148 lines
4.1 KiB
JavaScript
148 lines
4.1 KiB
JavaScript
/**
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* Serve tiles
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*/
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const path = require('path')
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const express = require('express')
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const mapnik = require('mapnik')
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const SphericalMercator = require('@mapbox/sphericalmercator')
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// config file with connection details
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const config = require('./config')
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// db connection pool
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const db = require('./db')
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const TILE_SIZE = 256
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const TILE_BUFFER_SIZE = 64
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const PROJ4_STRING = '+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over';
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// set up convertor (tile tms -> lat-lon envelope)
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const mercator = new SphericalMercator({
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size: TILE_SIZE
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});
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// register datasource adapters for mapnik
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if (mapnik.register_default_input_plugins) mapnik.register_default_input_plugins();
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// set up app
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const app = express()
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// send static files if the match stuff in 'public'
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app.use(express.static('public'))
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// root is index.html
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app.get('/', (req, res) => res.sendFile(path.join(__dirname,'public', 'index.html')))
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// building geometry by lat/lon - TODO join geometry against buildings, move to apiserver
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app.get('/buildings', function(req, res){
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const { lng, lat } = req.query
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db.query(
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`SELECT geometry_id
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FROM geometries
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WHERE
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ST_Intersects(
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ST_Transform(
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ST_SetSRID(ST_MakePoint($1, $2), 4326),
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3857
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),
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geometries.geometry_geom
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)
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`,
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[lng, lat]
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).then(function(data){
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const rows = data.rows
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if (rows.length){
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res.send({geometry_id: rows[0].geometry_id})
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} else {
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res.status(404).send({error:'Not Found'})
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}
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}).catch(function(error){
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console.error('Error:', error)
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res.status(500).send({error:'Database error'})
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})
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})
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// basic geometry tiles - TODO join against buildings and start parameterising with style
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app.get('/tiles/:z/:x/:y.png', function(req, res) {
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const { z, x, y } = req.params
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const { highlight } = req.query
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const geometry_id = parseInt(highlight);
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console.log(z, x, y, highlight)
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const int_z = parseInt(z);
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const int_x = parseInt(x);
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const int_y = parseInt(y);
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if (!int_x || !int_y || !int_z){
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console.error("Missing x or y or z")
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res.status(400).send({error:'Bad parameter'})
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return
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}
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var bbox = mercator.bbox(
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int_x,
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int_y,
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int_z,
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false,
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'900913'
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);
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var map = new mapnik.Map(TILE_SIZE, TILE_SIZE, PROJ4_STRING);
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map.bufferSize = TILE_BUFFER_SIZE;
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var layer = new mapnik.Layer('tile', PROJ4_STRING);
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var postgis = new mapnik.Datasource(get_datasource_config());
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layer.datasource = postgis;
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layer.styles = ['polygon'];
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if (geometry_id){
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var layer_h = new mapnik.Layer('highlight', PROJ4_STRING);
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var conf_h = get_datasource_config()
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conf_h.table = '(select * from geometries where geometry_id = '+geometry_id+') as highlight'
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var postgis_h = new mapnik.Datasource(conf_h);
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layer_h.datasource = postgis_h;
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layer_h.styles = ['highlight'];
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}
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map.load(
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path.join(__dirname, 'map_styles', 'polygon.xml'),
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{ strict: true },
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function(err, map){
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if (err) throw err
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map.add_layer(layer)
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if(geometry_id){
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map.add_layer(layer_h)
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}
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var im = new mapnik.Image(map.width, map.height)
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map.extent = bbox
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map.render(im, function(err, im) {
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if (err) throw err
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res.writeHead(200, {'Content-Type': 'image/png'})
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res.end(im.encodeSync('png'))
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});
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}
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)
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});
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function get_datasource_config(){
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return {
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'table': 'geometries',
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'dbname': config.database.dbname,
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'user': config.database.user,
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'password': config.database.password,
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'port': config.database.port,
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'geometry_field': 'geometry_geom',
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'extent' : '-20005048.4188,-9039211.13765,19907487.2779,17096598.5401',
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'srid': 3857,
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'type': 'postgis'
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}
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}
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app.listen(3000, () => console.log('App listening on port 3000'))
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