firmware semver proof of concept

semver-http.js

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

const app = express();

/**
 * Get list of available files
 */
app.get('/:name', (req, res, next) => {
  const { name } = req.params;

  const folder = path.resolve(__dirname, 'fw', name);

  fs.readdir(folder, (err, files) => {
    if (err) return next(err);
    res.send(files.sort(semver.compare));
  });
});

/**
 * Find and serve best matching version
 */
app.get('/:name/:version', (req, res, next) => {
  const { name, version } = req.params;

  const root = path.resolve(__dirname, 'fw', name);

  fs.readdir(root, (err, files) => {
    if (err) return next(err);
    const satisfy = files
    // sort descending
      .sort((v1, v2) => semver.compare(v2, v1))
      // find first hit
      .find(v => semver.satisfies(v, version));

    if (satisfy === undefined) return next(new Error(`No firmware matches version: ${version}`));

    const options = {
      root: root,
      dotfiles: 'deny',
      headers: {
        'x-timestamp': Date.now(),
        'x-sent': true
      }
    };

    res.sendFile(satisfy, options, err => {
      if (err) {
        next(err);
      } else {
        console.log('Sent:', satisfy);
      }
    });
  });
});

app.listen(5000, () => console.log('Example app listening on port 5000!'));

semver-prepare-test-data.js

const https = require('https');
const path = require('path');
const fs = require('fs');
const crypto = require('crypto');

const mkdir = (dir) => {
  !fs.existsSync(dir) && fs.mkdirSync(dir);
};

const writeFile = (name) => {
  const fileName = path.resolve(__dirname, 'fw', 'ibr', name);
  crypto.randomBytes(256, (err, buf) => {
    if (err) throw err;
    fs.writeFileSync(fileName, `v.${name} data: ${buf}`);
  });
};

mkdir(path.resolve(__dirname, 'fw'));
mkdir(path.resolve(__dirname, 'fw', 'ibr'));

https.get('https://registry.npmjs.org/lodash', (res) => {
  let data = '';
  res.on('data', buf => data += buf);

  res.on('end', () => {
    const versions = Object.keys(JSON.parse(data).versions);
    versions.forEach(writeFile);
  });

}).on('error', (e) => {
  console.error(e);
});