初めてのStripe: 完全にサーバーレスのチケット販売

{"stripe_api_secret_key":"sk_test_51JU2XXXXXXXXXXXX",
"webhook_signing_secret":"whsec_TqW4TXXXXXXXXXXXX",
"product_visitor_ticket":"price_1JX1zXXXXXXXXXXXX",
"product_bronze_ticket":"price_1JrKaXXXXXXXXXXXX",
"product_tshirt_s":"price_1JrKlXXXXXXXXXXXX",
"product_tshirt_m":"price_1JrKmXXXXXXXXXXXX",
"product_tshirt_l":"price_1JrKnXXXXXXXXXXXX",
"product_tshirt_xl":"price_1JrKoXXXXXXXXXXXX",
"success_url":"https://tokyodemofest.jp/success.html",
"cancel_url":"https://tokyodemofest.jp#registration",
"shipping_rate":"shr_1JrKNXXXXXXXXXXXX",
"shipping_countries":"US,JP,IE,GB,NO,SE,FI,RU,PT,ES,FR,DE,CH,IT,PL,CZ,AT,HU,BA,BY,UA,RO,BG,GR,AU,NZ,KR,TW,IS"}

const loadConfig = async function() {
  const aws = require('aws-sdk');
  const ssm = new aws.SSM();
  const res = await ssm.getParameter( { Name: '/tdf/config-stripe', WithDecryption: true } ).promise();
  return JSON.parse(res.Parameter.Value);
}

exports.handler = async (event) => {
  const config = await loadConfig();
  const stripe = require('stripe')(config.stripe_api_secret_key);
  // ...
}

exports.handler = async (event) => {
  const config = await loadConfig();
  const stripe = require('stripe')(config.stripe_api_secret_key);

  const session = await stripe.checkout.sessions.create( {
    line_items: /* TODO */,
    payment_method_types: [ 'card' ],
    mode: 'payment',
    success_url: config.success_url,
    cancel_url: config.cancel_url
  } );

  const response = {
    statusCode: 303,
    headers: {
      'Location': session.url
    }
  };

  return response;
}

  if (event.body) {
    let payload = event.body;
    if (event.isBase64Encoded)
      payload = Buffer.from(event.body, 'base64').toString();

    const querystring = require('querystring');
    const res = querystring.parse(payload);
    if ((res.type) && (res.type == 'bronze')) {
      // ...
    }
  }

  let items = [ {
    price: config.product_visitor_ticket,
    quantity: 1
  } ];

  let tshirt_type = config.product_tshirt_s;

  if (res.tshirt) {
    if (res.tshirt == 's') tshirt_type = config.product_tshirt_s;
    if (res.tshirt == 'm') tshirt_type = config.product_tshirt_m;
    if (res.tshirt == 'l') tshirt_type = config.product_tshirt_l;
    if (res.tshirt == 'xl') tshirt_type = config.product_tshirt_xl;
  }

  items = [ {
    price: config.product_bronze_ticket,
    quantity: 1
  }, {
    price: tshirt_type,
    quantity: 1
  } ];

  const session = await stripe.checkout.sessions.create( {
    line_items: [ {
      price: config.product_bronze_ticket,
      quantity: 1
    }, {
      price: tshirt_type,
      quantity: 1
    } ],
    payment_method_types: [ 'card' ],
    mode: 'payment',
    success_url: config.success_url,
    cancel_url: config.cancel_url,
    shipping_rates: [ config.shipping_rate ],
    shipping_address_collection: {
      allowed_countries: config.shipping_countries.split(',')
    }
  } );

exports.handler = async (event) => {
  // require Stripe signature in header
  if (!event.headers['stripe-signature']) {
    console.log('no Stripe signature received in header, returning 400 Bad Request');
    return {
      statusCode: 400
    };
  }

  const sig = event.headers['stripe-signature'];

  // require an event body
  if (!event.body) {
    console.log('no event body received in POST, returning 400 Bad Request');
    return {
      statusCode: 400
    };
  }

  // decode payload
  let payload = event.body;
  if (event.isBase64Encoded)
    payload = Buffer.from(event.body, 'base64').toString();

  // construct a Stripe Webhook event
  const config = await loadConfig();
  const stripe = require('stripe')(config.stripe_api_secret_key);

  try {
    let ev = stripe.webhooks.constructEvent(payload, sig, config.webhook_signing_secret);
  } catch (err) {
    console.log('error creating Stripe Webhook event');
    console.log(err);
    return {
      statusCode: 400
    };
  }

  // ...TODO...

  return {
    statusCode: 200
  };
}

const createOrder = async function(session) {
  // we (TDF) don't need to do anything here
}

const fulfillOrder = async function(session) {
  // send ticket info to customer by email
  console.log('customer email is: ' + session.customer_details.email);
}

const emailCustomerAboutFailedPayment = async function(session) {
  // send email about failed payment
}

exports.handler = async (event) => {
  // ...
  const session = ev.data.object;
  switch (ev.type) {
    case 'checkout.session.completed':
      // save an order in your database, marked as 'awaiting payment'
      await createOrder(session);

      // check if the order is paid (e.g., from a card payment)
      // a delayed notification payment will have an `unpaid` status
      if (session.payment_status === 'paid') {
        await fulfillOrder(session);
      }
      break;

    case 'checkout.session.async_payment_succeeded':
      // fulfill the purchase...
      await fulfillOrder(session);
      break;

    case 'checkout.session.async_payment_failed':
      // send an email to the customer asking them to retry their order
      await emailCustomerAboutFailedPayment(session);
      break;
  }