hexo/node_modules/workbox-expiration/ExpirationPlugin.js

255 lines
11 KiB
JavaScript

/*
Copyright 2018 Google LLC
Use of this source code is governed by an MIT-style
license that can be found in the LICENSE file or at
https://opensource.org/licenses/MIT.
*/
import { assert } from 'workbox-core/_private/assert.js';
import { cacheNames } from 'workbox-core/_private/cacheNames.js';
import { dontWaitFor } from 'workbox-core/_private/dontWaitFor.js';
import { getFriendlyURL } from 'workbox-core/_private/getFriendlyURL.js';
import { logger } from 'workbox-core/_private/logger.js';
import { registerQuotaErrorCallback } from 'workbox-core/registerQuotaErrorCallback.js';
import { WorkboxError } from 'workbox-core/_private/WorkboxError.js';
import { CacheExpiration } from './CacheExpiration.js';
import './_version.js';
/**
* This plugin can be used in a `workbox-strategy` to regularly enforce a
* limit on the age and / or the number of cached requests.
*
* It can only be used with `workbox-strategy` instances that have a
* [custom `cacheName` property set](/web/tools/workbox/guides/configure-workbox#custom_cache_names_in_strategies).
* In other words, it can't be used to expire entries in strategy that uses the
* default runtime cache name.
*
* Whenever a cached response is used or updated, this plugin will look
* at the associated cache and remove any old or extra responses.
*
* When using `maxAgeSeconds`, responses may be used *once* after expiring
* because the expiration clean up will not have occurred until *after* the
* cached response has been used. If the response has a "Date" header, then
* a light weight expiration check is performed and the response will not be
* used immediately.
*
* When using `maxEntries`, the entry least-recently requested will be removed
* from the cache first.
*
* @memberof workbox-expiration
*/
class ExpirationPlugin {
/**
* @param {ExpirationPluginOptions} config
* @param {number} [config.maxEntries] The maximum number of entries to cache.
* Entries used the least will be removed as the maximum is reached.
* @param {number} [config.maxAgeSeconds] The maximum age of an entry before
* it's treated as stale and removed.
* @param {Object} [config.matchOptions] The [`CacheQueryOptions`](https://developer.mozilla.org/en-US/docs/Web/API/Cache/delete#Parameters)
* that will be used when calling `delete()` on the cache.
* @param {boolean} [config.purgeOnQuotaError] Whether to opt this cache in to
* automatic deletion if the available storage quota has been exceeded.
*/
constructor(config = {}) {
/**
* A "lifecycle" callback that will be triggered automatically by the
* `workbox-strategies` handlers when a `Response` is about to be returned
* from a [Cache](https://developer.mozilla.org/en-US/docs/Web/API/Cache) to
* the handler. It allows the `Response` to be inspected for freshness and
* prevents it from being used if the `Response`'s `Date` header value is
* older than the configured `maxAgeSeconds`.
*
* @param {Object} options
* @param {string} options.cacheName Name of the cache the response is in.
* @param {Response} options.cachedResponse The `Response` object that's been
* read from a cache and whose freshness should be checked.
* @return {Response} Either the `cachedResponse`, if it's
* fresh, or `null` if the `Response` is older than `maxAgeSeconds`.
*
* @private
*/
this.cachedResponseWillBeUsed = async ({ event, request, cacheName, cachedResponse, }) => {
if (!cachedResponse) {
return null;
}
const isFresh = this._isResponseDateFresh(cachedResponse);
// Expire entries to ensure that even if the expiration date has
// expired, it'll only be used once.
const cacheExpiration = this._getCacheExpiration(cacheName);
dontWaitFor(cacheExpiration.expireEntries());
// Update the metadata for the request URL to the current timestamp,
// but don't `await` it as we don't want to block the response.
const updateTimestampDone = cacheExpiration.updateTimestamp(request.url);
if (event) {
try {
event.waitUntil(updateTimestampDone);
}
catch (error) {
if (process.env.NODE_ENV !== 'production') {
// The event may not be a fetch event; only log the URL if it is.
if ('request' in event) {
logger.warn(`Unable to ensure service worker stays alive when ` +
`updating cache entry for ` +
`'${getFriendlyURL(event.request.url)}'.`);
}
}
}
}
return isFresh ? cachedResponse : null;
};
/**
* A "lifecycle" callback that will be triggered automatically by the
* `workbox-strategies` handlers when an entry is added to a cache.
*
* @param {Object} options
* @param {string} options.cacheName Name of the cache that was updated.
* @param {string} options.request The Request for the cached entry.
*
* @private
*/
this.cacheDidUpdate = async ({ cacheName, request, }) => {
if (process.env.NODE_ENV !== 'production') {
assert.isType(cacheName, 'string', {
moduleName: 'workbox-expiration',
className: 'Plugin',
funcName: 'cacheDidUpdate',
paramName: 'cacheName',
});
assert.isInstance(request, Request, {
moduleName: 'workbox-expiration',
className: 'Plugin',
funcName: 'cacheDidUpdate',
paramName: 'request',
});
}
const cacheExpiration = this._getCacheExpiration(cacheName);
await cacheExpiration.updateTimestamp(request.url);
await cacheExpiration.expireEntries();
};
if (process.env.NODE_ENV !== 'production') {
if (!(config.maxEntries || config.maxAgeSeconds)) {
throw new WorkboxError('max-entries-or-age-required', {
moduleName: 'workbox-expiration',
className: 'Plugin',
funcName: 'constructor',
});
}
if (config.maxEntries) {
assert.isType(config.maxEntries, 'number', {
moduleName: 'workbox-expiration',
className: 'Plugin',
funcName: 'constructor',
paramName: 'config.maxEntries',
});
}
if (config.maxAgeSeconds) {
assert.isType(config.maxAgeSeconds, 'number', {
moduleName: 'workbox-expiration',
className: 'Plugin',
funcName: 'constructor',
paramName: 'config.maxAgeSeconds',
});
}
}
this._config = config;
this._maxAgeSeconds = config.maxAgeSeconds;
this._cacheExpirations = new Map();
if (config.purgeOnQuotaError) {
registerQuotaErrorCallback(() => this.deleteCacheAndMetadata());
}
}
/**
* A simple helper method to return a CacheExpiration instance for a given
* cache name.
*
* @param {string} cacheName
* @return {CacheExpiration}
*
* @private
*/
_getCacheExpiration(cacheName) {
if (cacheName === cacheNames.getRuntimeName()) {
throw new WorkboxError('expire-custom-caches-only');
}
let cacheExpiration = this._cacheExpirations.get(cacheName);
if (!cacheExpiration) {
cacheExpiration = new CacheExpiration(cacheName, this._config);
this._cacheExpirations.set(cacheName, cacheExpiration);
}
return cacheExpiration;
}
/**
* @param {Response} cachedResponse
* @return {boolean}
*
* @private
*/
_isResponseDateFresh(cachedResponse) {
if (!this._maxAgeSeconds) {
// We aren't expiring by age, so return true, it's fresh
return true;
}
// Check if the 'date' header will suffice a quick expiration check.
// See https://github.com/GoogleChromeLabs/sw-toolbox/issues/164 for
// discussion.
const dateHeaderTimestamp = this._getDateHeaderTimestamp(cachedResponse);
if (dateHeaderTimestamp === null) {
// Unable to parse date, so assume it's fresh.
return true;
}
// If we have a valid headerTime, then our response is fresh iff the
// headerTime plus maxAgeSeconds is greater than the current time.
const now = Date.now();
return dateHeaderTimestamp >= now - this._maxAgeSeconds * 1000;
}
/**
* This method will extract the data header and parse it into a useful
* value.
*
* @param {Response} cachedResponse
* @return {number|null}
*
* @private
*/
_getDateHeaderTimestamp(cachedResponse) {
if (!cachedResponse.headers.has('date')) {
return null;
}
const dateHeader = cachedResponse.headers.get('date');
const parsedDate = new Date(dateHeader);
const headerTime = parsedDate.getTime();
// If the Date header was invalid for some reason, parsedDate.getTime()
// will return NaN.
if (isNaN(headerTime)) {
return null;
}
return headerTime;
}
/**
* This is a helper method that performs two operations:
*
* - Deletes *all* the underlying Cache instances associated with this plugin
* instance, by calling caches.delete() on your behalf.
* - Deletes the metadata from IndexedDB used to keep track of expiration
* details for each Cache instance.
*
* When using cache expiration, calling this method is preferable to calling
* `caches.delete()` directly, since this will ensure that the IndexedDB
* metadata is also cleanly removed and open IndexedDB instances are deleted.
*
* Note that if you're *not* using cache expiration for a given cache, calling
* `caches.delete()` and passing in the cache's name should be sufficient.
* There is no Workbox-specific method needed for cleanup in that case.
*/
async deleteCacheAndMetadata() {
// Do this one at a time instead of all at once via `Promise.all()` to
// reduce the chance of inconsistency if a promise rejects.
for (const [cacheName, cacheExpiration] of this._cacheExpirations) {
await self.caches.delete(cacheName);
await cacheExpiration.delete();
}
// Reset this._cacheExpirations to its initial state.
this._cacheExpirations = new Map();
}
}
export { ExpirationPlugin };