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https://github.com/caty21/forex-dashboard.git
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Capucine Gest
51 lines
2.3 KiB
TypeScript
51 lines
2.3 KiB
TypeScript
import { NextResponse } from "next/server";
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// AV primary (real-time) → Frankfurter fallback (ECB daily)
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// AV free plan: 25 req/day, 5 req/min
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// With revalidate:86400, server fetches each URL at most once per day → 7 calls/day total
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const CURRENCIES = ["EUR", "GBP", "JPY", "CHF", "CAD", "AUD", "NZD"];
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const AV_BASE = "https://www.alphavantage.co/query";
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export async function GET() {
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const avKey = process.env.ALPHA_VANTAGE_KEY;
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if (avKey) {
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const result = await fetchAV(avKey);
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if (result) return NextResponse.json(result);
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}
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return fetchFrankfurter();
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}
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async function fetchAV(apiKey: string) {
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// Sequential (not parallel) to respect AV's 5 req/min limit
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const rates: Record<string, number> = {};
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for (const ccy of CURRENCIES) {
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try {
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const url = `${AV_BASE}?function=CURRENCY_EXCHANGE_RATE&from_currency=USD&to_currency=${ccy}&apikey=${apiKey}`;
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const res = await fetch(url, { next: { revalidate: 86400 } }); // 24h server cache
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if (!res.ok) continue;
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const json = await res.json();
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const rate = json?.["Realtime Currency Exchange Rate"]?.["5. Exchange Rate"];
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if (rate) rates[ccy] = parseFloat(rate);
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} catch { /* skip on error */ }
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}
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if (Object.keys(rates).length < 4) return null; // too many failures → fall back
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// Approximate DXY from fetched pairs (no extra AV call needed)
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// DXY = 50.14 × EUR^0.576 × (1/JPY)^0.136 × GBP^0.119 × (1/CAD)^0.091 × (1/CHF)^0.036
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const e = rates.EUR, g = rates.GBP, j = rates.JPY, c = rates.CAD, ch = rates.CHF;
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const dxy = (e && g && j && c && ch)
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? parseFloat((50.14348112 * Math.pow(e,0.576) * Math.pow(1/j,0.136) * Math.pow(g,0.119) * Math.pow(1/c,0.091) * Math.pow(1/ch,0.036)).toFixed(3))
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: null;
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return { rates, dxy, base: "USD", source: "alphavantage", timestamp: Date.now() };
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}
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async function fetchFrankfurter() {
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try {
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const res = await fetch("https://api.frankfurter.app/latest?from=USD", { next: { revalidate: 86400 } });
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if (!res.ok) throw new Error(`Frankfurter ${res.status}`);
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const data = await res.json();
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return NextResponse.json({ rates: data.rates, dxy: null, base: "USD", source: "frankfurter", date: data.date });
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} catch (err) {
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return NextResponse.json({ error: String(err) }, { status: 502 });
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}
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}
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