local.js

/**
 * A minimal web server that converts the request
 * object to something the Lambda normalizer understands.
 */

const api = require('./api')
const http = require('http')

const serverWrapper = http.createServer(function (request, response) {
  const url = new URL(request.url, `http://${request.headers.host}/`)

  // The event object we're faking is a lightweight based on:
  // https://docs.aws.amazon.com/lambda/latest/dg/eventsources.html#eventsources-api-gateway-request
  const event = {
    httpMethod: request.method.toUpperCase(),
    path: url.pathname,
    resource: '/{proxy+}',
    queryStringParameters: [...url.searchParams.keys()].reduce((output, key) => { output[key] = url.searchParams.get(key); return output }, {}),
    headers: request.headers,
    requestContext: {},
    pathParameters: {},
    stageVariables: {},
    isBase64Encoded: false,
    body: request.body,
  }

  api.run(event, {})
    .then((res) => {
      let {
        body,
        headers,
        statusCode,
      } = res

      if (res.isBase64Encoded) {
        body = Buffer.from(body, 'base64')
      }

      if (!headers['content-length'] && body) {
        headers['content-length'] = body.length
      }

      response.writeHead(statusCode, headers)
      response.end(body)
    })
    .catch((err) => {
      console.error('Something went horribly, horribly wrong')
      response.writeHead(500, { 'content-length': 0 })
      response.end('')
      throw err
    })
})

serverWrapper.listen(process.env.PORT || 3000, () => {
  console.log(`Listening on http://localhost:${serverWrapper.address().port}/`)
})