Node.js — Serve generated PNG from SVG, specifying dimensions in the url/filename. This node.js express server generates 'checkmark.svg.107x94.png' from 'checkmark.svg' with Inkscape CLI

server.js

var fs      = require('fs'),
    exec    = require('child_process').exec,
    express = require('express'),
    app     = express();

app.get('/static/img/*.svg.*.png', function(req, res) {
    var pngFile = 'src' + req.url,
        svgFile = pngFile.substring(0, pngFile.indexOf('.svg') + 4);
    if (!fs.existsSync(svgFile)) {
        return res.render('404', {
            baseUrl: (new Array(req.url.split('/').length)).join('../')
        });
    }
    if (fs.existsSync(pngFile)) {
        return res.sendfile(pngFile);
    }
    var size = pngFile.split('.')[pngFile.split('.').length - 2].split('x'),
        cmd  = '"C:\\Program Files (x86)\\Inkscape\\inkscape.com" -z -e "' + pngFile + '" -w ' + size[0] + ' -h ' + size[1] + ' "' + svgFile + '"';
    exec(cmd, function(err, stdout) {
        if (err) throw err;
        res.sendfile(pngFile);
    });
});