Loading data from PostGIS into CouchDB

loadcouchdata.js

var pg = require('pg'),
    cradle = require('cradle');

var pgConnString = 'tcp://spatial:spatial@localhost/spatial';
var couchServer = 'localhost';
var couchPort = 5984;
var couchDatabase = 'spatial';
var couchConn = new cradle.Connection(couchServer, couchPort);
var couchDb = couchConn.database(couchDatabase);

var now = new Date();
console.log("Start " + now.getHours() + ":" + now.getMinutes() + ":" + now.getSeconds());

// call the main function, telling it the total number of records, the start point and the record block size
loadPostgisRecords(2583598, 0, 1000);

// retrieve blocks of PostGIS records and save them in CouchDB
function loadPostgisRecords(total, lower, number) {

    // make a connection to PostGIS
    pg.connect(pgConnString, function(err, client) {

        var upper = lower + number;
        
        if (upper > total) {
            upper = total + 1;
        }

        // build up the sql to select the range of records from PostGIS
        var sql = 'select gid, objectid, lot, plan, lot_area, acc_code, shire_name, segpar, shape_area, shape_len, ST_AsGeoJSON(geog) as shape ';
        sql += 'from spatialschema.state_1 ';
        sql += 'where gid >= ' + lower.toString() + ' and gid < ' + upper.toString();

        // execute the query
        client.query(sql, function(err, result) {

            var resultsLength = result.rows.length;
            var features = [];

            // loop through the resulting records and build a collection of features
            for (var i = 0; i < resultsLength; i += 1)
            {
                var record = result.rows[i];

                var feature = { "_id": record.gid.toString(),
                                "type": "Feature",
                                "geometry": JSON.parse(record.shape),
                                "properties": { "gid": record.gid,
                                                "objectid": record.objectid,
                                                "lot": record.lot,
                                                "plan": record.plan,
                                                "lot_area": record.lot_area,
                                                "acc_code": record.acc_code,
                                                "shire_name": record.shire_name,
                                                "segpar": record.segpar,
                                                "shape_area": record.shape_area,
                                                "shape_len": record.shape_len
                                }
                };
                features.push(feature);
            }

            client = null;

            // save the collection of features in CouchDB
            couchDb.save(features, function(err, ok) {
                if (err) {
                    console.log(err.message);
                }
                else {
                    features = null;
                    // if there are more records to load, call the main function recursively
                    if (upper < total) {
                        loadPostgisRecords(total, upper, number);
                    } else {
                        now = new Date();
                        console.log("End " + now.getHours() + ":" + now.getMinutes() + ":" + now.getSeconds());
                    }
                }
            });
        });
    });
}