41 lines
1.0 KiB
TypeScript
41 lines
1.0 KiB
TypeScript
import { fetchUnifiedRates } from "@/lib/api/normalize";
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import type { RatesResponse } from "@/lib/rates";
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export const RATES_CACHE_TTL_MS = 60_000;
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export const RATES_CACHE_CONTROL_VALUE =
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"s-maxage=60, stale-while-revalidate=600";
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let cachedRates: RatesResponse | null = null;
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let cacheTimestamp = 0;
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let inFlightRequest: Promise<RatesResponse> | null = null;
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export async function getRatesWithCache(): Promise<RatesResponse> {
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const now = Date.now();
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const hasFreshCache = cachedRates && now - cacheTimestamp < RATES_CACHE_TTL_MS;
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if (hasFreshCache && cachedRates) {
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return cachedRates;
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}
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if (inFlightRequest) {
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return inFlightRequest;
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}
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inFlightRequest = (async () => {
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const freshRates = await fetchUnifiedRates();
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cachedRates = freshRates;
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cacheTimestamp = Date.now();
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return freshRates;
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})();
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try {
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return await inFlightRequest;
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} finally {
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inFlightRequest = null;
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}
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}
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export function getLastCachedRates(): RatesResponse | null {
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return cachedRates;
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}
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