CartoDB-SQL-API/lib/models/formats/pg/geojson.js

'use strict';

var _ = require('underscore');

var Pg = require('./../pg');
const errorHandlerFactory = require('../../../services/error-handler-factory');

function GeoJsonFormat () {
    this.buffer = '';
}

GeoJsonFormat.prototype = new Pg('geojson');

GeoJsonFormat.prototype._contentType = 'application/json; charset=utf-8';

GeoJsonFormat.prototype.getQuery = function (sql, options) {
    var gn = options.gn;
    var dp = options.dp;
    return 'SELECT *, ST_AsGeoJSON(' + gn + ',' + dp + ') as the_geom FROM (' + sql + ') as foo';
};

GeoJsonFormat.prototype.startStreaming = function () {
    this.total_rows = 0;
    if (this.opts.beforeSink) {
        this.opts.beforeSink();
    }
    if (this.opts.callback) {
        this.buffer += this.opts.callback + '(';
    }
    this.buffer += '{"type": "FeatureCollection", "features": [';
    this._streamingStarted = true;
};

GeoJsonFormat.prototype.handleQueryRow = function (row) {
    if (!this._streamingStarted) {
        this.startStreaming();
    }

    var geojson = [
        '{',
        '"type":"Feature",',
        '"geometry":' + row[this.opts.gn] + ',',
        '"properties":'
    ];
    delete row[this.opts.gn];
    delete row.the_geom_webmercator;
    geojson.push(JSON.stringify(row));
    geojson.push('}');

    this.buffer += (this.total_rows++ ? ',' : '') + geojson.join('');

    if (this.total_rows % (this.opts.bufferedRows || 1000)) {
        this.opts.sink.write(this.buffer);
        this.buffer = '';
    }
};

GeoJsonFormat.prototype.handleQueryEnd = function (/* result */) {
    if (this.error && !this._streamingStarted) {
        this.callback(this.error);
        return;
    }

    if (this.opts.profiler) {
        this.opts.profiler.done('gotRows');
    }

    if (!this._streamingStarted) {
        this.startStreaming();
    }

    this.buffer += ']'; // end of features

    if (this.error) {
        this.buffer += ',"error":' + JSON.stringify(errorHandlerFactory(this.error).getResponse().error);
    }

    this.buffer += '}'; // end of root object

    if (this.opts.callback) {
        this.buffer += ')';
    }

    this.opts.sink.write(this.buffer);
    this.opts.sink.end();
    this.buffer = '';

    this.callback();
};

function _toGeoJSON (data, gn, callback) {
    try {
        var out = {
            type: 'FeatureCollection',
            features: []
        };

        _.each(data.rows, function (ele) {
            var _geojson = {
                type: 'Feature',
                properties: { },
                geometry: { }
            };
            _geojson.geometry = JSON.parse(ele[gn]);
            delete ele[gn];
            delete ele.the_geom_webmercator; // TODO: use skipfields
            _geojson.properties = ele;
            out.features.push(_geojson);
        });

        // return payload
        callback(null, out);
    } catch (err) {
        callback(err, null);
    }
}

module.exports = GeoJsonFormat;
module.exports.toGeoJSON = _toGeoJSON;