server.js

/*eslint-env node */

// Simulates a mosaic server.
//
// /             serves mosaic.html
// /js/*         servers static files
// /color/<hex>  generates a tile for the color <hex>
//
var mosaic = require('./js/mosaic.js');
var fs = require('fs');
var http = require('http');
var url = require('url');
var path = require('path');
var util = require('util');

var dir = path.dirname(fs.realpathSync(__filename));
var svgTemplate = [
    '<svg xmlns="http://www.w3.org/2000/svg" version="1.1" xmlns:xlink="http://www.w3.org/1999/xlink" width="%d" height="%d">',
    '<ellipse cx="50%" cy="50%" rx="50%" ry="50%" fill="#%s"></ellipse>',
    '</svg>'
].join('');

http.createServer(function (req, res) {
    var pathname = url.parse(req.url).pathname;
    var m;
    if (pathname === '/') {
        res.writeHead(200, {'Content-Type': 'text/html'});
        fs.createReadStream(dir + '/mosaic.html').pipe(res);
        return;
    }
    if (m = pathname.match(/^\/js\//)) {
        var filename = dir + pathname;
        var stats = fs.existsSync(filename) && fs.statSync(filename);
        if (stats && stats.isFile()) {
            res.writeHead(200, {'Content-Type': 'application/javascript'});
            fs.createReadStream(filename).pipe(res);
            return;
        }
    } else if (m = pathname.match(/^\/color\/([0-9a-fA-F]{6})/)) {
        res.writeHead(200, {
            'Content-Type': 'image/svg+xml',
            'Cache-Control': 'max-age=31536000'
        });
        res.write(util.format(svgTemplate, mosaic.TILE_WIDTH, mosaic.TILE_HEIGHT, m[1]));
        res.end();
        return;
    }
    res.writeHead(404, {'Content-Type': 'text/plain'});
    res.write('404 Not Found\n');
    res.end();
}).listen(8765, 'localhost');

console.log('mosaic server running on port 8765');