TypeError: Cannot read property 'getTile' of undefined

[jvaldezch]

Hi, I'm trying to pass the layer name dynamically but when trying to run I'm getting an error "TypeError: Cannot read property 'getTile' of undefined".

const express = require('express');
const fs = require('fs');

const app = express();

app.get('/', function (req, res, next) {
    res.send('Hello World!');
});

app.get('/tileserver/:layer/:z/:x/:y/tile.png', function (req, res, next) {
    const layer = req.params.layer;
    const x = req.params.x;
    const y = req.params.y;
    const z = req.params.z;
    
    const mapfile = __dirname + '/maps/' + layer + '.xml';
    const dircache = '../cache/' + layer;
    
    fs.exists(mapfile, function(exists) {
        if (exists) {

            var tilestrata = require('tilestrata');
            var disk = require('tilestrata-disk');
            var sharp = require('tilestrata-sharp');
            var mapnik = require('tilestrata-mapnik');
            var dependency = require('tilestrata-dependency');

            var strata = tilestrata();

            strata.layer('basemap')
                .route('tile@2x.png')
                    .use(disk.cache({dir: dircache}))
                    .use(mapnik({
                        pathname: mapfile,
                        tileSize: 512,
                        layer: 'all',
                        scale: 2
                    }))
                .route('tile.png')
                    .use(disk.cache({dir: dircache}))
                    .use(dependency('basemap', 'tile@2x.png'))
                    .use(sharp(function(image, sharp) {
                        return image.resize(256);
                    }));
            strata.listen();

            strata.getTile('basemap', 'tile.png', x, y, z, function(err, img, hdr) {
                if (err) {
                    console.log(err);
                    res.statusCode = 401;
                    res.send('None shall pass');
                } else {
                    res.writeHead(200, {
                        'Content-Type': 'image/png',
                        'Content-Length': img.length
                    });
                    res.end(img); 
                }
            });

        } else {
            res.statusCode = 401;
            res.send("Mapfile dont exists");
        }
    });
    
});

app.use(function(req, res, next) {
    res.header("Access-Control-Allow-Origin", "*");
    res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
    next();
});

app.listen(3000);

[brianreavis]

Do you have a stacktrace you can post?

[jvaldezch]

@brandonreavis

/home/jvaldez/Repositories/tile_server/node_modules/tilestrata-mapnik/index.js:50
		source.getTile(req.z, req.x, req.y, function(err, buffer, headers) {
		       ^

TypeError: Cannot read property 'getTile' of undefined
    at Object.serveImage [as serve] (/home/jvaldez/Repositories/tile_server/node_modules/tilestrata-mapnik/index.js:50:10)
    at step_runProvider (/home/jvaldez/Repositories/tile_server/node_modules/tilestrata/lib/TileRequestHandler.js:222:25)
    at /home/jvaldez/Repositories/tile_server/node_modules/tilestrata/node_modules/async/lib/async.js:689:13
    at iterate (/home/jvaldez/Repositories/tile_server/node_modules/tilestrata/node_modules/async/lib/async.js:265:13)
    at /home/jvaldez/Repositories/tile_server/node_modules/tilestrata/node_modules/async/lib/async.js:277:29
    at /home/jvaldez/Repositories/tile_server/node_modules/tilestrata/node_modules/async/lib/async.js:44:16
    at /home/jvaldez/Repositories/tile_server/node_modules/tilestrata/node_modules/async/lib/async.js:694:17
    at /home/jvaldez/Repositories/tile_server/node_modules/tilestrata/node_modules/async/lib/async.js:173:37
    at complete (/home/jvaldez/Repositories/tile_server/node_modules/tilestrata/lib/TileRequestHandler.js:207:6)
    at /home/jvaldez/Repositories/tile_server/node_modules/tilestrata/node_modules/async/lib/async.js:52:16
[nodemon] app crashed - waiting for file changes before starting...

[brianreavis]

Thanks! This is because the source hasn't been initialized yet. I should make getTile() wait for full initialization before attempting to produce the tile... I can work on that.

This said, there a few problems with your approach your here:

• You don't want to listen() for every request coming in. This will cause an error whenever a second request comes in. Furthermore, listen is missing the required port argument.
• You shouldn't create a new tilestrata instance for every request. Especially with mapnik in the picture, this will be extremely inefficient to setup and teardown every request.

If you're wanting to integrate with Express, check out the middleware. It should simplify what it seems you're intending: https://github.com/naturalatlas/tilestrata#integrate-with-expressjs--connect

If you have a lot of layers you don't want to hard-code, I'd recommend setting them up before starting the server. Tilestrata doesn't support adding / removing of layers once listening. You can use tools like node-glob to find the XMLs, setting up a layer for each.

[jvaldezch]

@brandonreavis thanks for the advice I will try both approaches then.

[yh371174229]

@brandonreavis thanks for the advice I will try both approaches then.
Do you solve it ?? I meet this error too.
naturalatlas/tilestrata-mapnik#9