NodeJS wrapper functions around Amazon Dash Replenishment API

amazon-drs-helpers.js

const fetch = require('node-fetch')
const { URLSearchParams } = require('url')
const { dateFromJSON, dateToJSON } = require('../database/utils')
const { User } = require('../database')
const DRS_API_BASE_URL = 'https://dash-replenishment-service-na.amazon.com'
const CLIENT_SECRET = process.env.DRS_CLIENT_SECRET
// const REDIRECT_URL = `${process.env.BASE_URL}/api/amazonLWA`

async function handleErrors (response) {
  const json = await response.json()
  if (!response.ok) {
    console.log('ERROR: ' + JSON.stringify(json))
    throw Error(json.error_description || json.error || response.statusText)
  }
  return json
}

async function deregisterUserFromDRSIfHesRegistered ({ _id, amazon_drs_token: amazonDRSToken, os, bundle_id: bundleId }) {
  if (amazonDRSToken && amazonDRSToken.access_token) {
    const { access_token: accessToken } = await ensureTokenValid({ _id, amazon_drs_token: amazonDRSToken }, { os: os, bundleId: bundleId })
    return Promise.all([
      deregisterDRS(accessToken),
      User.findByIdAndUpdate(_id, { amazon_drs_token: {}, is_subscribed_to_drs: false }).lean()
    ])
  } else {
    return Promise.resolve()
  }
}
function getOrderInfo (eventInstanceId, token) {
  return fetch(`${DRS_API_BASE_URL}/getOrderInfo/${eventInstanceId}`, {
    method: 'GET',
    headers: {
      'x-amzn-accept-type': '[email protected]',
      'x-amzn-type-version': '[email protected]',
      Authorization: `Bearer ${token}`
    }
  })
    .then(handleErrors)
}

function getSubscriptionInfo (token) {
  return fetch(`${DRS_API_BASE_URL}/subscriptionInfo`, {
    method: 'GET',
    headers: {
      'x-amzn-accept-type': '[email protected]',
      'x-amzn-type-version': '[email protected]',
      Authorization: `Bearer ${token}`
    }
  })
    .then(handleErrors)
}

function cancelTestOrder (slotId, token) {
  return fetch(`${DRS_API_BASE_URL}/testOrders/slots/${slotId}`, {
    method: 'DELETE',
    headers: {
      'x-amzn-accept-type': '[email protected]',
      'x-amzn-type-version': '[email protected]',
      Authorization: `Bearer ${token}`
    }
  })
    .then(handleErrors)
}

function cancelAllTestOrders (token) {
  return fetch(`${DRS_API_BASE_URL}/testOrders`, {
    method: 'DELETE',
    headers: {
      'x-amzn-accept-type': '[email protected]',
      'x-amzn-type-version': '[email protected]',
      Authorization: `Bearer ${token}`
    }
  })
    .then(handleErrors)
}

function deregisterDRS (token) {
  return fetch(`${DRS_API_BASE_URL}/registration`, {
    method: 'DELETE',
    headers: {
      'x-amzn-accept-type': '[email protected]',
      'x-amzn-type-version': '[email protected]',
      Authorization: `Bearer ${token}`
    }
  })
    .then(handleErrors)
}

function sendSlotStatus (slotId, token, body) {
  /*
  {
    "expectedReplenishmentDate" : "2015-12-28T10:00:00Z",
    "remainingQuantityInUnit" : 3.5,
    "originalQuantityInUnit" : 10,
    "totalQuantityOnHand" : 20,
    "lastUseDate" : "2015-12-21T10:00:00Z"
}
*/
  return fetch(`${DRS_API_BASE_URL}/slotStatus/${slotId}`, {
    method: 'POST',
    headers: {
      'x-amzn-accept-type': '[email protected]',
      'x-amzn-type-version': '[email protected]',
      'Content-Type': 'application/json',
      Authorization: `Bearer ${token}`
    },
    body: JSON.stringify(body)
  })
    .then(async function handleErrors (response) {
      const text = await response.text()
      if (!response.ok) {
        console.log('ERROR: ' + text)
        throw Error(text || response.statusText)
      }
      return text
    })
}

function sendDeviceStatus (token, mostRecentlyActiveDate) {
  return fetch(`${DRS_API_BASE_URL}/deviceStatus`, {
    method: 'POST',
    headers: {
      'x-amzn-accept-type': '[email protected]',
      'x-amzn-type-version': '[email protected]',
      'Content-Type': 'application/json',
      Authorization: `Bearer ${token}`
    },
    body: JSON.stringify({
      mostRecentlyActiveDate
    })
  })
    .then(handleErrors)
}

function replenish (slotId, token) {
  return fetch(`${DRS_API_BASE_URL}/replenish/${slotId}`, {
    method: 'POST',
    headers: {
      'x-amzn-accept-type': '[email protected]',
      'x-amzn-type-version': '[email protected]',
      'Content-Type': 'application/json',
      Authorization: `Bearer ${token}`
    }
  })
    .then(handleErrors)
}

function createToken (code, os, bundleId) {
  const REDIRECT_URL = `${process.env.BASE_URL}/api/amazonLWA`
  const CLIENT_ID = os === 'iOS' ? process.env.DRS_CLIENT_ID_IOS : process.env.DRS_CLIENT_ID
  // const REDIRECT_URL = `amzn://${bundleId}`
  const params = new URLSearchParams()
  params.append('grant_type', 'authorization_code')
  params.append('client_id', CLIENT_ID)
  params.append('client_secret', CLIENT_SECRET)
  params.append('redirect_uri', REDIRECT_URL)
  params.append('code', code)

  return fetch('https://api.amazon.com/auth/o2/token', {
    method: 'POST',
    body: params,
    headers: {
      'Content-Type': 'application/x-www-form-urlencoded'
    }
  })
    .then(handleErrors)
}

function createTokenFromSDK ({ redirectURL, code, codeVerifier, os, bundleId }) {
  const CLIENT_ID = os === 'iOS' ? process.env.DRS_CLIENT_ID_IOS : process.env.DRS_CLIENT_ID
  // const REDIRECT_URL = `amzn://${bundleId}`

  const params = new URLSearchParams()
  params.append('grant_type', 'authorization_code')
  params.append('client_id', CLIENT_ID)
  params.append('redirect_uri', redirectURL)
  params.append('code', code)
  params.append('code_verifier', codeVerifier)

  console.log({ CLIENT_ID, redirectURL, code, codeVerifier })

  return fetch('https://api.amazon.com/auth/o2/token', {
    method: 'POST',
    body: params,
    headers: {
      'Content-Type': 'application/x-www-form-urlencoded'
    }
  })
    .then(handleErrors)
}

// authorization code, client ID, and redirect UR, code_verifier
/*
The access token is valid for one hour. When the access token expires, or is about to expire, you can exchange the refresh token for a new access token.
*/
function refreshAccessToken (refreshToken, { os }) {
  const CLIENT_ID = os === 'iOS' ? process.env.DRS_CLIENT_ID_IOS : process.env.DRS_CLIENT_ID
  // const REDIRECT_URL = `amzn://${bundleId}`
  const params = new URLSearchParams()
  params.append('grant_type', 'refresh_token')
  params.append('client_id', CLIENT_ID)
  params.append('client_secret', CLIENT_SECRET)
  // params.append('redirect_uri', REDIRECT_URL)
  params.append('refresh_token', refreshToken)

  return fetch('https://api.amazon.com/auth/o2/token', {
    method: 'POST',
    body: params,
    headers: {
      'Content-Type': 'application/x-www-form-urlencoded'
    }
  })
    .then(handleErrors)
}

async function ensureTokenValid ({ _id, amazon_drs_token: amazonDRSToken }, { os, bundleId }) {
  const { access_token: accessToken, expires_in: expiresIn, refresh_token: refreshToken, created_at: createdAt } = amazonDRSToken
  if (accessToken && refreshToken && expiresIn && createdAt) {
    const creationDate = dateFromJSON(createdAt)
    if (Date.now() >= creationDate.getTime() + (expiresIn * 1000)) {
      // refresh token
      const newTokenInfo = await refreshAccessToken(refreshToken, { os, bundleId })
      await User.findByIdAndUpdate(_id, { amazon_drs_token: { ...newTokenInfo, created_at: dateToJSON(new Date()) } })
        .select({ _id: 1 })
        .lean()
      return newTokenInfo
    } else {
      // token still valid
      return { access_token: accessToken, expires_in: expiresIn, refresh_token: refreshToken, created_at: createdAt }
    }
  } else {
    // user not logged in wih DRS, or DRS not enabled
    throw Error('no token found')
  }
}

module.exports = {
  refreshAccessToken,
  createToken,
  createTokenFromSDK,
  replenish,
  sendDeviceStatus,
  sendSlotStatus,
  deregisterDRS,
  cancelAllTestOrders,
  cancelTestOrder,
  getOrderInfo,
  getSubscriptionInfo,
  ensureTokenValid,
  deregisterUserFromDRSIfHesRegistered
}