44 lines
1.3 KiB
JavaScript
44 lines
1.3 KiB
JavaScript
import LRUCache from 'lru-cache';
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import fetchNpmPackageInfo from './fetchNpmPackageInfo';
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const maxMegabytes = 40; // Cap the cache at 40 MB
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const maxLength = maxMegabytes * 1024 * 1024;
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const oneSecond = 1000;
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const oneMinute = 60 * oneSecond;
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const cache = new LRUCache({
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max: maxLength,
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maxAge: oneMinute,
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length: Buffer.byteLength
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});
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const notFound = '';
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export default function getNpmPackageInfo(packageName) {
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return new Promise((resolve, reject) => {
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const key = `npmPackageInfo-${packageName}`;
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const value = cache.get(key);
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if (value != null) {
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resolve(value === notFound ? null : JSON.parse(value));
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} else {
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fetchNpmPackageInfo(packageName).then(info => {
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if (info == null) {
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// Cache 404s for 5 minutes. This prevents us from making
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// unnecessary requests to the registry for bad package names.
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// In the worst case, a brand new package's info will be
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// available within 5 minutes.
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cache.set(key, notFound, oneMinute * 5);
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resolve(null);
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} else {
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// Cache valid package info for 1 minute. In the worst case,
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// new versions won't be available for 1 minute.
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cache.set(key, JSON.stringify(info), oneMinute);
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resolve(info);
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}
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}, reject);
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}
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});
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}
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