v1.0 with SW PWA enabled

frontend/node_modules/workbox-expiration/src/models/CacheTimestampsModel.ts

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+/*
+  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 {openDB, DBSchema, IDBPDatabase, deleteDB} from 'idb';
+import '../_version.js';
+
+const DB_NAME = 'workbox-expiration';
+const CACHE_OBJECT_STORE = 'cache-entries';
+
+const normalizeURL = (unNormalizedUrl: string) => {
+  const url = new URL(unNormalizedUrl, location.href);
+  url.hash = '';
+
+  return url.href;
+};
+
+interface CacheTimestampsModelEntry {
+  id: string;
+  cacheName: string;
+  url: string;
+  timestamp: number;
+}
+
+interface CacheDbSchema extends DBSchema {
+  'cache-entries': {
+    key: string;
+    value: CacheTimestampsModelEntry;
+    indexes: {cacheName: string; timestamp: number};
+  };
+}
+
+/**
+ * Returns the timestamp model.
+ *
+ * @private
+ */
+class CacheTimestampsModel {
+  private readonly _cacheName: string;
+  private _db: IDBPDatabase<CacheDbSchema> | null = null;
+
+  /**
+   *
+   * @param {string} cacheName
+   *
+   * @private
+   */
+  constructor(cacheName: string) {
+    this._cacheName = cacheName;
+  }
+
+  /**
+   * Performs an upgrade of indexedDB.
+   *
+   * @param {IDBPDatabase<CacheDbSchema>} db
+   *
+   * @private
+   */
+  private _upgradeDb(db: IDBPDatabase<CacheDbSchema>) {
+    // TODO(philipwalton): EdgeHTML doesn't support arrays as a keyPath, so we
+    // have to use the `id` keyPath here and create our own values (a
+    // concatenation of `url + cacheName`) instead of simply using
+    // `keyPath: ['url', 'cacheName']`, which is supported in other browsers.
+    const objStore = db.createObjectStore(CACHE_OBJECT_STORE, {keyPath: 'id'});
+
+    // TODO(philipwalton): once we don't have to support EdgeHTML, we can
+    // create a single index with the keyPath `['cacheName', 'timestamp']`
+    // instead of doing both these indexes.
+    objStore.createIndex('cacheName', 'cacheName', {unique: false});
+    objStore.createIndex('timestamp', 'timestamp', {unique: false});
+  }
+
+  /**
+   * Performs an upgrade of indexedDB and deletes deprecated DBs.
+   *
+   * @param {IDBPDatabase<CacheDbSchema>} db
+   *
+   * @private
+   */
+  private _upgradeDbAndDeleteOldDbs(db: IDBPDatabase<CacheDbSchema>) {
+    this._upgradeDb(db);
+    if (this._cacheName) {
+      void deleteDB(this._cacheName);
+    }
+  }
+
+  /**
+   * @param {string} url
+   * @param {number} timestamp
+   *
+   * @private
+   */
+  async setTimestamp(url: string, timestamp: number): Promise<void> {
+    url = normalizeURL(url);
+
+    const entry: CacheTimestampsModelEntry = {
+      url,
+      timestamp,
+      cacheName: this._cacheName,
+      // Creating an ID from the URL and cache name won't be necessary once
+      // Edge switches to Chromium and all browsers we support work with
+      // array keyPaths.
+      id: this._getId(url),
+    };
+    const db = await this.getDb();
+    const tx = db.transaction(CACHE_OBJECT_STORE, 'readwrite', {
+      durability: 'relaxed',
+    });
+    await tx.store.put(entry);
+    await tx.done;
+  }
+
+  /**
+   * Returns the timestamp stored for a given URL.
+   *
+   * @param {string} url
+   * @return {number | undefined}
+   *
+   * @private
+   */
+  async getTimestamp(url: string): Promise<number | undefined> {
+    const db = await this.getDb();
+    const entry = await db.get(CACHE_OBJECT_STORE, this._getId(url));
+    return entry?.timestamp;
+  }
+
+  /**
+   * Iterates through all the entries in the object store (from newest to
+   * oldest) and removes entries once either `maxCount` is reached or the
+   * entry's timestamp is less than `minTimestamp`.
+   *
+   * @param {number} minTimestamp
+   * @param {number} maxCount
+   * @return {Array<string>}
+   *
+   * @private
+   */
+  async expireEntries(
+    minTimestamp: number,
+    maxCount?: number,
+  ): Promise<string[]> {
+    const db = await this.getDb();
+    let cursor = await db
+      .transaction(CACHE_OBJECT_STORE)
+      .store.index('timestamp')
+      .openCursor(null, 'prev');
+    const entriesToDelete: CacheTimestampsModelEntry[] = [];
+    let entriesNotDeletedCount = 0;
+    while (cursor) {
+      const result = cursor.value;
+      // TODO(philipwalton): once we can use a multi-key index, we
+      // won't have to check `cacheName` here.
+      if (result.cacheName === this._cacheName) {
+        // Delete an entry if it's older than the max age or
+        // if we already have the max number allowed.
+        if (
+          (minTimestamp && result.timestamp < minTimestamp) ||
+          (maxCount && entriesNotDeletedCount >= maxCount)
+        ) {
+          // TODO(philipwalton): we should be able to delete the
+          // entry right here, but doing so causes an iteration
+          // bug in Safari stable (fixed in TP). Instead we can
+          // store the keys of the entries to delete, and then
+          // delete the separate transactions.
+          // https://github.com/GoogleChrome/workbox/issues/1978
+          // cursor.delete();
+
+          // We only need to return the URL, not the whole entry.
+          entriesToDelete.push(cursor.value);
+        } else {
+          entriesNotDeletedCount++;
+        }
+      }
+      cursor = await cursor.continue();
+    }
+
+    // TODO(philipwalton): once the Safari bug in the following issue is fixed,
+    // we should be able to remove this loop and do the entry deletion in the
+    // cursor loop above:
+    // https://github.com/GoogleChrome/workbox/issues/1978
+    const urlsDeleted: string[] = [];
+    for (const entry of entriesToDelete) {
+      await db.delete(CACHE_OBJECT_STORE, entry.id);
+      urlsDeleted.push(entry.url);
+    }
+
+    return urlsDeleted;
+  }
+
+  /**
+   * Takes a URL and returns an ID that will be unique in the object store.
+   *
+   * @param {string} url
+   * @return {string}
+   *
+   * @private
+   */
+  private _getId(url: string): string {
+    // Creating an ID from the URL and cache name won't be necessary once
+    // Edge switches to Chromium and all browsers we support work with
+    // array keyPaths.
+    return this._cacheName + '|' + normalizeURL(url);
+  }
+
+  /**
+   * Returns an open connection to the database.
+   *
+   * @private
+   */
+  private async getDb() {
+    if (!this._db) {
+      this._db = await openDB(DB_NAME, 1, {
+        upgrade: this._upgradeDbAndDeleteOldDbs.bind(this),
+      });
+    }
+    return this._db;
+  }
+}
+
+export {CacheTimestampsModel};