108 lines
2.5 KiB
JavaScript
108 lines
2.5 KiB
JavaScript
var _ = require('underscore'),
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pg = require('./pg');
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function GeoJsonFormat() {
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this.buffer = '';
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}
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GeoJsonFormat.prototype = new pg('geojson');
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GeoJsonFormat.prototype._contentType = "application/json; charset=utf-8";
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GeoJsonFormat.prototype.getQuery = function(sql, options) {
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var gn = options.gn;
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var dp = options.dp;
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return 'SELECT *, ST_AsGeoJSON(' + gn + ',' + dp + ') as the_geom FROM (' + sql + ') as foo';
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};
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GeoJsonFormat.prototype.startStreaming = function() {
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this.total_rows = 0;
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if (this.opts.beforeSink) {
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this.opts.beforeSink();
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}
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if (this.opts.callback) {
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this.buffer += this.opts.callback + '(';
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}
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this.buffer += '{"type": "FeatureCollection", "features": [';
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this._streamingStarted = true;
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};
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GeoJsonFormat.prototype.handleQueryRow = function(row) {
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if ( ! this._streamingStarted ) {
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this.startStreaming();
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}
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var geojson = [
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'{',
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'"type":"Feature",',
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'"geometry":' + row[this.opts.gn] + ',',
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'"properties":'
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];
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delete row[this.opts.gn];
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delete row['the_geom_webmercator'];
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geojson.push(JSON.stringify(row));
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geojson.push('}');
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this.buffer += (this.total_rows++ ? ',' : '') + geojson.join('');
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if (this.total_rows % (this.opts.bufferedRows || 1000)) {
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this.opts.sink.write(this.buffer);
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this.buffer = '';
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}
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};
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GeoJsonFormat.prototype.handleQueryEnd = function(result) {
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if (this.error) {
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this.callback(this.error);
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return;
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}
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if ( this.opts.profiler ) this.opts.profiler.done('gotRows');
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if ( ! this._streamingStarted ) {
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this.startStreaming();
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}
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this.buffer += ']}'; // end of features
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if (this.opts.callback) {
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this.buffer += ')';
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}
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this.opts.sink.write(this.buffer);
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this.opts.sink.end();
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this.buffer = '';
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this.callback();
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};
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function _toGeoJSON(data, gn, callback){
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try {
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var out = {
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type: "FeatureCollection",
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features: []
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};
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_.each(data.rows, function(ele){
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var _geojson = {
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type: "Feature",
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properties: { },
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geometry: { }
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};
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_geojson.geometry = JSON.parse(ele[gn]);
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delete ele[gn];
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delete ele["the_geom_webmercator"]; // TODO: use skipfields
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_geojson.properties = ele;
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out.features.push(_geojson);
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});
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// return payload
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callback(null, out);
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} catch (err) {
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callback(err,null);
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}
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}
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module.exports = GeoJsonFormat;
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module.exports.toGeoJSON = _toGeoJSON;
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