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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 { assert } from 'workbox-core/_private/assert.js';
import { logger } from 'workbox-core/_private/logger.js';
import { WorkboxError } from 'workbox-core/_private/WorkboxError.js';
import { Strategy } from './Strategy.js';
import { messages } from './utils/messages.js';
import './_version.js';
/**
* An implementation of a [cache-first](https://developer.chrome.com/docs/workbox/caching-strategies-overview/#cache-first-falling-back-to-network)
* request strategy.
*
* A cache first strategy is useful for assets that have been revisioned,
* such as URLs like `/styles/example.a8f5f1.css`, since they
* can be cached for long periods of time.
*
* If the network request fails, and there is no cache match, this will throw
* a `WorkboxError` exception.
*
* @extends workbox-strategies.Strategy
* @memberof workbox-strategies
*/
class CacheFirst extends Strategy {
/**
* @private
* @param {Request|string} request A request to run this strategy for.
* @param {workbox-strategies.StrategyHandler} handler The event that
* triggered the request.
* @return {Promise<Response>}
*/
async _handle(request, handler) {
const logs = [];
if (process.env.NODE_ENV !== 'production') {
assert.isInstance(request, Request, {
moduleName: 'workbox-strategies',
className: this.constructor.name,
funcName: 'makeRequest',
paramName: 'request',
});
}
let response = await handler.cacheMatch(request);
let error = undefined;
if (!response) {
if (process.env.NODE_ENV !== 'production') {
logs.push(`No response found in the '${this.cacheName}' cache. ` +
`Will respond with a network request.`);
}
try {
response = await handler.fetchAndCachePut(request);
}
catch (err) {
if (err instanceof Error) {
error = err;
}
}
if (process.env.NODE_ENV !== 'production') {
if (response) {
logs.push(`Got response from network.`);
}
else {
logs.push(`Unable to get a response from the network.`);
}
}
}
else {
if (process.env.NODE_ENV !== 'production') {
logs.push(`Found a cached response in the '${this.cacheName}' cache.`);
}
}
if (process.env.NODE_ENV !== 'production') {
logger.groupCollapsed(messages.strategyStart(this.constructor.name, request));
for (const log of logs) {
logger.log(log);
}
messages.printFinalResponse(response);
logger.groupEnd();
}
if (!response) {
throw new WorkboxError('no-response', { url: request.url, error });
}
return response;
}
}
export { CacheFirst };