ProvenanceAccessScenarioUsingPAQ

From Provenance WG Wiki

Revision as of 13:05, 18 August 2011

Walk through of how the Provenance Access Scenario is satisfied using the Provenance Access and Query (W3C Editor's Draft 17 August 2011) proposal.

Online HTML Documents D1 and D2 (Resource provider aware of provenance)

• Obtaining the document D
  • HTML documents D1 and D2 are accessed using HTTP GET, and the web servers return provenance and anchor Link: headers. We show examples using both the alternate proposals for anchor as a parameter and as a relation.

Using anchor parameter

GET https://github.com/timrdf/vsr/raw/master/data/source/tim-lebo/london-crime/version/2011-Jul-07/manual/crime.html HTTP/1.1
...

HTTP/1.1 200 OK
...
Link: http://example.com/provenance/d1.prov; rel="provenance"; anchor="https://github.com/timrdf/vsr/raw/master/data/source/tim-lebo/london-crime/version/2011-Jul-07/manual/crime.html"

GET http://lists.w3.org/Archives/Public/public-prov-wg/2011Jul/att-0031/crime.html HTTP/1.1
...

HTTP/1.1 200 OK
...
Link: http://example.com/provenance/d2.prov; rel="provenance"; anchor="http://lists.w3.org/Archives/Public/public-prov-wg/2011Jul/att-0031/crime.html"

Using anchor relation

GET https://github.com/timrdf/vsr/raw/master/data/source/tim-lebo/london-crime/version/2011-Jul-07/manual/crime.html HTTP/1.1
...

HTTP/1.1 200 OK
...
Link: http://example.com/provenance/d1.prov; rel="provenance"; 
Link: https://github.com/timrdf/vsr/raw/master/data/source/tim-lebo/london-crime/version/2011-Jul-07/manual/crime.html; rel="anchor" 

GET http://lists.w3.org/Archives/Public/public-prov-wg/2011Jul/att-0031/crime.html HTTP/1.1
...

HTTP/1.1 200 OK
...
Link: http://example.com/provenance/d2.prov; rel="provenance"; 
Link: http://lists.w3.org/Archives/Public/public-prov-wg/2011Jul/att-0031/crime.html; rel="anchor" 

• Enacting the "Oh yeah?" feature
• A user requests a web browser (W) used to obtain the web documents (D1-2) to enact the "Oh yeah?" feature on the whole documents
  1. The web browser examines the HTTP response headers of the web documents to identify Link: headers and selects those that contain the relations, provenance or anchor.
  2. The browser extracts the provenance-uri information, I_P, from the provenance relation header. In the above example, I_P is http://example.com/provenance/d1.prov for D1 and http://example.com/provenance/d2.prov for D2.
  3. The browser also extracts the context-uri information, I_C, from the headers if the anchor parameter or relation were present. Otherwise, it uses the URL to the documents D1 and D2 that was used to access them as the value of I_C. In the above example, the anchor parameter or relation was present and the value of I_C is https://github.com/timrdf/vsr/raw/master/data/source/tim-lebo/london-crime/version/2011-Jul-07/manual/crime.html and http://lists.w3.org/Archives/Public/public-prov-wg/2011Jul/att-0031/crime.html for D1 and D2 respectively.

• Accessing the provenance
• What information (I) does the clients (W) need in order to access and retrieve the provenance for the documents D1-2?
  • The browser uses the default mechanism for dereferencing the provenance-uris I_P for the two documents, which in our example is using a HTTP GET to retrieve the provenance document P.
  • The browser examines the provenance document P to locate the "section" that corresponds to the context-uri I_C that is relevant for the documents D1 and D2.

Online Image Document D3 (Resource provider aware of provenance)

This case is similar to the previous in all respects. The fact that the document D3 is an image and not a HTML document makes no difference. The HTTP GET request and response are shown as example. The means for enacting the "Oh yeah?" button and accessing the provenance are the same as before.

Using anchor parameter

GET https://github.com/timrdf/vsr/raw/11e4a2ab0315ba7808a393e2a0b5f69f952b7235/data/source/tim-lebo/london-crime/version/2011-Jul-07/manual/crime.png HTTP/1.1
...

HTTP/1.1 200 OK
...
Link: http://example.com/provenance/d1.prov; rel="provenance"; anchor="https://github.com/timrdf/vsr/raw/11e4a2ab0315ba7808a393e2a0b5f69f952b7235/data/source/tim-lebo/london-crime/version/2011-Jul-07/manual/crime.png"

Using anchor relation

GET https://github.com/timrdf/vsr/raw/11e4a2ab0315ba7808a393e2a0b5f69f952b7235/data/source/tim-lebo/london-crime/version/2011-Jul-07/manual/crime.png HTTP/1.1
...

HTTP/1.1 200 OK
...
Link: http://example.com/provenance/d1.prov; rel="provenance"; 
Link: https://github.com/timrdf/vsr/raw/11e4a2ab0315ba7808a393e2a0b5f69f952b7235/data/source/tim-lebo/london-crime/version/2011-Jul-07/manual/crime.png; rel="anchor" 
 

HTML Documents D5 and D7 as Email attachments or in File System

• Obtaining the document D
• HTML document D5 arrived as an attachment to the email http://lists.w3.org/Archives/Public/public-prov-wg/2011Jul/0031.html while HTML document D7 is present in the file system at //acme/downloads/crime.html. The contents of these documents are accessible to the local client. Say the two documents are identical for this example.
• The HTML documents have link elements embedded under in their HTML HEAD section as follows:

 <html>
   <head>
     <link rel="provenance" href="http://example.com/provenance/d5_d7.prov">
     <link rel="anchor" href="urn:uuid:2d26db96-7174-4c26-9353-cbbf9b5991d2">
   </head>
   <body>
     <p>There was a lot of crime in London last month.</p>
   </body> 
 </html>
 

• Enacting the "Oh yeah?" feature
• A user requests an email client (E) and a command shell (S) used to obtain the HTML document (D5, D7) to enact the "Oh yeah?" feature on the whole documents
  1. Both clients examine the HTML documents D5 and D7 to identify the link elements present under in the HTML HEAD section.
  2. The clients extracts the provenance-uri information, I_P, from the href attribute of the provenance relation link element. In the above example, the value of I_P is http://example.com/provenance/d5_d7.prov for D5 and D7.
  3. The clients also extract the context-uri information, I_C, from the href attribute of the anchor relation link element. In the above example, the value of I_C is urn:uuid:2d26db96-7174-4c26-9353-cbbf9b5991d2 for D5 and D7.

Online Image Document D4 (Resource provider NOT aware of provenance)

Image Documents D6 and D8 as Email attachments or in File System