Arnaud
94 lines
2.9 KiB
TypeScript
94 lines
2.9 KiB
TypeScript
import { NextRequest, NextResponse } from "next/server";
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import crypto from "node:crypto";
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// Stripe webhook handler — verifies stripe-signature header using HMAC-SHA256.
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// Handles:
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// - checkout.session.completed → upgrade user to pro
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// - customer.subscription.deleted → downgrade user to free
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const STRIPE_TOLERANCE_SECONDS = 300; // 5 minutes
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function verifyStripeSignature(
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rawBody: string,
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sigHeader: string,
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secret: string
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): { valid: boolean; payload: string | null } {
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// sigHeader format: "t=<timestamp>,v1=<hmac>[,v1=<hmac>...]"
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const parts = sigHeader.split(",");
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const tPart = parts.find((p) => p.startsWith("t="));
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const v1Parts = parts.filter((p) => p.startsWith("v1="));
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if (!tPart || v1Parts.length === 0) {
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return { valid: false, payload: null };
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}
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const timestamp = tPart.slice(2);
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const tsNum = parseInt(timestamp, 10);
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if (isNaN(tsNum)) return { valid: false, payload: null };
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// Reject stale webhooks
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const nowSec = Math.floor(Date.now() / 1000);
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if (Math.abs(nowSec - tsNum) > STRIPE_TOLERANCE_SECONDS) {
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return { valid: false, payload: null };
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}
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const signedPayload = `${timestamp}.${rawBody}`;
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const expected = crypto
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.createHmac("sha256", secret)
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.update(signedPayload, "utf8")
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.digest();
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const matched = v1Parts.some((v1Part) => {
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const provided = v1Part.slice(3); // strip "v1="
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let providedBuf: Buffer;
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try {
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providedBuf = Buffer.from(provided, "hex");
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} catch {
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return false;
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}
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if (providedBuf.length !== expected.length) return false;
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return crypto.timingSafeEqual(expected, providedBuf);
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});
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return { valid: matched, payload: matched ? rawBody : null };
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}
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export async function POST(req: NextRequest) {
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const body = await req.text();
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const sig = req.headers.get("stripe-signature");
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const webhookSecret = process.env["STRIPE_WEBHOOK_SECRET"];
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if (!sig || !webhookSecret) {
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return NextResponse.json({ error: "Stripe not configured" }, { status: 400 });
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}
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const { valid } = verifyStripeSignature(body, sig, webhookSecret);
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if (!valid) {
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return NextResponse.json({ error: "Invalid signature" }, { status: 400 });
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}
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let event: { type: string; data: { object: Record<string, unknown> } };
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try {
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event = JSON.parse(body) as typeof event;
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} catch {
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return NextResponse.json({ error: "Invalid JSON" }, { status: 400 });
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}
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// TODO: wire up DB calls when Stripe billing is fully configured
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switch (event.type) {
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case "checkout.session.completed":
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// upgrade user to pro
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console.log("[stripe-webhook] checkout.session.completed", event.data.object["id"]);
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break;
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case "customer.subscription.deleted":
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// downgrade user to free
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console.log("[stripe-webhook] customer.subscription.deleted", event.data.object["id"]);
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break;
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default:
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// ignore unhandled event types
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break;
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}
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return NextResponse.json({ received: true });
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}
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