151 lines
3.9 KiB
TypeScript
151 lines
3.9 KiB
TypeScript
import { getRedisCache } from './redis';
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export async function getCache<T>(
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key: string,
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expireInSec: number,
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fn: () => Promise<T>,
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): Promise<T> {
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const hit = await getRedisCache().get(key);
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if (hit) {
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return JSON.parse(hit, (_, value) => {
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if (
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typeof value === 'string' &&
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/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.*Z$/.test(value)
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) {
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return new Date(value);
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}
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return value;
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});
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}
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const data = await fn();
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await getRedisCache().setex(key, expireInSec, JSON.stringify(data));
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return data;
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}
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function stringify(obj: unknown): string {
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if (obj === null) return 'null';
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if (obj === undefined) return 'undefined';
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if (typeof obj === 'boolean') return obj ? 'true' : 'false';
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if (typeof obj === 'number') return String(obj);
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if (typeof obj === 'string') return obj;
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if (typeof obj === 'function') return obj.toString();
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if (Array.isArray(obj)) {
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return `[${obj.map(stringify).join(',')}]`;
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}
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if (typeof obj === 'object') {
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const pairs = Object.entries(obj)
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.sort(([a], [b]) => a.localeCompare(b))
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.map(([key, value]) => `${key}:${stringify(value)}`);
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return pairs.join(':');
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}
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// Fallback for any other types
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return String(obj);
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}
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function hasResult(result: unknown): boolean {
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// Don't cache undefined or null
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if (result === undefined || result === null) {
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return false;
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}
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// Don't cache empty strings
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if (typeof result === 'string') {
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return result.length > 0;
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}
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// Don't cache empty arrays
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if (Array.isArray(result)) {
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return result.length > 0;
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}
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// Don't cache empty objects
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if (typeof result === 'object' && result !== null) {
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return Object.keys(result).length > 0;
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}
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// Cache everything else (booleans, numbers, etc.)
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return true;
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}
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export function cacheable<T extends (...args: any) => any>(
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fnOrName: T | string,
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fnOrExpireInSec: number | T,
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_expireInSec?: number,
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) {
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const name = typeof fnOrName === 'string' ? fnOrName : fnOrName.name;
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const fn =
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typeof fnOrName === 'function'
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? fnOrName
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: typeof fnOrExpireInSec === 'function'
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? fnOrExpireInSec
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: null;
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const expireInSec =
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typeof fnOrExpireInSec === 'number'
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? fnOrExpireInSec
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: typeof _expireInSec === 'number'
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? _expireInSec
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: null;
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if (typeof fn !== 'function') {
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throw new Error('fn is not a function');
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}
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if (typeof expireInSec !== 'number') {
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throw new Error('expireInSec is not a number');
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}
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const cachePrefix = `cachable:${name}`;
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const getKey = (...args: Parameters<T>) =>
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`${cachePrefix}:${stringify(args)}`;
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const cachedFn = async (
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...args: Parameters<T>
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): Promise<Awaited<ReturnType<T>>> => {
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// JSON.stringify here is not bullet proof since ordering of object keys matters etc
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const key = getKey(...args);
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const cached = await getRedisCache().get(key);
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if (cached) {
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try {
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const parsed = JSON.parse(cached, (_, value) => {
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if (
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typeof value === 'string' &&
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/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.*Z$/.test(value)
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) {
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return new Date(value);
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}
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return value;
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});
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if (hasResult(parsed)) {
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return parsed;
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}
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} catch (e) {
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console.error('Failed to parse cache', e);
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}
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}
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const result = await fn(...(args as any));
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if (hasResult(result)) {
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getRedisCache().setex(key, expireInSec, JSON.stringify(result));
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}
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return result;
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};
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cachedFn.getKey = getKey;
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cachedFn.clear = async (...args: Parameters<T>) => {
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const key = getKey(...args);
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return getRedisCache().del(key);
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};
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cachedFn.set =
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(...args: Parameters<T>) =>
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async (payload: Awaited<ReturnType<T>>) => {
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const key = getKey(...args);
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return getRedisCache().setex(key, expireInSec, JSON.stringify(payload));
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};
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return cachedFn;
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}
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