_3"> <xpath:expression>/x:html/x:body/x:p[2]</xpath:expression> <ns:namespace rdf:resource="http://www.example.org/ns0" /> </xpath:XPath> <ns:Namespace rdf:about="http://www.example.org/ns0"> <ns:prefix>x</ns:prefix> <ns:uri>http://www.w3.org/1999/xhtml</ns:uri> </ns:Namespace> <!-- ... --> </rdf:RDF>
[Editor's note: Self-explanatory.]
http://www.dublincore.org/documents/dces/
http://www.dublincore.org/documents/dcmi-terms/
http://xmlns.com/foaf/0.1/
http://www.w3.org/TR/1999/REC-rdf-syntax-19990222/
http://www.w3.org/TR/rdf-primer/
http://www.w3.org/TR/rdf-schema/
http://www.w3.org/TR/rdf-syntax-grammar/
http://www.w3.org/DesignIssues/RDF-XML
http://www.ietf.org/rfc/rfc2119.txt
http://www.w3.org/TR/owl-features/
http://www.w3.org/TR/WCAG10/
[Editor's note: To be determined.]