/*
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 {WorkboxError} from 'workbox-core/_private/WorkboxError.js';
import {logger} from 'workbox-core/_private/logger.js';
import {assert} from 'workbox-core/_private/assert.js';
import {getFriendlyURL} from 'workbox-core/_private/getFriendlyURL.js';
import {QueueStore} from './lib/QueueStore.js';
import {QueueStoreEntry, UnidentifiedQueueStoreEntry} from './lib/QueueDb.js';
import {StorableRequest} from './lib/StorableRequest.js';
import './_version.js';
// Give TypeScript the correct global.
declare let self: ServiceWorkerGlobalScope;
interface OnSyncCallbackOptions {
queue: Queue;
}
interface OnSyncCallback {
(options: OnSyncCallbackOptions): void | Promise<void>;
}
export interface QueueOptions {
forceSyncFallback?: boolean;
maxRetentionTime?: number;
onSync?: OnSyncCallback;
}
interface QueueEntry {
request: Request;
timestamp?: number;
// We could use Record<string, unknown> as a type but that would be a breaking
// change, better do it in next major release.
// eslint-disable-next-line @typescript-eslint/ban-types
metadata?: object;
}
const TAG_PREFIX = 'workbox-background-sync';
const MAX_RETENTION_TIME = 60 * 24 * 7; // 7 days in minutes
const queueNames = new Set<string>();
/**
* Converts a QueueStore entry into the format exposed by Queue. This entails
* converting the request data into a real request and omitting the `id` and
* `queueName` properties.
*
* @param {UnidentifiedQueueStoreEntry} queueStoreEntry
* @return {Queue}
* @private
*/
const convertEntry = (
queueStoreEntry: UnidentifiedQueueStoreEntry,
): QueueEntry => {
const queueEntry: QueueEntry = {
request: new StorableRequest(queueStoreEntry.requestData).toRequest(),
timestamp: queueStoreEntry.timestamp,
};
if (queueStoreEntry.metadata) {
queueEntry.metadata = queueStoreEntry.metadata;
}
return queueEntry;
};
/**
* A class to manage storing failed requests in IndexedDB and retrying them
* later. All parts of the storing and replaying process are observable via
* callbacks.
*
* @memberof workbox-background-sync
*/
class Queue {
private readonly _name: string;
private readonly _onSync: OnSyncCallback;
private readonly _maxRetentionTime: number;
private readonly _queueStore: QueueStore;
private readonly _forceSyncFallback: boolean;
private _syncInProgress = false;
private _requestsAddedDuringSync = false;
/**
* Creates an instance of Queue with the given options
*
* @param {string} name The unique name for this queue. This name must be
* unique as it's used to register sync events and store requests
* in IndexedDB specific to this instance. An error will be thrown if
* a duplicate name is detected.
* @param {Object} [options]
* @param {Function} [options.onSync] A function that gets invoked whenever
* the 'sync' event fires. The function is invoked with an object
* containing the `queue` property (referencing this instance), and you
* can use the callback to customize the replay behavior of the queue.
* When not set the `replayRequests()` method is called.
* Note: if the replay fails after a sync event, make sure you throw an
* error, so the browser knows to retry the sync event later.
* @param {number} [options.maxRetentionTime=7 days] The amount of time (in
* minutes) a request may be retried. After this amount of time has
* passed, the request will be deleted from the queue.
* @param {boolean} [options.forceSyncFallback=false] If `true`, instead
* of attempting to use background sync events, always attempt to replay
* queued request at service worker startup. Most folks will not need
* this, unless you explicitly target a runtime like Electron that
* exposes the interfaces for background sync, but does not have a working
* implementation.
*/
constructor(
name: string,
{forceSyncFallback, onSync, maxRetentionTime}: QueueOptions = {},
) {
// Ensure the store name is not already being used
if (queueNames.has(name)) {
throw new WorkboxError('duplicate-queue-name', {name});
} else {
queueNames.add(name);
}
this._name = name;
this._onSync = onSync || this.replayRequests;
this._maxRetentionTime = maxRetentionTime || MAX_RETENTION_TIME;
this._forceSyncFallback = Boolean(forceSyncFallback);
this._queueStore = new QueueStore(this._name);
this._addSyncListener();
}
/**
* @return {string}
*/
get name(): string {
return this._name;
}
/**
* Stores the passed request in IndexedDB (with its timestamp and any
* metadata) at the end of the queue.
*
* @param {QueueEntry} entry
* @param {Request} entry.request The request to store in the queue.
* @param {Object} [entry.metadata] Any metadata you want associated with the
* stored request. When requests are replayed you'll have access to this
* metadata object in case you need to modify the request beforehand.
* @param {number} [entry.timestamp] The timestamp (Epoch time in
* milliseconds) when the request was first added to the queue. This is
* used along with `maxRetentionTime` to remove outdated requests. In
* general you don't need to set this value, as it's automatically set
* for you (defaulting to `Date.now()`), but you can update it if you
* don't want particular requests to expire.
*/
async pushRequest(entry: QueueEntry): Promise<void> {
if (process.env.NODE_ENV !== 'production') {
assert!.isType(entry, 'object', {
moduleName: 'workbox-background-sync',
className: 'Queue',
funcName: 'pushRequest',
paramName: 'entry',
});
assert!.isInstance(entry.request, Request, {
moduleName: 'workbox-background-sync',
className: 'Queue',
funcName: 'pushRequest',
paramName: 'entry.request',
});
}
await this._addRequest(entry, 'push');
}
/**
* Stores the passed request in IndexedDB (with its timestamp and any
* metadata) at the beginning of the queue.
*
* @param {QueueEntry} entry
* @param {Request} entry.request The request to store in the queue.
* @param {Object} [entry.metadata] Any metadata you want associated with the
* stored request. When requests are replayed you'll have access to this
* metadata object in case you need to modify the request beforehand.
* @param {number} [entry.timestamp] The timestamp (Epoch time in
* milliseconds) when the request was first added to the queue. This is
* used along with `maxRetentionTime` to remove outdated requests. In
* general you don't need to set this value, as it's automatically set
* for you (defaulting to `Date.now()`), but you can update it if you
* don't want particular requests to expire.
*/
async unshiftRequest(entry: QueueEntry): Promise<void> {
if (process.env.NODE_ENV !== 'production') {
assert!.isType(entry, 'object', {
moduleName: 'workbox-background-sync',
className: 'Queue',
funcName: 'unshiftRequest',
paramName: 'entry',
});
assert!.isInstance(entry.request, Request, {
moduleName: 'workbox-background-sync',
className: 'Queue',
funcName: 'unshiftRequest',
paramName: 'entry.request',
});
}
await this._addRequest(entry, 'unshift');
}
/**
* Removes and returns the last request in the queue (along with its
* timestamp and any metadata). The returned object takes the form:
* `{request, timestamp, metadata}`.
*
* @return {Promise<QueueEntry | undefined>}
*/
async popRequest(): Promise<QueueEntry | undefined> {
return this._removeRequest('pop');
}
/**
* Removes and returns the first request in the queue (along with its
* timestamp and any metadata). The returned object takes the form:
* `{request, timestamp, metadata}`.
*
* @return {Promise<QueueEntry | undefined>}
*/
async shiftRequest(): Promise<QueueEntry | undefined> {
return this._removeRequest('shift');
}
/**
* Returns all the entries that have not expired (per `maxRetentionTime`).
* Any expired entries are removed from the queue.
*
* @return {Promise<Array<QueueEntry>>}
*/
async getAll(): Promise<Array<QueueEntry>> {
const allEntries = await this._queueStore.getAll();
const now = Date.now();
const unexpiredEntries = [];
for (const entry of allEntries) {
// Ignore requests older than maxRetentionTime. Call this function
// recursively until an unexpired request is found.
const maxRetentionTimeInMs = this._maxRetentionTime * 60 * 1000;
if (now - entry.timestamp > maxRetentionTimeInMs) {
await this._queueStore.deleteEntry(entry.id);
} else {
unexpiredEntries.push(convertEntry(entry));
}
}
return unexpiredEntries;
}
/**
* Returns the number of entries present in the queue.
* Note that expired entries (per `maxRetentionTime`) are also included in this count.
*
* @return {Promise<number>}
*/
async size(): Promise<number> {
return await this._queueStore.size();
}
/**
* Adds the entry to the QueueStore and registers for a sync event.
*
* @param {Object} entry
* @param {Request} entry.request
* @param {Object} [entry.metadata]
* @param {number} [entry.timestamp=Date.now()]
* @param {string} operation ('push' or 'unshift')
* @private
*/
async _addRequest(
{request, metadata, timestamp = Date.now()}: QueueEntry,
operation: 'push' | 'unshift',
): Promise<void> {
const storableRequest = await StorableRequest.fromRequest(request.clone());
const entry: UnidentifiedQueueStoreEntry = {
requestData: storableRequest.toObject(),
timestamp,
};
// Only include metadata if it's present.
if (metadata) {
entry.metadata = metadata;
}
switch (operation) {
case 'push':
await this._queueStore.pushEntry(entry);
break;
case 'unshift':
await this._queueStore.unshiftEntry(entry);
break;
}
if (process.env.NODE_ENV !== 'production') {
logger.log(
`Request for '${getFriendlyURL(request.url)}' has ` +
`been added to background sync queue '${this._name}'.`,
);
}
// Don't register for a sync if we're in the middle of a sync. Instead,
// we wait until the sync is complete and call register if
// `this._requestsAddedDuringSync` is true.
if (this._syncInProgress) {
this._requestsAddedDuringSync = true;
} else {
await this.registerSync();
}
}
/**
* Removes and returns the first or last (depending on `operation`) entry
* from the QueueStore that's not older than the `maxRetentionTime`.
*
* @param {string} operation ('pop' or 'shift')
* @return {Object|undefined}
* @private
*/
async _removeRequest(
operation: 'pop' | 'shift',
): Promise<QueueEntry | undefined> {
const now = Date.now();
let entry: QueueStoreEntry | undefined;
switch (operation) {
case 'pop':
entry = await this._queueStore.popEntry();
break;
case 'shift':
entry = await this._queueStore.shiftEntry();
break;
}
if (entry) {
// Ignore requests older than maxRetentionTime. Call this function
// recursively until an unexpired request is found.
const maxRetentionTimeInMs = this._maxRetentionTime * 60 * 1000;
if (now - entry.timestamp > maxRetentionTimeInMs) {
return this._removeRequest(operation);
}
return convertEntry(entry);
} else {
return undefined;
}
}
/**
* Loops through each request in the queue and attempts to re-fetch it.
* If any request fails to re-fetch, it's put back in the same position in
* the queue (which registers a retry for the next sync event).
*/
async replayRequests(): Promise<void> {
let entry;
while ((entry = await this.shiftRequest())) {
try {
await fetch(entry.request.clone());
if (process.env.NODE_ENV !== 'production') {
logger.log(
`Request for '${getFriendlyURL(entry.request.url)}' ` +
`has been replayed in queue '${this._name}'`,
);
}
} catch (error) {
await this.unshiftRequest(entry);
if (process.env.NODE_ENV !== 'production') {
logger.log(
`Request for '${getFriendlyURL(entry.request.url)}' ` +
`failed to replay, putting it back in queue '${this._name}'`,
);
}
throw new WorkboxError('queue-replay-failed', {name: this._name});
}
}
if (process.env.NODE_ENV !== 'production') {
logger.log(
`All requests in queue '${this.name}' have successfully ` +
`replayed; the queue is now empty!`,
);
}
}
/**
* Registers a sync event with a tag unique to this instance.
*/
async registerSync(): Promise<void> {
// See https://github.com/GoogleChrome/workbox/issues/2393
if ('sync' in self.registration && !this._forceSyncFallback) {
try {
await self.registration.sync.register(`${TAG_PREFIX}:${this._name}`);
} catch (err) {
// This means the registration failed for some reason, possibly due to
// the user disabling it.
if (process.env.NODE_ENV !== 'production') {
logger.warn(
`Unable to register sync event for '${this._name}'.`,
err,
);
}
}
}
}
/**
* In sync-supporting browsers, this adds a listener for the sync event.
* In non-sync-supporting browsers, or if _forceSyncFallback is true, this
* will retry the queue on service worker startup.
*
* @private
*/
private _addSyncListener() {
// See https://github.com/GoogleChrome/workbox/issues/2393
if ('sync' in self.registration && !this._forceSyncFallback) {
self.addEventListener('sync', (event: SyncEvent) => {
if (event.tag === `${TAG_PREFIX}:${this._name}`) {
if (process.env.NODE_ENV !== 'production') {
logger.log(
`Background sync for tag '${event.tag}' ` + `has been received`,
);
}
const syncComplete = async () => {
this._syncInProgress = true;
let syncError;
try {
await this._onSync({queue: this});
} catch (error) {
if (error instanceof Error) {
syncError = error;
// Rethrow the error. Note: the logic in the finally clause
// will run before this gets rethrown.
throw syncError;
}
} finally {
// New items may have been added to the queue during the sync,
// so we need to register for a new sync if that's happened...
// Unless there was an error during the sync, in which
// case the browser will automatically retry later, as long
// as `event.lastChance` is not true.
if (
this._requestsAddedDuringSync &&
!(syncError && !event.lastChance)
) {
await this.registerSync();
}
this._syncInProgress = false;
this._requestsAddedDuringSync = false;
}
};
event.waitUntil(syncComplete());
}
});
} else {
if (process.env.NODE_ENV !== 'production') {
logger.log(`Background sync replaying without background sync event`);
}
// If the browser doesn't support background sync, or the developer has
// opted-in to not using it, retry every time the service worker starts up
// as a fallback.
void this._onSync({queue: this});
}
}
/**
* Returns the set of queue names. This is primarily used to reset the list
* of queue names in tests.
*
* @return {Set<string>}
*
* @private
*/
static get _queueNames(): Set<string> {
return queueNames;
}
}
export {Queue};