Gerhard Scheikl
56 lines
2.0 KiB
TypeScript
56 lines
2.0 KiB
TypeScript
import crypto from "node:crypto";
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import { optionalEnv } from "../config/env.server";
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/**
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* Resolves the GiroCode URL signing key lazily (per call, not at module load)
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* so the process can boot even when only the fallback secret is present.
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*
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* Prefers the dedicated `GIROCODE_SIGNING_KEY`; falls back to
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* `SHOPIFY_API_SECRET` ONLY when the dedicated key is unset, so existing
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* signed URLs and deployments keep working. Throws if neither is set
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* (fail closed) — an empty key would make signatures forgeable.
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*/
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function getSigningKey(): string {
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const key = optionalEnv("GIROCODE_SIGNING_KEY") ?? optionalEnv("SHOPIFY_API_SECRET");
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if (!key) {
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throw new Error(
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"GiroCode signing key missing: set GIROCODE_SIGNING_KEY (preferred) " +
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"or SHOPIFY_API_SECRET.",
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);
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}
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return key;
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}
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function hmac(payload: string): string {
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return crypto.createHmac("sha256", getSigningKey()).update(payload).digest("hex");
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}
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export interface GiroCodeUrlParams {
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shop: string;
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orderId: string;
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exp: number; // unix seconds
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}
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export function signGiroCodeUrl(params: GiroCodeUrlParams): string {
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const base = `shop=${params.shop}&orderId=${params.orderId}&exp=${params.exp}`;
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const sig = hmac(base);
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return `${base}&sig=${sig}`;
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}
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export function verifyGiroCodeUrl(query: URLSearchParams): { ok: boolean; shop?: string; orderId?: string; reason?: string } {
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const shop = query.get("shop") || "";
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const orderId = query.get("orderId") || "";
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const exp = parseInt(query.get("exp") || "0", 10);
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const sig = query.get("sig") || "";
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if (!shop || !orderId || !exp || !sig) return { ok: false, reason: "missing-params" };
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if (Date.now() / 1000 > exp) return { ok: false, reason: "expired" };
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const expected = hmac(`shop=${shop}&orderId=${orderId}&exp=${exp}`);
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// timing-safe compare
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const a = Buffer.from(sig);
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const b = Buffer.from(expected);
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if (a.length !== b.length) return { ok: false, reason: "bad-sig" };
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if (!crypto.timingSafeEqual(a, b)) return { ok: false, reason: "bad-sig" };
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return { ok: true, shop, orderId };
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}
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