Wikidata Query Service/Categories: number of pages/subcategories and HiddenCategory attributes

Question

using gas:service or mediawiki:categoryTree services of Wikidata API is it possible somehow to include mediawiki:pages, mediawiki:subcategories and mediawiki:HiddenCategory attributes in query results? I see these attributes in dumps, but have no luck trying to access them programmatically (with SPARQL or some other API)...

Answer 1

You just need to add your conditions e.g for pages add:

  ?out  mediawiki:pages ?pages .

Result

   {
      "out" : {
        "type" : "uri",
        "value" : "https://en.wikipedia.org/wiki/Category:Fictional_ducks"
      },
      "depth" : {
        "datatype" : "http://www.w3.org/2001/XMLSchema#int",
        "type" : "literal",
        "value" : "1"
      },
      "pages" : {
        "datatype" : "http://www.w3.org/2001/XMLSchema#integer",
        "type" : "literal",
        "value" : "113"
      }

They warn that you can't access this through the UI, so you need to encode your query and pass it in the URL:https://query.wikidata.org/bigdata/namespace/categories/sparql?query=&format=json

Full query:

PREFIX gas: <http://www.bigdata.com/rdf/gas#>
prefix mediawiki: <https://www.mediawiki.org/ontology#> 

SELECT * WHERE {
SERVICE gas:service {
     gas:program gas:gasClass "com.bigdata.rdf.graph.analytics.BFS" .

     gas:program gas:linkType mediawiki:isInCategory .
     gas:program gas:traversalDirection "Reverse" .
     gas:program gas:in <https://en.wikipedia.org/wiki/Category:Ducks>. # one or more times, specifies the initial frontier.
     gas:program gas:out ?out . # exactly once - will be bound to the visited vertices.
     gas:program gas:out1 ?depth . # exactly once - will be bound to the depth of the visited vertices.
     gas:program gas:maxIterations 8 . # optional limit on breadth first expansion.
  }
  ?out  mediawiki:pages ?pages .
} ORDER BY ASC(?depth)