remote-storage.js

/*
Copyright 2019 Adobe. All rights reserved.
This file is licensed to you under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License. You may obtain a copy
of the License at http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under
the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
OF ANY KIND, either express or implied. See the License for the specific language
governing permissions and limitations under the License.
*/

const { S3 } = require('@aws-sdk/client-s3')
const path = require('path')
const mime = require('mime-types')
const fs = require('fs-extra')
const joi = require('joi')
const klaw = require('klaw')
const http = require('http')
const { codes, logAndThrow } = require('./StorageError')

const fileExtensionPattern = /\*\.[0-9a-zA-Z]+$/

// /**
//  * Joins url path parts
//  * @param {...string} args url parts
//  * @returns {string}
//  */
function urlJoin (...args) {
  let start = ''
  if (args[0] &&
      args[0].startsWith('/')) {
    start = '/'
  }
  return start + args.map(a => a && a.replace(/(^\/|\/$)/g, ''))
    .filter(a => a) // remove empty strings / nulls
    .join('/')
}

module.exports = class RemoteStorage {
  /**
   * @param  {object} creds
   * @param  {string} creds.accessKeyId
   * @param  {string} creds.secretAccessKey
   * @param  {string} creds.params.Bucket
   * @param  {string} [creds.sessionToken]
   */
  constructor (creds) {
    const res = joi.object().keys({
      sessionToken: joi.string(),
      accessKeyId: joi.string().required(),
      secretAccessKey: joi.string().required(),
      // hacky needs s3Bucket in creds.params.Bucket
      params: joi.object().keys({ Bucket: joi.string().required() }).required()
    }).unknown()
      .validate(creds)
    if (res.error) {
      throw res.error
    }

    // the TVM response could be passed as is to the v2 client constructor, but the v3 client follows a different format
    // see https://github.com/adobe/aio-tvm/issues/85
    const region = creds.region || 'us-east-1'
    // note this must supports TVM + BYO use cases
    // see https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-s3/interfaces/credentials.html
    const credentials = {
      accessKeyId: creds.accessKeyId,
      secretAccessKey: creds.secretAccessKey,
      sessionToken: creds.sessionToken,
      expiration: creds.expiration ? new Date(creds.expiration) : undefined
    }
    this.bucket = creds.params.Bucket

    // https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-s3/classes/s3.html#constructor
    this.s3 = new S3({ credentials, region })
  }

  /**
   * Checks if prefix exists
   * @param  {string} prefix
   * @returns {boolean}
   */
  async folderExists (prefix) {
    if (typeof prefix !== 'string') {
      throw new Error('prefix must be a valid string')
    }
    const listParams = {
      Bucket: this.bucket,
      Prefix: prefix
    }
    const listedObjects = await this.s3.listObjectsV2(listParams)

    return listedObjects.KeyCount > 0
  }

  /**
   * Deletes all files in a prefix location
   * @param  {string} prefix
   */
  async emptyFolder (prefix) {
    if (typeof prefix !== 'string') throw new Error('prefix must be a valid string')
    const listParams = {
      Bucket: this.bucket,
      Prefix: prefix
    }
    const listedObjects = await this.s3.listObjectsV2(listParams)

    if (listedObjects.KeyCount < 1) {
      return
    }
    const deleteParams = {
      Bucket: this.bucket,
      Delete: { Objects: [] }
    }
    listedObjects.Contents.forEach(({ Key }) => {
      deleteParams.Delete.Objects.push({ Key })
    })
    await this.s3.deleteObjects(deleteParams)
    if (listedObjects.IsTruncated) {
      await this.emptyFolder(prefix)
    }
  }

  /**
   * Uploads a file
   * @param  {string} file
   * @param  {string} prefix - prefix to upload the file to
   * @param  {Object} appConfig - application config
   * @param  {string} distRoot - Distribution root dir
   */
  async uploadFile (file, prefix, appConfig, distRoot) {
    if (typeof prefix !== 'string') {
      throw new Error('prefix must be a valid string')
    }
    const content = await fs.readFile(file)
    const mimeType = mime.lookup(path.extname(file))
    const cacheControlString = this._getCacheControlConfig(mimeType, appConfig.app)
    const uploadParams = {
      Bucket: this.bucket,
      Key: urlJoin(prefix, path.basename(file)),
      Body: content,
      CacheControl: cacheControlString
    }
    // add response headers if specified in manifest
    const responseHeaders = this.getResponseHeadersForFile(file, distRoot, appConfig)
    if (responseHeaders) {
      uploadParams.Metadata = responseHeaders
    }
    // s3 misses some mime types like for css files
    if (mimeType) {
      uploadParams.ContentType = mimeType
    }

    // Note: putObject is recommended for files < 100MB and has a limit of 5GB, which is ok for our use case of storing static web assets
    // if we intend to store larger files, we should use multipart upload and https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/modules/_aws_sdk_lib_storage.html
    return this.s3.putObject(uploadParams)
  }

  getResponseHeadersForFile (file, distRoot, appConfig) {
    let responseHeaders
    if (appConfig.web && appConfig.web['response-headers']) {
      responseHeaders = {}
      const cdnConfig = appConfig.web['response-headers']
      const headerPrefix = 'adp-'

      Object.keys(cdnConfig).forEach(rule => {
        if (this.canAddHeader(file, distRoot, rule)) {
          Object.keys(cdnConfig[rule]).forEach(header => {
            this.validateHTTPHeader(header, cdnConfig[rule][header])
            responseHeaders[headerPrefix + header] = cdnConfig[rule][header]
          })
        }
      })
    }
    return responseHeaders
  }

  canAddHeader (file, distRoot, rule) {
    const filePath = path.parse(file)
    const normalisedRule = rule.replace(/\//g, path.sep)
    const ruleFolderPath = path.parse(normalisedRule)
    let folderPathToMatch = path.join(distRoot, ruleFolderPath.dir)
    if (folderPathToMatch.endsWith(path.sep)) {
      folderPathToMatch = folderPathToMatch.substring(0, folderPathToMatch.length - 1) // remove any trailing path separator
    }

    if (rule === '/*') { // all content
      return true
    } else if (rule.endsWith('/*')) { // all content in a folder ex. /test/*
      if (filePath.dir.startsWith(folderPathToMatch)) { // matches with the folder
        return true
      }
    } else if (fileExtensionPattern.test(rule)) { // all content with a given extension ex. /*.html or /test/*.js
      // check file has same extension as specified in header
      if ((filePath.ext === ruleFolderPath.ext) && (filePath.dir.startsWith(folderPathToMatch))) {
        return true
      }
    } else { // specific file match ex. /test/foo.js
      const uploadFilePath = path.join(distRoot, normalisedRule)
      if (file === uploadFilePath) {
        return true
      }
    }
    return false
  }

  validateHTTPHeader (headerName, value) {
    try {
      http.validateHeaderName(headerName)
    } catch (e) {
      logAndThrow(new codes.ERROR_INVALID_HEADER_NAME({ messageValues: [headerName], sdkDetails: {} }))
    }

    try {
      http.validateHeaderValue(headerName, value)
    } catch (e) {
      logAndThrow(new codes.ERROR_INVALID_HEADER_VALUE({ messageValues: [value, headerName], sdkDetails: {} }))
    }
  }

  async walkDir (dir) {
    return new Promise((resolve, reject) => {
      const items = []
      klaw(dir)
        .on('data', fd => {
          if (fd.stats.isFile()) {
            items.push(fd.path)
          }
        })
        .on('end', () => resolve(items))
    })
  }

  /**
   * Uploads all files in a dir to - recursion is supported
   * @param  {string} dir - directory with files to upload
   * @param  {string} prefix - prefix to upload the dir to
   * @param  {Object} appConfig - application config
   * @param  {function} [postFileUploadCallback] - called for each uploaded file
   */
  async uploadDir (dir, prefix, appConfig, postFileUploadCallback) {
    if (typeof prefix !== 'string') {
      throw new Error('prefix must be a valid string')
    }
    // walk the whole directory recursively using klaw.
    const files = await this.walkDir(dir)

    // parallel upload
    return Promise.all(files.map(async f => {
      // get file's relative folder to the base directory.
      let prefixDirectory = path.dirname(path.relative(dir, f))
      // base directory returns ".", ignore that.
      prefixDirectory = prefixDirectory === '.' ? '' : prefixDirectory
      // newPrefix is now the initial prefix plus the files relative directory path.
      const newPrefix = urlJoin(prefix, prefixDirectory)
      const s3Res = await this.uploadFile(f, newPrefix, appConfig, dir)

      if (postFileUploadCallback) {
        postFileUploadCallback(f)
      }
      return s3Res
    }))
  }

  /**
    * Get cache control string based on mime type and config
    * @param {string|boolean} mimeType - string if valid mimeType or false for unknown files
    * @param  {Object} appConfig - application config
    */
  _getCacheControlConfig (mimeType, appConfig) {
    const cacheControlStr = 's-maxage=0'
    if (!mimeType) {
      return cacheControlStr
    } else if (mimeType === mime.lookup('html')) {
      return cacheControlStr + ', max-age=' + appConfig.htmlCacheDuration
    } else if (mimeType === mime.lookup('js')) {
      return cacheControlStr + ', max-age=' + appConfig.jsCacheDuration
    } else if (mimeType === mime.lookup('css')) {
      return cacheControlStr + ', max-age=' + appConfig.cssCacheDuration
    } else if (mimeType.startsWith('image')) {
      return cacheControlStr + ', max-age=' + appConfig.imageCacheDuration
    } else { return cacheControlStr }
  }
}