@adobe/helix-pipeline/src/html/shared-cache.js

(formerly known as Hypermedia Pipeline)

/*
 * Copyright 2018 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 { setdefault, pairs, foldl } = require('ferrum');

function uncached({ response }) {
  return !(response && response.headers && response.headers['Cache-Control']);
}

function cache(context) {
  const res = setdefault(context, 'response', {});
  const headers = setdefault(res, 'headers', {});
  const directives = {
    's-maxage': 30 * 24 * 3600, // serve from cache (without revalidation) for 30 days
    'stale-while-revalidate': 365 * 24 * 3600, // serve stale (while revalidating in background) for a year
  };

  headers['Cache-Control'] = foldl(
    pairs(directives),
    '',
    (a, [key, value]) => `${a + (a ? ', ' : '') + key}=${value}`,
  );
}

module.exports = { uncached, cache };