slidesToRDF.js

var ndjson = require('ldjson-stream');
var fs = require('fs');

const prefixes = `
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix swV: <http://rdf.slidewiki.org/vocab/> .
@prefix swR: <https://slidewiki.org/slideview/> .
@prefix swTagR: <https://slidewiki.org/tag/> .
@prefix swUserR: <https://slidewiki.org/user/> .
@prefix swDeckR: <https://slidewiki.org/deck/> .
@prefix prv: <http://purl.org/net/provenance/ns#> .
`;
//write prefixes
console.log(prefixes);

fs.createReadStream('data/slides.txt')
  .pipe(ndjson.parse({strict: false}))
  .on('data', function(obj) {
    convertToRDF(obj);
  })
  .on('error', function(obj) {
    console.log('#######Error#########');
  });

//list of selected properties
const selected = [
  '_id',
  'user',
  'timestamp',
  'lastUpdate',
  'license',
  'contributors', //esp
  'revisions' //esp
];
const idField = '_id';

function convertToRDF(obj) {
  //print turtle
  let id = obj[idField];
console.log('#######'+id+'#########');
  console.log(`
swR:${id} a swV:Slide .
  `);
  for(let prop in obj){
    if(selected.indexOf(prop) !== -1){
      //custom properties
      if(prop === 'user'){
        console.log(`swR:${id} prv:createdBy swUserR:${obj[prop]} .`);
        continue;
      }
      if(prop === 'contributors'){
        obj[prop].forEach((item)=>{
          console.log(`swR:${id} swV:hasContibutor swUserR:${item.user} .`);
        });
        continue;
      }
      if(prop === 'revisions'){
        obj[prop].forEach((item)=>{
          let dt = new Date(item.timestamp) ;
          console.log(`
swR:${id} swV:hasRevision swR:${id}-${item.id}  .
swR:${id}-${item.id} a swV:SlideRevision ;
    swV:title """${JSON.stringify(item.title)}""" ;
    swV:timestamp """${item.timestamp}""" ;
    swV:timestampYear "${dt.getFullYear()}" ;
    swV:timestampMonth "${dt.getMonth() + 1}" ;
    swV:timestampDay "${dt.getDate()}" ;
    swV:timestampDate "${dt.toLocaleDateString()}" ;
    swV:content """${encodeURIComponent(item.content)}""" ;
    swV:speakernotes """${item.speakernotes ? encodeURIComponent(item.speakernotes) : '-'}""" ;
    prv:createdBy swUserR:${item.user} .`);

        });
        continue;
      }
      //additional triples
      if(prop === 'timestamp'){
        if(obj[prop]){
          let dt = new Date(obj[prop]) ;
          console.log(`swR:${id} swV:timestampYear "${dt.getFullYear()}" .`);
          console.log(`swR:${id} swV:timestampMonth "${dt.getMonth() + 1}" .`);
          console.log(`swR:${id} swV:timestampDay "${dt.getDate()}" .`);
          console.log(`swR:${id} swV:timestampDate "${dt.toLocaleDateString()}" .`);
        }
      }
      console.log(`swR:${id} swV:${prop} """${obj[prop] ? obj[prop] : '-'}""" .`);
    }
  }
}