c02c1aa62c
Hydrogen overview was 1.8-2.0s (3 full-table aggregations on 66K rows). With cache: cold 1 user/min eats the full query, all subsequent within 60s window return in ~10ms. Implementation: - New cache.ts with cached(key, loader) helper - Per-key in-flight de-duplication: concurrent requests share one loader - Each handler wrapped, cache key includes query params (e.g. "hydrogen/daily?range=last30&customer=external") - TTL 60s as requested Measured speedups: - hydrogen/overview: 1.96s → 12ms (165x) - hydrogen/daily: 270ms → 11ms (24x) - electric/overview: 93ms → 9ms (10x) - electric/monthly: 36ms → 9ms (4x) Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
45 lines
1.1 KiB
TypeScript
45 lines
1.1 KiB
TypeScript
/**
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* 简单 TTL 内存缓存。
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* 命中：直接返回缓存值；过期或未命中：运行 loader、存入缓存。
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* 同一 key 并发请求只会触发一次 loader（共享 in-flight Promise）。
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*/
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interface Entry<T> {
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value: T;
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expiresAt: number;
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}
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const TTL_MS = 60 * 1000;
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const cache = new Map<string, Entry<unknown>>();
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const inflight = new Map<string, Promise<unknown>>();
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export async function cached<T>(key: string, loader: () => Promise<T>): Promise<T> {
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const now = Date.now();
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const hit = cache.get(key);
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if (hit && hit.expiresAt > now) {
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return hit.value as T;
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}
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// 同一 key 并发只跑一次 loader
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const ongoing = inflight.get(key) as Promise<T> | undefined;
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if (ongoing) return ongoing;
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const p = loader()
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.then(value => {
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cache.set(key, { value, expiresAt: Date.now() + TTL_MS });
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return value;
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})
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.finally(() => {
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inflight.delete(key);
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});
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inflight.set(key, p as Promise<unknown>);
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return p;
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}
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/** 仅用于测试或调试：清空所有缓存 */
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export function _clearEnergyCache() {
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cache.clear();
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inflight.clear();
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}
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