34 lines
1.4 KiB
JavaScript
34 lines
1.4 KiB
JavaScript
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import { toHex } from "@smithy/util-hex-encoding";
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import { toUint8Array } from "@smithy/util-utf8";
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import { KEY_TYPE_IDENTIFIER, MAX_CACHE_SIZE } from "./constants";
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const signingKeyCache = {};
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const cacheQueue = [];
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export const createScope = (shortDate, region, service) => `${shortDate}/${region}/${service}/${KEY_TYPE_IDENTIFIER}`;
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export const getSigningKey = async (sha256Constructor, credentials, shortDate, region, service) => {
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const credsHash = await hmac(sha256Constructor, credentials.secretAccessKey, credentials.accessKeyId);
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const cacheKey = `${shortDate}:${region}:${service}:${toHex(credsHash)}:${credentials.sessionToken}`;
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if (cacheKey in signingKeyCache) {
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return signingKeyCache[cacheKey];
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}
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cacheQueue.push(cacheKey);
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while (cacheQueue.length > MAX_CACHE_SIZE) {
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delete signingKeyCache[cacheQueue.shift()];
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}
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let key = `AWS4${credentials.secretAccessKey}`;
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for (const signable of [shortDate, region, service, KEY_TYPE_IDENTIFIER]) {
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key = await hmac(sha256Constructor, key, signable);
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}
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return (signingKeyCache[cacheKey] = key);
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};
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export const clearCredentialCache = () => {
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cacheQueue.length = 0;
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Object.keys(signingKeyCache).forEach((cacheKey) => {
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delete signingKeyCache[cacheKey];
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});
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};
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const hmac = (ctor, secret, data) => {
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const hash = new ctor(secret);
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hash.update(toUint8Array(data));
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return hash.digest();
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};
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