makestatic-manifest/index.js

Generates a JSON manifest of the output files

const path = require('path')

/**
 *  Generates a JSON manifest of the output files that is written to
 *  `manifest.json` in the output directory.
 *
 *  @class Manifest
 *
 *  @see /docs/api/core-standard/ Core Standard
 */
class Manifest {

  /**
   *  Creates a Manifest plugin.
   *
   *  The structure of the generated document is:
   *
   *  ```json
   *  {
   *    "algorithm": "sha512",
   *    "files": {}
   *  }
   *  ```
   *
   *  Each key in the `files` map is the path of the file relative to the output
   *  directory. Each file entry contains the fields:
   *
   *  + `source` the original source file.
   *  + `hash` object containing checksums.
   *  + `size` the size of the file in bytes.
   *
   *  Transient files are not included in the manifest.
   *
   *  @constructor Manifest
   *  @param {Object} context the processing context.
   *  @param {Object} [options] the plugin options.
   *
   *  @option {String=sha512} algorithm checksum generation algorithm.
   */
  constructor (context, options = {}) {
    this.data = {}
    this.algorithm = options.algorithm || 'sha512'
  }

  /**
   *  Adds files to the manifest data.
   *
   *  If the `manifest` context option is not set this function call is a noop.
   *
   *  @function sources
   *  @member Manifest
   *  @param {Object} file the current file.
   *  @param {Object} context the processing context.
   */
  sources (file, context) {
    if (!context.options.manifest) {
      return
    }

    const log = context.log

    // can be configured with no resolve phase
    // in which case we skip the file
    if (file.transient || !file.output) {
      return
    }

    // relative to output directory
    let key = file.output
    key = key.replace(context.options.output, '')
    key = key.replace(/^\//, '')

    let name = file.name

    if (path.isAbsolute(name)) {
      name = file.relative(context.options.input)
    }

    const item = {
      source: name,
      hash: file.hash
    }

    if (file.content) {
      if (!item.hash.content) {
        item.hash.content = file.checksum(file.content, this.algorithm)
      }

      item.size = Buffer.byteLength(file.content)
    }

    log.debug('[manifest] %s', key)

    this.data[key] = item
  }

  /**
   *  Adds the manifest file to the pipeline.
   *
   *  If the `manifest` context option is not set this function call is a noop.
   *
   *  @function after
   *  @member Manifest
   *  @param {Object} context the processing context.
   */
  after (context) {
    const log = context.log
    const manifest = context.options.manifest

    if (!manifest) {
      return
    }

    let output = path.join(context.options.output, manifest)

    const content = {
      algorithm: this.algorithm,
      files: this.data
    }

    context.manifest = content

    const out = context.getFile({
      name: manifest,
      output: output,
      content: JSON.stringify(content, undefined, 2)
    })

    log.debug(
      `[manifest] ${out.path} (${Object.keys(this.data).length} files)`)

    // add file to the list
    context.list.add(out)
  }
}

module.exports = Manifest