--- a/paq/working/prov-aq.html Thu Mar 29 14:07:18 2012 -0400
+++ b/paq/working/prov-aq.html Thu Mar 29 14:07:41 2012 -0400
@@ -211,42 +211,44 @@
<dd>refers to provenance represented in some fashion.</dd>
<dt><dfn>Provenance-URI</dfn></dt>
<dd>a URI denoting some <a class="internalDFN">provenance information</a>.</dd>
- <dt><dfn>Entity</dfn></dt>
- <dd>an aspect of a <a class="internalDFN">resource</a>, about which one wishes to present some <a class="internalDFN">provenance information</a>. For example, a weather report for a given date may be an aspect of a resource that is maintained as the current weather report. An entity is itself a <a class="internalDFN">resource</a>. See also [[PROV-DM]], and [[WEBARCH]] <a href="http://www.w3.org/TR/webarch/#representation-reuse">section 2.3.2</a>.</dd>
- <dt><dfn>Entity-URI</dfn></dt>
- <dd>a URI denoting an <a class="internalDFN">entity</a>, which allows that entity to be identified for the purpose of finding and expressing <a class="internalDFN">provenance information</a> (see <a href="#provenance-entities-resources" class="sectionRef"></a> for discussion)</dd>
+ <dt><dfn>Constrained resource</dfn></dt>
+ <dd>an aspect, version or instance of a <a class="internalDFN">resource</a>, about which one may wish to present some <a class="internalDFN">provenance information</a>. For example, a weather report for a given date may be an aspect of a resource that is maintained as the current weather report. An constrained resource is itself a <a class="internalDFN">resource</a>, and may have it's own URI different from that of the original. See also [[PROV-DM]], and [[WEBARCH]] <a href="http://www.w3.org/TR/webarch/#representation-reuse">section 2.3.2</a>.</dd>
+ <dt><dfn>Resource-URI</dfn></dt>
+ <dd>a URI denoting a <a class="internalDFN">resource</a> (including any <a class="internalDFN">constrained resource</a>), which identifies that resource for the purpose of finding and expressing <a class="internalDFN">provenance information</a> (see <a href="#provenance-entities-resources" class="sectionRef"></a> for discussion)</dd>
<dt><dfn>Provenance service</dfn></dt>
- <dd>a service that provides <class="internalDFN">provenance information</a> given a <a class="internalDFN">resource</a> URI or an <a class="internalDFN">entity-URI</a>.</dd>
+ <dd>a service that provides <class="internalDFN">provenance information</a> given a <a class="internalDFN">resource-URI</a>.</dd>
<dt><dfn>Service-URI</dfn></dt>
<dd>the URI of a <a class="internalDFN">provenance service</a>.</dd>
<dt><dfn>Resource</dfn></dt>
- <dd>also referred to as <dfn>web resource</dfn>: a resource as described by the Architecture of the World Wide Web [[WEBARCH]], <a href="http://www.w3.org/TR/webarch/#id-resources">section 2.2</a>. A resource may be associated with multiple <a title="Entity" class="internalDFN">entities</a> (see <a href="#provenance-entities-resources" class="sectionRef"></a> for discussion)</dd>
+ <dd>also referred to as <dfn>web resource</dfn>: a resource as described by the Architecture of the World Wide Web [[WEBARCH]], <a href="http://www.w3.org/TR/webarch/#id-resources">section 2.2</a>. A resource may be associated with multiple instances or views (<a class="internalDFN">constrained resource</a>s) with differing provenance.</dd>
</dl>
</p>
</section>
<section>
- <h2 id="provenance-entities-resources">Provenance, entities and resources</h2>
+ <h2 id="provenance-entities-resources">Provenance and resources</h2>
<p>
- Fundamentally, <a class="internalDFN">provenance information</a> is <em>about</em> <a class="internalDFN">resources</a>. In general, resources may vary over time and context. E.g., a resource describing the weather in London changes from day-to-day, or one listing restaurants near you will vary depending on your location. Provenance information, to be useful, must be persistent and not itself dependent on context. Yet we may still want to make provenance assertions about dynamic or context-dependent web resources (e.g. the weather forecast for London on a particular day may have been derived from a particular set of Meteorological Office data).
+ Fundamentally, <a class="internalDFN">provenance information</a> is <em>about</em> <a class="internalDFN">resource</a>s. In general, resources may vary over time and context. E.g., a resource describing the weather in London changes from day-to-day, or one listing restaurants near you will vary depending on your location. Provenance information, to be useful, must be persistent and not itself dependent on context. Yet we may still want to make provenance assertions about dynamic or context-dependent web resources (e.g. the weather forecast for London on a particular day may have been derived from a particular set of Meteorological Office data).
</p>
<p>
- Provenance descriptions of dynamic and context-dependent resources are possible through the notion of entities. An <a class="internalDFN">entity</a> is simply a resource (in the sense defined by [[WEBARCH]], <a href="http://www.w3.org/TR/webarch/#id-resources">section 2.2</a>) that is a contextualized view or instance of an original resource. For example, a W3C specification typically undergoes several public revisions before it is finalized. A URI that refers to the "current" revision might be thought of as denoting the specification through its lifetime. Separate URIs for each individual revision would then be <a class="internalDFN">entity-URIs</a>, denoting the specification at a particular stage in its development. Using these, we can make provenance assertions that a particular revision was published on a particular date, and was last modified by a particular editor. Entity-URIs may use any URI scheme, and are not required to be dereferencable.
+ Provenance descriptions of dynamic and context-dependent resources are possible through a notion of constrained resources. A <a class="internalDFN">constrained resource</a> is simply a resource (in the sense defined by [[WEBARCH]], <a href="http://www.w3.org/TR/webarch/#id-resources">section 2.2</a>) that is a contextualized view or instance of some other resource. For example, a W3C specification typically undergoes several public revisions before it is finalized. A URI that refers to the "current" revision might be thought of as denoting the specification through its lifetime. Separate URIs for each individual revision would also be <a class="internalDFN">resource-URI</a>s, each denoting the specification at a particular stage in its development. Using these, we can make provenance assertions that a particular revision was published on a particular date, and was last modified by a particular editor. Resource-URIs may use any URI scheme, and are not required to be dereferencable.
</p>
<p>
- Requests for provenance about a resource may return provenance information that uses one or more entity-URIs to refer to versions of that resource. Some given provenance information may use multiple entity-URIs if there are assertions referring to the same underlying resource in different contexts. For example, provenance information describing a W3C document might include information about all revisions of the document using statements that use the different entity-URIs of the various revisions.
+ Requests for provenance about a resource may return provenance information that uses one or more resource-URIs to refer to versions of that resource. Some given provenance information may use multiple resource-URIs if there are assertions referring to the same underlying resource in different contexts. For example, provenance information describing a W3C document might include information about all revisions of the document using statements that use the different resource-URIs of the various revisions.
</p>
<p>
- In summary, a key notion within the concepts outlined above is that <a class="internalDFN">provenance information</a> may be not universally applicable to a <a class="internalDFN">resource</a>, but may be expressed with respect to that resource in a restricted context (e.g. at a particular time). This restricted view is called an <a class="internalDFN">entity</a>, and an <a class="internalDFN">entity-URI</a> is used to refer to it within provenance information.
+ In summary, <a class="internalDFN">provenance information</a> may be not universally applicable to a <a class="internalDFN">resource</a>, but may be expressed with respect to that resource in a restricted context (e.g. at a particular time). This restriction is itself just another resource (e.g. the weather forecast for a give date as opposed to the current weather forecast), with its own URI for referring to it within provenance information.
</p>
</section>
<section>
<h2>Interpreting provenance information</h2>
- <p><a class="internalDFN">Provenance information</a> describes relationships between entities, activities and agents. As such, any given provenance information may contain information about several <a title="Entity" class="internalDFN">entities</a>. Within some provenance information, the entities thus described are identified by their <a class="internalDFN">Entity-URI</a>s.
+ <p>
+ <a class="internalDFN">Provenance information</a> describes relationships between <a class="internalDFN">resource</a>s, including activities and agents. Any given provenance information may contain information about several resources, referring to them using their <a class="internalDFN">resource-URI</a>s.
</p>
- <p>When interpreting provenance information, it is important to be aware that statements about several entities may be present, and to be accordingly selective when using the information provided. (In some exceptional cases, it may be that the provenance information returned does not contain any information relating to a specific associated entity.)
+ <p>
+ Thus, when interpreting provenance information, it is important to be aware that statements about several resources may be present, and to be accordingly selective when using the information provided. (In some exceptional cases, it may be that the provenance information returned does not contain any information relating to a specific associated resource.)
</p>
</section>
@@ -256,19 +258,21 @@
<section>
<h2>Accessing provenance information</h2>
- <p>Web applications may access <a class="internalDFN">provenance information</a> in the same way as any web resource, by dereferencing its URI. Thus, any provenance information may be associated with a <a class="internalDFN">provenance-URI</a>, and may be accessed by dereferencing that URI using web mechanisms.
+ <p>
+ Web applications may access <a class="internalDFN">provenance information</a> in the same way as any web resource, by dereferencing its URI. Thus, any provenance information may be associated with a <a class="internalDFN">provenance-URI</a>, and may be accessed by dereferencing that URI using web mechanisms.
</p>
<p>
How much or how little provenance information is returned in response to a retrieval request is a matter for the provenance provider application.
</p>
<p>
- It may be useful to provide provenance information through a service interface. A REST protocol for provenance retrieval is defined in Section <a href="#provenance-services" class="sectionRef"></a>.
+ It may be useful to provide provenance information through a service interface. A REST protocol for provenance retrieval is defined in Section <a href="#provenance-services" class="sectionRef"></a>.
</p>
- When publishing provenance information, the location of that information either at a URI or within a Service should be discoverable using one or more of the mechanisms described in <a href="#locating-provenance-information" class="sectionRef"></a>.
+ <p>
+ When publishing provenance information, the location of that information either at a URI or within a Service should be discoverable using one or more of the mechanisms described in <a href="#locating-provenance-information" class="sectionRef"></a>.
</p>
-
-
-
+ <p>
+ Some alternative practices for accessing provenance information are discussed in <a href="#best-practice" class="sectionRef"></a>
+ </p>
</section>
<!-- == Sect 3 =================================================================================== -->
@@ -276,16 +280,15 @@
<section>
<h2>Locating provenance information</h2>
<p>
- When <a class="internalDFN">provenance information</a> is a resource that can be accessed using web retrieval, one needs to know a <a class="internalDFN">provenance-URI</a> to dereference. If this is known in advance, there is nothing more to specify. If a provenance-URI is not known then a mechanism to discover one must be based on information that is available to the would-be accessor. Likewise, provenance information may be exposed by a service. In this case, the <a class="internalDFN">service-URI</a> needs to be known.
+ When <a class="internalDFN">provenance information</a> is a resource that can be accessed using web retrieval, one needs to know its <a class="internalDFN">provenance-URI</a> to dereference. If this is known in advance, there is nothing more to specify. If a provenance-URI is not known then a mechanism to discover one must be based on information that is available to the would-be accessor. Likewise, provenance information may be exposed by a service. In this case, the <a class="internalDFN">service-URI</a> needs to be known.
</p>
<p>Provenance information about a resource may be provided by several parties other than the provider of that resource, each using different locations, and each with different concerns. (It is possible that these different parties may provide contradictory provenance information.)
</p>
<p>
- Once provenance information about a resource is retrieved, one also needs to know how to locate the view of that resource within that provenance information. This view is an <a class="internalDFN">entity</a> and is identified by an <a class="internalDFN">entity-URI</a>.
+ Once provenance information about a resource is retrieved, one may also need to know how to locate information about that resource within the provenance information. This may be a <a class="internalDFN">constrained resource</a> identified by a separate <a class="internalDFN">resource-URI</a>.
</p>
<p>
- We start by considering mechanisms for the resource provider to indicate a <a class="internalDFN">provenance-URI</a> or <a class="internalDFN">Service-URI</a>along with a <a class="internalDFN">entity-URI</a>.
-
+ We start by considering mechanisms for the resource provider to indicate a <a class="internalDFN">provenance-URI</a> or <a class="internalDFN">Service-URI</a> along with a <a class="internalDFN">resource-URI</a>.
Three mechanisms are described here:
<ul>
<li>The requester knows the resource URI <em>and</em> the resource is accessible using HTTP</li>
@@ -301,15 +304,15 @@
<section>
<h2>Resource accessed by HTTP</h2>
<p>
- For a document accessible using HTTP, provenance information may be indicated using an HTTP <code>Link</code> header field, as defined by <a href="http://tools.ietf.org/html/rfc5988">Web Linking (RFC 5988)</a> [[LINK-REL]]. The <code>Link</code> header field is included in the HTTP response to a GET or HEAD operation (other HTTP operations are not excluded, but are not considered here).
+ For a resource accessible using HTTP, provenance information may be indicated using an HTTP <code>Link</code> header field, as defined by <a href="http://tools.ietf.org/html/rfc5988">Web Linking (RFC 5988)</a> [[LINK-REL]]. The <code>Link</code> header field is included in the HTTP response to a GET or HEAD operation (other HTTP operations are not excluded, but are not considered here).
</p>
<p>
A <code>provenance</code> link relation type for referencing provenance information is registered according to the template in <a href="#iana-considerations" class="sectionRef"></a>, and may be used as shown:
- <pre class="pattern">Link: <cite>provenance-URI</cite>; rel="provenance"; anchor="<cite>entity-URI</cite>"</pre>
- When used in conjunction with an HTTP success response code (<code>2xx</code>), this HTTP header field indicates that <code><cite>provenance-URI</cite></code> is the URI of some provenance information associated with the requested resource and that the associated entity is identified within the referenced provenance information as <code><cite>entity-URI</cite></code>. (See also <a href="#interpreting-provenance-information" class="sectionRef"></a>.)
+ <pre class="pattern">Link: <cite>provenance-URI</cite>; rel="provenance"; anchor="<cite>resource-URI</cite>"</pre>
+ When used in conjunction with an HTTP success response code (<code>2xx</code>), this HTTP header field indicates that <code><cite>provenance-URI</cite></code> is the URI of some provenance information associated with the requested resource and that the associated resource is identified within the referenced provenance information as <code><cite>resource-URI</cite></code>. (See also <a href="#interpreting-provenance-information" class="sectionRef"></a>.)
</p>
<p>
- If no <code>anchor</code> link is provided then the <code><cite>entity-URI</cite></code> is assumed to be the URI of the resource.
+ If no <code>anchor</code> link is provided then the <code><cite>resource-URI</cite></code> is assumed to be the URI of the resource, used in the corresponding HTTP request.
</p>
<p>
At this time, the meaning of these links returned with other HTTP response codes is not defined: future revisions of this specification may define interpretations for these.
@@ -327,12 +330,12 @@
<section>
<h2>Specifying Provenance Services</h2>
<p>
- The document provider may indicate that provenance information about the document is provided by a <a class="internalDFN">provenance service</a>. This is done through the use of a <code>provenance-service</code> link relation type following the same pattern as above:
+ The resource provider may indicate that provenance information about the document is provided by a <a class="internalDFN">provenance service</a>. This is done through the use of a <code>provenance-service</code> link relation type following the same pattern as above:
</p>
<pre class="pattern">
-Link: <cite>provenance-service-URI</cite>; anchor="<cite>entity-URI</cite>"; rel="provenance-service"</pre>
+Link: <cite>provenance-service-URI</cite>; anchor="<cite>resource-URI</cite>"; rel="provenance-service"</pre>
<p>
- The <code>provenance-service</code> link identifies the <a class="internalDFN">service-URI</a>. Dereferencing this URI yields a service description that provides further information to enable a client to determine a <a class="internalDFN">provenance-URI</a> or retrieve <a class="internalDFN">provenance information</a> for an <a class="internalDFN">entity</a>; see <a href="#provenance-services" class="sectionRef"></a> for more details.
+ The <code>provenance-service</code> link identifies the <a class="internalDFN">service-URI</a>. Dereferencing this URI yields a service description that provides further information to enable a client to determine a <a class="internalDFN">provenance-URI</a> or retrieve <a class="internalDFN">provenance information</a> for a <a class="internalDFN">resource</a>; see <a href="#provenance-services" class="sectionRef"></a> for more details.
</p>
<p>
There may be multiple <code>provenance-service</code> link header fields, and these may appear in an HTTP response together with <code>provenance</code> link header fields (though, in simple cases, we anticipate that <code>provenance</code> and <code>provenance-service</code> link relations will not be used together).
@@ -350,7 +353,7 @@
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<link rel="provenance" href="<cite>provenance-URI</cite>">
- <link rel="anchor" href="<cite>entity-URI</cite>">
+ <link rel="anchor" href="<cite>resource-URI</cite>">
<title>Welcome to example.com</title>
</head>
<body>
@@ -362,18 +365,18 @@
The <code><cite>provenance-URI</cite></code> given by the <code>provenance</code> link element identifies the provenance-URI for the document.
</p>
<p>
- The <code><cite>entity-URI</cite></code> given by the <code>anchor</code> link element specifies an specifies an identifier for the entity that may be used within the provenance information when referring to the document.
+ The <code><cite>resource-URI</cite></code> given by the <code>anchor</code> link element specifies an specifies an identifier for the document that may be used within the provenance information when referring to the document.
</p>
<p>
- An HTML document header MAY include multiple <code>provenance</code> link elements, indicating a number of different provenance resources that are known to the creator of the document, each of which may provide provenance information about the document.
+ An HTML document header MAY include multiple <code>provenance</code> link elements, indicating a number of different provenance sources that are known to the creator of the document, each of which may provide provenance information about the document.
</p>
<!--
<p>
- Likewise, the header MAY include multiple "anchor" link elements indicating that, e.g., different revisions of the document can be identified in the provenance information using the different <code><cite>entity-URIs</cite></code>.
+ Likewise, the header MAY include multiple "anchor" link elements indicating that, e.g., different revisions of the document can be identified in the provenance information using the different <code><cite>resource-URIs</cite></code>.
</p>
-->
<p>
- If no "anchor" link element is provided then the <code><cite>entity-URI</cite></code> is assumed to be the URI of the document. It is RECOMMENDED that this convention be used only when the document is static.
+ If no "anchor" link element is provided then the <code><cite>resource-URI</cite></code> is assumed to be the URI of the document. It is RECOMMENDED that this convention be used only when the document is static and has an easily-determined URI.
</p>
<section>
@@ -385,7 +388,7 @@
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<link rel="provenance-service" href="<cite>service-URI</cite>">
- <link rel="anchor" href="<cite>entity-URI</cite>">
+ <link rel="anchor" href="<cite>resource-URI</cite>">
<title>Welcome to example.com</title>
</head>
<body>
@@ -393,10 +396,10 @@
</body>
</html></pre>
<p>
- The <code>provenance-service</code> link element identifies the <a class="internalDFN">service-URI</a>. Dereferencing this URI yields a service description that provides further information to enable a client to access <a class="internalDFN">provenance information</a> for an <a class="internalDFN">entity</a>; see <a href="#provenance-services" class="sectionRef"></a> for more details.
+ The <code>provenance-service</code> link element identifies the <a class="internalDFN">service-URI</a>. Dereferencing this URI yields a service description that provides further information to enable a client to access <a class="internalDFN">provenance information</a> for a <a class="internalDFN">resource</a>; see <a href="#provenance-services" class="sectionRef"></a> for more details.
</p>
<p>
- There may be multiple <code>provenance-service</code> link elements, and these MAY appear in the same document as <code>provenance</code> link elements (though, in simple cases, we anticipate that <code>provenance</code> and <code>provenance-service</code> link relations would not be used together).
+ There MAY be multiple <code>provenance-service</code> link elements, and these MAY appear in the same document as <code>provenance</code> link elements (though, in simple cases, we anticipate that <code>provenance</code> and <code>provenance-service</code> link relations would not be used together).
</p>
</section>
</section>
@@ -411,7 +414,7 @@
The RDF property <code>prov:hasProvenance</code> is defined as a relation between two resources, where the object of the property is a resource that provides provenance information about the subject resource. Multiple <code>prov:hasProvenance</code> assertions may be made about a subject resource. This property corresponds to a <a href="#registration-template-for-link-relation---provenance">provenance link relation</a> used with an HTTP <code>Link</code> header field, or HTML <code><link></code> element.
</p>
<p>
- Property <code>prov:hasAnchor</code> specifies an <a class="internalDFN">entity-URI</a> used in the provenance information to refer to the containing RDF document.
+ Property <code>prov:hasAnchor</code> specifies an <a class="internalDFN">resource-URI</a> used in the provenance information to refer to the containing RDF document.
This corresponds to use of the <code>anchor</code> parameter in an HTTP provenance <code>Link</code> header field, or an <a href="#registration-template-for-link-relation---anchor">anchor link relation</a> in an HTML <code><link></code> element, which similarly indicate a URI used by the provenance information to refer to the described document.
</p>
<p>
@@ -421,7 +424,7 @@
@prefix prov: <<provns/>>
<> dcterms:title "Welcome to example.com" ;
- prov:anchor <http://example.com/data/resource.rdf> ;
+ prov:hasAnchor <http://example.com/data/resource.rdf> ;
prov:hasProvenance <http://example.com/provenance/resource.rdf> ;
prov:hasProvenanceService <http://example.com/provenance-service/> .
:
@@ -436,7 +439,7 @@
If a resource is represented using a data format other than HTML or RDF, and no URI for the resource is known, provenance discovery becomes trickier to achieve. This specification does not define a specific mechanism for such arbitrary resources, but this section discusses some of the options that might be considered.
</p>
<p>
- For formats which have provision for including metadata within the file (e.g. JPEG images, PDF documents, etc.), use the format-specific metadata to include a <a class="internalDFN">entity-URI</a>, <a class="internalDFN">provenance-URI</a> and/or <a class="internalDFN">service-URI</a>. Format-specific metadata provision might also be used to include <a class="internalDFN">provenance information</a> directly in the resource.
+ For formats which have provision for including metadata within the file (e.g. JPEG images, PDF documents, etc.), use the format-specific metadata to include a <a class="internalDFN">resource-URI</a>, <a class="internalDFN">provenance-URI</a> and/or <a class="internalDFN">service-URI</a>. Format-specific metadata provision might also be used to include <a class="internalDFN">provenance information</a> directly in the resource.
</p>
<p>
Use a generic packaging format that can combine an arbitrary data file with a separate metadata file in a known format, such as RDF. At this time, it is not clear what format that should be, but some possible candidates are:
@@ -450,7 +453,7 @@
Packaging formats along the lines of those used for shipping Java web applications (basically, a ZIP file with a manifest and some imposed structure)
</li>
<li>
- Ongoing work in the research community (e.g. <a href="http://eprints.ecs.soton.ac.uk/21587/">Why Linked Data is Not Enough for Scientists</a>, ePub, etc.) to encapsulate data, code, annotations and metadata into a common exchangeable format.
+ Ongoing work in the research community (e.g. <a href="http://eprints.ecs.soton.ac.uk/21587/">Why Linked Data is Not Enough for Scientists</a>, <a href="http://idpf.org/epub/30/spec/epub30-overview.html">ePub</a>, etc.) to encapsulate data, code, annotations and metadata into a common exchangeable format.
</li>
</ul>
</p>
@@ -467,27 +470,26 @@
</p>
<p>The introduction of this protocol is motivated by the following possible considerations:
<ul>
- <li>the naming authority associated with the <a class="internalDFN">entity-uri</a> is not the same as the service offering provenance information</li>
- <li>multiple services have <a class="internalDFN">provenance information</a> about the same entity</li>
- <li>the service associated with the entity-uri is not accessible for adding additional information when handling retrieval requests</li>
- <li>there is no dereferencable <a class="internalDFN">provenance-uri</a> containing provenance information for a particular entity</li>
+ <li>the naming authority associated with the <a class="internalDFN">resource-URI</a> is not the same as the service offering provenance information</li>
+ <li>multiple services have <a class="internalDFN">provenance information</a> about the same resource</li>
+ <li>the service associated with the resource-URI is not accessible for adding additional information when handling retrieval requests</li>
+ <li>there is no dereferencable <a class="internalDFN">provenance-uri</a> containing provenance information for a particular resource</li>
<li>provenance services may provide additional extensibility points for control over returned provenance information.</li>
</ul>
</p>
<section>
<h2>HTTP GET</h2>
- <p>This protocol combines the <a class="internalDFN">entity-URI</a> with the <a class="internalDFN">service-URI</a> to formulate an HTTP GET request, according to the following convention:
+ <p>This protocol combines the <a class="internalDFN">resource-URI</a> with the <a class="internalDFN">service-URI</a> to formulate an HTTP GET request, according to the following convention:
<pre class="pattern">
GET /provenance/service?<b>provenance-element</b>=http://www.example.com/entity HTTP/1.1
- Host: example.com
- </pre>
+ Host: example.com</pre>
</p>
- <p>The embedded entity-uri (<code>http://www.example.com/entity</code>) identifies the entity for which provenance information is to be returned. Any server that implements this protocol and receives a request URI in this form SHOULD return provenance information for the entity-URI embedded in the query component where that URI is the result of percent-decoding the value associated with the provenance-element key. The embedded URI MUST be an absolute URI and the server MUST respond with a 400 Bad Request if it is not. If the supplied entity-URI includes a fragment identifier, the '#' MUST be %-encoded as <code>%23</code> when constructing the provenance-URI value; similarly, any '&' character in the entity-URI must be %-encoded as <code>%26</code>.
+ <p>The embedded resource-URI (<code>http://www.example.com/entity</code>) identifies the resource for which provenance information is to be returned. Any server that implements this protocol and receives a request URI in this form SHOULD return provenance information for the resource-URI embedded in the query component where that URI is the result of percent-decoding the value associated with the provenance-element key. The embedded URI MUST be an absolute URI and the server MUST respond with a 400 Bad Request if it is not. If the supplied resource-URI includes a fragment identifier, the '#' MUST be %-encoded as <code>%23</code> when constructing the provenance-URI value; similarly, any '&' character in the resource-URI must be %-encoded as <code>%26</code>.
</p>
<p>If the provenance information identified in the request does not exist in the server, a 404 Not Found response code SHOULD be returned.
</p>
- <p>The format of returned provenance information is not defined here, but may be established through content type negotiation using <code>Accept:</code> header fields in the HTTP request. A provenance service SHOULD be capable of returning RDF using the vocabulary defined by [[PROV-O]], in any standard RDF serialization (e.g. RDF/XML), or any other standard serialization of the Provenance Model specification [[PROV-DM]]. Services MUST identity the <code>Content-Type</code> of the information returned.
+ <p>The format of returned provenance information is not defined here, but may be established through content type negotiation using <code>Accept:</code> header fields in the HTTP request. A provenance service SHOULD be capable of returning RDF using the vocabulary defined by [[PROV-O]], in any standard RDF serialization (e.g. RDF/XML), or any other standard serialization of the Provenance Model specification [[PROV-DM]]. Services MUST identify the <code>Content-Type</code> of the information returned.
</p>
</section>
@@ -498,28 +500,24 @@
This specification does not define any specific mechanism for discovering provenance services. Applications may use any appropriate mechanism, including but not limited to: prior configuration, search engines, service registries, etc.
</p>
<p>
- To facilitate service discovery, we recommend that RDF publication of service descriptions uses the provenance service type <code><provns/>ProvenanceService</code>, defined by the <a href="http://dvcs.w3.org/hg/prov/file/0abd4c442b42/ontology/components/ProvenanceService.ttl">provenance ontology</a> [[PROV-O]].
+ To facilitate service discovery, we recommend that RDF publication of service descriptions uses the provenance service type <code><provns/>ProvenanceService</code>, defined by the provenance ontology [[PROV-O]].
The RDF service description example below in <a href="#provenance-service-description" class="sectionRef"></a> shows this use.
</p>
- <p class="TODO">
- @@TODO: Fix up URI used in the "provenance ontology" link above, when finalized. <br/>
- </p>
</section>
<!-- <section class="informative"> -->
<section>
<h2>Provenance service description</h2>
- <p>The provenance service interface as described above violates REST constraints by requiring the client to know about the structure of URIs offered by the service (see [[REST-APIs]], 4th bullet point). The provenance service description mitigates this coupling by providing a mechanism for discovering the URI format to be used, knowing just the service URI.
+ <p>The provenance service interface as described above violates REST constraints by requiring the client to know about the structure of URIs offered by the service (see [[REST-APIs]], 4th bullet point). The provenance service description mitigates this coupling by providing a mechanism for discovering the URI format to be used, starting with just the service URI.
</p>
- <p>Dereferencing a provenance service URI should yield a provenance service description. The provenance service description should be available as RDF (in any of its common serializations, and determined through HTTP content negotiation), and it should contain an RDF statement of the form:
+ <p>Dereferencing a provenance service URI should yield a provenance service description. The provenance service description should be available as RDF (in any of its common serializations, and determined through HTTP content negotiation), and it should contain RDF statements of the form:
</p>
<pre class="pattern">
<<cite>service-URI</cite>> a prov:ProvenanceService ;
- prov:provenance-uri-template "<cite>service-URI</cite>?provenance-element={+entity_uri}" .
- </pre>
- <p>where <cite><code>service-URI</code></cite> is the URI of the provenance service. Note that the object of this RDF statement is a literal text value., not a resource URI.
+ prov:provenanceUriTemplate "<cite>service-URI</cite>?provenance-element={+uri}" .</pre>
+ <p>where <cite><code>service-URI</code></cite> is the URI of the provenance service. Note that the object of the <code>prov:provenanceUriTemplate</code> statement is a literal text value, not a URI.
</p>
- <p>A client may retrieve this service description and extract the associated value for <code>prov:provenance-uri-template</code>. This value is a string containing a URI template [[URI-template]] (level 2). A URI for the desired provenance information is obtained by expanding the URI template with the variable <code>entity_uri</code> set to the entity-URI for which provenance is required. If entity-URI contains '#'or '&' these must be %-escaped as <code>%23</code> or <code>%26</code> respectively before template expansion.
+ <p>A client may retrieve this service description and extract the associated value for <code>prov:provenance-uri-template</code>. This value is a string containing a URI template [[URI-template]] (level 2). A URI for the desired provenance information is obtained by expanding the URI template with the variable <code>uri</code> set to the resource-URI for which provenance is required. If the resource-URI contains '#' or '&' these must be %-escaped as <code>%23</code> or <code>%26</code> respectively before template expansion.
</p>
</section>
@@ -535,14 +533,14 @@
<p>
Simply identifying and retrieving provenance information as a web resource may not always meet the requirements of a particular application or service, e.g.:
<ul>
- <li>the entity for which provenance information is required is not identified by a known URI</li>
- <li>the provenance information for an entity is not directly identified by a known URI</li>
- <li>a requirement to access provenance information for a number of distinct but related entities in a single atomic operation</li>
+ <li>the resource for which provenance information is required is not identified by a known URI</li>
+ <li>the provenance information for an resource is not directly identified by a known URI</li>
+ <li>a requirement to access provenance information for a number of distinct but related resources in a single atomic operation</li>
<li><i>etc.</i></li>
</ul>
</p>
<p>
- A provenance query service provides an alternative way to access provenance information and/or provenance-URIs. An application will need a provenance query service URI, and some relevant information about the entity whose provenance is to be accessed.
+ A provenance query service provides an alternative way to access provenance information and/or provenance-URIs. An application will need a provenance query service URI, and some relevant information about the resource whose provenance is to be accessed.
</p>
<p>
The details of a provenance query service is an implementation choice, but for interoperability between different providers and users we recommend use of SPARQL [[RDF-SPARQL-PROTOCOL]] [[RDF-SPARQL-QUERY]]. The query service URI would then be the URI of a SPARQL endpoint (or, to use the SPARQL specification language, a <a href="http://www.w3.org/TR/rdf-sparql-protocol/#conformant-sparql-protocol-service">SPARQL protocol service</a>). The following subsections provide examples for what are considered to be some plausible common scenarios for using SPARQL, and are not intended to cover all possibilities.
@@ -552,9 +550,9 @@
</p>
<section>
- <h2>Find a provenance-URI given the entity-URI of a resource</h2>
+ <h2>Find a provenance-URI given a resource-URI</h2>
<p>
- If the requester has an <a class="internalDFN">entity-URI</a>, a simple SPARQL query may be used to return the corresponding <a class="internalDFN">provenance-URI</a>. E.g., if the original resource has a entity-URI <code>http://example.org/resource</code>:
+ If the requester has an <a class="internalDFN">resource-URI</a>, a simple SPARQL query may be used to return the corresponding <a class="internalDFN">provenance-URI</a>. E.g., if the original resource has a resource-URI <code>http://example.org/resource</code>:
<pre class="example code">
@prefix prov: <<provns/>>
SELECT ?provenance_uri WHERE
@@ -568,7 +566,7 @@
<section>
<h2>Find Provenance-URI given identifying information about a resource</h2>
<p>
- If the requester has identifying information that is not the URI of the original resource, then they will need to construct a more elaborate query to locate an entity description and obtain its provenance-URI(s). The nature of identifying information that can be used in this way will depend upon the third party service used, further definition of which is out of scope for this specification. For example, a query for a document identified by a DOI, say <code>1234.5678</code>, using the PRISM vocabulary [[PRISM]] recommended by FaBio [[FABIO]], might look like this:
+ If the requester has identifying information that is not the URI of the original resource, then they will need to construct a more elaborate query to locate a resource description and obtain its provenance-URI(s). The nature of identifying information that can be used in this way will depend upon the third party service used, further definition of which is out of scope for this specification. For example, a query for a document identified by a DOI, say <code>1234.5678</code>, using the PRISM vocabulary [[PRISM]] recommended by FaBio [[FABIO]], might look like this:
<pre class="example code">
@prefix prov: <<provns/>>
@prefix prism: <http://prismstandard.org/namespaces/basic/2.0/>
@@ -581,12 +579,12 @@
</section>
<section>
- <h2>Obtain provenance information directly given an entity-URI of a resource</h2>
+ <h2>Obtain provenance information directly given a resource-URI</h2>
<p>
- This scenario retrieves provenance information directly given the URI of a resource or entity, and may be useful where the provenance information has not been assigned a specific URI, or when the calling application is interested only in specific elements of provenance information.
+ This scenario retrieves provenance information directly given the URI of a resource, and may be useful where the provenance information has not been assigned a specific URI, or when the calling application is interested only in specific elements of provenance information.
</p>
<p>
- If the original resource has an entity-URI <code>http://example.org/resource</code>, a SPARQL query for provenance information might look like this:
+ If the original resource has a URI <code>http://example.org/resource</code>, a SPARQL query for provenance information might look like this:
<pre class="example code">
@prefix prov: <<provns/>>
CONSTRUCT
@@ -600,10 +598,10 @@
</pre>
</p>
<p>
- This query essentially extracts all available properties and values available from the query service used that are directly about the specified entity, and returns them as an RDF graph. This may be fine if the service contains <em>only</em> provenance information about the indicated resource, or if the non-provenance information is also of interest. A more complex query using specific provenance vocabulary terms may be needed to selectively retrieve just provenance information when other kinds of information are also available.
+ This query essentially extracts all available properties and values available from the query service used that are directly about the specified resource, and returns them as an RDF graph. This may be fine if the service contains <em>only</em> provenance information about the indicated resource, or if the non-provenance information is also of interest. A more complex query using specific provenance vocabulary terms may be needed to selectively retrieve just provenance information when other kinds of information are also available.
</p>
<p class="TODO">
- @@TODO: specific provenance namespace and property to be determined by the model specification? The above query pattern assumes provenance information is included in direct properties about the entity. When an RDF provenance vocabulary is fully formulated, this may well turn out to not be the case. A better example would be one that retrieves specific provenance information when the vocabulary terms have been defined.
+ @@TODO: specific provenance namespace and property to be determined by the model specification? The above query pattern assumes provenance information is included in direct properties about the resource. When an RDF provenance vocabulary is fully formulated, this may well turn out to not be the case. A better example would be one that retrieves specific provenance information when the vocabulary terms have been defined.
</p>
</section>
@@ -618,17 +616,17 @@
<section>
<h2>Via Web Retrieval</h2>
- <p>Publishers are not required to publish all the provenance information associated with a given entity at a particular <a class="internalDFN">provenance-URI</a>. The amount of provenance information exposed is application dependent. However, it is possible to incrementally retrieve (i.e. walk the provenance graph) by progressively looking up provenance information using HTTP. The pattern is as follows:
+ <p>Publishers are not required to publish all the provenance information associated with a given resource at a particular <a class="internalDFN">provenance-URI</a>. The amount of provenance information exposed is application dependent. However, it is possible to incrementally retrieve (i.e. walk the provenance graph) by progressively looking up provenance information using HTTP. The pattern is as follows:
<ol>
- <li>For a given entity (<code>entity-uri-1</code>) retrieve it's associated <code>provenance-uri-1</code> and its associated <code>entity-uri-1</code> using the HTTP <code>Link</code> header (<a href="#resource-accessed-by-http" class="sectionRef"></a>)</li>
+ <li>For a given resource (<code>resource-uri-1</code>) retrieve it's associated <code>provenance-uri-1</code> and its associated <code>resource-uri-1</code> using a returned HTTP <code>Link:</code> header field (<a href="#resource-accessed-by-http" class="sectionRef"></a>)</li>
<li>Dereference <code>provenance-uri-1</code></li>
<li>Navigate the provenance information</li>
- <li>When reaching a dead-end during navigation, that is on encountering a reference to an entity (<code>entity-uri-2</code>) with no provided provenance information, find its provenance-URI and continue from Step 2. (Note: an HTTP HEAD request for <code>entity-uri-2</code> may be used to obtain the Link headers without retrieving the entity content.)</li>
+ <li>When reaching a dead-end during navigation, that is on encountering a reference to a resource (<code>resource-uri-2</code>) with no provided provenance information, find its provenance-URI and continue from Step 2. (Note: an HTTP HEAD request for <code>resource-uri-2</code> may be used to obtain the <code>Link:</code> headers without retrieving the resource representation.)</li>
</ol>
</p>
- <p>To reduce the overhead of multiple HTTP requests, a provenance information publisher are encouraged to link entities to their associated provenance information using the <code>prov:hasProvenance</code> predicate. Thus, the same pattern above applies, except instead of having to retrieve a new <code>Link</code> header field, one can immediately dereference the entity's associated provenance.
+ <p>To reduce the overhead of multiple HTTP requests, a provenance information publishers are encouraged to link entities to their associated provenance information using the <code>prov:hasProvenance</code> predicate. Thus, the same pattern above applies, except instead of having to retrieve a new <code>Link</code> header field, one can immediately access the resource's associated provenance.
</p>
- <p>The same approach can be adopted when using the <a class="internalDFN">provenance service</a> API (<a href="#provenance-services" class="sectionRef"></a>). However, instead of performing an HTTP HEAD or GET against a resource one queries the provenance service using the given <a class="internalDFN">entity-uri</a>.
+ <p>The same approach can be adopted when using the <a class="internalDFN">provenance service</a> API (<a href="#provenance-services" class="sectionRef"></a>). However, instead of performing an HTTP HEAD or GET against a resource one queries the provenance service using the given <a class="internalDFN">resource-URI</a>.
</p>
</section>
@@ -661,7 +659,7 @@
</dd>
<dt>Description:</dt>
<dd>
- the resource identified by target IRI of the link provides provenance information about the entity identified by the context link
+ the resource identified by target IRI of the link provides provenance information about the resource identified by the context link
</dd>
<dt>Reference:</dt>
<dd>
@@ -680,9 +678,6 @@
</section>
<section>
<h2>Registration template for link relation: "anchor"</h2>
- <p class="pending">
- The name "anchor" has been used for the link relation name, despite the corresponding URI being described as an entity-URI. This terminology has been chosen to align with usage in the description of the HTTP <code>Link</code> header field, per <a href="http://tools.ietf.org/html/rfc5988#section-5.2">RFC 5988</a>.
- </p>
<p>
<dl>
<dt>Relation Name:</dt>
@@ -691,7 +686,7 @@
</dd>
<dt>Description:</dt>
<dd>
- when used in conjunction with a "provenance" link, the resource identified by target IRI of the link is an entity for which provenance information may be provided. This may be used, for example, to isolate relevant information from a referenced document that contains provenance information for several entities.
+ when used in conjunction with a "provenance" link, the resource identified by target IRI of the link is one for which provenance information may be provided. This may be used, for example, to isolate relevant information from a referenced document that contains provenance information for several entities.
</dd>
<dt>Reference:</dt>
<dd>
@@ -786,7 +781,7 @@
<td>ProvenanceService</td><td>Class for a service described by a provenance service description</td><td>...</td>
</tr>
<tr>
- <td>anchor</td><td>Indicates anchor URI for a potentially dynamic resource instance</td><td>...</td>
+ <td>hasAnchor</td><td>Indicates anchor URI for a potentially dynamic resource instance</td><td>...</td>
</tr>
<tr>
<td>hasProvenance</td><td>Relates a resource to its provenance</td><td>...</td>
@@ -794,6 +789,9 @@
<tr>
<td>hasProvenanceService</td><td>Relates a resource to a provenance service</td><td>...</td>
</tr>
+ <tr>
+ <td>provenanceUriTemplate</td><td>Relates a provenance service to a URI template string for constructing provenance-URIs</td><td>...</td>
+ </tr>
</table>
</p>
</section>