The identification of resources on the Web by 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 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 IANA. These terms can also be used to record HTTPS exchanges.
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/.
This Working Draft of the HTTP Vocabulary in RDF document was published on 8 September 2008 by the Evaluation and Repair Tools Working Group (ERT WG). It is an update of the previous HTTP Vocabulary in RDF Working Draft of 23 March 2007, and addresses the comments received since (see history of document changes). This document is part of the W3C Evaluation And Report Language (EARL). It is expected to be the last working draft before publication as a W3C Working Group Note.
The RDF terms defined by this document can be used to extend the Evaluation And Report Language (EARL) 1.0 Schema, but can also be used separately to record an HTTP exchange between a client and a server for any purpose. The Working Group encourages feedback about the approach, as well as about the completeness and maturity of this document by developers and researchers who have interest in a representation of the HTTP vocabulary in RDF format. Feedback from the W3C Quality Assurance Interest Group, the W3C Semantic Web Interest Group, and the Protocol for Web Description Resources Working Group is particularly welcome. Please send comments on this document by 29 September 2008 to the public mailing list of the working group public-wai-ert@w3.org. The archives of the working group mailing list are publicly available.
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 by a group operating under the 5 February 2004 W3C Patent Policy. The group does not expect this document to become a W3C Recommendation. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; 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) must disclose the information in accordance with section 6 of the W3C Patent Policy.
This document defines a representation of the Hyper Text 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 HTTPS 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 1.3. Use Cases.
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 D: References. This document is also not intended to be an introduction to RDF, the reader is referred to the RDF Primer and RDF specifications [RDF] for this purpose.
The RDF representation of the HTTP vocabulary defined by this document uses the namespace http://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 (rdfs and owl namespaces are normally only used in the schema); and Table 2 presentes additional RDF data 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 1: namespaces used by this document.
| Namespace prefix |
Namespace URI |
Description |
http |
http://www.w3.org/2006/http# |
Core HTTP vocabulary in RDF terms. |
cnt |
http://www.w3.org/2008/content# |
Default namespace for Representing Content in RDF [Content in RDF]. |
dc |
http://purl.org/dc/elements/1.1/ |
Dublin Core Metadata Element Set 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 [RDF]. |
owl |
http://www.w3.org/2002/07/owl# |
Default OWL namespace [OWL]. |
Table 2: RDF data used by this document.
| Namespace prefix |
Namespace URI |
Description |
http-header |
http://www.w3.org/2006/http-header# |
Additional HTTP headers. |
http-methods |
http://www.w3.org/2006/http-methods# |
HTTP methods for requests. |
http-statusCodes |
http://www.w3.org/2006/http-statusCodes# |
HTTP status codes for responses. |
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].
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. [Editor Note: the Working Group is exploring the relationship to POWDER].
- 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.
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, etc.) 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.
This section defines RDF terms for the HTTP 1.1 specification according to [RFC 2616].
A connection that is used for the HTTP transfer. The following properties have the domain Connection:
Conformance Note: A connection must have exactly 1 connection authority and 0 or 1 requests collection.
@@@ SPARQL query TBD
Example 2.1: A Connection resource.
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:http="http://www.w3.org/2006/http#"
xml:base="http://www.example.org/connection#">
<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>
</rdf:RDF>
An HTTP message. The following properties have the domain Message:
Additional properties not defined in this document:
dc:date- Message date (see the usage of this property in requests and responses).
Conformance Note: A Message must have exactly 1 HTTP version and 0 or 1 headers collection, body and date.
Example 2.2: A Message resource.
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:http="http://www.w3.org/2006/http#"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xml:base="http://example.org/message#">
<http:Message rdf:ID="mess0">
<http:httpVersion>1.1</http:httpVersion>
<dc:date>2007-09-13</dc: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>
</rdf:RDF>
There are two subclasses from the Message class: Request and Response.
The Request class is a subclass of the Message class. A resource of this type represents an HTTP request. Additional to the properties mentioned in 2.2 Message Class, the following properties have the domain Request:
The dc:date property when used in a Request resource represents the date the request was sent by the client.
Conformance Note: methodName and requestURI must appear once, method and response may appear 0 or 1 times in Request.
Example 2.3: A Request resource.
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:http="http://www.w3.org/2006/http#"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xml:base="http://example.org/reqs#">
<http:Request rdf:ID="reqs0">
<http:abs_path>/</http:abs_path>
<http:methodName>GET</http:methodName>
<http:method rdf:resource="http://www.w3.org/2008/http-methods#GET"/>
<http:response rdf:resource="#resp0"/>
<dc:date>2007-09-13</dc: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>
<http:MessageHeader rdf:ID="mh0"/>
<http:MessageHeader rdf:ID="mh1"/>
</rdf:RDF>
An HTTP response as defined in [RFC 2616]. The Response class is a subclass of the Message class.
Properties with domain Response |
Properties with range Response |
|
response |
The dc:date property when used in a Response resource represents the date the response was received by the client.
Conformance Note: A Response must have exactly 1 status code number (literal) and reason phrase, and 0 or 1 status code (resource).
Example 2.5: A Response resource.
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:http="http://www.w3.org/2006/http#"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:cnt="http://www.w3.org/2008/content#"
xml:base="http://example.org/resp#">
<http:Response rdf:ID="resp0">
<http:httpVersion>1.1</http:httpVersion>
<dc:date>2008-01-11</dc:date>
<http:statusCodeNumber>200</http:statusCodeNumber>
<http:statusCode rdf:resource="http://www.w3.org/2008/http-statusCodes#statusCode200"/>
<http:headers rdf:parseType="Collection">
<http:MessageHeader rdf:about="#mh0"/>
<http:MessageHeader rdf:about="#mh1"/>
</http:headers>
<http:body>
<cnt:Content rdf:ID="cont0"/>
</http:body>
</http:Response>
<http:MessageHeader rdf:ID="mh1"/>
<http:MessageHeader rdf:ID="mh0"/>
</rdf:RDF>
A resource of type MessageHeader represents an HTTP header. The following properties may appear in resources of type MessageHeader:
Conformance Note: fieldName and fieldValue must appear once, headerName and headerElements may appear 0 or 1 times in MessageHeader.
Example 2.6: A MessageHeader resource.
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:http="http://www.w3.org/2006/http#"
xml:base="http://example.org/mh#">
<http:MessageHeader rdf:ID="mh0">
<http:fieldValue>text/html, image/png, image/gif;q=0.8</http:fieldValue>
<http:fieldName>Accept</http:fieldName>
<http:headerName rdf:resource="http://www.w3.org/2008/http-header#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>
<http:HeaderElement rdf:ID="he0"/>
<http:HeaderElement rdf:ID="he2"/>
<http:HeaderElement rdf:ID="he1"/>
</rdf:RDF>
A resource of type HeaderElement represents an element in a header value. The following properties have the domain HeaderElement:
Conformance Note: elementName must appear once, elementValue and params may appear 0 or 1 times in HeaderElement.
Example 2.7: A HeaderElement resource.
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:http="http://www.w3.org/2006/http#"
xml:base="http://example.org/he#">
<http:HeaderElement rdf:ID="he0">
<http:elementName>image/gif</http:elementName>
<http:params rdf:parseType="Collection">
<http:Param rdf:ID="param0"/>
</http:params>
</http:HeaderElement>
</rdf:RDF>
A resource of type Param represents an element in a header value parameter. The following properties have the domain Param:
Conformance Note: paramName and paramValue must appear once in Param.
Example 2.8: A Param resource.
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:http="http://www.w3.org/2006/http#"
xml:base="http://example.org/param#">
<http:Param rdf:ID="param0">
<http:paramName>q</http:paramName>
<http:paramValue>0.8</http:paramValue>
</http:Param>
</rdf:RDF>
The HTTP 1.1 specification defines eight methods: OPTIONS, GET, HEAD, POST, PUT, DELETE, TRACE, CONNECT. The resource at http://www.w3.org/2006/http-methods provides Method resources for each of these to be used as objects for the method property. A resource of type Method represents the name of a method used with HTTP.
[HTTP Status Codes] is a registry for status codes too be used in HTTP. The resource at http://www.w3.org/2006/http-statusCodes provides StatusCode resources for each of these to be used as objects for the statusCode property. A resource of type StatusCode represents a status code.
Status codes in HTTP may be grouped. The resource at http://www.w3.org/2006/http-statusCodes provides StatusCodeGroup resources for some groupings of status codes. A resource of type StatusCodeGroup represents a group of status codes.
Header names to be used in HTTP are registered by the IANA (see [RFC4229], [Permanent Headers], and [Provisional Headers]). The resource at http://www.w3.org/2006/http-header provides HeaderName resources for each of these to be used as objects for the headerName property. A resource of type HeaderName represents the name of a header used with HTTP.
Introductory paragraph: TBD
The body property represents an HTTP entity body as defined in [RFC 2616]. It can appear in resources of both type Request or Response. The object for this property must be a resource of the type cnt:Content or a subclass thereof. HTTP bodies are series of bytes. Thus it is always possible to point to a cnt:Base64Content resource. If the body is textual content, you can also point to a cnt:TextContent resource. If the body is XML content, you can also point to a cnt:XMLContent resource (see [Content in RDF] for more information on content representations in RDF).
Note: for multiple representations of the same entity body, an RDF container must be used to describe the relationship. For example the rdf:Bag container may be useful if all representations are equivalent, or in other cases rdf:Alt may be useful if there is a prefered representation with alternatives.
Example 2.2.1: Multiple representations of the same entity body.
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:http="http://www.w3.org/2006/http#"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xml:base="http://example.org/message#">
<http:Message rdf:ID="mess0">
<http:body>
<rdf:Alt>
<rdf:li>
<cnt:XMLContent rdf:ID="cont0"/>
<rdf:li>
<rdf:li>
<cnt:TextContent rdf:ID="cont0-alt1"/>
<rdf:li>
<rdf:li>
<cnt:Base64Content rdf:ID="cont0-alt2"/>
<rdf:li>
</rdf:Alt>
</http:body>
</http:Message>
</rdf:RDF>
Connection authority - server host and port for a connection.
Property representing the header element name as a Literal.
Property representing the header element value as a Literal (optional).
Property representing the header name as a Literal.
Property representing the header value as a Literal.
Property representing the HTTP headers sent with the message as a Collection of MessageHeader resources.
Property representing the header value as a Collection of HeaderElement resources (optional).
Property pointing to a HeaderName resource representing the header name (optional, see 3.4. Header Names).
Property representing the HTTP version number as a Literal (the format is 'digit.digit').
Property poining to a Method resource representing the HTTP method (optional, see 3.1 Methods).
Property representing the method name as a Literal.
Property representing the parameter name as a Literal.
Property representing the parameter value as a Literal.
Property representing header element parameters as a Collection of Param resources (optional).
Property representing the reason phrase sent by the server as a Literal.
Property representing the HTTP requests sent via the connection as a Collection of Request resources.
The requestURI property represents the request URI as specified in section 5.1.2 of [RFC 2616]. The value of the property is either the constant value http:asterisk or a Literal value of the absolute URI, the absolute path, or an authority. This vocabulary defines the following sub-properties to reference these values:
absoluteURI- Property to be used when the request URI is an absolute URI.
abs_path- Property to be used when the request URI is an absolute path.
authority- Property to be used when the request URI is an authority.
Example 2.4: The use of the requestURI property and its sub-properties.
<http:Request>
<http:methodName>OPTIONS</http:methodName>
<http:requestURI rdf:resource="http://www.w3.org/2006/http#asterisk"/>
...
</http:Request>
<http:Request>
<http:methodName>GET</http:methodName>
<http:absoluteURI>http://www.example.org:80/foo/bar</http:absoluteURI>
...
</http:Request>
<http:Request>
<http:methodName>GET</http:methodName>
<http:abs_path>/foo/bar</http:abs_path>
...
</http:Request>
<http:Request>
<http:methodName>CONNECT</http:methodName>
<http:authority>www.example.org:80</http:authority>
...
</http:Request>
Property pointing to a Response resource representing the response resulting from this request (see 2.4. Response Class).
Property pointing to a StatusCode resource representing the status code (optional, see 3.2. Status Codes).
Property representing the status code sent by the server as a Literal.
<?xml version="1.0"?>
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:http="http://www.w3.org/2006/http#"
xmlns:owl="http://www.w3.org/2002/07/owl#"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
xml:base="http://www.w3.org/2006/http">
<rdf:Description rdf:about="#">
<rdfs:comment xml:lang="en">A namespace for describing HTTP messages (http://www.w3.org/Protocols/rfc2616/rfc2616.html)</rdfs:comment>
</rdf:Description>
<owl:Ontology rdf:about="">
<owl:imports rdf:resource="http://purl.org/dc/dcam/"/>
<owl:imports rdf:resource="http://purl.org/dc/elements/1.1/"/>
</owl:Ontology>
<!-- Classes -->
<rdfs:Class rdf:about="#Connection">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:comment xml:lang="en">The connection</rdfs:comment>
<rdfs:label xml:lang="en">Connection</rdfs:label>
</rdfs:Class>
<rdfs:Class rdf:about="#HeaderElement">
<rdfs:comment xml:lang="en">The header element</rdfs:comment>
<rdfs:label xml:lang="en">Header element</rdfs:label>
</rdfs:Class>
<rdfs:Class rdf:about="#HeaderName">
<rdfs:comment xml:lang="en">The header name</rdfs:comment>
<rdfs:label xml:lang="en">Header name</rdfs:label>
</rdfs:Class>
<rdfs:Class rdf:about="#Message">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:comment xml:lang="en">The HTTP message</rdfs:comment>
<rdfs:label xml:lang="en">Message</rdfs:label>
</rdfs:Class>
<rdfs:Class rdf:about="#MessageHeader">
<rdfs:comment xml:lang="en">The message header</rdfs:comment>
<rdfs:label xml:lang="en">Message header</rdfs:label>
</rdfs:Class>
<rdfs:Class rdf:about="#Method">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:comment xml:lang="en">The HTTP method</rdfs:comment>
<rdfs:label xml:lang="en">Method</rdfs:label>
</rdfs:Class>
<rdfs:Class rdf:about="#Param">
<rdfs:comment xml:lang="en">The field value parameter</rdfs:comment>
<rdfs:label xml:lang="en">Parameter</rdfs:label>
</rdfs:Class>
<rdfs:Class rdf:about="#Request">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:subClassOf rdf:resource="#Message"/>
<rdfs:comment xml:lang="en">The request</rdfs:comment>
<rdfs:label xml:lang="en">Request</rdfs:label>
</rdfs:Class>
<rdfs:Class rdf:about="#Response">
<rdfs:subClassOf rdf:resource="#Message"/>
<rdfs:comment xml:lang="en">The response</rdfs:comment>
<rdfs:label xml:lang="en">Response</rdfs:label>
</rdfs:Class>
<rdfs:Class rdf:about="#StatusCode">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:comment xml:lang="en">The status code</rdfs:comment>
<rdfs:label xml:lang="en">Status code</rdfs:label>
</rdfs:Class>
<rdfs:Class rdf:about="#StatusCodeGroup">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:comment xml:lang="en">The tatus code group</rdfs:comment>
<rdfs:label xml:lang="en">Status code group</rdfs:label>
</rdfs:Class>
<!-- Properties -->
<rdf:Property rdf:about="#absoluteURI">
<rdfs:subPropertyOf rdf:resource="#requestURI"/>
<rdfs:comment xml:lang="en">The absolute request URI</rdfs:comment>
<rdfs:label xml:lang="en">Absolute URI</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#abs_path">
<rdfs:subPropertyOf rdf:resource="#requestURI"/>
<rdfs:comment xml:lang="en">The absolute path sort of request URI</rdfs:comment>
<rdfs:label xml:lang="en">Absolute path</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#authority">
<rdfs:subPropertyOf rdf:resource="#requestURI"/>
<rdfs:comment xml:lang="en">The authority sort of request URI</rdfs:comment>
<rdfs:label xml:lang="en">Authority</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#body">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:domain rdf:resource="#Message"/>
<rdfs:comment xml:lang="en">The message body; cnt:Content or rdf:Alt/rdf:Bag of cnt:Content</rdfs:comment>
<rdfs:label xml:lang="en">Body</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#connectionAuthority">
<rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/>
<rdfs:domain rdf:resource="#Connection"/>
<rdfs:comment xml:lang="en">The connection authority</rdfs:comment>
<rdfs:label xml:lang="en">Connection authority</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#elementName">
<rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/>
<rdfs:domain rdf:resource="#HeaderElement"/>
<rdfs:comment xml:lang="en">The header element name</rdfs:comment>
<rdfs:label xml:lang="en">Element name</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#elementValue">
<rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/>
<rdfs:domain rdf:resource="#HeaderElement"/>
<rdfs:comment xml:lang="en">The header element value</rdfs:comment>
<rdfs:label xml:lang="en">Element value</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#fieldName">
<rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/>
<rdfs:domain rdf:resource="#MessageHeader"/>
<rdfs:comment xml:lang="en">The field name; literal header name</rdfs:comment>
<rdfs:label xml:lang="en">Field name</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#fieldValue">
<rdfs:domain rdf:resource="#MessageHeader"/>
<rdfs:comment xml:lang="en">The field value; rdfs:Literal or http:HeaderElement</rdfs:comment>
<rdfs:label xml:lang="en">Field value</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#headerElements">
<rdfs:domain rdf:resource="#MessageHeader"/>
<rdfs:comment xml:lang="en">The header elements; (RDF collection of) http:HeaderElement</rdfs:comment>
<rdfs:label xml:lang="en">Header elements</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#headerName">
<rdfs:range rdf:resource="#HeaderName"/>
<rdfs:domain rdf:resource="#MessageHeader"/>
<rdfs:comment xml:lang="en">The header name; interpreted field name</rdfs:comment>
<rdfs:label xml:lang="en">Header name</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#headers">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:domain rdf:resource="#Message"/>
<rdfs:comment xml:lang="en">The headers; (RDF collection of) http:MessageHeader</rdfs:comment>
<rdfs:label xml:lang="en">Headers</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#httpVersion">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/>
<rdfs:domain rdf:resource="#Message"/>
<rdfs:comment xml:lang="en">The HTTP version</rdfs:comment>
<rdfs:label xml:lang="en">HTTP version</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#method">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:range rdf:resource="#Method"/>
<rdfs:domain rdf:resource="#Request"/>
<rdfs:comment xml:lang="en">The HTTP method</rdfs:comment>
<rdfs:label xml:lang="en">Method</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#methodName">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/>
<rdfs:domain rdf:resource="#Request"/>
<rdfs:comment xml:lang="en">The HTTP method name</rdfs:comment>
<rdfs:label xml:lang="en">Method name</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#paramName">
<rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/>
<rdfs:domain rdf:resource="#Param"/>
<rdfs:comment xml:lang="en">The header parameter name</rdfs:comment>
<rdfs:label xml:lang="en">Header parameter name</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#paramValue">
<rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/>
<rdfs:domain rdf:resource="#Param"/>
<rdfs:comment xml:lang="en">The header parameter value</rdfs:comment>
<rdfs:label xml:lang="en">Header parameter value</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#params">
<rdfs:domain rdf:resource="#HeaderElement"/>
<rdfs:comment xml:lang="en">The header parameters; (RDF collection of) http:Param</rdfs:comment>
<rdfs:label xml:lang="en">Header parameters</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#reasonPhrase">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/>
<rdfs:domain rdf:resource="#Response"/>
<rdfs:comment xml:lang="en">The reason phrase (status text)</rdfs:comment>
<rdfs:label xml:lang="en">Reason phrase</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#requests">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:domain rdf:resource="#Connection"/>
<rdfs:comment xml:lang="en">The HTTP requests; (RDF collection of) http:Request</rdfs:comment>
<rdfs:label xml:lang="en">Requests</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#requestURI">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:domain rdf:resource="#Request"/>
<rdfs:comment xml:lang="en">The request URI; rdfs:Literal or http://www.w3.org/2006/http#asterisk</rdfs:comment>
<rdfs:label xml:lang="en">Request URI</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#response">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:range rdf:resource="#Response"/>
<rdfs:domain rdf:resource="#Request"/>
<rdfs:comment xml:lang="en">The HTTP response</rdfs:comment>
<rdfs:label xml:lang="en">Response</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#statusCode">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:range rdf:resource="#StatusCode"/>
<rdfs:domain rdf:resource="#Response"/>
<rdfs:comment xml:lang="en">The HTTP status code</rdfs:comment>
<rdfs:label xml:lang="en">Status code</rdfs:label>
</rdf:Property>
<rdf:Property rdf:about="#statusCodeNumber">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/>
<rdfs:domain rdf:resource="#Response"/>
<rdfs:comment xml:lang="en">The HTTP status code number; rdfs:Literal (typed: 3digit)</rdfs:comment>
<rdfs:label xml:lang="en">Status code</rdfs:label>
</rdf:Property>
<rdf:Description rdf:about="#asterisk">
<rdfs:isDefinedBy rdf:resource="http://www.rfc-editor.org/rfc/rfc2616.txt"/>
<dc:description xml:lang="en">The asterisk as a request URI</dc:description>
<dc:title xml:lang="en">Asterisk</dc:title>
</rdf:Description>
</rdf:RDF>
The following example shows an RDF/XML representation of an HTTP request and response pair.
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.
<?xml version="1.0" encoding="utf-8"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:http="http://www.w3.org/2006/http#"
xmlns:cnt="http://www.w3.org/2008/content#">
<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:method rdf:resource="http://www.w3.org/2008/http-methods#GET"/>@@@TBD@@@
<http:abs_path>/</http:abs_path>
<http:headers rdf:parseType="Collection">
<http:MessageHeader>
<http:fieldName>Host</http:fieldName>
<http:headerName rdf:resource="http://www.w3.org/2008/http-header#host"/>@@@TBD@@@
<http:fieldValue>www.example.org</http:fieldValue>
</http:MessageHeader>
<http:MessageHeader>
<http:fieldName>User-Agent</http:fieldName>
<http:headerName rdf:resource="http://www.w3.org/2008/http-header#user-agent"/>@@@TBD@@@
<http:fieldValue>My User Agent</http:fieldValue>
</http:MessageHeader>
<http:MessageHeader>
<http:fieldName>Accept</http:fieldName>
<http:headerName rdf:resource="http://www.w3.org/2008/http-header#accept"/>@@@TBD@@@
<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:Param>
<http:paramName>q</http:paramName>
<http:paramValue>0.8</http:paramValue>
</http:Param>
</http:params>
</http:HeaderElement>
</http:headerElements>
</http:MessageHeader>
</http:headers>
<http:response rdf:resource="#resp0"/>
</http:Request>
<http:Request rdf:about="#req1">
<http:httpVersion>1.1</http:httpVersion>
<http:methodName>GET</http:methodName>
<http:method rdf:resource="http://www.w3.org/2008/http-methods#GET"/>@@@TBD@@@
<http:abs_path>/image</http:abs_path>
<http:headers rdf:parseType="Collection">
<http:MessageHeader>
<http:fieldName>Host</http:fieldName>
<http:headerName rdf:resource="http://www.w3.org/2008/http-header#host"/>@@@TBD@@@
<http:fieldValue>www.example.org</http:fieldValue>
</http:MessageHeader>
<http:MessageHeader>
<http:fieldName>User-Agent</http:fieldName>
<http:headerName rdf:resource="http://www.w3.org/2008/http-header#user-agent"/>@@@TBD@@@
<http:fieldValue>My User Agent</http:fieldValue>
</http:MessageHeader>
<http:MessageHeader>
<http:fieldName>Accept</http:fieldName>
<http:headerName rdf:resource="http://www.w3.org/2008/http-header#accept"/>@@@TBD@@@
<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:Param>
<http:paramName>q</http:paramName>
<http:paramValue>0.8</http:paramValue>
</http:Param>
</http:params>
</http:HeaderElement>
</http:headerElements>
</http:MessageHeader>
</http:headers>
<http:response rdf:resource="#resp1"/>
</http:Request>
<http:Response rdf:ID="resp0">
<http:httpVersion>1.1</http:httpVersion>
<http:statusCodeNumber>200</http:statusCodeNumber>
<http:statusCode rdf:resource="http://www.w3.org/2008/http-statusCodes#200"/>@@@TBD@@@
<http:reasonPhrase>OK</http:reasonPhrase>
<http:headers rdf:parseType="Collection">
<http:MessageHeader>
<http:fieldName>Date</http:fieldName>
<http:headerName rdf:resource="http://www.w3.org/2008/http-header#date"/>@@@TBD@@@
<http:fieldValue>.......</http:fieldValue>
</http:MessageHeader>
<http:MessageHeader>
<http:fieldName>Content-Type</http:fieldName>
<http:headerName rdf:resource="http://www.w3.org/2008/http-header#content-type"/>@@@TBD@@@
<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:Param>
<http:paramName>charset</http:paramName>
<http:paramValue>utf-8</http:paramValue>
</http:Param>
</http:params>
</http:HeaderElement>
</http:headerElements>
</http:MessageHeader>
</http:headers>
<http:body>
<cnt:XMLContent>
<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="http://www.w3.org/2001/XMLSchema#anyURI">http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd</cnt:systemId>
</cnt:DocTypeDecl>
</cnt:docTypeDecl>
<cnt:xmlRest rdf:parseType="Literal"><html xmlns="http://www.w3.org/1999/xhtml" lang="en">
<head>
<title>My document</title>
</head>
<body>
<p><!-- ...... --></p>
</body>
</html></cnt:xmlRest>
</cnt:XMLContent>
</http:body>
</http:Response>
<http:Response rdf:ID="resp1">
<http:httpVersion>1.1</http:httpVersion>
<http:statusCodeNumber>200</http:statusCodeNumber>
<http:statusCode rdf:resource="http://www.w3.org/2008/http-statusCodes#200"/>@@@TBD@@@
<http:reasonPhrase>OK</http:reasonPhrase>
<http:headers rdf:parseType="Collection">
<http:MessageHeader>
<http:fieldName>Date</http:fieldName>
<http:headerName rdf:resource="http://www.w3.org/2008/http-header#date"/>@@@TBD@@@
<http:fieldValue>.......</http:fieldValue>
</http:MessageHeader>
<http:MessageHeader>
<http:fieldName>Content-Type</http:fieldName>
<http:headerName rdf:resource="http://www.w3.org/2008/http-header#content-type"/>@@@TBD@@@
<http:fieldValue>image/png</http:fieldValue>
</http:MessageHeader>
<http:MessageHeader>
<http:fieldName>Vary</http:fieldName>
<http:headerName rdf:resource="http://www.w3.org/2008/http-header#vary"/>@@@TBD@@@
<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:Base64Content>
<cnt:bytes rdf:datatype="http://www.w3.org/2001/XMLSchema#base64Binary">qouh3908t38hohfrf..........</cnt:bytes>
</cnt:Base64Content>
</http:body>
</http:Response>
</rdf:RDF>
- [Content in RDF]
- Representing Content in RDF - Johannes Koch, Carlos A Velasco (eds.). 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 Message Header Field Names - IANA.
- Provisional Message Header Field Names - IANA.
- [POWDER-DR]
- Protocol for Web Description Resources (POWDER): Description Resources - K. Smith, P. Archer, A. Perego (eds.). W3C Working Draft 17 March 2008.
- [POWDER-GR]
- Protocol for Web Description Resources (POWDER): Grouping of Resources - P. Archer, A. Perego, K. Smith (eds.). W3C Working Draft 24 March 2008.
- [RDF]
- Resource Description Framework (RDF) Overview - W3C
- [RFC2119]
- Request for Comments: 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.
Besides several editorial changes, the following is a list of substantial changes since the 23 March, 2007 Working Draft:
- split three RDF models for request methods, header names and status codes from the HTTP model to be updated separately from external registries
- changed the http:request property to http:requests
- introduced the http:Message class to be a base for the http:Request and http:Response class
- changed the http:version property to http:httpVersion
- added the dc:date property to the http:Message class
- introduced the http:methodName (with object literal), http:method (with object resource from external RDF model for header names) properties and the http:Method class instead of different http:Request sub-classes
- changed the multiple use of the http:header property to http:headers with an RDF collection
- changed the http:responseCode property to http:statusCode (with object literal from external RDF model for status codes), and introduced the literal http:statusCodeNumber and http:reasonPhrase properties
- changed the http:fieldName property to have a object literal
- introduced the http:headerName property having an object resource (from the external RDF model for header names)