[contents]

HTTP Vocabulary in RDF 1.0

W3C Working Draft 29 October 2009

This version:

https://www.w3.org/TR/2009/WD-HTTP-in-RDF10-20091029/

Latest version:

https://www.w3.org/TR/HTTP-in-RDF10/

Previous version:

https://www.w3.org/TR/2008/WD-HTTP-in-RDF-20080908/

Editors:

Johannes Koch, Fraunhofer-Gesellschaft (Fraunhofer Institute for Applied Information Technology FIT)

Carlos A Velasco, Fraunhofer-Gesellschaft (Fraunhofer Institute for Applied Information Technology FIT)

The terms defined by this document are also provided in RDF Schema format.

Copyright © 2009 W3C^® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark and document use rules apply.

Abstract

The identification of resources on the Web by a Uniform Resource Identifier(URI) alone may not be sufficient, as other factors such as HTTP content negotiation might come into play. This issue is particularly significant for quality assurance testing, conformance claims, and reporting languages like the W3C Evaluation And Report Language (EARL). This document provides a representation of the HTTP vocabulary in the Resource Description Framework (RDF), to allow quality assurance tools to record the HTTP headers that have been exchanged between a client and a server. The RDF terms defined by this document represent the core HTTP specification defined by RFC 2616, as well as additional HTTP headers registered by the Internet Assigned Numbers Authority (IANA). These terms can also be used to record HTTPS exchanges.

1 Introduction

This document defines a representation of the Hypertext Transfer Protocol (HTTP) using the Resource Description Framework (RDF). It defines a collection of RDF classes and properties that represent the HTTP vocabulary as defined by the HTTP specification. These RDF terms can be used to record HTTP or secure HTTP request and response messages in RDF format, such as by automated Web accessibility evaluation tools that want to describe Web resources, including the various headers exchanged between the client and server during content negotiation. More usage examples for these terms are described in section 1.2 Use Cases.

Note: The version 1.0 specifies the version of the HTTP Vocabulary in RDF document and not the version of HTTP. The vocabulary defined in this specification is usable for HTTP versions up to 1.1.

[Editor's note: The working group asks for comments about potential confusion because of the versioning.]

This document is not intended to be a clarification or extension of the different concepts of the HTTP specification. The HTTP specification is defined by a series of Request for Comments (RFC) publications and other documentation, including RFC 2616 and RFC 4229. These are listed in Appendix C: References.

Additionally this document assumes the following background knowledge:

• Basic knowledge of the Extensible Markup Language (XML) [XML] and its associated technologies.
• Basic knowledge about the Semantic Web and RDF. For references, consult [RDF], [RDF-PRIMER] and [RDFS].

By default, the vocabulary introduced by this document uses names starting with upper-case letters for classes and names starting with lower-case letters for properties. The keywords must, required, recommended, should, may, and optional are used in accordance with [RFC2119].

1.1 Namespaces

The RDF representation of the HTTP vocabulary defined by this document uses the namespace https://www.w3.org/2006/http#. The prefix http is used throughout this document to denote this namespace. Table 1 presents the namespaces used by this document. The prefix notation presents the typical conventions used in the Web and in this document to denote a given namespace, and can be freely modified. Table 2 presents additional RDF data used by this document.

1.2 Use Cases

The following (non-exhaustive) list of use cases aims to highlight some of the different usages of the terms provided by this document:

Reporting Test Results

When Web resources are tested, for example for accessibility or other quality assurance testing, it may be significant to record the exact headers exchanged between the server and the client during the testing. Without a record of the exchanged headers, it may not be possible to re-identify the exact resource (or representation of the resource) that has been tested. The terms provided by this document allow quality assurance tools to record the HTTP exchange between a client and a server, for example to record the POST parameters or the headers used during content negotiation. The terms provided by this document can be used in combination with the W3C Evaluation And Report Language (EARL) [EARL].

Precising Conformance Claims

Conformance claims that are made about a Web resource or group of Web resource, are sometimes only applicable under certain constraints. For example, conformance of a Web site to the W3C Web Content Accessibility Guidelines (WCAG) [WCAG], may only be applicable for a certain language of the Web site that is using language negotiation. When provding machine-readable conformance claims, for example using the W3C Protocol for Describing Web Resources (POWDER): Description Resources [POWDER-DR], it is important to precise any such constraints that may apply.

Debugging Web Applications

Web applications using client-side scripting such as AJAX may exchange additional HTTP messages with the server without using a different URI. In order to debug such Web applications, it must be possible to reconstruct the exact history of the states through which the Web application passed. Web authoring tools that are designed to develop and debug Web applications could use the terms provided by this document to record the exact HTTP messages exchanged bewteen a client and a server. This information could be provided to the developer as a log to help debug errors in the Web application..

Indexing Information Resources

When indexing RDF information resources that are available through the HTTP protocol (also called "scuttering" in Semantic Web parlance), it is often useful to record information about the HTTP request and response messages that were exchanged, along with the data for later use. In some instances, different representations of the RDF information may be retrieved from the server depending on the HTTP headers and paramters exchanged. The terms provided by this document can be used to supplement the collected data with the HTTP messages as part of a comprehensive indexing repository.

1.3 Limitations

There are also notable schema limitations with regards to security and privacy since the content recorded by this vocabulary could potentially contain sensitive information, for example authentication information in HTTP headers or other information (login user name, passwords, and so on) within the body of the message. Since the schema of this document is limited to terms defined by the HTTP vocabulary, security and privacy considerations need to be made at the application level. For example, certain parts of the data may be restricted to appropriate user permissions or obfuscated.

2 Classes

This section defines RDF classes for the HTTP 1.1 specification according to [RFC2616].

2.1 Connection Class

A connection that is used for the HTTP transfer.

Related Properties

• Domain of:
  • http:connectionAuthority
  • http:requests
• Range of: none

Examples

<http:Connection rdf:ID="conn">
  <http:connectionAuthority>www.example.org:80</http:connectionAuthority>
  <http:requests rdf:parseType="Collection">
    <http:Request rdf:ID="req0"/>
    <http:Request rdf:ID="req1"/>
  </http:requests>
</http:Connection>

2.2 Message Class

An HTTP message.

Related Properties

• Domain of:
  • http:httpVersion
  • http:headers
  • http:body
• Range of: none

It may be appropriate to provide additional information about the Message by using the following from external vocabularies:

dct:date

Message date (see the usage of this property in requests and responses).

Examples

<http:Message rdf:ID="mess0">
  <http:httpVersion>1.1</http:httpVersion>
  <dct:date>2007-09-13</dct:date>
  <http:headers rdf:parseType="Collection">
    <http:MessageHeader rdf:ID="mh0"/>
    <http:MessageHeader rdf:ID="mh1"/>
  </http:headers>
  <http:body>
    <cnt:Content rdf:ID="cont0"/>
  </http:body>
</http:Message>

There are two subclasses from the http:Message class: http:Request and http:Response.

2.2.1 Request Class

An HTTP request. The http:Request class is a subclass of the http:Message class.

Related Properties

• Domain of:
  • http:methodName
  • http:mthd
  • http:requestURI
  • http:resp
• Range of: none

The dct:date property when used in a Request resource represents the date the request was sent by the client.

Examples

<http:Request rdf:ID="reqs0">
  <http:abs_path>/</http:abs_path>
  <http:methodName>GET</http:methodName>
  <http:mthd rdf:resource="https://www.w3.org/2008/http-methods#GET"/>
  <http:resp rdf:resource="#resp0"/>
  <dct:date>2007-09-13</dct:date>
  <http:httpVersion>1.1</http:httpVersion>
  <http:headers rdf:parseType="Collection">
    <http:MessageHeader rdf:about="#mh0"/>
    <http:MessageHeader rdf:about="#mh1"/>
  </http:headers>
</http:Request>

2.2.2 Response Class

An HTTP response. The http:Response class is a subclass of the http:Message class.

Related Properties

• Domain of:
  • http:statusCodeNumber
  • http:sc
  • http:reasonPhrase
• Range of:
  • http:resp

The dct:date property when used in a Response resource represents the date the response was received by the client.

Examples

<http:Response rdf:ID="resp0">
  <http:httpVersion>1.1</http:httpVersion>
  <dct:date>2008-01-11</dct:date>
  <http:statusCodeNumber>200</http:statusCodeNumber>
  <http:sc rdf:resource="https://www.w3.org/2008/http-statusCodes#statusCode200"/>
  <http:headers rdf:parseType="Collection">
    <http:MessageHeader rdf:about="#mh2"/>
    <http:MessageHeader rdf:about="#mh3"/>
  </http:headers>
  <http:body>
    <cnt:Content rdf:ID="cont0"/>
  </http:body>
</http:Response>

2.3 MessageHeader Class

A header in an HTTP message.

Related Properties

• Domain of:
  • http:fieldName
  • http:hdrName
  • http:fieldValue
  • http:headerElements
• Range of: none

Examples

<http:MessageHeader rdf:ID="mh0">
  <http:fieldValue>text/html, image/png, image/gif;q=0.8</http:fieldValue>
  <http:fieldName>Accept</http:fieldName>
  <http:hdrName rdf:resource="https://www.w3.org/2008/http-headers#accept"/>
  <http:headerElements rdf:parseType="Collection">
    <http:HeaderElement rdf:about="#he0"/>
    <http:HeaderElement rdf:about="#he1"/>
    <http:HeaderElement rdf:about="#he2"/>
  </http:headerElements>
</http:MessageHeader>

2.4 HeaderElement Class

An element in a header value, if a Message Header value can be decomposed into several parts.

Related Properties

• Domain of:
  • http:elementName
  • http:elementValue
  • http:params
• Range of: none

Examples

<http:HeaderElement rdf:ID="he0">
  <http:elementName>image/gif</http:elementName>
  <http:params rdf:parseType="Collection">
    <http:Parameter rdf:ID="param0"/>
  </http:params>
</http:HeaderElement>

2.5 Parameter Class

A parameter in a Header Element.

Related Properties

• Domain of:
  • http:paramName
  • http:paramValue
• Range of: none

Examples

<http:Parameter rdf:ID="param0">
  <http:paramName>q</http:paramName>
  <http:paramValue>0.8</http:paramValue>
</http:Parameter>

2.6 Method Class

The HTTP 1.1 specification defines eight methods: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, CONNECT. The RDF graph available in RDF/XML at https://www.w3.org/2008/http-methods provides http:Method resources for each of these to be used as objects for the http:mthd property. A resource of type http:Method represents the name of a method used with HTTP.

Related Properties

• Domain of: none
• Range of:
  • http:mthd

2.7 StatusCode Class

[HTTP Status Codes] is a registry for status codes too be used in HTTP. The RDF graph available in RDF/XML at https://www.w3.org/2008/http-statusCodes provides http:StatusCode resources for each of these to be used as objects for the http:sc property. A resource of type http:StatusCode represents a status code.

Related Properties

• Domain of: none
• Range of:
  • http:sc

2.8 HeaderName Class

Header names to be used in HTTP are registered by the IANA (see [RFC4229], [Permanent Headers], and [Provisional Headers]). The RDF graph available in RDF/XML at https://www.w3.org/2008/http-headers provides http:HeaderName resources for each of these to be used as objects for the http:hdrName property. A resource of type http:HeaderName represents the name of a header used with HTTP.

Related Properties

Properties defined by this document:

• Domain of: none
• Range of:
  • http:hdrName

3 Properties

This section defines RDF properties for the HTTP 1.1 specification according to [RFC2616].

3.1 body Property

This property relates a resource object of the type Message to a resource object of the type cnt:Content or a subclass thereof to be the Message's entity body as defined in [RFC2616]. HTTP bodies are series of bytes. Thus for the resource object, it is appropriate to point to a cnt:ContentAsBase64 resource (see [Content-in-RDF] for more information on content representations using the Resource Desription Framework (RDF)).

Domain:

http:Message

Range:

cnt:ContentAsBase64

Examples

<http:Message rdf:ID="mess0">
    <http:body>
      <cnt:ContentAsBase64 rdf:ID="cont0-bin"/>
    </http:body>
  </http:Message>

3.2 connectionAuthority Property

Connection authority - server host and port for a connection.

Domain:

http:Connection

Range:

Literal

3.3 elementName Property

Header element name (Literal).

Domain:

http:HeaderElement

Range:

Literal

3.4 elementValue Property

Header element value (Literal).

Domain:

http:HeaderElement

Range:

Literal

3.5 fieldName Property

Header name (Literal).

Domain:

http:MessageHeader

Range:

Literal

3.6 fieldValue Property

Header value (Literal).

Domain:

http:MessageHeader

Range:

Literal

3.7 headers Property

HTTP headers sent with the message.

Domain:

http:Message

Range:

unspecified

3.8 headerElements Property

Header value elements.

Domain:

http:MessageHeader

Range:

unspecified

3.9 hdrName Property

This property relates a resource of type http:MessageHeader to a resource of type http:HeaderName.

Domain:

http:MessageHeader

Range:

http:HeaderName

3.10 httpVersion Property

Property representing the HTTP version number as a Literal (the format is 'digit.digit').

Domain:

http:Message

Range:

Literal

3.11 mthd Property

HTTP method.

Domain:

http:Request

Range:

http:Method

3.12 methodName Property

HTTP method name (Literal).

Domain:

http:Request

Range:

Literal

3.13 params Property

Header element parameters.

Domain:

http:HeaderElement

Range:

unspecified

3.14 paramName Property

Parameter name.

Domain:

http:Parameter

Range:

Literal

3.15 paramValue Property

Parameter value.

Domain:

http:Parameter

Range:

Literal

3.16 reasonPhrase Property

Reason phrase sent by the server.

Domain:

http:Response

Range:

Literal

3.17 requests Property

HTTP requests sent via the connection.

Domain:

http:Connection

Range:

unspecified

3.18 requestURI Property

The request URI as specified in section 5.1.2 of [RFC2616]. This vocabulary defines the following sub-properties:

• http:absoluteURI
• http:abs_path
• http:authority

Domain:

http:Request

Range:

Literal

Examples

<http:Request>
  <http:methodName>OPTIONS</http:methodName>
  <http:requestURI>*</http:requestURI>
  ...
</http:Request>

3.18.1 absoluteURI Property

Request URI that is an absolute URI.

Conformance Note: The object for this property must be a Literal (absolute URI).

Examples

<http:Request>
  <http:methodName>GET</http:methodName>
  <http:absoluteURI>https://www.example.org:80/foo/bar</http:absoluteURI>
  ...
</http:Request>

3.18.2 abs_path Property

Request URI that is an absolute path.

Conformance Note: The object for this property must be a Literal (absolute path).

Examples

<http:Request>
  <http:methodName>GET</http:methodName>
  <http:abs_path>/foo/bar</http:abs_path>
  ...
</http:Request>

3.18.3 authority Property

Request URI that is an authority.

Conformance Note: The object for this property must be a Literal (host and optional port number).

Examples

<http:Request>
  <http:methodName>CONNECT</http:methodName>
  <http:authority>www.example.org:80</http:authority>
  ...
</http:Request>

3.19 resp Property

This property relates a resource of type http:Request to a resource of type http:Response.

Domain:

http:Request

Range:

http:Response

3.20 sc Property

This property relates a resource of type http:Response to a resource of type http:StatusCode.

Domain:

http:Response

Range:

http:StatusCode

3.21 statusCodeNumber Property

The status code sent by the server (Literal).

Domain:

http:Response

Range:

Literal

4 Conformance

This section describes conformance with this HTTP-in-RDF specification. It differentiates between the following entities:

[Editor's note: The working group asks for comments about a more colloquial word for "HTTP-in-RDF Graph".]

HTTP-in-RDF Graph

An individual file or collection of files that contain HTTP-in-RDF data

HTTP-in-RDF Producer

A software tool or Web-based application that produces HTTP-in-RDF data

HTTP-in-RDF Consumer

A software tool or Web-based application that processes HTTP-in-RDF data

4.1 Conforming HTTP-in-RDF graphs

Graphs conforming to this HTTP-in-RDF specification must meet the following requirements:

1. A Connection must have exactly one connection authority (specified by http:connectionAuthority).
2. A Connection may have one collection of Requests (referenced by http:requests).
3. A Message must have exactly one HTTP version (specified by http:httpVersion).
4. A Message may have one collection of Message Headers (referenced by http:headers).
5. A Message may have one message body (referenced by http:body).
6. A Message may have one date (specified by dct:date ).
7. A Request must have exactly one method name (specified by http:methodName).
8. A Request must have exactly one request URI (specified by http:requestURI).
9. A Request may be connected to one Method (referenced by http:mthd).
10. A Request may be connected to one Response (referenced by http:resp).
11. A Response must have exactly one status code number (specified by http:statusCodeNumber).
12. A Response must have exactly one reason phrase (specified by http:reasonPhrase).
13. A Response may be conected to one Status Code (referenced by http:sc).
14. A Message Header must have exactly one field name (specified by http:fieldName).
15. A Message Header must have exactly one field value (specified by http:fieldValue).
16. A Message Header may be connected to one Header Name (referenced by http:hdrName).
17. A Message Header may have one collection of Header Elements (referenced by http:headerElements).
18. A Header Element must have exactly one header element name (specified by http:elementName).
19. A Header Element may have one header element value (specified by http:elementValue).
20. A Header Element may have one collection of Parameters (referenced by http:params).
21. A Parameter must have exactly one parameter name (specified by http:paramName).
22. A Parameter must have exactly one parameter value (specified by http:paramValue).
23. The objects for the headers property must be an RDF Collection of Message Headers.
24. The objects for the http:headerElements property must be an RDF Collection of Header Elements.
25. The object for the http:params property must be an RDF Collection of Parameters.
26. The object for the http:requests property must be an RDF Collection of Requests.
27. Every instance of cnt:ContentAsBase64 must conform with the respective specification.

4.2 Conforming Producers

Producers conforming to this HTTP-in-RDF specification must meet the following requirements:

1. A Producer must generate conforming graphs
2. A Producer must be able to generate graphs in RDF/XML serialization and should also support other RDF serializations
3. A Producer must generate all of the terms summarized in Appendix B: Terms for which there is information available to it

4.3 Conforming Consumers

Consumers conforming to this HTTP-in-RDF specification must meet the following requirements:

1. A Consumer must process conforming graphs
2. A Consumer must process graphs in any RDF/XML serialization and should also support other RDF serializations
3. A Consumer must process all of the terms summarized in Appendix B: Terms for which there is information available to it

Appendix A: A practical Example

The following example shows an RDF/XML representation of an HTTP request and response pair.

Scenario Description

A client sends two requests to a server at www.example.org port 80 via HTTP 1.1 GET. With each request, it sends request headers. The first request is for a resource in the document root (/), the second for a resource at /image. While handling the second request the server performs content negotiation respecting the request's Accept header and so sends a PNG image. This is indicated by the response's Vary header.

Resulting RDF/XML

<?xml version="1.0" encoding="utf-8"?>
<rdf:RDF xmlns:rdf="https://www.w3.org/1999/02/22-rdf-syntax-ns#"
  xmlns:http="https://www.w3.org/2006/http#"
  xmlns:cnt="https://www.w3.org/2008/content#"
  xmlns:dct="https://purl.org/dc/terms/">
  <http:Connection rdf:ID="conn">
    <http:connectionAuthority>www.example.org:80</http:connectionAuthority>
    <http:requests rdf:parseType="Collection">
      <http:Request rdf:about="#req0"/>
      <http:Request rdf:about="#req1"/>
    </http:requests>
  </http:Connection>
  <http:Request rdf:about="#req0">
    <http:httpVersion>1.1</http:httpVersion>
    <http:methodName>GET</http:methodName>
    <http:mthd rdf:resource="https://www.w3.org/2008/http-methods#GET"/>
    <http:abs_path>/</http:abs_path>
    <http:headers rdf:parseType="Collection">
      <http:MessageHeader>
        <http:fieldName>Host</http:fieldName>
        <http:hdrName rdf:resource="https://www.w3.org/2008/http-headers#host"/>
        <http:fieldValue>www.example.org</http:fieldValue>
      </http:MessageHeader>
      <http:MessageHeader>
        <http:fieldName>User-Agent</http:fieldName>
        <http:hdrName rdf:resource="https://www.w3.org/2008/http-headers#user-agent"/>
        <http:fieldValue>My User Agent</http:fieldValue>
      </http:MessageHeader>
      <http:MessageHeader>
        <http:fieldName>Accept</http:fieldName>
        <http:hdrName rdf:resource="https://www.w3.org/2008/http-headers#accept"/>
        <http:fieldValue>text/html, image/png, image/gif;q=0.8</http:fieldValue>
        <http:headerElements rdf:parseType="Collection">
          <http:HeaderElement>
            <http:elementName>text/html</http:elementName>
          </http:HeaderElement>
          <http:HeaderElement>
            <http:elementName>image/png</http:elementName>
          </http:HeaderElement>
          <http:HeaderElement>
            <http:elementName>image/gif</http:elementName>
            <http:params rdf:parseType="Collection">
              <http:Parameter>
                <http:paramName>q</http:paramName>
                <http:paramValue>0.8</http:paramValue>
              </http:Parameter>
            </http:params>
          </http:HeaderElement>
        </http:headerElements>
      </http:MessageHeader>
    </http:headers>
    <http:resp rdf:resource="#resp0"/>
  </http:Request>
  <http:Request rdf:about="#req1">
    <http:httpVersion>1.1</http:httpVersion>
    <http:methodName>GET</http:methodName>
    <http:mthd rdf:resource="https://www.w3.org/2008/http-methods#GET"/>
    <http:abs_path>/image</http:abs_path>
    <http:headers rdf:parseType="Collection">
      <http:MessageHeader>
        <http:fieldName>Host</http:fieldName>
        <http:hdrName rdf:resource="https://www.w3.org/2008/http-headers#host"/>
        <http:fieldValue>www.example.org</http:fieldValue>
      </http:MessageHeader>
      <http:MessageHeader>
        <http:fieldName>User-Agent</http:fieldName>
        <http:hdrName rdf:resource="https://www.w3.org/2008/http-headers#user-agent"/>
        <http:fieldValue>My User Agent</http:fieldValue>
      </http:MessageHeader>
      <http:MessageHeader>
        <http:fieldName>Accept</http:fieldName>
        <http:hdrName rdf:resource="https://www.w3.org/2008/http-headers#accept"/>
        <http:fieldValue>image/png, image/gif;q=0.8</http:fieldValue>
        <http:headerElements rdf:parseType="Collection">
          <http:HeaderElement>
            <http:elementName>image/png</http:elementName>
          </http:HeaderElement>
          <http:HeaderElement>
            <http:elementName>image/gif</http:elementName>
            <http:params rdf:parseType="Collection">
              <http:Parameter>
                <http:paramName>q</http:paramName>
                <http:paramValue>0.8</http:paramValue>
              </http:Parameter>
            </http:params>
          </http:HeaderElement>
        </http:headerElements>
      </http:MessageHeader>
    </http:headers>
    <http:resp rdf:resource="#resp1"/>
  </http:Request>
  <http:Response rdf:ID="resp0">
    <http:httpVersion>1.1</http:httpVersion>
    <http:statusCodeNumber>200</http:statusCodeNumber>
    <http:sc rdf:resource="https://www.w3.org/2008/http-statusCodes#200"/>
    <http:reasonPhrase>OK</http:reasonPhrase>
    <http:headers rdf:parseType="Collection">
      <http:MessageHeader>
        <http:fieldName>Date</http:fieldName>
        <http:hdrName rdf:resource="https://www.w3.org/2008/http-headers#date"/>
        <http:fieldValue>.......</http:fieldValue>
      </http:MessageHeader>
      <http:MessageHeader>
        <http:fieldName>Content-Type</http:fieldName>
        <http:hdrName rdf:resource="https://www.w3.org/2008/http-headers#content-type"/>
        <http:fieldValue>text/html; charset=utf-8</http:fieldValue>
        <http:headerElements rdf:parseType="Collection">
          <http:HeaderElement>
            <http:elementName>text/html</http:elementName>
            <http:params rdf:parseType="Collection">
              <http:Parameter>
                <http:paramName>charset</http:paramName>
                <http:paramValue>utf-8</http:paramValue>
              </http:Parameter>
            </http:params>
          </http:HeaderElement>
        </http:headerElements>
      </http:MessageHeader>
    </http:headers>
    <http:body>
      <cnt:ContentAsBase64 rdf:ID="cont0-bin">
        <cnt:bytes rdf:datatype="https://www.w3.org/2001/XMLSchema#base64Binary"
          >ajrq9qguojbglj48z..........</cnt:bytes>
      </cnt:ContentAsBase64>
    </http:body>
  </http:Response>
  <cnt:XMLContent rdf:ID="cont0-xml">
    <dct:source rdf:resource="#cont0-bin"/>
    <cnt:xmlLeadingMisc rdf:parseType="Literal"><!-- This is the start of the document -->
</cnt:xmlLeadingMisc>
    <cnt:docTypeDecl>
      <cnt:DocTypeDecl>
        <cnt:dtdName>html</cnt:dtdName>
        <cnt:publicId>-//W3C//DTD XHTML 1.0 Strict//EN</cnt:publicId>
        <cnt:systemId rdf:datatype="https://www.w3.org/2001/XMLSchema#anyURI"
          >https://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd</cnt:systemId>
      </cnt:DocTypeDecl>
    </cnt:docTypeDecl>
    <cnt:xmlRest rdf:parseType="Literal"><html xmlns="https://www.w3.org/1999/xhtml" lang="en">
  <head>
    <title>My document</title>
  </head>
  <body>
    <p><!-- ...... --></p>
  </body>
</html></cnt:xmlRest>
  </cnt:XMLContent>
  <http:Response rdf:ID="resp1">
    <http:httpVersion>1.1</http:httpVersion>
    <http:statusCodeNumber>200</http:statusCodeNumber>
    <http:sc rdf:resource="https://www.w3.org/2008/http-statusCodes#200"/>
    <http:reasonPhrase>OK</http:reasonPhrase>
    <http:headers rdf:parseType="Collection">
      <http:MessageHeader>
        <http:fieldName>Date</http:fieldName>
        <http:hdrName rdf:resource="https://www.w3.org/2008/http-headers#date"/>
        <http:fieldValue>.......</http:fieldValue>
      </http:MessageHeader>
      <http:MessageHeader>
        <http:fieldName>Content-Type</http:fieldName>
        <http:hdrName rdf:resource="https://www.w3.org/2008/http-headers#content-type"/>
        <http:fieldValue>image/png</http:fieldValue>
      </http:MessageHeader>
      <http:MessageHeader>
        <http:fieldName>Vary</http:fieldName>
        <http:hdrName rdf:resource="https://www.w3.org/2008/http-headers#vary"/>
        <http:fieldValue>accept</http:fieldValue>
        <http:headerElements rdf:parseType="Collection">
          <http:HeaderElement>
            <http:elementName>accept</http:elementName>
          </http:HeaderElement>
        </http:headerElements>
      </http:MessageHeader>
    </http:headers>
    <http:body>
      <cnt:ContentAsBase64>
        <cnt:bytes rdf:datatype="https://www.w3.org/2001/XMLSchema#base64Binary"
          >qouh3908t38hohfrf..........</cnt:bytes>
      </cnt:ContentAsBase64>
    </http:body>
  </http:Response>
</rdf:RDF>

Appendix B: Terms

The following terms are defined by this specification:

Classes

Properties

Appendix C: References

[Content-in-RDF]

Representing Content in RDF - Johannes Koch, Carlos A Velasco (editors). W3C Working Draft 17 July 2008.

[EARL]

Evaluation and Report Language (EARL) Overview - W3C

[HTTP Status Codes]

"HTTP Status Code Registry" - IANA.

[OWL]

Web Ontology Language (OWL) Overview - W3C

[Permanent Headers]

Permanent Message Header Field Names - IANA.

[Provisional Headers]

Provisional Message Header Field Names - IANA.

[POWDER-DR]

Protocol for Web Description Resources (POWDER): Description Resources - P. Archer, K. Smith, A. Perego (editors). W3C Proposed Recommendation 04 June 2009.

[RDF]

Resource Description Framework (RDF) Overview - W3C

[RDF-PRIMER]

RDF Primer - Frank Manola, Eric Miller (editors). W3C Recommendation, 10 February 2004.

[RDFS]

RDF Vocabulary Description Language 1.0: RDF Schema - Dan Brickley, R.V. Guha (editors). W3C Recommendation 10 February 2004

[RFC2119]

Request for Comments (RFC): 2119. Key words for use in RFCs to Indicate Requirement Levels - IETF March 1997.

[RFC2616]

Hypertext Transfer Protocol -- HTTP/1.1 - R. Fielding, J. Gettys, J. Mogul, H. Frystyk Nielsen, L. Masinter, P. Leach and T. Berners-Lee. IETF June 1999.

[RFC4229]

HTTP Header Field Registrations - M. Nottingham, J. Mogul. IETF December 2005.

[WCAG]

Web Content Accessibility Guidelines (WCAG) Overview - W3C.

[XML]

Extensible Markup Language (XML) 1.0 (Fifth Edition) - Tim Bray, Jean Paoli, C. M. Sperberg-McQueen, Eve Maler, François Yergeau (editors). W3C Recommendation 26 November 2008

Appendix D: Document Changes

The following is a list of substantial changes since the 8 September 2008 Working Draft:

• at most one body property is allowed for Message resources; this property relates the message to Base64 encoded message content;
• several properties were renamed because their names differed from class names only by case: headername (now hdrName), method (now mthd), response (now resp), statusCode (now sc);
• the asterisk resource was removed in favour of the use of the Literal "*";
• the StatusCodeGroup class was removed in favour of sub-classes of StatusCode;
• a section about conformance was added.