Dataset: Read

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The Dataset: Read Web service is used to get information (title, description, creator, contributor(s), creation date and last modification date) for a dataset belonging to the WSF (Web Services Framework).

Developers communicate with the Dataset: Read Web service using the HTTP GET method. You may request one of the following mime types: (1) text/xml, (2) application/rdf+xml, (3) application/rdf+n3 or (4) application/json. The content returned by the Web service will be serialized using the mime type requested and the data returned will depend on the parameters selected.

Contents

Usage

This Web service is intended to be used by any user that wants to get some information about a dataset registered to a WSF (Web Service Framework) for querying or other purposes.

Web Service Endpoint Information

This section describes all you permissions you need in the WSF (Web Service Framework) to send a query to this Web service endpoint, and it describes how to access it.

To access this Web service endpoint you need the proper CRUD (Create, Read, Update and Delete) permissions on a specific graph (dataset) of the WSF. Without the proper permissions on this graph you won't be able to send any queries to the endpoint.

Needed registered CRUD permission:
  • Create: False
  • Read: True
  • Update: False
  • Delete: False

As shown on the graph URI:

  • http://[...]/wsf/dataset/

Here is the information needed to communicate with this Web service's endpoint. Descriptions of the parameters are included below.

Note: if a parameter has a default value, the requester can omit it and the default value will be used. Also, some baseline Web services may not offer other values than the default.

HTTP Method:
  • GET

Possible "Accept:" HTTP header field value:

URI:

  • http://[...]/ws/dataset/read/ ?uri=param1&meta=param2&registered_ip=param3

URI dynamic parameters description:

Note: All parameters have to be URL-encoded

  • param1. Unique identifier used to refer to this new dataset
    • Optionally, the user can specify "all" for the URI to get the description of all datasets accessible to him.
  • param2. Include meta information, about the dataset, to the resultset. One of:
    • True
    • False (default)
  • param3. Target IP address registered in the WSF

Example of Returned XML Document

This is an example of the XML document returned by this Web service endpoint for a given dataset URI.

This example returns the description of a dataset registered to a WSF.

Query:
  • http://[...]/ws/dataset/read/?uri=http://[...]/wsf/datasets/237/& registered_ip=24.200.138.116

"Accept:" HTTP header field value:

  • text/xml

Result: 

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <!DOCTYPE resultset PUBLIC "-//Structured Dynamics LLC//Dataset Read DTD 0.1//EN" "http://bknetwork.org:8890/ws/dtd/dataset/datasetRead.dtd">
  3. <resultset>
  4.    <prefix entity="wsf" uri="http://purl.org/ontology/wsf#"/>
  5.    <prefix entity="void" uri="http://rdfs.org/ns/void#"/>
  6.    <prefix entity="rdf" uri="http://www.w3.org/1999/02/ 22-rdf-syntax-ns#"/>
  7.    <prefix entity="sioc" uri="http://rdfs.org/sioc/ns#"/>
  8.    <prefix entity="dcterms" uri="http://purl.org/dc/terms/"/>
  9.    <subject type="void:Dataset" uri="http://bknetwork.org/wsf/ datasets/237/">
  10.       <predicate type="dcterms:title">
  11.          <object type="rdfs:Literal">RePEC</object>
  12.       </predicate>
  13.       <predicate type="dcterms:created">
  14.          <object type="rdfs:Literal">2009-05-13</object>
  15.       </predicate>
  16.       <predicate type="dcterms:creator">
  17.          <object type="sioc:User" uri="http://bknetwork.org/drupal/ user/1/"/>
  18.       </predicate>
  19.    </subject>
  20. </resultset>

DTD of the XML Document 

  1. <!ELEMENT resultset (subject)+ (prefix)* >
  2. <!ELEMENT prefix EMPTY>
  3. <!ATTLIST prefix entity CDATA #IMPLIED>
  4. <!ATTLIST prefix uri CDATA #IMPLIED>
  5. <!ELEMENT subject (predicate)*>
  6. <!ATTLIST subject type (void:Dataset) "void:Dataset">
  7. <!ATTLIST subject uri CDATA #IMPLIED>
  8. <!ELEMENT predicate (object)>
  9. <!ATTLIST predicate type (dcterms:title | dcterms:description | dcterms:creator | dcterms:contributor | dcterms:created | dcterms:modified) "dcterms:creator">
  10. <!ELEMENT object EMPTY>
  11. <!ATTLIST object type (sioc:User | rdfs:Literal) "rdfs:Literal">
  12. <!ATTLIST object uri CDATA #IMPLIED>
  13. <!ATTLIST object label CDATA #IMPLIED>
Descriptions of the Types of XML Elements

Here are descriptions of the types of XML elements that might be returned from from this Web service. Please read the XML data structure documentation to understand how the data is structured within these XML documents.

Example of Returned RDF/XML Document

Here is an example of a RDF/XML document returned by this Web service endpoint for a given URI.

Query:
  • http://[...]/ws/dataset/read/?uri=http://[...]/wsf/datasets/237/& registered_ip=24.200.138.116

"Accept:" HTTP header field value:

  • application/rdf+xml

Result: 

  1. <?xml version="1.0"?>
  2. <rdf:RDF xmlns:void="http://rdfs.org/ns/void#" xmlns:dcterms= "http://purl.org/dc/terms/" xmlns:rdfs="http://www.w3.org/2000/ 01/rdf-schema#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf- syntax-ns#">
  3.    <void:Dataset rdf:about="http://bknetwork.org/wsf/datasets/237/">
  4.       <dcterms:title>RePEC</dcterms:title>
  5.       <dcterms:created>2009-05-13</dcterms:created>
  6.       <dcterms:creator rdf:resource="http://bknetwork.org/drupal/ user/1/" />
  7.    </void:Dataset>
  8. </rdf:RDF>

Example of Returned RDF/N3 Document

Here is an example of a RDF/N3 document returned by this Web service endpoint for a given URI.

Query:
  • http://[...]/ws/dataset/read/?uri=http://[...]/wsf/datasets/237/& registered_ip=24.200.138.116

"Accept:" HTTP header field value:

  • application/rdf+n3

Result: 

  1. @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
  2. @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
  3. @prefix void: <http://rdfs.org/ns/void#> .
  4. @prefix dcterms: < [http://purl.org/dc/terms/%3E http://purl.org/dc/terms/>] .
  5. <http://bknetwork.org/wsf/datasets/237/> a void:Dataset ;
  6. dcterms:title """RePEC""" ;
  7. dcterms:created """2009-05-13""" ;
  8. dcterms:creator <http://bknetwork.org/drupal/user/1/> .

HTTP Status Codes

Here are the possible HTTP status (error) codes returned by this Web service endpoint.

On error code and the specific error, a different message description can be issued (meaning a different error has been returned).

  • Code: 200
    • Message: OK
  • Code: 400
    • Message: Bad Request
    • Message description: No URI specified for any dataset
    • Message description: This dataset doesn't exist in this WSF
    • Message description: No requester IP available
    • Message description: No Web service URI available
    • Message description: Target Web service XYZ not registered to this Web Services Framework
    • Message description: No access defined for this requester IP XYZ, dataset (XYZ) and Web service (XYZ)
    • Message description: The target Web service (XYZ) needs create access and the requested user (XYZ) doesn't have this access for that dataset (XYZ)
    • Message description: The target Web> service (XYZ) needs read access and the requested user (XYZ) doesn't have this access for that dataset (XYZ)
    • Message description: The target Web service (XYZ) needs update access and the requested user (XYZ) doesn't have this access for that dataset (XYZ)
    • Message description: The target Web service (XYZ) needs delete access and the requested user (XYZ) doesn't have this access for that dataset (XYZ)
  • Code: 406
    • Message: Not Acceptable
    • Message description: Unacceptable mime type requested
  • Code: 500
    • Message: Internal Error
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