yelp-edges.js

//--------------------------------------------------
// This script creates 'review' edges in OrientDB
//
// Reviews are available from the Yelp dataset as a
// JSON formatted input file with one record per line
//--------------------------------------------------

// declare some variables
var counter = 0;  
var record = 0;

// require dependencies
var LineByLineReader = require('line-by-line');  
var OrientDB = require('./orientdb-backend.js');    // include backend stuff

// create an instance of Class
var orient = new OrientDB;

// create a line-by-line object. process.argv[2] contains the input filename
var lr = new LineByLineReader(process.argv[2], {encoding: 'utf8',  
                skipEmptyLines: true
            });

// on error
lr.on('error', function (err){  
    console.log('an error occured :' + err);
    process.exit(1);
});

// on eof
lr.on('end', function () {  
    console.log('All lines are read, file is closed now.');
});

// on line
lr.on('line', function (line){  
    // increment counter
    counter += 1;
    record += 1;

    // check that line contains valid JSON
    try {
        var obj = JSON.parse(line);
    } catch (e) {
        console.log('ERROR : not JSON --> '+ line);
        process.exit(1);
    }
    console.log('Read record ' + record + ' --> ' + obj.stars + 'stars');

    // if we read 10 lines, pause emitting new line events
    if (counter == 10) {
        lr.pause();
        counter = 0; // reset counter
    };
    setTimeout(function(){
        lr.resume();
    }, 10);

    // create an edge
    orient.createEdge('business.business_id', 
                obj.business_id, 
                'user.user_id', 
                obj.user_id, 
                obj
    );
});