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  • VOS.VirtFacetBrowserAPIs(Last) -- DAVWikiAdmin? , 2017-06-13 05:41:50 Edit WebDAV System Administrator 2017-06-13 01:41:50

    Virtuoso APIs for FCT REST services

    What

    A Virtuoso Stored Procedure that enables faceted browsing over Linked Data hosted in the RDF Quad Store. This also includes Linked Data that is progressively added to the Quad Store via URI de-referencing.

    Why

    Enables the use Virtuoso's VSP/VSPX technology to produce (X)HTML-based Linked Data explorer pages that are endowed with high-performance (in-process) faceted browsing capability.

    How

    You can use this API with Virtuoso SQL calls that provide data to your VSP/VSPX, ASP.NET, PHP, etc., -based interfaces using ODBC, JDBC, ADO.NET, or XMLA connectivity (SPASQL) to Virtuoso.

    Examples:

    API Definition


    CREATE PROCEDURE
    fct_exec 
      ( 
        IN  tree     ANY , 
        IN  timeout  INT
      )
    {
      DECLARE  start_time, 
               view3, 
               inx, 
               n_rows      INT     ;
      DECLARE  sqls, 
               msg, 
               qr,
               qr2,
               act,
               query       VARCHAR ;
      DECLARE  md, 
               res, 
               results, 
               more        ANY     ;
      DECLARE  tmp         ANY     ;
      DECLARE  offs, 
               lim         INT     ;
    
      SET result_timeout = _min 
                             ( 
                               timeout, 
                               ATOI 
                                 (
                                   registry_get ('fct_timeout_max')
                                 )
                             )
      ;
    
      offs := xpath_eval ('//query/view/@offset', tree);
      lim := xpath_eval ('//query/view/@limit', tree);
    
      -- db_activity ();
    
      results := vector (null, null, null);
      more := vector ();
    
      IF 
        ( 
          xpath_eval 
            (
              '//query[@view3="yes"]//view[@type="text"]', 
              tree
            ) 
          IS NOT NULL
        )
        {
          more := VECTOR ('classes', 'properties');
        }
    
      sqls := '00000';
      qr := fct_query 
              (
                xpath_eval ('//query', tree, 1)
              )
      ;
      query := qr;
    --  dbg_obj_print (qr);
      qr2 := fct_xml_wrap (tree, qr);
      start_time := msec_time ();
    
      dbg_printf('query: %s', qr2);
    
      EXEC 
        (
          qr2, 
          sqls, 
          msg,
          vector (),
          0,
          md,
          res
        )
      ;
      n_rows := row_count ();
      act := db_activity ();
      SET result_timeout = 0;
      IF (
           sqls <> '00000'
           AND
           sqls <> 'S1TAT'
         )
        SIGNAL (sqls, msg);
      IF (
           NOT ISARRAY (res) 
           OR 
           0 = length (res) 
           OR 
           NOT ISARRAY (res[0]) 
           OR 
           0 = length (res[0])
         )
        results[0] := xtree_doc ('<result/>');
      ELSE
        results[0] := res[0][0];
    
      inx := 1;
    
      FOREACH (VARCHAR tp IN more) DO
        {
          tree := XMLUpdate (
                              tree, 
                              '/query/view/@type', 
                              tp,
                              '/query/view/@limit',
                              '40',
                              '/query/view/@offset',
                              '0'
                            )
          ;
          qr := fct_query (xpath_eval ('//query', tree, 1));
          qr2 := fct_xml_wrap (tree, qr);
          sqls := '00000';
          SET result_timeout = _min (
                                      timeout, 
                                      ATOI 
                                        ( 
                                          registry_get ('fct_timeout_max')
                                        )
                                    )
          ;
          EXEC ( 
                 qr2, 
                 sqls, 
                 msg,
                 vector (), 
                 0,
                 md,
                 res
               );
          n_rows := row_count ();
          act := db_activity ();
          SET result_timeout = 0;
          IF ( sqls <> '00000' 
               AND 
               sqls <> 'S1TAT'
             )
        SIGNAL (sqls, msg);
          IF ( 
               ISARRAY (res) 
               AND 
               LENGTH (res) 
               AND 
               ISARRAY (res[0]) 
               AND
               LENGTH (res[0])
             )
        {
          tmp := res[0][0];
          tmp := XMLUpdate (tmp, '/result/@type', tp);
          results[inx] := tmp;
        }
          inx := inx + 1;
        }
    
    
    
      res := XMLELEMENT 
               (
                 "facets", 
                 XMLELEMENT 
                   ( "sparql", query ), 
                 XMLELEMENT 
                   ( "time", msec_time () - start_time ),
                 XMLELEMENT 
                   ( 
                     "complete", 
                     CASE WHEN sqls = 'S1TAT' 
                          THEN 'no' 
                          ELSE 'yes' 
                      END
                    ),
                 XMLELEMENT 
                   (
                     "timeout",
                     _min 
                       (
                         timeout * 2, 
                         ATOI 
                           (
                             registry_get 
                               ( 'fct_timeout_max' )
                           )
                       )
                   ),
                 XMLELEMENT 
                   ("db-activity", act),
                 XMLELEMENT
                   ("processed", n_rows), 
                 XMLELEMENT
                   (
                     "view", 
                     XMLATTRIBUTES 
                       ( 
                         offs AS "offset", 
                         lim AS "limit"
                       )
                   ),
                 results[0], 
                 results[1], 
                 results[2]
               );
    
    ---- for debugging:
    --string_to_file ('ret.xml', serialize_to_UTF8_xml (res), -2);
    --  dbg_obj_print (res);
    
      RETURN res;
    }
    ;
    

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