server.js

#!/usr/bin/env node

var fs = require('fs'),
    parse = require('url').parse,
    http = require('http'),
    createServer = http.createServer,
    STATUS_CODES = http.STATUS_CODES,
    printlet = require('../lib/printlet'),

    args = process.argv.slice(2),
    port = parseInt(args[0] || 41462),
    tileJson = require(
      (args[1] != null) ? process.cwd()+'/'+args[1] : './osm.json'
    ),

    render = printlet(tileJson),
    server;

server = createServer(function(req, res) {
  try {
    var url = parse(req.url, true),
        pathname = url.pathname,
        query = url.query,
        params = pathname.substr(1).split('/'),
        zoom = parseInt(params[0]),
        lng = parseFloat(params[1]),
        lat = parseFloat(params[2]),
        dimensions = params[3].split('x'),
        end = dimensions[1].split('.'),
        width = parseInt(dimensions[0]),
        height = parseInt(end[0]),
        format = end[1],
        opt = {
          width: width,
          height: height,
          zoom: zoom,
          lat: lat,
          lng: lng,
          format: format
        };
    if ((tileJson.maxzoom != null && zoom > tileJson.maxzoom) ||
        (tileJson.minzoom != null && zoom < tileJson.minzoom)) {
      res.writeHead(400);
      res.end(STATUS_CODES[400] + ": Supplied zoom level is out of bounds.");
      return;
    }
    if (query.geojson != null) {
      opt.geojson = JSON.parse(query.geojson);
    }
    render(opt, function(err, data) {
      if (err != null) {
        res.writeHead(500);
        res.end(STATUS_CODES[500] + ": " + err);
      } else {
        res.writeHead(200, {
          'Content-Type': 'image/'+format
        });
        data.stream.pipe(res);
      }
    });
  } catch (err) {
    res.writeHead(500);
    res.end(STATUS_CODES[500] + ": " + err);
  }
});

server.listen(port);