/*
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 { assert } from 'workbox-core/_private/assert.js';
import { cacheMatchIgnoreParams } from 'workbox-core/_private/cacheMatchIgnoreParams.js';
import { Deferred } from 'workbox-core/_private/Deferred.js';
import { executeQuotaErrorCallbacks } from 'workbox-core/_private/executeQuotaErrorCallbacks.js';
import { getFriendlyURL } from 'workbox-core/_private/getFriendlyURL.js';
import { logger } from 'workbox-core/_private/logger.js';
import { timeout } from 'workbox-core/_private/timeout.js';
import { WorkboxError } from 'workbox-core/_private/WorkboxError.js';
import './_version.js';
function toRequest(input) {
return typeof input === 'string' ? new Request(input) : input;
}
/**
* A class created every time a Strategy instance instance calls
* {@link workbox-strategies.Strategy~handle} or
* {@link workbox-strategies.Strategy~handleAll} that wraps all fetch and
* cache actions around plugin callbacks and keeps track of when the strategy
* is "done" (i.e. all added `event.waitUntil()` promises have resolved).
*
* @memberof workbox-strategies
*/
class StrategyHandler {
/**
* Creates a new instance associated with the passed strategy and event
* that's handling the request.
*
* The constructor also initializes the state that will be passed to each of
* the plugins handling this request.
*
* @param {workbox-strategies.Strategy} strategy
* @param {Object} options
* @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] The return value from the
* {@link workbox-routing~matchCallback} (if applicable).
*/
constructor(strategy, options) {
this._cacheKeys = {};
/**
* The request the strategy is performing (passed to the strategy's
* `handle()` or `handleAll()` method).
* @name request
* @instance
* @type {Request}
* @memberof workbox-strategies.StrategyHandler
*/
/**
* The event associated with this request.
* @name event
* @instance
* @type {ExtendableEvent}
* @memberof workbox-strategies.StrategyHandler
*/
/**
* A `URL` instance of `request.url` (if passed to the strategy's
* `handle()` or `handleAll()` method).
* Note: the `url` param will be present if the strategy was invoked
* from a workbox `Route` object.
* @name url
* @instance
* @type {URL|undefined}
* @memberof workbox-strategies.StrategyHandler
*/
/**
* A `param` value (if passed to the strategy's
* `handle()` or `handleAll()` method).
* Note: the `param` param will be present if the strategy was invoked
* from a workbox `Route` object and the
* {@link workbox-routing~matchCallback} returned
* a truthy value (it will be that value).
* @name params
* @instance
* @type {*|undefined}
* @memberof workbox-strategies.StrategyHandler
*/
if (process.env.NODE_ENV !== 'production') {
assert.isInstance(options.event, ExtendableEvent, {
moduleName: 'workbox-strategies',
className: 'StrategyHandler',
funcName: 'constructor',
paramName: 'options.event',
});
}
Object.assign(this, options);
this.event = options.event;
this._strategy = strategy;
this._handlerDeferred = new Deferred();
this._extendLifetimePromises = [];
// Copy the plugins list (since it's mutable on the strategy),
// so any mutations don't affect this handler instance.
this._plugins = [...strategy.plugins];
this._pluginStateMap = new Map();
for (const plugin of this._plugins) {
this._pluginStateMap.set(plugin, {});
}
this.event.waitUntil(this._handlerDeferred.promise);
}
/**
* Fetches a given request (and invokes any applicable plugin callback
* methods) using the `fetchOptions` (for non-navigation requests) and
* `plugins` defined on the `Strategy` object.
*
* The following plugin lifecycle methods are invoked when using this method:
* - `requestWillFetch()`
* - `fetchDidSucceed()`
* - `fetchDidFail()`
*
* @param {Request|string} input The URL or request to fetch.
* @return {Promise<Response>}
*/
async fetch(input) {
const { event } = this;
let request = toRequest(input);
if (request.mode === 'navigate' &&
event instanceof FetchEvent &&
event.preloadResponse) {
const possiblePreloadResponse = (await event.preloadResponse);
if (possiblePreloadResponse) {
if (process.env.NODE_ENV !== 'production') {
logger.log(`Using a preloaded navigation response for ` +
`'${getFriendlyURL(request.url)}'`);
}
return possiblePreloadResponse;
}
}
// If there is a fetchDidFail plugin, we need to save a clone of the
// original request before it's either modified by a requestWillFetch
// plugin or before the original request's body is consumed via fetch().
const originalRequest = this.hasCallback('fetchDidFail')
? request.clone()
: null;
try {
for (const cb of this.iterateCallbacks('requestWillFetch')) {
request = await cb({ request: request.clone(), event });
}
}
catch (err) {
if (err instanceof Error) {
throw new WorkboxError('plugin-error-request-will-fetch', {
thrownErrorMessage: err.message,
});
}
}
// The request can be altered by plugins with `requestWillFetch` making
// the original request (most likely from a `fetch` event) different
// from the Request we make. Pass both to `fetchDidFail` to aid debugging.
const pluginFilteredRequest = request.clone();
try {
let fetchResponse;
// See https://github.com/GoogleChrome/workbox/issues/1796
fetchResponse = await fetch(request, request.mode === 'navigate' ? undefined : this._strategy.fetchOptions);
if (process.env.NODE_ENV !== 'production') {
logger.debug(`Network request for ` +
`'${getFriendlyURL(request.url)}' returned a response with ` +
`status '${fetchResponse.status}'.`);
}
for (const callback of this.iterateCallbacks('fetchDidSucceed')) {
fetchResponse = await callback({
event,
request: pluginFilteredRequest,
response: fetchResponse,
});
}
return fetchResponse;
}
catch (error) {
if (process.env.NODE_ENV !== 'production') {
logger.log(`Network request for ` +
`'${getFriendlyURL(request.url)}' threw an error.`, error);
}
// `originalRequest` will only exist if a `fetchDidFail` callback
// is being used (see above).
if (originalRequest) {
await this.runCallbacks('fetchDidFail', {
error: error,
event,
originalRequest: originalRequest.clone(),
request: pluginFilteredRequest.clone(),
});
}
throw error;
}
}
/**
* Calls `this.fetch()` and (in the background) runs `this.cachePut()` on
* the response generated by `this.fetch()`.
*
* The call to `this.cachePut()` automatically invokes `this.waitUntil()`,
* so you do not have to manually call `waitUntil()` on the event.
*
* @param {Request|string} input The request or URL to fetch and cache.
* @return {Promise<Response>}
*/
async fetchAndCachePut(input) {
const response = await this.fetch(input);
const responseClone = response.clone();
void this.waitUntil(this.cachePut(input, responseClone));
return response;
}
/**
* Matches a request from the cache (and invokes any applicable plugin
* callback methods) using the `cacheName`, `matchOptions`, and `plugins`
* defined on the strategy object.
*
* The following plugin lifecycle methods are invoked when using this method:
* - cacheKeyWillByUsed()
* - cachedResponseWillByUsed()
*
* @param {Request|string} key The Request or URL to use as the cache key.
* @return {Promise<Response|undefined>} A matching response, if found.
*/
async cacheMatch(key) {
const request = toRequest(key);
let cachedResponse;
const { cacheName, matchOptions } = this._strategy;
const effectiveRequest = await this.getCacheKey(request, 'read');
const multiMatchOptions = Object.assign(Object.assign({}, matchOptions), { cacheName });
cachedResponse = await caches.match(effectiveRequest, multiMatchOptions);
if (process.env.NODE_ENV !== 'production') {
if (cachedResponse) {
logger.debug(`Found a cached response in '${cacheName}'.`);
}
else {
logger.debug(`No cached response found in '${cacheName}'.`);
}
}
for (const callback of this.iterateCallbacks('cachedResponseWillBeUsed')) {
cachedResponse =
(await callback({
cacheName,
matchOptions,
cachedResponse,
request: effectiveRequest,
event: this.event,
})) || undefined;
}
return cachedResponse;
}
/**
* Puts a request/response pair in the cache (and invokes any applicable
* plugin callback methods) using the `cacheName` and `plugins` defined on
* the strategy object.
*
* The following plugin lifecycle methods are invoked when using this method:
* - cacheKeyWillByUsed()
* - cacheWillUpdate()
* - cacheDidUpdate()
*
* @param {Request|string} key The request or URL to use as the cache key.
* @param {Response} response The response to cache.
* @return {Promise<boolean>} `false` if a cacheWillUpdate caused the response
* not be cached, and `true` otherwise.
*/
async cachePut(key, response) {
const request = toRequest(key);
// Run in the next task to avoid blocking other cache reads.
// https://github.com/w3c/ServiceWorker/issues/1397
await timeout(0);
const effectiveRequest = await this.getCacheKey(request, 'write');
if (process.env.NODE_ENV !== 'production') {
if (effectiveRequest.method && effectiveRequest.method !== 'GET') {
throw new WorkboxError('attempt-to-cache-non-get-request', {
url: getFriendlyURL(effectiveRequest.url),
method: effectiveRequest.method,
});
}
// See https://github.com/GoogleChrome/workbox/issues/2818
const vary = response.headers.get('Vary');
if (vary) {
logger.debug(`The response for ${getFriendlyURL(effectiveRequest.url)} ` +
`has a 'Vary: ${vary}' header. ` +
`Consider setting the {ignoreVary: true} option on your strategy ` +
`to ensure cache matching and deletion works as expected.`);
}
}
if (!response) {
if (process.env.NODE_ENV !== 'production') {
logger.error(`Cannot cache non-existent response for ` +
`'${getFriendlyURL(effectiveRequest.url)}'.`);
}
throw new WorkboxError('cache-put-with-no-response', {
url: getFriendlyURL(effectiveRequest.url),
});
}
const responseToCache = await this._ensureResponseSafeToCache(response);
if (!responseToCache) {
if (process.env.NODE_ENV !== 'production') {
logger.debug(`Response '${getFriendlyURL(effectiveRequest.url)}' ` +
`will not be cached.`, responseToCache);
}
return false;
}
const { cacheName, matchOptions } = this._strategy;
const cache = await self.caches.open(cacheName);
const hasCacheUpdateCallback = this.hasCallback('cacheDidUpdate');
const oldResponse = hasCacheUpdateCallback
? await cacheMatchIgnoreParams(
// TODO(philipwalton): the `__WB_REVISION__` param is a precaching
// feature. Consider into ways to only add this behavior if using
// precaching.
cache, effectiveRequest.clone(), ['__WB_REVISION__'], matchOptions)
: null;
if (process.env.NODE_ENV !== 'production') {
logger.debug(`Updating the '${cacheName}' cache with a new Response ` +
`for ${getFriendlyURL(effectiveRequest.url)}.`);
}
try {
await cache.put(effectiveRequest, hasCacheUpdateCallback ? responseToCache.clone() : responseToCache);
}
catch (error) {
if (error instanceof Error) {
// See https://developer.mozilla.org/en-US/docs/Web/API/DOMException#exception-QuotaExceededError
if (error.name === 'QuotaExceededError') {
await executeQuotaErrorCallbacks();
}
throw error;
}
}
for (const callback of this.iterateCallbacks('cacheDidUpdate')) {
await callback({
cacheName,
oldResponse,
newResponse: responseToCache.clone(),
request: effectiveRequest,
event: this.event,
});
}
return true;
}
/**
* Checks the list of plugins for the `cacheKeyWillBeUsed` callback, and
* executes any of those callbacks found in sequence. The final `Request`
* object returned by the last plugin is treated as the cache key for cache
* reads and/or writes. If no `cacheKeyWillBeUsed` plugin callbacks have
* been registered, the passed request is returned unmodified
*
* @param {Request} request
* @param {string} mode
* @return {Promise<Request>}
*/
async getCacheKey(request, mode) {
const key = `${request.url} | ${mode}`;
if (!this._cacheKeys[key]) {
let effectiveRequest = request;
for (const callback of this.iterateCallbacks('cacheKeyWillBeUsed')) {
effectiveRequest = toRequest(await callback({
mode,
request: effectiveRequest,
event: this.event,
// params has a type any can't change right now.
params: this.params, // eslint-disable-line
}));
}
this._cacheKeys[key] = effectiveRequest;
}
return this._cacheKeys[key];
}
/**
* Returns true if the strategy has at least one plugin with the given
* callback.
*
* @param {string} name The name of the callback to check for.
* @return {boolean}
*/
hasCallback(name) {
for (const plugin of this._strategy.plugins) {
if (name in plugin) {
return true;
}
}
return false;
}
/**
* Runs all plugin callbacks matching the given name, in order, passing the
* given param object (merged ith the current plugin state) as the only
* argument.
*
* Note: since this method runs all plugins, it's not suitable for cases
* where the return value of a callback needs to be applied prior to calling
* the next callback. See
* {@link workbox-strategies.StrategyHandler#iterateCallbacks}
* below for how to handle that case.
*
* @param {string} name The name of the callback to run within each plugin.
* @param {Object} param The object to pass as the first (and only) param
* when executing each callback. This object will be merged with the
* current plugin state prior to callback execution.
*/
async runCallbacks(name, param) {
for (const callback of this.iterateCallbacks(name)) {
// TODO(philipwalton): not sure why `any` is needed. It seems like
// this should work with `as WorkboxPluginCallbackParam[C]`.
await callback(param);
}
}
/**
* Accepts a callback and returns an iterable of matching plugin callbacks,
* where each callback is wrapped with the current handler state (i.e. when
* you call each callback, whatever object parameter you pass it will
* be merged with the plugin's current state).
*
* @param {string} name The name fo the callback to run
* @return {Array<Function>}
*/
*iterateCallbacks(name) {
for (const plugin of this._strategy.plugins) {
if (typeof plugin[name] === 'function') {
const state = this._pluginStateMap.get(plugin);
const statefulCallback = (param) => {
const statefulParam = Object.assign(Object.assign({}, param), { state });
// TODO(philipwalton): not sure why `any` is needed. It seems like
// this should work with `as WorkboxPluginCallbackParam[C]`.
return plugin[name](statefulParam);
};
yield statefulCallback;
}
}
}
/**
* Adds a promise to the
* [extend lifetime promises]{@link https://w3c.github.io/ServiceWorker/#extendableevent-extend-lifetime-promises}
* of the event event associated with the request being handled (usually a
* `FetchEvent`).
*
* Note: you can await
* {@link workbox-strategies.StrategyHandler~doneWaiting}
* to know when all added promises have settled.
*
* @param {Promise} promise A promise to add to the extend lifetime promises
* of the event that triggered the request.
*/
waitUntil(promise) {
this._extendLifetimePromises.push(promise);
return promise;
}
/**
* Returns a promise that resolves once all promises passed to
* {@link workbox-strategies.StrategyHandler~waitUntil}
* have settled.
*
* Note: any work done after `doneWaiting()` settles should be manually
* passed to an event's `waitUntil()` method (not this handler's
* `waitUntil()` method), otherwise the service worker thread my be killed
* prior to your work completing.
*/
async doneWaiting() {
let promise;
while ((promise = this._extendLifetimePromises.shift())) {
await promise;
}
}
/**
* Stops running the strategy and immediately resolves any pending
* `waitUntil()` promises.
*/
destroy() {
this._handlerDeferred.resolve(null);
}
/**
* This method will call cacheWillUpdate on the available plugins (or use
* status === 200) to determine if the Response is safe and valid to cache.
*
* @param {Request} options.request
* @param {Response} options.response
* @return {Promise<Response|undefined>}
*
* @private
*/
async _ensureResponseSafeToCache(response) {
let responseToCache = response;
let pluginsUsed = false;
for (const callback of this.iterateCallbacks('cacheWillUpdate')) {
responseToCache =
(await callback({
request: this.request,
response: responseToCache,
event: this.event,
})) || undefined;
pluginsUsed = true;
if (!responseToCache) {
break;
}
}
if (!pluginsUsed) {
if (responseToCache && responseToCache.status !== 200) {
responseToCache = undefined;
}
if (process.env.NODE_ENV !== 'production') {
if (responseToCache) {
if (responseToCache.status !== 200) {
if (responseToCache.status === 0) {
logger.warn(`The response for '${this.request.url}' ` +
`is an opaque response. The caching strategy that you're ` +
`using will not cache opaque responses by default.`);
}
else {
logger.debug(`The response for '${this.request.url}' ` +
`returned a status code of '${response.status}' and won't ` +
`be cached as a result.`);
}
}
}
}
}
return responseToCache;
}
}
export { StrategyHandler };