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/*
Copyright 2020 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 { cacheNames } from 'workbox-core/_private/cacheNames.js';
import { WorkboxError } from 'workbox-core/_private/WorkboxError.js';
import { logger } from 'workbox-core/_private/logger.js';
import { getFriendlyURL } from 'workbox-core/_private/getFriendlyURL.js';
import { StrategyHandler } from './StrategyHandler.js';
import './_version.js';
/**
* An abstract base class that all other strategy classes must extend from:
*
* @memberof workbox-strategies
*/
class Strategy {
/**
* Creates a new instance of the strategy and sets all documented option
* properties as public instance properties.
*
* Note: if a custom strategy class extends the base Strategy class and does
* not need more than these properties, it does not need to define its own
* constructor.
*
* @param {Object} [options]
* @param {string} [options.cacheName] Cache name to store and retrieve
* requests. Defaults to the cache names provided by
* {@link workbox-core.cacheNames}.
* @param {Array<Object>} [options.plugins] [Plugins]{@link https://developers.google.com/web/tools/workbox/guides/using-plugins}
* to use in conjunction with this caching strategy.
* @param {Object} [options.fetchOptions] Values passed along to the
* [`init`](https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch#Parameters)
* of [non-navigation](https://github.com/GoogleChrome/workbox/issues/1796)
* `fetch()` requests made by this strategy.
* @param {Object} [options.matchOptions] The
* [`CacheQueryOptions`]{@link https://w3c.github.io/ServiceWorker/#dictdef-cachequeryoptions}
* for any `cache.match()` or `cache.put()` calls made by this strategy.
*/
constructor(options = {}) {
/**
* Cache name to store and retrieve
* requests. Defaults to the cache names provided by
* {@link workbox-core.cacheNames}.
*
* @type {string}
*/
this.cacheName = cacheNames.getRuntimeName(options.cacheName);
/**
* The list
* [Plugins]{@link https://developers.google.com/web/tools/workbox/guides/using-plugins}
* used by this strategy.
*
* @type {Array<Object>}
*/
this.plugins = options.plugins || [];
/**
* Values passed along to the
* [`init`]{@link https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch#Parameters}
* of all fetch() requests made by this strategy.
*
* @type {Object}
*/
this.fetchOptions = options.fetchOptions;
/**
* The
* [`CacheQueryOptions`]{@link https://w3c.github.io/ServiceWorker/#dictdef-cachequeryoptions}
* for any `cache.match()` or `cache.put()` calls made by this strategy.
*
* @type {Object}
*/
this.matchOptions = options.matchOptions;
}
/**
* Perform a request strategy and returns a `Promise` that will resolve with
* a `Response`, invoking all relevant plugin callbacks.
*
* When a strategy instance is registered with a Workbox
* {@link workbox-routing.Route}, this method is automatically
* called when the route matches.
*
* Alternatively, this method can be used in a standalone `FetchEvent`
* listener by passing it to `event.respondWith()`.
*
* @param {FetchEvent|Object} options A `FetchEvent` or an object with the
* properties listed below.
* @param {Request|string} options.request A request to run this strategy for.
* @param {ExtendableEvent} options.event The event associated with the
* request.
* @param {URL} [options.url]
* @param {*} [options.params]
*/
handle(options) {
const [responseDone] = this.handleAll(options);
return responseDone;
}
/**
* Similar to {@link workbox-strategies.Strategy~handle}, but
* instead of just returning a `Promise` that resolves to a `Response` it
* it will return an tuple of `[response, done]` promises, where the former
* (`response`) is equivalent to what `handle()` returns, and the latter is a
* Promise that will resolve once any promises that were added to
* `event.waitUntil()` as part of performing the strategy have completed.
*
* You can await the `done` promise to ensure any extra work performed by
* the strategy (usually caching responses) completes successfully.
*
* @param {FetchEvent|Object} options A `FetchEvent` or an object with the
* properties listed below.
* @param {Request|string} options.request A request to run this strategy for.
* @param {ExtendableEvent} options.event The event associated with the
* request.
* @param {URL} [options.url]
* @param {*} [options.params]
* @return {Array<Promise>} A tuple of [response, done]
* promises that can be used to determine when the response resolves as
* well as when the handler has completed all its work.
*/
handleAll(options) {
// Allow for flexible options to be passed.
if (options instanceof FetchEvent) {
options = {
event: options,
request: options.request,
};
}
const event = options.event;
const request = typeof options.request === 'string'
? new Request(options.request)
: options.request;
const params = 'params' in options ? options.params : undefined;
const handler = new StrategyHandler(this, { event, request, params });
const responseDone = this._getResponse(handler, request, event);
const handlerDone = this._awaitComplete(responseDone, handler, request, event);
// Return an array of promises, suitable for use with Promise.all().
return [responseDone, handlerDone];
}
async _getResponse(handler, request, event) {
await handler.runCallbacks('handlerWillStart', { event, request });
let response = undefined;
try {
response = await this._handle(request, handler);
// The "official" Strategy subclasses all throw this error automatically,
// but in case a third-party Strategy doesn't, ensure that we have a
// consistent failure when there's no response or an error response.
if (!response || response.type === 'error') {
throw new WorkboxError('no-response', { url: request.url });
}
}
catch (error) {
if (error instanceof Error) {
for (const callback of handler.iterateCallbacks('handlerDidError')) {
response = await callback({ error, event, request });
if (response) {
break;
}
}
}
if (!response) {
throw error;
}
else if (process.env.NODE_ENV !== 'production') {
logger.log(`While responding to '${getFriendlyURL(request.url)}', ` +
`an ${error instanceof Error ? error.toString() : ''} error occurred. Using a fallback response provided by ` +
`a handlerDidError plugin.`);
}
}
for (const callback of handler.iterateCallbacks('handlerWillRespond')) {
response = await callback({ event, request, response });
}
return response;
}
async _awaitComplete(responseDone, handler, request, event) {
let response;
let error;
try {
response = await responseDone;
}
catch (error) {
// Ignore errors, as response errors should be caught via the `response`
// promise above. The `done` promise will only throw for errors in
// promises passed to `handler.waitUntil()`.
}
try {
await handler.runCallbacks('handlerDidRespond', {
event,
request,
response,
});
await handler.doneWaiting();
}
catch (waitUntilError) {
if (waitUntilError instanceof Error) {
error = waitUntilError;
}
}
await handler.runCallbacks('handlerDidComplete', {
event,
request,
response,
error: error,
});
handler.destroy();
if (error) {
throw error;
}
}
}
export { Strategy };
/**
* Classes extending the `Strategy` based class should implement this method,
* and leverage the {@link workbox-strategies.StrategyHandler}
* arg to perform all fetching and cache logic, which will ensure all relevant
* cache, cache options, fetch options and plugins are used (per the current
* strategy instance).
*
* @name _handle
* @instance
* @abstract
* @function
* @param {Request} request
* @param {workbox-strategies.StrategyHandler} handler
* @return {Promise<Response>}
*
* @memberof workbox-strategies.Strategy
*/