Metalsmith css cache busting md5 hash

metalsmith.js

var Metalsmith = require('metalsmith');

// Plugins
var markdown = require('metalsmith-markdown');
var markdownPrecompiler = require('metalsmith-markdown-precompiler');
var sass = require('metalsmith-sass');
var layouts = require('metalsmith-layouts');
var discoverHelpers = require('metalsmith-discover-helpers');
var discoverPartials = require('metalsmith-discover-partials');
var path = require('path');
var paths = require('metalsmith-paths');
var metadata = require('metalsmith-collections');
var json_to_files = require('metalsmith-json-to-files');
var moonSearch = require('./metalsmith-moonsearch/metalsmith-moonsearch.js');
var siteMap = require('metalsmith-sitemap');
var redirect = require('metalsmith-redirect');
var crypto = require('crypto');
var fs = require('fs');

// Data
var blogData = require('./src/blog/data.json');
var boxesData = require('./src/boxes/data.json');
var boxesMetadata = require('./src/data/boxes.json');
var careersData = require('./src/careers/data.json');
var docsData = require('./src/docs/data.json');
var eventsData = require('./src/events/data.json');
var pressReleasesData = require('./src/press-releases/data.json');
var staffData = require('./src/staff/data.json');
var tutorialsData = require('./src/tutorials/data.json');

var srcDir = path.join('./', 'src');
var buildDir = 'build' + path.sep;
var cssOutputDir = 'css' + path.sep;
var cssOutputFile = path.join(buildDir, cssOutputDir, 'index.css');

function app(clean) {
  return Metalsmith(__dirname)
  .source(srcDir)
  .destination(buildDir)
  .clean(clean)
  .use(sass({
    outputStyle: 'expanded',
    outputDir: 'css/'
  }))
  .metadata({
    blog: blogData,
    boxes: boxesData,
    boxMeta: boxesMetadata,
    careers: careersData,
    docs: docsData,
    events: eventsData,
    pressReleases: pressReleasesData,
    staff: staffData,
    tutorials: tutorialsData,
    cssVersion: crypto.createHash('md5').update(fs.readFileSync(cssOutputFile, { encoding: 'utf8' })).digest('hex'),
  })
  .use(discoverHelpers({
    directory: 'helpers',
    pattern: /\.js$/
  }))
  .use(discoverPartials({
    directory: 'partials',
    pattern: /\.hbs$/
  }))
  .use(json_to_files({
    source_path: './src/boxes/'
  }))
  .use(paths())
  .use(markdownPrecompiler({
    engine: "handlebars",
    pattern: /\.md$/,
    partialsPath: './../partials',
    partials: ["partial"]
  }))
  .use(markdown({
    renderer: require('./renderers/markdown.js')
  }))
  .use(layouts({
    "default": "blog-post-single.hbs",
    "pattern": ["blog/*.html"]
  }))
  .use(layouts({
    "default": "pr-single.hbs",
    "pattern": ["press-releases/*.html"]
  }))
  .use(layouts({
    "default": "career-single.hbs",
    "pattern": "careers/*.html"
  }))
  .use(layouts({
    "default": "tutorial-single.hbs",
    "pattern": "tutorials/*.html"
  }))
  .use(layouts())
  .use(moonSearch())
  .use(siteMap({
    hostname: "https://www.truffleframework.com"
  }))
  .use(redirect({
    redirections: {
      "/docs/truffle/getting-started/working-with-quorum": "/docs/truffle/distributed-ledger-support/working-with-quorum",
      "/docs/truffle/getting-started/working-with-hyperledger-evm": "/docs/truffle/distributed-ledger-support/working-with-hyperledger-evm",
    }
  }));
}

module.exports = app;