Building a simple nodejs tiles server

[francois-baptiste]

Hi!

I tried but failed to build a simple tile server for pmtiles in nodejs like this one but for mbtiles.
PMTiles lib doesn't seem to like local pmtiles files. I've tried to provide a self-hosted PMTiles file url with as little success, it returns a 500 after a while.
Does anyone have a clue?

var express = require("express"),
    app = express(),
    pmtiles = require('pmtiles'),
    p = require("path");

const asyncHandler = (fun) => (req, res, next) => {
  Promise.resolve(fun(req, res, next))
    .catch(next)
}

// Enable CORS and set correct mime type/content encoding
var header = {
  "Access-Control-Allow-Origin":"*",
  "Access-Control-Allow-Headers":"Origin, X-Requested-With, Content-Type, Accept",
  "Content-Type":"application/x-protobuf",
  "Content-Encoding":"gzip"
};


app.get('/tiles/:source/:z/:x/:y.pbf', asyncHandler(async (req, res) => {
  let source = new pmtiles.PMTiles(p.join(__dirname, req.params.source + '.pmtiles'));
  let arr = await source.getZxy(req.params.z, req.params.x, req.params.y);
  let tileData = Buffer.from(arr.data).toString('base64');
  res.set(header);
  res.send(tileData);
}));

app.listen(3000);

[bdon]

please provide any error messages you get

for NodeJS and local files you probably need to implement a new Source class that uses the nodeJS standard library to read from the filesystem

[francois-baptiste]

For self-hosted way here is the error I got:

PS C:\Users\user> curl http://127.0.0.1:3000/tiles/mypmtiles/8/89/125.pbf
curl : The magic number in GZip header is not correct. Make sure you are passing in a GZip stream.
At line:1 char:1
+ curl http://127.0.0.1:3000/tiles/mypmtiles/8/89/125.pbf
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Invoke-WebRequest], InvalidDataException
    + FullyQualifiedErrorId : System.IO.InvalidDataException,Microsoft.PowerShell.Commands.InvokeWebRequestCommand

Removing the "Content-Encoding":"gzip" header did not solved the problem, as I'm getting an invalid MVT tile...

For the local file mode I will check how this is done in the node-mbtiles lib, thanks!