Framework recipes

create table orders (  id text primary key,  status text not null default 'pending',  total_cents integer not null,  summary text not null,  payment_id text);

// app/checkout/route.ts: the cart's form posts here.import { NextResponse } from "next/server";import { db } from "@/lib/db"; const API = "https://dash.402pay.co/api/v1"; export async function POST(request: Request) {  const form = await request.formData();  const {    rows: [order],  } = await db.query("select * from orders where id = $1 and status = 'pending'", [form.get("order_id")]);  if (!order) return new Response("Order not found", { status: 404 });   const response = await fetch(`${API}/payments`, {    method: "POST",    headers: {      Authorization: `Bearer ${process.env.PAY402_SECRET_KEY}`,      "Content-Type": "application/json",    },    body: JSON.stringify({      amount: order.total_cents,      currency: "USD",      reference: order.id,      description: order.summary,      success_url: `https://example.com/orders/${order.id}/complete`,      cancel_url: "https://example.com/cart",    }),  });  const body = await response.json();  // 201 is a new payment; 200 is the live one this order's reference already names.  if (!response.ok) {    console.error("402pay", body.error.code, response.headers.get("402pay-Request-Id"));    return new Response("Couldn't start checkout", { status: 502 });  }  return NextResponse.redirect(body.data.url, 303);}

// app/orders/[id]/complete/page.tsxconst API = "https://dash.402pay.co/api/v1"; async function getPayment(id: string) {  const response = await fetch(`${API}/payments/${encodeURIComponent(id)}`, {    headers: { Authorization: `Bearer ${process.env.PAY402_SECRET_KEY}` },    cache: "no-store",  });  return response.ok ? (await response.json()).data : null;} // Checkout adds ?payment_id= to your success_url.export default async function OrderComplete({  params,  searchParams,}: {  params: Promise<{ id: string }>;  searchParams: Promise<{ payment_id?: string }>;}) {  const { id } = await params;  const { payment_id } = await searchParams;  const payment = payment_id ? await getPayment(payment_id) : null;   // Anyone can edit a query string, so trust only a payment that names this order.  const paid = payment?.reference === id && payment.status === "succeeded";  return <h1>{paid ? "Thanks, your order is confirmed." : "We haven't received your payment yet."}</h1>;}

// app/webhooks/402pay/route.tsimport crypto from "node:crypto";import { db } from "@/lib/db";import { shipOrder } from "@/lib/fulfillment"; export async function POST(request: Request) {  // The signature covers the exact bytes sent, so read the body as text and verify it first.  const body = await request.text();  if (!verifyWebhook(process.env.PAY402_WEBHOOK_SECRET ?? "", request.headers, body)) {    return new Response("Invalid signature", { status: 400 });  }   const event = JSON.parse(body);  if (!event.test && event.type === "payment.succeeded") {    const payment = event.data;    // Only a pending order changes, so a repeated delivery can't ship it twice.    const { rowCount } = await db.query(      "update orders set status = 'paid', payment_id = $2 where id = $1 and status = 'pending'",      [payment.reference, payment.id],    );    if (rowCount === 1) await shipOrder(payment.reference);  }  return new Response(null, { status: 204 });} function verifyWebhook(secret: string, headers: Headers, body: string): boolean {  const id = headers.get("webhook-id") ?? "";  const timestamp = headers.get("webhook-timestamp") ?? "";  const signatures = headers.get("webhook-signature") ?? "";   // Refuse replays: the delivery must be less than five minutes old.  const sent = Number(timestamp);  if (!Number.isInteger(sent) || Math.abs(Date.now() / 1000 - sent) > 300) return false;   const key = Buffer.from(secret.slice("whsec_".length), "base64");  const expected = crypto.createHmac("sha256", key).update(`${id}.${timestamp}.${body}`).digest("base64");   // During a rotation the header carries one signature per secret.  return signatures.split(" ").some((entry) => {    const [version, signature = ""] = entry.split(",");    return (      version === "v1" &&      signature.length === expected.length &&      crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(expected))    );  });}

-- Only a pending order changes, so running this twice ships nothing twice.update orders set status = 'paid', payment_id = $2 where id = $1 and status = 'pending'; -- For a handler that does more than one thing: remember each event it finished,-- in the same transaction as the work, and skip an event whose insert changes nothing.create table processed_webhooks (  id text primary key,  processed_at timestamptz not null default now());insert into processed_webhooks (id) values ($1) on conflict (id) do nothing;

// replay.mjs: node replay.mjs dlv_... http://localhost:8000/webhooks/402pay// Resending gives the delivery a fresh timestamp and signature, so it passes// your handler's five-minute check.const [deliveryId, target] = process.argv.slice(2);const response = await fetch(`https://dash.402pay.co/api/v1/webhook-deliveries/${deliveryId}/resend`, {  method: "POST",  headers: { Authorization: `Bearer ${process.env.PAY402_SECRET_KEY}` },});const { data: delivery } = await response.json(); const local = await fetch(target, {  method: "POST",  headers: delivery.request_headers,  // Compact, with keys in the order they arrived: the bytes that were signed.  body: JSON.stringify(delivery.payload),});console.log(local.status, await local.text());