simple revision-er

simple-rev.js

'use strict'

const crypto = require('crypto')
const fs = require('fs')
const mkdirp = require('mkdirp')
const path = require('path')
const recursive = require('recursive-readdir')

const assign = Object.assign
const keys   = Object.keys

const HTML_EXTENSIONS  = ['.html', '.htm']
const UTF8_EXTENSIONS = HTML_EXTENSIONS.concat(
  ['.js', '.css']
)

const BASE_DIR   = path.resolve(__dirname, '../')
const SOURCE_DIR = path.join(BASE_DIR, './.dev')
const DEST_DIR   = path.join(BASE_DIR, './dist')

const inArray = (arr, member) => (arr.indexOf(member) !== -1)

const isHtml = (file) => (inArray(HTML_EXTENSIONS, path.extname(file)))
const isUTF8 = (file) => (inArray(UTF8_EXTENSIONS, path.extname(file)))

const createNewContent = (manifest, content) => {
  return keys(manifest).reduce((updatedContent, file) => {
    const asset = path.relative(SOURCE_DIR, file)
    return updatedContent.replace(`/${ asset }`, `/${ manifest[file].name }`)
  }, content)
}

const addHashToFile = (file, hash) => {
  const ext = path.extname(file)
  const name = path.basename(file, ext)
  return `${ name }-${ hash }${ ext }`
}

const newFileName = (file, hash) => {
  if (!isHtml(file) && !file.match(/main.js/)) {
    return path.relative(
      SOURCE_DIR,
      path.join(path.dirname(file),
      addHashToFile(file, hash))
    )
  } else {
    return path.relative(
      SOURCE_DIR,
      file
    )
  }
}

const process = (file, callback) => {
  const stream = fs.createReadStream(file)
  const hasher = crypto.createHash('sha1')
  let content = ''

  stream.on('data', (chunk) => {
    if (isUTF8(file)) { content += chunk }
    hasher.update(chunk)
  })

  stream.on('end', () => {
    const name = newFileName(file, hasher.digest('hex'))
    callback(null, { name, content })
  })
}

const createManifest = (files, callback) => {
  let remaining = files.length
  let manifest = {}

  files.forEach((file) => {
    process(file, (err, result) => {
      if (err) {
        return callback(err)
      }
      manifest[file] = result

      --remaining
      if (remaining <= 0) {
        callback(null, manifest)
      }
    })
  })
}

recursive(SOURCE_DIR, (err, files) => {
  createManifest(files, (err, manifest) => {
    const manifestFiles = keys(manifest)
    let remaining = manifestFiles.length

    manifestFiles.forEach((file) => {
      const properties = manifest[file]
      const content    = createNewContent(manifest, properties.content)
      const fullPath   = path.join(DEST_DIR, properties.name)
      const directory  = path.dirname(fullPath)
      mkdirp(directory, () => {
        fs.writeFile(fullPath, content, (err) => {
          console.log('Reved: ', fullPath)
          --remaining
          if (remaining <= 0) {
            console.log('Rev all complete')
          }
        })
      })
    })
  })
})